* LLLLJ / / /

JEAN *. BILL LANE

HORTICULTURAL LIBRARY

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I

ER B:

LARGE SIZE AND COMPACT
GROWTH

A quality sought by Mr. Burbank in
the development of the gladiolus was
the habit of compact growth on the
stem, so that the flowers should be
solidly massed, instead of being scat-
tered along the stem. The brilliant
blossoms pictured here indicate striking
success in the matter of compact
growth, as well as in the increased size
and symmetrical form of the flowers
themselves.

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HOW PLANTS ARE TRAINED
TO WORK FOR MAN

BY LUTHER BURBANK Sc.D

F LOWERS

VOLUME VII

EIGHT VOLUMES ILLUSTRATED

PREFATORY NOTE BY DAVID STARR JORDAN

P. F. COLLIER & SON COMPANY
NEW YORK

Unrv Ubrarv <JC Santa Cruz 1999

Copyright, 1914

BY THE LUTHER BURBANK SOCIETY
All rights reserved

Copyright, 1914

BY THE LUTHER BURBANK SOCIETY

Entered at Stationers' Hall, London

All rights reserved

Copyright, 1915

BY THE LUTHER BURBANK SOCIETY

Entered at Stationers' Hall, London

All rights reserved

Copyright, 1921
BY P. P. COLLIER & SON COMPANY

MANUFACTURED IN U S. A.

CONTENTS

PAGE

TEACHING THE GLADIOLUS NEW HABITS 7
THE CANNA AND THE CALLA .... 33
THE PUREST WHITE IN NATURE ... 63
How TO OBTAIN VARIATION AMONG

FLOWERS 95

IMPROVEMENTS IN THE MUCH IMPROVED

IRIS 117

THE TIGRIDIA AND SOME INTERESTING

HYBRIDS 141

FOUR COMMON FLOWERS AND THEIR

IMPROVEMENT 163

EVERLASTING FLOWERS AND SOME COM-
MON EXOTICS 185

THE HYBRID LARKSPUR AND OTHER

TRANSFORMATIONS 211

ORNAMENTAL PALMS AND CLIMBING

VINES 237

Vol. 7— Bur. 1 A

2 CONTENTS

PAGE

LAWNS AND THEIR BEAUTIFICATION . . 263

THE FIELD AND FLOWER GARDEN . . . 305

THE ALMOND AND ITS IMPROVEMENT . . 323

WALNUTS AND OTHER EXPERIMENTS 347

LIST OF ILLUSTRATIONS

LARGE SIZE AND COMPACT GROWTH

Frontispiece

PAGE

A NEW GIANT GLADIOLUS ...... 12

ONE OF TEN THOUSAND VARIATIONS . . 18

AN UNUSUAL COLOR IN THE GLADIOLUS . 24
A SAMPLE GANDAVENSIS PRIMULINUS

HYBRID 30

A SEEDLING CANNA 36

ANOTHER SEEDLING CANNA 42

GIANT AND DWARF CALLAS 48

THE LEMON GIANT CALLA 52

THE SIBERIAN LILY 58

SOME OF MY NEW SEEDLING WATSONIAS 66

A SPECTACULAR IRIS . 80

A LUXURIOUS TYPE 90

SELECTED CHILEAN IRIS 102

A JAPANESE IRIS , 112

3

4 LIST OF ILLUSTRATIONS

PAGE

SEEDLING JAPANESE IRIS 124

A NEW EVENING PRIMROSE — THE

AMERICA 134

HYBRID TIGRIDIAS 144

ANOTHER HYBRID TIGRIDIA ..... 148

SEEDLING TIGRIDIAS 152

A BLUE TIGRIDIA 158

BURBANK VERBENAS 166

MORE BURBANK HYBRID VERBENAS . . 170

ONE OF THE FRAGRANT ONES 174

AUSTRALIAN STAR FLOWER ..... 188

A PLANT OF AUSTRALIAN STAR FLOWER . 192

A HYBRID CRINUM 196

A HYBRID EVERBLOOMING POPPY . . . 202

STILL ANOTHER HYBRID POPPY .... 206

IMPROVED HYBRID LARKSPUR . ... * 214

MORE HYBRID LARKSPURS 218

EDUCATING THE CALENDULA 222

A CALENDULA OF REAL DISTINCTION . . 226

THE VARIEGATED NEGUNDO 232

FLOWERS OF THE TECOMA . . . 258

LIST OF ILLUSTRATIONS 5

PAGE

SPANISH BROOM 268

A FRITILLARIA 274

DlERAMA PULCHERRIMA 280

LARKSPURS WITH WONDERFUL COLORING . 286

A BEAUTIFUL HYBRID LARKSPUR . . . 292

THE BOTTLE-BRUSH BUSH 298

A SELECTED NIGHT-BLOOMING CEREUS . 312

THE ALMOND AND ITS RELATIVES . . . 326

SELECTED ALMONDS 330

SOME MAMMOTH SPECIMENS 334

MEATS OF SELECTED ALMONDS .... 338

ALMONDS GROWN IN PEACHES .... 342

HYBRID WALNUTS 358

THE ROYAL WALNUT 372

TEACHING THE GLADIOLUS
NEW HABITS

THE MUTABILITY OF SPECIES

THE history of the growth of ideas shows
some curious paradoxes. As a minor illus-
tration, it may be recalled that an English
clergyman was doing his best — and a very good
best it was — to build up evidence of the mutability
of natural species at a time when it was rankest
heresy to suggest that species are mutable.

The clergyman in question was the Honorable
and Reverend Dr. William Herbert, Dean of
Manchester. His work was carried out in the
early decades of the nineteenth century. He
was a horticulturist of great skill, and he labored
assiduously with many plants. And among
those with which he attained conspicuous and
striking results that seemed to belie the botanical
beliefs of the period, was the plant now familiar
in every garden as the gladiolus.

The time when the important work of this cler-
ical amateur was carried out was one in which

7

8 LUTHER BURBANK

such men as Erasmus Darwin, the poet Goethe,
and the French biologist Lamarck were advocat-
ing the idea of the mutability of species. And
no doubt the Rev. Herbert had some of their
theories in mind as he went about his plant ex-
periments in the gardens of the Manchester
Deanery.

Yet in the main he was probably quite uncon-
scious of the full significance of the experiments
that he was performing.

The particular experiments that are of interest
to us in the present connection are those in which
he hybridized one species of gladiolus with an-
other, and in so doing not only produced new
races of gladiolus, but proved to his own satis-
faction that these new races were altogether
fertile.

Almost half a century later Charles Darwin
in his "Origin of Species" had occasion to quote
the opinion of the Rev. Herbert, based on his ex-
periences with this flower and several others, to
the effect that hybrids are not necessarily sterile
—a point that was still ardently in debate. He
even cites Herbert as having claimed that the
hybrids gained in fertility over the original
species — a fact which Herbert himself regarded
as being "a strange truth," but regarding which
Darwin, writing with fuller knowledge, asserts

THE GLADIOLUS 9

that it was by no means so strange as it would
appear.

To be sure, nothing revolutionary came
directly from the reverend horticulturist's ex-
periments. He produced interesting new varie-
ties of flowers, but the theoretical bearings of
his work were doubtless quite ignored by his
fellow clergymen and, indeed, as I have already
suggested, were probably only vaguely realized
by himself.

Yet as we look back on this work now, from
the new point of vantage that Darwin gave us,
we can see that the work of this amateur horti-
culturist must have had its share in disturbing
the ideas of at least some of the persons to whose
attention it came, and in preparing the way for
the new view of the flexibility of species that now
seems so much a matter of course that we can
hardly realize how revolutionary it seemed to
our forbears of two generations ago.

A demonstration made with a plant that grows
in everybody's garden has force that comes home
to us more cogently than records of any num-
ber of observations of animals and plants of
tropical forests and South Sea archipelagoes.
And a number of new species of plants, gladioli
among others, that the Dean of Manchester cre-
ated by hybridizing old ones made their way into

10 LUTHER BURBANK

the gardens of Europe, and gave their message,
we may be sure, here and there to a receptive
mind in substantiation of the disputed evolution-
ary doctrine, which, even before the publication
of Darwin's "Origin of Species," was exciting
the interest of the thoughtful.

OTHER GLADIOLUS HYBRIDS

Before the gladiolus made its full conquest of
the popular gardens, however, it was further im-
proved by other gardeners, both in England and
in continental Europe.

The species that the Rev. Herbert had crossed
were the showy Gladiolus cardinalis and the
smaller but more free-flowering Gladiolus
blandus. Subsequently he crossed a number of
other species, and produced races of great beauty
and fertility. But a race produced by Mr. Col-
ville at Chelsea in 1823, by fertilizing the form
known as Gladiolus cristus with the pollen of
Gladiolus cardinalis gained additional popu-
larity.

It was not until 1837, however, that the form
was originated which was to make actual con-
quest of gardens throughout Europe, and pres-
ently to attain corresponding popularity even in
America. This new form which became the
parent from which most modern varieties of

THE GLADIOLUS 11

gladiolus have been developed was raised in 1839
by M. Bodinghaus, gardener to the Due d'Aren-
berg of Enghien. Like the other hybridizers, he
used Gladiolus cardinalis for one parent form,
the other parent being a species known as Gla-
diolus psitt acinus.

We have seen that the cardinalis was used by
the earlier hybridizers. It appears that the psit-
tacinus was also used in hybridizing experiments
by the Dean of Manchester. But either he did
not make the precise cross that was now made
by the Belgian gardener, or the strains he used
were somewhat variant; for the hybrid now pro-
duced had qualities that gave it a new appeal to
flower lovers in general, and in particular made
it a flower of such easy cultivation and such
striking appearance as to make a strong bid for
popularity among amateurs.

It gained such vogue as to be thought of every-
where not only as a distinct species but as repre-
senting a type form of the race of gladioli. It
was named gandavensis, from Gand (Ghent),
the place of its origin.

It is believed, however, that the form of gladio-
lus that came to be known everywhere as the
gandavensis has in its racial strains the blood
of many other species beside the original parents.
. It is almost certain, for example, that the strain

A NEW GIANT GLADIOLUS

This is a variety selected for size of
the individual flower, rather than for
arrangement of flowers on the stalk.
It illustrates the accentuation of size
to about its present limit. (One-half
life size.)

THE GLADIOLUS 13

of G. oppositiflorus accounts for the modifica-
tions of form and for the introduction of a
tendency to produce white flowers; and that
strains of G. blandus and G. ramosus have also
been introduced.

In a word, the form of gladiolus that came to
be familiar everywhere under the name ganda-
vensis is not merely a hybrid, but a hybrid that
probably carries the racial strains of at least four
or five species, and possibly of many more than
that.

All of which is essential to an understand-
ing of the later developments of the race of
gladioli.

For when we come to investigate the pedigrees
of the chief races of gladiolus that are now found
in our gardens, we learn that, practically with-
out exception, they are hybrids that carry the
gandavensis strain among others, and hence are
multiple hybrids, the precise lineage of which is
too intricate for tracing.

It is this fact that accounts for the wide range
of variation as to form and color that charac-
terizes the gladioli of our gardens. For the
hybrid races have practically supplanted the
original species everywhere.

The same thing is of course largely true of
most other cultivated flowers, and it is altogether

U LUTHER BURBANK

true of the cultivated fruits and vegetables. As
regards a large proportion of these, the culti-
vated varieties have not only supplanted the
original species, but no definite record remains
of the original species themselves. The case of
the gladiolus differs, and gains added interest,
in that the original species were brought from
southern Africa to Europe only a little more
than a century ago. The development of the
new hybrid races under cultivation, and the elimi-
nation of the parent forms by their improved
descendants, has taken place in so comparatively
short a time that its chief steps are matter of
record, as we have seen.

So the story of the gladiolus has elements of
educational interest for the plant developer that
are quite lacking in many of the cultivated plants
which attained relative perfection at an earlier

period.

EARLY WORK AT SANTA ROSA

There are a few species of gladiolus that are
native to Europe and Asia, but the ones that
were chiefly used by the early hybridizers came
from South Africa, as already related.

Doubtless this fact was not without signifi-
cance in determining the results of the work of
the early cultivators. We have seen illustrated
more than once the effect of transplanting a

THE GLADIOLUS 15

plant to new soils, and in particular of transport-
ing it from one hemisphere to the other.

We cannot doubt, then, that the change in
the seasons and in the soils and climatic condi-
tions in general had a share in promoting the
variability of the gladiolus when brought to
Europe, although, as we have seen, the tangible
Stimulus to variation was given through the now
familiar method of hybridization.

And, by the same token, we may suppose that
when the gladiolus was finally brought to Cali-
fornia, shifted thus halfway round the globe
from its new home in Europe, there was an added
stimulus given, urging the plant to still further
modifications of habit, and supplying yet other
elements of variation with which the plant devel-
oper might work.

At all events the gladioli in my gardens at
Santa Rosa and Sebastopol have proved respon-
sive and adaptable. And further modifications
have been produced in the much modified flower
that add greatly to the value of what was from
the outset one of the most popular of ornamental
plants.

I began work with the gladiolus about the
year 1882, starting with the gandavensis
hybrid, the origin of which has already been
described.

16 LUTHER BURBANK

At that time there was no great interest taken
in America in growing gladiolus seedlings, but I
was able to secure a large number of the best
types of gandavensis, and also obtained bulbs
of about a dozen of the natural species.

The material was obtained not alone from
American growers and the cultivators of Europe,
but also directly from South Africa.

From the outset experiments were begun on a
comprehensive scale, raising the gladioli by the
half acre and acre on my Sebastopol place. The
first fault observed in the gladiolus was that the
blooms would not stand our California sunshine.

Under the glare of the California sun, the
blooms would wither in a single day, sometimes
in a single hour.

Other serious defects were that the stalks were
too slender, and the flowers too far apart on the
stalk. Moreover, the flowers were small, they
were illy arranged on the stalks, giving an untidy
appearance to the plants; and often they were
only half open when at their best.

The colors of many varieties, on the other
hand, were fine, it being evident that selection
had been made largely for color, by some at least
of the earlier experimenters. My first object,
then, was to remedy the defects just mentioned
rather than to modify the color of the gladioli.

THE GLADIOLUS 17

In particular I sought, while improving the
stalks and the arrangement of flowers on
the stalks, to make the petals of the individ-
ual blossoms stand out flat and in regular
sequence.

The work progressed along the lines of hybrid-
izing and selection with which the reader is
already familiar, introducing strains of the long-
neglected natural species to give added virility
and stimulate still further variation, thus provid-
ing materials for selection.

Growing the plants by the acre, abundant
material for choice was at hand and my usual
method of choosing only a few of the very best
representatives of the different forms that
seemed worth developing, destroying the rest,
was rigidly exercised.

In the course of a few years there were de-
veloped varieties which were introduced with
new names, and which made their way every-
where, and were highly prized by gardeners
throughout the United States.

Doubtless the most interesting development in
this early period was the form named the Cali-
fornia. This was a really magnificent semi-
double variety which not only excelled in the
form and size and color of the individual blos-
soms, but which had the added peculiarity of

ONE OF TEN THOUSAND
VARIATIONS

The arrangement of color shades and
color patterns in the newer gladioli is
very remarkable and could never have
been believed possible except by its
actual demonstration in evidence.
(One-third life size.}

THE GLADIOLUS 19

bearing the blossoms all around the stalk like a
hyacinth, instead of merely on one side of the
stalk as had been customary with all other
varieties of gladiolus.

Even at the present time, although the varie-
ties of gladiolus have been subject to rapid de-
velopment within the past few years, I recall the
California as one of the most beautiful flowers
of the family.

Unfortunately this variety was lost, probably
by freezing, along with the entire stock of other
gladioli, by a Philadelphia dealer to whom it was
sold.

My gladiolus colony progressed admirably,
and the new forms attained a degree of virility
that made it no more difficult to raise them than
to raise potatoes; indeed, much less difficult, in-
asmuch as the gladiolus bulbs in California do
not require to be dug or stored, but continue
their growth throughout the year. The only
object in digging them is to divide and separate
them for multiplication.

The forms of the plants, and the manner of
bearing, as well as the shape and arrangement
of the blossoms, improved year by year, and the
new varieties of gladiolus came to be well known
to dealers throughout the country, and were still
under process of development when an unex-

20 LUTHER BURBANK

pected complication put an end, for the time
being, to my further work with this plant.

WAR WITH THE GOPHER

The complication manifested itself in the dis-
covery that entire rows of the gladiolus bulbs
had been eaten by pocket gophers, which had
tunneled their way into the grounds, and, boring
beneath the gladiolus beds, had feasted on the
bulbs, destroying large numbers of them (mostly
during the dormant season) before I discovered
the presence of the marauders.

The plants do not wither at once even when
the bulbs are greatly injured, or in the dormant
season totally destroyed. So long rows were
destroyed before I knew the necessity of combat-
ing the enemy.

The attempts to exterminate the pests were at
first so unsuccessful that I presently decided to
give up the gladiolus colony altogether. I sold
the entire lot to an amateur Canadian horticul-
turist, Mr. H. H. Groff, a banker, of Simcoe,
Ontario, and for a good many years my experi-
ments with the gladiolus were not renewed.

Meantime, every effort was made to extermi-
nate the pestiferous gophers, whose depredations5
were of course not confined to the gladiolus, and
through which I suffered an annual loss of cer-

THE GLADIOLUS 21

tainly not less than a thousand dollars year after
year.

Not alone with the gladiolus but with other
bulbs it seemed that the animals took special de-
light in attacking the choicest plants. And the
question of their destruction became finally a
very urgent one.

Numerous methods of combating the pests
were tested. A double box trap set in gopher
holes was cumbersome and not very effective.
An awkward iron trap was supposed to catch the
gopher when he poked his nose against the trig-
ger, but missed fire or failed to score a hit of tener
than otherwise. One form of trap after another
was tried and given up. Attempts to smoke out
the animals proved ineffective, as the gopher in-
stantly builds a wall to shut out the smoke.

Bisulphid of carbon, which gives off a poison-
ous, heavy gas, was tested with equal lack of
success. About the only resource was the use of
poison, commonly called strychnin, placed on a
piece of apple, potato, or carrot, combined with
the use of a wire trap, in the hope that if one
failed the other might prove effective. But in
spite of all these methods the gophers multiplied,
mostly from neighboring fields, where their dam-
age to ordinary farm crops was not so marked.
A few years ago, however, a gopher gun was

22 LUTHER BURBANK

invented that practically solved the problem.
This consisted of a trap so arranged that when
the gopher pokes his nose against the trigger a
charge of powder explodes beneath the animal,
killing him instantly by concussion.

This device proved more effective than all
others. Sometimes thirty-five or forty gophers
were destroyed in a day about the borders of my
gardens. And in a short time the gophers were
so nearly exterminated that they ceased to be a
serious pest.

When these old enemies of the bulbous plants
were thus finally subjugated, after years of
effort, I determined to take up again the culti-
vation of the gladiolus.

In the meantime, the gladiolus had been much
under cultivation elsewhere, and its general and
special qualities had been greatly improved.

But there remained plenty of modifications
that could be made to advantage, and in starting
a new series of experiments I had no difficulty
in discovering faults to be remedied.

RECENT WORK WITH THE GLADIOLUS

One of the modifications, to which reference
has already been made, had to do with the
arrangement of the flowers on the stalk. My
success in developing a race having the flowers

THE GLADIOLUS 23

arranged on all sides of the stalks has already
been referred to. In taking up a new series of
experiments, the attempt was made to improve
on the earlier varieties, by shortening the stems
of the flowers, so that they were compelled to ar-
range themselves more compactly around it; by
insuring regularity of placement; and by diver-
sifying the plant arrangements in various ways.

Some forms were developed having two
ranks of flowers, one on either side of the stem.
Other races were developed with flowers in four
ranks; yet others with flowers in a spiral.
Meantime the individual blossoms were en-
larged in size, and their stems shortened, so
that, when grown in a spiral about the stem,
they crowd one another, making practically a
solid mass of petals.

The contrast in appearance of a stem of
gladiolus flowers arranged on this new plant
with the old form in which the blossoms grew
only on one side of the stem, or at most on
opposite sides, is very striking.

Attention was given also to the modifications
of the form of the individual flowers. In one
'form, petals were developed that are broad and
ruffled so that they overlap, and thus give the
appearance of a double flower. In another form
the tendency of the anthers to turn to petals was

AN UNUSUAL COLOR IN
THE GLADIOLUS

This is a rather unusual color. Notice
the flat, open flower — a quality prized
in the gladiolus. (One-third life size.)

THE GLADIOLUS 25

accentuated through selection until double vari-
eties were produced; and in some cases the
extra petals were added without affecting the
stamens.

In yet another form, and one that I person-
ally admire most, two flowers appear to be fused
into one, so that twelve petals are presented in-
stead of six. The variety was fixed so that the
flowers on every stalk come in the same way,
constituting a double flower of an unusual
type.

Particular attention was also paid to the de-
velopment of regularity of petal in the case of
the double gladiolus flowers. Irregularity of
petals may be attractive in such flowers as the
rose and the carnation, but with the gladiolus
the double blossoms are less beautiful than the
single ones, unless the petals are very regular.

There was no great difficulty, however, in
making the petals regular, as well as increasing
their number by selection.

STUDIES IN COLOR

In the newer series of experiments, especial
heed was given, also, to the matter of color vari-
ation, seeking for clear and brilliant colors of
varying shades. The blending of shades, and
the arrangement of lines, dots, and edges of

26 LUTHER BURBANK

different color on the petals were all carefully
taken into account.

There is opportunity for skill in the blending
of different shades in a flower of such diversity
of color as the gladiolus, far greater than
the painter's skill in applying colors to the
canvas.

One learns that there are certain combina-
tions that will produce disagreeable colors,
whereas others will result in new shades of
exceptional brilliancy.

The characteristics of each flower to be
selected for combination must be carefully
studied.

If, for example, we cross a yellow gladiolus
with a white one, we are likely to get a dingy
white that is by no means agreeable, though not
by any means necessarily so. The cross of a pale
pink with a white form is likely to give us a
still paler pink, which would not be regarded as
an improvement. Again, from the blending of
two nearly white strains, you may even get
dark colors in unpredictable combinations.

By studying the combinations, however, and
making rigid selection among the seedlings, it
will be discovered that there are certain tenden-
cies that tend to be dominant and that as a rule
may be expected to repeat themselves in the

THE GLADIOLUS 27

hybrid offspring, overshadowing the less fixed
colors. Still the races of gladioli are so
blended, and their color factors so mixed, that
one may confidently expect to find new and
interesting combinations among any large lot
of hybrid seedlings.

Indeed, it is not necessary to make new
crosses in order to get interesting new types,
since, as we have seen, all cultivated races of
gladiolus are hybrids that carry many racial
strains, and hence manifest the tendency to vary
that we have seen everywhere manifested by
hybrids in second and later generations.

It is of course possible to exert a powerful
directive influence through selecting parents for
crossing, and further direction may be given by
selection among the seedlings for any given
color or combination of colors. So new races
with unique color combinations may be very
readily developed, and, even if these are not at
once fixed, they can of course be propagated in-
definitely by bulb multiplication. Here, as with
other plants, all forms grown from the offshoots
of a bulb- will reproduce the qualities of the
parent form, and a new race may thus be multi-
plied indefinitely.

Notwithstanding the great diversity of colors
of the different races of gladiolus, there have

28 LUTHER BURBANK

until recently been no good gladioli that could
accurately be described as pure white.

Where so-called white varieties have appeared,
they have a dinginess that suggests the presence
of an underlying color; also there are spots,
stripes, or featherings of other colors, especially
on the lower petals. That the hereditary factors
for color are really present in these so-called
white flowers is demonstrated by the fact, already
noted, that in crossing two of these we may pro-
duce varieties that bear colored flowers.

But the fact that these crosses of white gladi-
oli produce flowers showing a great diversity of
color, suggests obviously the possibility of select-
ing among these offspring, in the second genera-
tion, some that contain only the hereditary fac-
tors for whiteness, and by rigid selection I have
produced a race of white gladioli which, when
further perfected, will constitute an interesting
acquisition. Already these are partially fixed.
Other growers of gladioli have observed the
same fact.

Already the white gladioli breed fairly true,
and further selections, with reference to the per-
fection and fixation of the type, will give us a
race of white gladioli that will meet the approval
of the public. But here as elsewhere there is
danger that in selecting for one quality other

THE GLADIOLUS 29

qualities will be neglected, so that the flowers are
not kept up to their best standard.

Until quite lately there has been no blue color
in gladioli, any more than in the poppy, except,
perhaps, submerged in combination with some
of the darker colors. And for this reason, it has
been found by all growers of the plants far more
difficult to produce a blue flower than any
other color, and until quite recently nothing
approaching the really blue gladiolus had
been produced.

The first blue ones introduced were in reality
more purple than blue. Nearly all hybrid vari-
eties have shown lines of pale or smoky blue at
times.

The first gladiolus that could really be called
blue was the one sent out from Europe under
the name of Madame Hulot. This had a small
flower, and in other respects resembled the older
gladioli — a dark purplish blue in color. By
crossing this with white varieties of large size,
pale blue with extra large fine flowers were pro-
duced. Two years ago one appeared, of very
large size, and perfect in all respects with a true
blue color.

The crossing of the gladiolus presents no dif-
ficulties. It is merely necessary to cover the
three-parted stigmas with pollen of the desired

A SAMPLE GANDAVENSIS
PRIMULINUS HYBRID

The gladiolus having this type of
spike has departed rather strikingly
from the traditions of its tribe as to
arrangement of the flowers along the
stem. But there is something strikingly
attractive about the manner of cluster-
ing adopted by this variety, and we may
feel sure that this specimen will be
among those selected and allowed to go
to seed, in the interests of future gen-
erations. (Not quite one-half life size.)

THE GLADIOLUS 31

parent so thickly that bees and humming birds
cannot interfere with the experiment.

In working on a large scale, it is convenient to
place rows of different forms that one wishes to
hybridize side by side, so that pollen may be
readily transferred from one row to another, in
walking along the rows each forenoon when the
stigmas are receptive. Also this arrangement
allows the hybridizing to be carried out by the
humming birds which are always aids in the fer-
tilization of these tubular flowers. Here, as in
most other experiments, I have found that the
results of the reciprocal cross are the same;
it makes no difference which parent is the
staminate and which the pistillate member.
So the seed from the contiguous rows of
gladioli thus hybridized may be saved in a
single lot.

New crosses and rigid selection are giving
larger flowers, brighter colors, more compact
stalks, and a tendency to multiply more rapidly
from the bulblets — and especially with greater
freedom from disease. The propensity to revert
toward the original type of the wild species —
small flowers, long slender stalks, closed blooms,
dull coloring, narrow leaves, and poor constitu-
tion— is being subordinated as the selection is
carried through successive generations.

32 LUTHER BURBANK

And while there will be no metamorphosis in
the essential characteristics of this beautiful and
popular flower, further modifications of detail
that are of no small practical significance may
confidently be expected.

We may well suppose that when
the gladiolus was finally brought
to California, having been shipped
first from South Africa to
Europe and then from Europe
halfway round the globe, there
was an added stimulus, urging the
plant to still further modifications
of habit, and supplying yet other
elements of variation, such as
form the basis of all plant
development work.

Vol. 7 — Bur.

THE CANNA AND THE CALLA

AND SOME INTERESTING WORK WITH
THESE SO-CALLED LILIES

THE first canna of my own production is
the one named the Tarrytown. This canna
took the grand gold medal, at the Pan-
American Exposition at Buffalo, as the best
canna exhibited at that time. There were large
numbers in competition.

In addition to receiving the gold medal,
the Tarrytown was given special mention
as being the most profusely blooming canna
ever seen.

This canna is a rich brilliant crimson in color,
and is rather dwarf in size, standing not higher
than three feet. Instead of producing a single
offshoot from each stalk or at most three or four,
as a good many even of the better varieties of
canna did at the time when this was produced,
the Tarrytown grows from six to nine offshoots
of the main stalk. Thus it makes a splendid and
highly effective display.

33

Vol. 7— Bur.

34 LUTHER BURBANK

The individual flowers are of good substance,
enduring the sun well.

After the blossoms fade, the petals drop to
the ground. This is a special feature for which
careful selection has been made, as many cannas
tend to hold shriveled blossoms, thus having an
untidy appearance.

ORIGIN OF THE NEW CANNA

The Tarrytown canna was developed from the
type known as the Crozy canna, hybridized with
a native species of the Florida swamps known as
Canna ftaccida, a plant with extremely large
flowers of pure lemon yellow.

The Crozy canna was a well-known horticul-
tural variety, developed in somewhat recent
years, which differs from the varieties that were
previously in vogue in that its flowers are very
large, notably attractive, and of varying colors.
Until the cannas of the Crozy type were devel-
oped, this plant was prized chiefly for its foliage,
the flowers being rather insignificant. But the
Crozy canna has large flowers, to casual inspec-
tion similar to those of the gladiolus.

The Florida species (C. flaccida) that was
used to hybridize with the Crozy, has very fine
large petals, but the flowers are not lasting. But
it blended well with the other type, and intro-

THE CANNA AND CALLA 35

duced an element of variability that facilitated
selection and development along the lines similar
to those characterizing the perfected Tarrytown ;
also the Burbank, Austria, and Italia, since
introduced.

The Crozy canna is itself a hybrid, one of the
parents being a form known as Canna iridiflora,
a tall plant with long, dark green leaves, and
with a long drooping panicle of rich crimson
flowers. I have experimented with this form,
but have never known it to produce seed.

The new cross that I effected between the
Crozy hybrid and the native Florida species,
brought together strains widely diversified. The
tendency to variation was very obvious even in
the first generation, as might have been expected
considering that one of the parents was itself a
hybrid.

From the same hybrid strain it was possible to
select a number of plants showing individual
peculiarities that seemed worthy of perpetuation.

The qualities developed in the Tarrytown have
already been outlined. Another race developed
simultaneously, through a different series of
selections, differed very markedly, in particular
as regards the character of the flower, which took
on so characteristic a form, and colors of such
elusive quality, as to merit the name of Orchid-

A SEEDLING CANNA

While the canna does not vary from
seed nearly as much as the gladioli and
dahlias, yet the variation is sufficient
to make the growing of seedlings
interesting.

THE CANNA AND CALLA 37

flowered Canna. It chanced that experimenters
in Italy produced simultaneously and quite
independently a race of cannas having closely
similar qualities.

The best of my cannas of this type was intro-
duced under the name of The Burbank.

This plant rather closely resembles a variety
known as the "Austria," which was introduced
about the same time from Europe. The Bur-
bank, however, is somewhat larger, and has
thicker and more rubberlike foliage; and its
flower is slightly less crimson in the throat.

WORKING WITH THE CANNA

The cross-fertilization of the canna should
seemingly present no particular difficulties to
anyone who studies the mechanism of the flower.

The stamens have a petallike appearance, and
the pollen mass could not be transported by the
bee or any other small insect. Large moths may
carry it from one flower to another, but the usual
pollenizer of the canna, in this country, is the
humming bird.

The hand-pollenizer may readily enough de-
tach the pollen mass, and transfer it to the stigma
of another flower.

But it does not follow that hybridizing is easy.
In fact, I found it exceedingly difficult, especially

38 LUTHER BURBANK

when attempting to cross the ordinary canna
with the Florida species already mentioned. I
worked for eight years with that purpose in view
before succeeding. And even then the seedlings
were greatly lacking in fecundity, producing
very little seed, notwithstanding the fact that
cannas in general usually produce seed abun-
dantly in California.

The infecundity of the canna hybrids suggests
that the species in question are almost at the
limits of affinity. But the seeds produced, al-
though few in number, were some of them fertile,
and the hybrid progeny showed possibilities of
development, as already suggested. Most of the
later generations, however, are almost or quite
sterile, refusing to seed.

The chief difficulty in growing seedlings of the
canna is to insure the germination of the seed.
The familiar name " Indian-shot plant" by which
the canna was first known suggests the character
of its seeds, which are not unlike small bullets in
appearance and in hardness of texture. The old
plan of germinating the seeds used to be to file
off part of the thick shell, in order that the seed
might absorb moisture. This works very well,
but can hardly be applied on a large scale.

My own method has been to disinfect the canna
seed with a solution of bluestone (sulphate of

THE C.ANNA AND CALLA 39

copper), and place them in coarse gravel, taking
pains to pour water through the gravel at fre-
quent intervals. Under these circumstances, the
seed is less likely to decay through attacks of
fungous pests than if planted in the soil. In the
coarse, clean, sterilized gravel, a high percentage
of the seed will come up in a few months. The
porosity of the gravel, giving free access to air,
is also an element that is advantageous to the seed
of the canna.

Seed treated in this way will germinate at a
relatively low temperature; but germination is
facilitated if the heat is kept between sixty and
seventy degrees.

As soon as the seedlings appear, they are trans-
planted thinly into boxes where they are allowed
to stand until May, when they are planted in the
field and cultivated like other crops.

A large proportion of the seedlings will prove
worthless. The weeding out of the first year is
done readily, but selection in the second year re-
quires skill, to judge as to which plants are wor-
thy of preservation. Beyond that, of course, the
usual process of selection through several years
will be carried out along the lines of the desired
modification at which the experimenter is aiming.

The objects that the experimenter may advan-
tageously bear in mind in developing new cannas

40 LUTHER BURBANK

include hardiness, the production of a double
flower, and the production of a white flower,
among others*

In California the canna may be left out-of-
doors over winter; indeed it does much better
when so treated than when the bulbs are lifted
and stored. In the northeastern States, it is
necessary to dig the roots and store them where
they will not be subject to too low a temperature.
It will be of advantage to develop the canna to a
stage of hardiness that would enable it to be
treated as an ordinary perennial, leaving the
roots in the ground and only dividing them now
and again for purposes of propagation. Still
this might require more work than is worth
giving to the task, inasmuch as the canna
is already grown far to the north, and the
work of digging and storing the bulbs is not
excessive.

A double canna would certainly be a novelty
and one that is worth working for. The same
is true of a pure white canna. By hybridizing
and careful selection, it should be possible to
develop this novelty, judging from analogy with
other flowers. Of course it is possible to increase
the size of the flower, and to produce other color
variations along the line of recent developments.
Most important of all, the flower should be made

THE CANNA AND CALLA 41

more lasting. Just now white cannas of very
good quality are appearing and every desirable
quality in plant and flower are being brought
forth from year to year.

IMPROVED CALLAS (RICHARDIAS)

The manner of production of my fragrant
calla was described in an earlier chapter.

It will be recalled that this anomaly was pro-
duced through selection from an individual found
among a large company.

The question of odor and its variation in
flowers was further discussed in a recent chapter.
There appears to be, in point of fact, as wide a
range of variation among flowers in the matter
of odor as in regard to color. But inasmuch as
most selective experiments have been made with
reference to color and quite without regard to the
matter of odor, the cultivated plants have natu-
rally developed along the lines of color variation,
and even those that were originally fragrant have
in many cases lost their perfume.

IMPROVING ESSENTIAL OILS

In recent years, however, much more attention
has been paid to this matter. In particular, the
studies of the chemistry of essential oils, with
reference to the production of artificial substi-

ANOTHER SEEDLING CANNA

This is a very pleasing variety of
canna, the characteristics of which are
well revealed in the picture opposite.
The blossoms are individually of large
size, and are borne in profusion.

THE CANNA AND CALLA 43

tutes for the natural ones, has given clues that the
plant developer is beginning to take up.

I have been requested, for example, to im-
prove the clove and the cinnamon, as well as the
coffee plant, in the production of races having a
higher percentage of the various essential oils for
which they are prized.

Coffee, as everyone knows, depends very
largely on its aroma and fragrance, and it has
been found that these may be greatly modified
according to the soil in which the plant is grown.
The fragrant qualities are often greatly intensi-
fied when the plant is grown on volcanic soil and
at a high altitude. It is known that various
spices differ markedly. In the same way the
quality of alkaloids, such as caffeine and quinine,
may vary in the same species under different
conditions of soil and climate. There is a species
of coffee that is practically without caffeine ; but
this has little aroma. It has been proposed to
combine it with the Arabian coffee and it may be
possible to produce a coffee without caffeine —
which may or may not be popular.

Among garden plants that are prized for their
aromatic quality, the thymes vary widely in the
amount and quality of their essential oils.

The notable variation in the odor of the calla,
which gave the scented variety, is duplicated in

44 LUTHER BURBANK

a good many species of plants. The individuals
even of the wild species vary, some of them
having a really delightful fragrance, and some
none at all. In crossing the different individuals,
you may accentuate the perfume, add one ele-
ment of fragrance to another; or, on the other
hand, you may make such a combination that the
two aromas seem to neutralize each other, pro-
ducing an odorless hybrid.

The plant developer who works with these
anomalies in mind, paying heed to the fragrance
of his flowers as well as to their other qualities, is
almost certain to produce varieties that will be
appreciated, for, as already suggested, the per-
fume of the flower and the flavors of foods
are nowadays receiving more attention than

formerly.

NEW GIANT CALLAS

I have introduced four main varieties of calla
in addition to the calla Fragrance.

This work began largely with raising seed-
lings for the trade, from the form of calla known
as Richardia albo-maculata, a dwarf variety
with spotted leaves that was at that time very
popular.

The leaves of this plant bore attractive white
or transparent markings on the bright green sur-
face. The flower was white, with a brown tinge

THE CANNA AND CALLA 45

at the base, and in the original form was
insignificant.

Among these almost numberless seedlings ap-
peared, now and then, a golden variety, but this
proved difficult to fix, although very handsome
and attractive.

Presently I secured another variety of calla
known as the Pride of the Congo, Richardia ha-
stata. This is a much stronger grower than the
other variety and has pale yellowish flowers
larger than those of the albo-maculata. Many
seedlings were raised from this variety on my
Sebastopol farm, and developed by selection
until it produced very large bulbs.

Then the two species were crossed, using our
own hybridized golden variety of the R. albo-
maculata and the highly developed varieties of
R. hastata. The cross was made reciprocally as
usual, and here as elsewhere it appeared to make
no difference which was the staminate and which
the pistillate parent.

The hybrids vary considerably as to bulb,
plant, and flower — much more so than either
parent species when raised from an uncrossed
seed. And among the hybrids there were some
plants that produced enormous bulbs, sometimes
eight or ten inches in diameter and weighing
from two to six pounds each. The plants that

46 LUTHER BURBANK

grew from these bulbs were of large size and bore
blossoms that were of much brighter yellow than
those of either parent.

This plant was introduced under the name of
the Giant Calla, a name later changed to Lemon
Giant.

Subsequently I obtained a number of other
species of calla, including those known as R.
Elliottiana, R. Pentlandi, R. melanoleuca, R.
Nelsomi, and R. Rehmanni. These were all hy-
bridized with one another, and with the species
that previously was in hand.

Among these complex hybrids were plants
that were very unique in form and foliage and
flower. The blossoms varied in color not only in
the different hybrid plants, but sometimes an
individual blossom would be partly deep purple,
partly deep yellow, and in part almost white.
Sometimes the colors were mottled or striped,
but usually the purple color appeared in the
throat of the flower.

The purple is apparently a combined inherit-
ance from the Elliottiana, Rehmanni and mel-
anoleuca; and the hastata also has a faint touch
of it. The yellow is heritage from hastata and
Elliottiana.

These plants varied as much in size as in qual-
ity of flower. Some of them grew three and a

THE CANNA AND CALLA 47

half feet in height, others only eight or ten inches.
In some cases the foliage and stalks were smooth
and in others actually hairy, covered with soft
excrescences of thornlike appearance. Some of
the hybrids were very easy to raise, but most of
them quite difficult.

Among the freak forms that appeared in this
hybrid colony were plants bearing double and
even triple flowers, and others in which the
flowers and leaves were combined in the most
curious manner. Of course the so-called flower
of the calla is a modified leaf that has not alto-
gether lost the leaflike form and manner of
growth. So the reversion through which the
flowers become still more leaflike in these mixed
hybrids was perhaps not altogether surprising.
But the particular manifestations of the tend-
ency to reversion were most astonishing.

OTHER NEW VARIETIES

Among the hybrids that departed less mark-
edly from the calla traditions were some that
bore flowers of a splendid deep yellow, and that
had all desirable qualities of easy multiplication
and abundant blooming.

Some of these have a purple spot low down in
the throat, others are a pure yellow, not dissimi-
lar in appearance to my early varieties.

GIANT AND DWARF CALLAS

We have developed the flower of the
calla in both directions, producing both
giants and dwarfs. The one at the left
in this picture is perhaps the smallest
calla ever developed. Its spathe
measures only two inches across, while
the blossom of the new giant measures
eight inches across.

THE CANNA AND CALLA 49

But while the new hybrids outwardly resemble
some of the early varieties developed by selection,
they showed their inherent difference in that they
are exceedingly easy to cultivate, whereas the
earlier ones were subject to decay without appar-
ent cause at any season of the year. The new
hybrids are hardier, and can be raised much more
readily. They will grow out-of-doors in any mild
climate, and require scarcely more attention than
so many potato plants. They are reasonably in-
different to the conditions of moisture and a
moderate degree of cold does not in the least
discourage them.

The contrast in this regard between the newer
hybrids and the earlier yellow varieties is very
striking. They furnish an illustration of the
added vitality that may come through crossing
and selection.

The original yellow calla is confined to a lim-
ited area in the subtropical regions of South
Africa. Its pure-bred descendants, as we have
seen, retain the sensitiveness of the parent. But
the selected hybrids, while retaining the yellow
color of the African plant, have acquired from
their other parental strains a degree of hardiness
that adapts them to our climate, and at the same
time have received increments of vigor that noth-
ing but hybridization appears to give.

50 LUTHER BURBANK

As to the latter point, I may mention a sport
that appeared among my white callas, in the
form of a plant that grew to gigantic size. The
sport appeared among the seedlings of the com-
mon calla (R. africana), but doubtless represents
a natural cross between different strains of this
species.

The plant bore its flowers on stems sometimes
six feet or even more in height. The foliage was
of corresponding size, and the flowers almost pro-
portionately immense.

The new sport was called the Giant Calla.

In contrast with this giant is a dwarf of the
same species, retaining the characteristics of the
calla, and having the peculiar interest that
attaches to a miniature flower reproducing the
qualities of a familiar flower which we ordinarily
think of as being of large size. Some of my
dwarf varieties, produced by selection, have
flowers only two inches in diameter.

Among the offspring of the Giant Calla, one
has appeared that has a shade of purplish crim-
son on the stalk and blossom. This color I have
never known to appear in the common calla
before, and its appearance suggests reversion to
a very remote ancestor. It is possible that the
giant bears blood of one of the other species, two
or three of which, as before mentioned, have

THE CANNA AND CALLA 51

strains of purple in their heredity, but this is
unlikely, as I have never been able to get these
species to cross.

It will appear that there is abundant oppor-
tunity for the making of interesting experiments
with the different races of callas. As to the
practicalities of cross-pollenizing, there are no
difficulties, notwithstanding the very curious
character of the floral envelope. The calla
flowers, as is well known, are very tiny, and
borne on the central spadix that stands like a
little post in the center of the leaflike spathe that
is ordinarily thought of as constituting the
flower.

To effect cross-pollenization, it is first neces-
sary to amputate the spadix, removing the upper
portion, with the staminate flowers.

Pollen gathered from another spadix may
then be dusted with a camel's-hair brush over the
pistillate flowers at the base of the amputated
spadix. Of course no attempt is made to operate
on the individual flowers, but the group as a
whole may thus readily be fertilized.

As the pistillate and staminate flowers on any
given spadix ripen at different times, there is no
danger of self-fertilization if the operation of
removing the upper part of the spadix is per-
formed at the right time.

THE LEMON GIANT CALLA

My calla experiments have had to do
with a number of species which have
been variously crossed. Here is an
improved variety produced by hybrid-
ization and selection that was intro-
duced under the name of the Lemon
Giant. The peculiarly flecked leaves,
together with the quality of the flower
itself, gives it distinction.

THE CANNA AND CALLA 53

COMMON LILIES

To a fair proportion of country folk, anything
that is not obviously a pink or a rose is char-
acterized as a lily.

In fact the diversity among the lilies and allied
species is so great as almost to justify the wide
implications given the name colloquially. A
gigantic calla and a tiny trillium, for example,
seem about as far removed from each other as
two flowering plants can well be. And the most
familiar forms of the tiger lily, which may per-
haps be said to be the typical member of its tribe,
assuredly bear small resemblance to either calla
or trillium.

Nevertheless there is a large group of lilies
that bear greater or less resemblance to the
typical species, having characteristics of form,
no less than of arrangement of stamens and
pistils, that are quite unmistakable to anyone
having the slightest botanical knowledge.

A large number of these may be hybridized
readily, and I have personally worked with a
great number of species. But while the results
have in many cases been interesting, they have
not been very spectacular, or very important,
and it is not necessary here to go into details
with regard to most of them. It will suffice to

54 LUTHER BURBANK

tell of two or three typical hybridizing experi-
ments made chiefly with the native leopard
lily (Lilium pardalinum) as the pistillate
parent.

The extent of my experiments with the tribe
may be gathered from the statement that at one
time on the two Sebastopol farms I had fully
five hundred thousand more or less distinct kinds
of hybrid seedling lilies. About three-quarters
of them were produced by pollenizing the native
species just named with all the species from dif-
ferent parts of the world of which I could obtain
specimens.

It was found that hybrids between the numer-
ous species of lilies that are native to the Pacific
Coast could be made with the greatest facility.
Tens of thousands of seedling hybrids between
the different indigenous species were produced.
But, on the other hand, hybridization with the
foreign lilies was found to be rather difficult,
different species having seemingly diverged some-
what toward the limits of affinity.

One of the most successful crosses was that
made between the species known as Lilium
Humboldtii and L. Parryi. The former has a
very large bold, thick petal, white, with large
distinct spots, and it is fragrant. The other
parent is a tall, slender variety, the flower being

THE CANNA AND CALLA 55

clear buttercup yellow, with very small spots or
none.

The cross was made with some difficulty, and
the result was a lily which some connoisseurs
have considered one of the most beautiful ever
developed. It grows about four feet in height,
and its flower is open bell-shaped, with partially
curved petals, brilliantly yellow in color, without
a spot or dot, and having a delightful fragrance.

Another interesting cross was that between
L. pardalinum and L. parvum. The hybrids of
this cross sometimes produce hundreds of blos-
soms on a single stem, and several hundred
clumps from a single bulb. Not only do they
multiply with astonishing rapidity, but in size,
color, and abundance of bloom they exceed
either parent, although both parents are prolific
bearers.

The crosses of the somewhat fragrant L.
Parryi with L. Washingtonianum and L. parda-
linum produce bulbs having similarly extraordi-
nary powers of multiplication, although in this
regard there was a most amazing variation. Cer-
tain individuals would produce a hundred bulbs
while others of the same fraternity were produc-
ing only one or two.

Some of these seedlings would grow eight or
ten feet in height, while here and there would be

56 LUTHER BURBANK

one from the same lot of seed growing only
eighteen inches or two feet in height.

But the most striking characteristic of these
hybrids was their exquisite fragrance. Even
though the seed were grown from L. parda-
linum, which is never fragrant, the hybrids hav-
ing the L. W ashing tonianum cross for the other
parent were so fragrant that when massed to-
gether their perfume saturated the air and could
be distinguished, down wind, at a distance of
several miles.

The individual plants differed widely on close
inspection as to their forms and colors, but when
viewed from a distance the effect was that of a
great gorgeous spread of cloth of gold.

The variations in form of stem and flower
among these hybrids extended also to the bulbs,
some of which were flat and of varying colors,
from pale rose and crimson to yellow, and others
of which were compact, resembling pears or
apples in form.

Another striking peculiarity of the bulb was
that some of them had scales that were solid, as
in the Washingtonianum, while in others of the
same lot the scales would be divided into sev-
eral separate divisions, each of which would grow
to form a new bulb under proper conditions.
Some of the bulbs when exposed to sunlight

THE CANNA AND CALLA 57

would turn to a brilliant crimson, while others
after exposure for any length of time were
white or yellow or variegated. There was
similar variation as to the resistance to
decay.

I may add that some of the lily bulbs, notably
those of L. Brownii, are edible and are considered
a great Christmas delicacy by the Chinese, who
make most delicious stews and soups from these
bulbs. I have eaten the bulbs of L. Browwi,
grown on the Sebastopol place, and have found
them to have a most delicious oysterlike flavor.
The possibilities of these lilies as food producers
have not hitherto been given the attention they
deserve. All other lilies have bitter bulbs, and
are therefore fairly resistant to eel worms, mil-
liped, thrip, etc., whereas the Brownii is invari-
ably destroyed in the second year, and can only
be grown in new soils. All the true lilies finally
succumb on old soils. I have tried to eliminate
the bitterness through crossing, but attained no
very favorable results.

SOME WIDER HYBRIDIZATIONS

It has already been stated that the California
lilies do not cross readily with the foreign species.
Nevertheless, I have made successful hybridiza-
tions in many cases.

THE SIBERIAN LILY

(Eremurus)

An improved variety of one of the
most attractive flowers, the original of
which grows wild on the Siberian
deserts. These specimens were about
six feet in height.

THE CANNA AND CALLA 59

Among the most interesting of these crosses
was one in which the so-called Lily of the Incas
(Alstroemeria — not a true lily, having no bulb),
of South America, was crossed with the familiar
California species (L. pardalinum) , already so
often referred to.

Of some of these hybrids I raised a large num-
ber, and they presented interesting variations.

Some of them, when they bloomed, seemed
almost counterparts of the South American
parent except that their petals recurved like
those of the California lily. Some were spotted
like the California parent, and some were quite
without spots. As a rule, however, these hy-
brids, even though producing fairly abundant
foliage, did not blossom at all, and at best they
were small and insignificant, and within a year
or two most of them had disappeared. They
seemed to produce inferior bulbs that could not
withstand the winter.

As further evidencing the lack of virility of
these hybrids, it may be noted that all of them
were dwarfs. In striking contrast to hybrids of
the pardalinum with other native lilies, none of
them grew more than a foot in height and many
of them not over six inches.

These dwarfs were rendered all the more
striking by the fact that the miniature lilies re-

60 LUTHER BUKBANK

produced in many respects the characteristics of
their South American parent.

Another interesting hybridization was that
effected between the pardalinum and a species
of the native Trillium, a plant familiar in our
woods under the name of wakerobin.

The Trillium is, of course, a lily, but, like
Alstroemeria, it belongs to a different genus
from the leopard lily, and its strikingly different
appearance has already been referred to.

The hybrids produced by this strange union
were dwarfs with broad, lilylike foliage, with
blossoms that resembled those of the Trillium —
having three very broad, flat, greenish-white or
yellow petals, and three narrower petals, like
sepals.

A plant that thus bore a close resemblance as
to foliage and general appearance to the leopard
lily, yet which had blossoms like those of the
wakerobin (though somewhat larger and coarser)
made a very striking and interesting exhibit.

The species of Trillium used in this cross was
the common native Trillium ovatum.

The hybrids, although in themselves so inter-
esting, proved lacking in vitality, and notwith-
standing my efforts all died — not, however,
before I had secured several photographs of
these strange trillium-lily combinations.

THE CANNA AND CALLA 61

Among all these experiments with the lilies
there is perhaps no other result quite as inter-
esting as this hybridization with the Trillium. Its
results suggest the desirability of further ex-
periments along similar lines.

There is an almost boundless opportunity for
new series of investigations with members of this
very extensive group. The plants may readily
be cross-fertilized by the amateur, and inter-
esting results must follow almost as a matter of
course.

The plant developer who pays
heed to the fragrance of his
flowers as well as to their other
qualities, is almost certain to pro-
duce varieties that will be appre-
ciated. The perfume of the
flower and the flavor of foods are
nowadays receiving more atten-
tion than formerly.

THE PUREST WHITE IN
NATURE

STRIKING COLOR CHANGES IN THE
WATSONIA

BULBS are not usually measured by the
cord. But I do not know how better to
give an idea of my work with the Wat-
sonia than to say that in recent years I have
destroyed about eight cords of bulbs of this plant
each season. A cord, it will be recalled, is 8 feet
long, 4 feet wide, and 4 feet high.

If you will picture in your mind's eye eight
cords of wood piled together, and recall that the
Watsonia bulbs have corresponding bulk in the
aggregate, and that each individual bulb is of
the size of a small gladiolus bulb, you will gain
a fairly clear conception of one of the least
satisfactory aspects of the plant experimenter's
work.

These discarded bulbs, it should be under-
stood, would produce very beautiful flowers. It
seems a pity to destroy them, when so many

63

64. LUTHER BURBANK

people would be glad to have them for cultiva-
tion. But past experience teaches me that I
have no alternative in the matter. If these
bulbs were permitted to go out they would pres-
ently be exploited by some one as "Burbank's
Best Watsonias," or under some still more
spectacular title, and my reputation as a
producer of fine varieties would suffer, as it
has many times in the past through similar
deception.

So there is no recourse, after selecting the
comparatively small numbers of bulbs that give
greatest promise for the carrying on of the ex-
periment, but to destroy all of the remainder,
even though, as in the case of the Watsonias,
these may number a quarter of a million bulbs
of considerable intrinsic merit, representing an
enormous amount of labor.

A FLOWER THAT RIVALS THE GLADIOLUS

The Watsonia has been somewhat recently in-
troduced, and has made its way slowly. So it
may not be superfluous to tell the general reader
that this plant bears a close resemblance to
the gladiolus. It is indigenous to South Africa,
one species being found also in Madagascar,
and is represented by a number of wild species,
among which two or three have preeminent

THE WATSONIA 65

importance from the standpoint of the horti-
culturist.

Perhaps the similarity of the Watsonia to the
familiar gladiolus has interfered with its rapid
introduction. Moreover the new plant is some-
what less hardy than the old one, and although
it thrives abundantly in the climate of California
it cannot as yet be grown satisfactorily in the
gardens of the northeastern United States.

But there is one quality of the Watsonia, in
its perfected varieties, that puts it quite beyond
rivalry of the gladiolus. It produces a beautiful
snow-white flower. As we have elsewhere noted,
there has been, until recently, no truly white
gladiolus. But the white of the Watsonia has
been characterized as the "whitest white" in
nature.

In the quality of its whiteness, this flower is
perhaps the only rival of the Shasta daisy.
Each of these flowers is of snowy whiteness, un-
dimmed by the slightest trace of pigment.

The original wild forms of Watsonia, to be
sure, are not white. On the contrary, they are
of various hues of red and pink. But there is
apparently a spontaneous tendency to produce
now and again a white variant, for at least two,
and perhaps more, of these have been introduced
from South Africa that were probably of inde-

Vol. 7 — Bur. C

SOME OF MY NEW SEEDLING
WATSONIAS

I am particularly partial to flowers
that have delicate hues. The Watsonias
are peculiarly responsive, and I have
produced varieties showing delicate
tints almost rivaling those of the
orchids. Here is a random cluster from
my enormous Watsonia colony, but no
color tints can be obtained to more than
give a hint of the beauty of the flowers
themselves.

THE WATSONIA 67

pendent origin. The white forms that are most
familiar under cultivation are so similar that
they have been thought to be identical, the ori-
gin of one of them being somewhat in doubt.

The white Watsonia whose origin is clearly
known is descended from a plant discovered
about eighty miles from the Cape of Good
Hope by Mr. H. W. Arderne, of Cape Town.
He took the plant to his garden and in 1892 had
a colony of the white flowers under cultivation.
In due course they were introduced, and gained
a measure of popularity among discriminating
horticulturists, chiefly because of the exquisite
whiteness of the flower.

Meantime, however, the original species has
not been neglected, although comparatively little
work had been done, in this country at any rate,
in the cultivation of any of the Watsonias at the
time my experiments commenced. Possibly
the flowers would not have been prized but for
the introduction of the white, as the others are
rather dull and not particularly attractive in

color.

HYBRIDIZING THE WATSONIA

I have never been able to determine clearly
whether the white variety named W. Ardernei
in honor of its discoverer is identical with the
variety introduced as W. O'BrienL They are

68 LUTHER BURBANK

closely similar, but it seems not to be clearly es-
tablished as to whether they come from the same
stock, although the individuals from which the
two races have developed were undoubtedly dis-
covered independently.

On receiving the first bulb of the white Wat-
sonia I planted it on a damp piece of sandy
land at Sebastopol, but the bulbs did not thrive
there, and it was two or three years before any
of them bloomed. I learned later through ex-
perience that the bulbs do not require too much
soil. They thrive especially in soil that contains
a mass of leaves, and under proper conditions
they put out numerous branching stalks, about
four feet in height, which for months together
are covered with beautiful snow-white flowers,
which have, as already stated, much the general
appearance of small gladioli.

The general conditions of soil under which
the Watsonia thrives are similar to those re-
quired by the gladiolus.

As soon as a colony of white Watsonias was.
fairly established, I began making crossing ex-
periments, using for the cross the reddish pur-
ple species and including, a few years later, also
a pink variety of the W. Ardernei that was sent
out by a Dutch florist. As usual in these experi-
ments, one species after another was crossed

THE WATSONIA 69

until in the course of a few seasons we had
crossbred forms of multiple ancestry.

There were strains of the white Watsonia in
them all, but also strains of the purplish and
pink species.

By 1904 I had a crossbred colony of Watson-
ias numbering about fifty thousand seedlings.
This doubled in the succeeding season, and in
recent years the colony has attained the propor-
tion suggested by what has already been said
about the elimination of bulbs by the cord.

Needless to say there is great variety among
these complex crossbred flowers. All of them
retain the essential characteristics of bulb and
stalk and manner of growth of the Watsonias.
But in their size of flower, and in various impor-
tant characteristics, they show wide departure
from either of the parent forms.

Perhaps the most striking individual develop
ment is that of a pure white form of Watsonia
that has double flowers. This double Watsonia
is an unusual flower. The doubling has been
brought about, not by the transformation of sta-
mens, as in the case of a double rose or dahlia,
but by growing a new circle of petals outside the
old ones. This form of doubling, to be sure, is
not altogether anomalous. It occasionally takes
place in the case of the rose and the carnation,

70 LUTHER BURBANK

and I have known it to occur with the apple
blossom. But it is not very common.

It is sometimes spoken of as supernumerary
doubling, to distinguish it from the usual type in
which each new petal takes the place of a stamen.

In addition to the double white Watsonia, the
crossbred colony has presented single white ones
that have very much larger and more regular
open blossoms than the original forms. Also
some that grow on much taller stems, and others
on the other hand, that are dwarfed, and of
more compact form. All of the newer ones
show great improvement over the original forms.
If possible, they surpass the original in snowy
whiteness, and not only bloom much earlier than
the type form, but they are the most persistent
bloomers, putting forth flowers almost continu-
ously throughout the whole season.

STRANGE FORMS AND ENTRANCING COLORS

But even these snow-white members of the
colony are surpassed in beauty by some of their
associates that show the most remarkable com-
binations and blendings of colors.

The parent forms, as we have seen, are red-
dish purple and white, but these blended hybrids
present such combinations of colors as I have
never seen in any other tribe of flowers except

THE WATSONIA 71

the orchids. It would be impossible to describe
with any degree of accuracy the varied hues that
these amazing and delightful blossoms present.

There are combinations of violet and rosy
pink, soft apricot yellows, salmon, nearly pure
yellow, yellow shading into pink, deep, dark
crimson, light crimson, and purplish tints of
many shades. And these various tones and
colors are so shaded and blended as to produce
an effect which can be matched only among the
far-famed orchids.

To produce races of flowers of such varied
and entrancing hues from parent forms that had
no exceptional distinction except for the white-
ness of one variety, is to experience in full meas-
ure the best rewards that await the patient plant
experimenter.

It chances also that these wonderful blossoms
are not only individually delightful, but they are
produced in such profusion as is not approached
by the uncrossed races of Watsonias. And to
cap the climax, these profusely borne and gor-
geously colored blossoms are put forth through-
out the season, early in life.

All in all, the new hybrid Watsonia must be
given high rank among the aristocrats of the
flower garden. They now lack nothing but an
element of hardiness that will adapt them to

72 LUTHER BURBANK

grow in regions of the country where the
climate is doubtful and the conditions are less
favorable than those that prevail in California.

Somewhat later, the species Watsonia coc-
cinea was introduced into the combination. It
had smaller and more scattered flowers, long
and tubular, and it was of doubtful value, and
introduced with trepidation.

Some of the new hybrid forms presently de-
veloped long slender tubes, while the flowers are
close to the main stalk. Some have star-shaped
flowers with narrow pointed petals, others have
wide rounded petals that give the flowers the ap-
pearance nearly of single dahlia blossoms. Still
others are of a curious intermediate form — three
of the petals being rounded, and three star-
shaped.

Flowers of the last named type are quite
anomalous. Petals of some of the old Watsonias
were star-shaped, and others were rounded, but
the combination of the two qualities is unique.

Among the hybrid seedlings there are some
that are only seven or eight inches high, appear-
ing with tufts of wide, dark green leaves at a
time when others with slender leaves have shot
up to a height of eighteen inches or two feet.

We have seen similar differences among other
hybrid plants. They show at once the diversity

THE WATSONIA 73

of the racial strains within their germ plasm,
and the possibility of segregating and recom-
bining traits of different ancestors.

There is a corresponding diversity as to the
bulbs, and in particular as to the degrees of
rapidity with which they multiply. There are
varieties that will produce a bushel of bulbs
from a single one in a comparatively short time,
whereas others multiply very tardily. It is
rather curious to note that the bulbs that are
the most rapid multipliers are usually the ones
that produce the best flowers and bloom most
abundantly.

In dividing the bulbs of the hybrid seedlings,
it is observed that some spread out naturally
into bulbs of even size and are easily pulled
apart, like gladioli, thus multiplied with facility.
Others grow together in clusters that must be
wrenched apart, breaking the bulb seriously, or
else cut with a knife. All these matters are
taken into consideration in the selection through
which the few are singled out for preservation
and the many are destroyed.

It is my custom, having selected a certain
number for preservation, to cut away nine-
tenths of the seed pods in order to strengthen
the bulb, thus stimulating the fullest de-
velopment.

74 LUTHER BURBANK

THE CARE or SEEDLINGS

As the Watsonia is not generally known, it
may be worth while to give a few specific direc-
tions as to the raising of seedlings of this inter-
esting plant.

In general it should be said that, where the
climate is suitable, the Watsonia may be raised
as easily from the seed as the gladiolus, and the
treatment required is altogether similar. My
method is to plant the seed in shallow, well
drained boxes of sandy soil, as soon as they are
ripe in the fall. By March we have, in each
box eighteen inches square, perhaps a thousand
Watsonias about six inches in height, if other
conditions are right. They thrive very well
when planted as thickly as this in the boxes.

In the spring the choicest appearing plants
are transplanted singly into rows. The ones
that are not quite so choice are set out in the
mass, by breaking up the soil into squares hold-
ing fifty to one hundred plants, all being
planted in the open field, and by fall are ready
to transplant into rows for testing.

A still more rapid method is to sprout the
seed in moist sand at the proper season in the
fall, just as the rains commence, sowing them
quite thickly in drills eight inches apart and an

THE WATSONIA 75

inch deep in sandy soil, half the covering being
sawdust. Scatter a few weeds over the surface
to keep the winter winds and heavy rains from
removing the sawdust. Early in the spring the
young Watsonia seedlings come up as lustily as
blue grass on a lawn.

Those that do not make a strong growth are
allowed to stand thickly in the row another year,
when they can be removed and planted.

For field culture, they should be planted four
inches apart in rows four feet apart, being set
quite deeply that they may resist the summer
droughts.

Of course the more careful method first sug-
gested is desirable if we are to raise plants of
the finest quality. You also get results a year
or two earlier by handling the plants individu-
ally. At the same time you insure the produc-
tion of a plant from each seed, while when the
plants are handled in a mass a good many of
them no doubt fall by the wayside.

When treated according to the first method,
many of the plants mature in the second year,
and all of them in the third, so that they can be
fully tested in that period. Moreover by the
third year each bulb has developed quite a nest
of bulbs about it, from each of which a new
plant may be grown.

76 LUTHER BURBANK

The results already attained with the Wat-
sonia mark this plant as one that must take high
place among the favorites of the flower garden.
What chiefly remains to be done is to make the
bulbs more hardy, so that they are adapted to
different conditions of soil and climate. At
present the flowers are chiefly grown in Cali-
fornia and shipped to the eastern market. But
in due course races will be developed that can
be grown in the east, and the Watsonia will
come to rival the gladiolus and in some respects
to outrival it for all the uses to which that flower
is adapted.

Moreover it will perhaps prove possible,
through hybridizing the Watsonia with the
gladiolus, to develop new races of plants com-
bining the qualities of each in a way that cannot
be definitely predicted. I have produced a great
number, say four or five hundred, hybrids be-
tween Gladiolus gandavensis and the Watsonia,
in most cases using the pollen of gladiolus
(chiefly because it is more abundant and the
Watsonia is more certain of seed), but some-
times making the reciprocal cross. Only three
or four of these blossomed, largely, perhaps,
because a great number of them were as
tender as the gladiolus, and persisting to
grow all winter were destroyed by the frost,

THE WATSONIA 77

although plants of the Watsonia withstood
the season.

It should be explained that the gladiolus does
not withstand the coldest part of our winter as
well as the Watsonia; but fortunately the gladi-
olus does not generally make a winter growth,
so it may be left in the ground with less danger.

Of the hybrids that blossomed, all died next
year from gladiolus diseases.

It may be of interest to add that double white
seedlings from the W.atsonia have been pro-
duced here; also double flowers of other colors,
pink, light and dark salmon, and white.

We have naturally had occasion, in recent
chapters, to pay more attention to the matter of
color than to any other single flower quality.
For it might almost be said that flowers have
been developed for color alone. A certain
amount of attention has been given to modi-
fying their forms, but this has always been
subordinated to the question of modifying
their color.

If attempts have been made to increase the
size of the flower, and to multiply its petals, the
central thought has been to produce a more
striking color display. In exceptional cases,
notably that of the orchid, anomalies of form
add greatly to the interest with which a flower

78 LUTHER BURBANK

is regarded; but even with the orchids it is un-
questionably the delicate beauty of the colora-
tion, and not merely the grotesqueness of form,
that gives the flower popularity.

From the standpoint of the plant experimenter
the question of color in the flower is one that
has perennial interest. In a very large number
of cases new varieties are developed solely along
the lines of color variation.

We have seen that there are almost endless
modifications of color in the same flower, par-
ticularly in such variable races as roses and pop-
pies and dahlias, and the case of the Watsonia,
which has just come to our attention, illustrates
the interest associated with the modifica-
tion of color even when no other change is
involved.

The white Watsonia that was discovered
among its pink fellows was given a new botani-
cal name, and went forth to conquer the world
captioned as a new subspecies. Yet it differed
in no obvious regard from myriads of its fellows
except in the matter of color.

It was pure white, and all of its fellows were
reddish purple. That fact gave the one Watso-
nia distinction among the millions and insured
the propagation of its progeny and their migra-
tion to the utmost corners of the earth.

THE WATSONIA 79

EVOLUTION or COLORED FLOWERS

Something has been said in various preced-
ing chapters as to the philosophy of color vari-
ation. The origin of the colored floral envelope
is ascribed to the influence of insects. We have
been made aware that the floral envelope was
developed as an advertising device to attract in-
sects, that their services may be engaged for the
transfer of pollen that is so essential in keeping
up the necessary adaptability and vitality of a
race of plants.

We have been led to infer that the floral en-
velope is one of the most recent developments in
plant evolution, inasmuch as the earlier forms of
plant life had no such apparatus and their suc-
cessors developed it only with the evolution of
the insect tribe. And we have doubtless been
correct in ascribing the ready variability of the
floral envelope to the fact of its relative newness.
The stalk and branches and leaves of the plant
have persisted, more or less modified in form
but essentially unchanged in functions, from the
remotest periods, and hence have attained a
fixed and determinate arrangement of their
hereditary factors that is difficult to disturb.

The conspicuous advertising sign that we call
a flower has been put forth so recently that it

A SPECTACULAR IRIS

Color variation is, of course, the most
conspicuous characteristic that will
appeal to the amateur in the case of the
iris. There are purple iris and yellow
ones and white ones in almost any
garden, and these may be combined in
endless ways. Here is a specimen that
shows an interesting and spectacular
color blending.

THE WATSONIA 81

lias not attained any such degree of stability.
And, in particular, the color of the flower is
an endowment that, as contrasted with the gen-
eral structure of the plant, must be thought of
as only a thing of yesterday. We are justified
in believing that even among the old tribes of
plants — those whose primeval forbears have
left their remains in the geological strata — the
flower is the one structure that has been most
subject to variation. And we may doubt
whether there is any flower whatever that has
not changed its color more or less within com-
paratively recent times, geologically speaking.

Something has been said as to the probable
relations of the different primary colors in their
various associations in the floral envelope. We
have seen that flowers of the same species may
vary from deep red to delicate violet, and that
it is the commonest thing for a species that is
usually gaudily colored to have representatives
that are pure white. And it is possible, by a
careful survey of the field, to draw conclusions
as to the probable sequence of development
through which the variously colored flowers
have been evolved.

In the first place, certain inferences may be
drawn from what is known as to the hereditary
responses of different flowers, in particular

82 LUTHER BURBANK

when hybridizing experiments are performed,,
that at least give clues to the story of the evolu-
tion of color.

Analogies drawn from the study of the spec-
trum are also of aid, in connection with these
practical observations, in developing theories of
the philosophy of flower coloration, which, if
they cannot be said to be definite, have at
least a large element of plausibility and are
full of interest.

THE PHYSICAL BASIS OF COLOR

It has even been suggested that the earlier
forms of vegetation were probably red in color
where now the leaf structures in general are uni-
versally green; the basis for this belief being the
observed manner of reaction between plants of
green foliage and those of red foliage when hy-
bridized, the fact that sea weeds are usually red,
and the further fact that young vegetation, such
as the buds of trees in the spring, is very gener-
ally red in color, the subsequent greenness being
due to the development of chlorophyll granules.

Just why the cholorophyll granule is green is
of course only matter for conjecture. But it is
obvious that this is the ideal color for this pur-
pose, otherwise it would not have been so uni-
versally adopted.

THE WATSONIA 83

The presumption is that the plant finds it
desirable to utilize the short rays of the upper
part of the spectrum and the long rays of the
lower part — those that stimulate chemical action
chiefly, and those that are the greatest convey-
ers of heat, respectively — and that the interme-
diate rays producing the color green are not
needed, hence are reflected or transmitted with-
out influencing the plant.

A possible clew to the reason for this is found
in the supposition that the plant needs the short
light waves to enable it to carry out its chemical
function of transforming water and carbon
into sugar, and that this process is facilitated
by having the tissues warmed by the long waves
of the lower end of the spectrum.

It has been calculated that the sun beating on
a leaf would raise its temperature to a point that
would destroy the protoplasm and kill the leaf
outright in a very short time were it not for
the transpiration of water from the pores of
the leaf, through which the temperature is
equalized.

In spite of this danger the sunlight is known
to be absolutely essential to the carrying on
of life processes, but it is obviously desirable
to limit the amount of heat as much as
possible.

84 LUTHER BURBANK

So the question of the heating effect of the
sun must have a share in determining the color
of the floral envelope.

A flower that blooms in the open and is ex-
posed to the blazing rays of the sun may advan-
tageously develop a glossy surface, just as a
leaf does, in order to reflect the largest possible
amount of light ; and may in addition take on to
advantage such transformation of its tissues as
will make them reflect the long heat-bearing
waves of the spectrum.

Such a flower, interpreted in ordinary lan-
guage, is red in color — for of course that is the
untechnical way of stating the facts that a given
object reflects the long rays of light, and ab-
sorbs the others.

Contrariwise, it would be almost fatal for a
blossom of ordinary texture to develop such con-
sistency as to absorb the main bulk of the light
waves, inasmuch as such a blossom would soon
be heated to a dangerous temperature. That,
doubtless, is why flowers that are even approxi-
mately black are the rarest of all blossoms.

On the other hand, a flower that reflects all
the rays of light, and hence that appears white
in color, is given protection against the heating
influence of the sun even though it grows in the
open. When we add that white is a conspicuous

THE WATSONIA 85

color the extreme abundance of white flowers is
sufficiently accounted for.

It is true that flowers that bloom in the
shadow, and particularly those that open in the
twilight or at night, are almost universally white
also, but this is sufficiently explained by natural
selection, since white flowers are more conspicu-
ous at night than those of any other color.
Moreover, it must be recalled that white objects
transmit heat less readily than dark ones, so
white is not a bad color for a night-blooming
flower, inasmuch as it conserves the internal
heat even if it is not called upon to shut out
heat from the sun's rays.

THE SEQUENCE OF COLOR DEVELOPMENT

All this is more or less axiomatic, but the fur-
ther development of the theory of flower colora-
tion involves a certain amount of assumption,
and must be held only as a tentative theory.

Briefly stated, the essentials of the theory are
that the original or earliest color of the flower
was green in imitation of the leaf. All the
older or primeval types of plants — cycads, pines,
cypress, ferns, etc. — have green flowers or sub-
stitutes for them even to this day; in some cases
slightly tinged with yellow. It is suggested that
the color next developed was blue, the genesis of

86 LUTHER BURBANK

which involved but a slight modification of the
molecular structure of the flower, inasmuch as
the light waves that produce blue lie next to the
green on one side in the spectrum.

The subsequent modifications of color were
made in two directions progressively.

Some flowers were modified in the direction
of the violet end of the spectrum, and others in
the direction of the red end of the spectrum.
The former were first light blue, then deep blue
and indigo — represented among existing plants,
let us say, by the larkspur and gentian — and
ultimately violet. Flowers modified in the other
direction were at first yellow, then orange, and
finally red.

Evidence is lacking to answer the question as
to which end of the spectrum was reached first—
that is to say, whether the flowers of violet color
or red were first evolved. But possibly the two
may have been developed somewhat contempo-
raneously, and they would thus take their place
in the hereditary scale more or less on an
equality.

In any event, we may be fairly assured that
there were blue flowers and yellow ones, and
probably also indigo-colored flowers and orange
ones in existence before there were flowers of
pure violet or of deep red.

THE WATSONIA 87

In other words, we may feel that the violet-
colored flower and the red flower are the
newest things in the way of color in the plant
world.

The time of development of white flowers is
more debatable. There is reason to suppose that
the white flower owes its whiteness to a combina-
tion of the conditions which by themselves would
be interpreted as greenish yellow and as blue
respectively. It is known that these are the only
colors that can be compounded to produce the
color white. So it is perhaps the safest assump-
tion that white flowers were evolved by the
hybridizing of greenish yellow ones and blue
ones, and that their origin antedates the develop-
ment of red flowers or of violet ones. In other
cases whiteness is due to air in the cells, and may
have been a very recent development.

Nor is all this a matter of mere unsupported
assumption. The inference that such was the
sequence of evolution of the different colors
seems logical, inasmuch as it presupposes the
modification of molecular structure of the flower
substance in such a way as to reflect successive
rays of light in a graded series — or rather in two
graded series, one involving shorter and shorter
rays as in the flowers that develop from blue to
violet; the other involving longer and longer

88 LUTHER BURBANK

rays in the series that developed from yellow
through orange to red.

But an assumption based solely on this
plausible analogy would not call for very serious
consideration. The real strength of the theory
lies in the support given it by the observed rela-
tions of the different flower colors when brought
together through cross-pollination of the flowers
themselves.

It is believed, on independent grounds, that
the relations of dominance and recessiveness in
Mendelian heredity are determined exclusively,
or at least in large part, by the newness or old-
ness, in an evolutionary sense, of the respective
elements that make up a pair of Mendelian fac-
tors— referring, it should be understood, to the
number of repetitions, not to the mere lapse of
time.

If this assumption is correct — and there is a
large amount of evidence drawn from many
fields to support it — then a guide is at hand with
which to test the theory of color evolution.

Indeed, it is largely through the application
of this guide that the theory of color evolution
itself has been developed.

Making a practical application, it would
appear that the color green, as manifested in a
flower, is so remote an inheritance that it would

THE WATSONIA 89

be recessive to any and every other color; that
blue would stand next in line of recessive-
ness; and that violet and red would be more
or less on a par as colors of preeminent
dominance.

White, according to theory, should be
dominant to green and blue, but should itself
be recessive or hypostatic when brought in com-
bination with red or with violet. As a corrobo-
rative illustration, note that our blue poppies,
crossed with white poppies, produce only white
progeny.

It would also appear that the factors for
yellow and for blue, which are really balanced or
masked to produce the color white, might be
segregated if a white flower were combined with
another white flower or with a flower of a
different color, white perhaps disappearing
altogether and being represented only by its
disunited elements.

Moreover, we have already seen that where
various colors are segregated, two dominant
colors such as red and yellow being brought
together in the same unit system, the two may
neutralize each other and fail of tangible repre-
sentation; just as the colors gray and black are
known to do in the color scheme of the coat of
the mouse.

A LUXURIOUS TYPE

There is something peculiarly
oriental and luxurious about the
appearance of this particular variety of
iris; the idea being carried out by the
richness of coloration and the softly
flowing contour of the petals. How-
ever,, the oriental iris is generally of a
somewhat different type, as will be seen
in succeeding pictures.

HI

THE WATSONIA 91

The practical working out of the scheme is
revealed in numerous cases that we have already
examined.

Thus, union of our yellow poppy with a white
one that produced a crimson progeny finds ready
explanation when we reflect that yellow is com-
monly formed by the blending of the pigments
red and green, and that white is probably due to
the blending of yellow and blue. The combina-
tion of the yellow flower and the white one may
thus be supposed to have resegregated the colors
in such a way that yellow and blue were grouped
to form white, which was in turn submerged
as a recessive factor when coupled with red;
the result being that the progeny were all out-
wardly red.

In a similar way may be explained the result
of combining the orange daisy with the white
daisy; and in general the multiplex presentation
of reds and pinks and yellows and whites in the
hybrids of poppies and roses and gladioli and
dahlias.

The fact that blue so seldom appears is
explained by the assumption that it was the first
color to be developed, after green itself, and
hence that it is recessive to all the other colors.
When a blue is brought out as in the case of my
blue poppy, it is unearthed, as it were, with

92 LUTHER BURBANK

difficulty, and represents the bringing forth of
a quality that has been submerged from time
immemorial.

Of course there are numerous flowers —
although as we have seen they are relatively rare
— that are blue in color. These are races that
have either retained the ancestral color unmodi-
fied because it served them well in adaptation to
their environment; or they are plants in whicK
the recessive blue, which must occasionally
appear in the course of hybridizations, was pre-
served and restored to prominence because it
served its purpose better than the other colors,
whatever they might be, that had supplanted it.
As might be expected, deep or indigo blue
flowers are more abundant than light or pure
blue ones.

It is perhaps not without significance that blue
flowers have usually a white counterpart — the
bluebell furnishes a familiar example. Blue and
white, according to the theory just presented, lie
close together in the evolutionary scale. Either
will be recessive to red or orange or violet; and
it is only flowers from the germ plasm of which
these dominant colors have been largely removed
that are likely to develop blue or white races.

Yet the fact that the white flower carries a
strain of yellow is an ever-present menace to its

THE WATSONIA 93

whiteness, as it may furnish the basis at any
time for variation that will introduce yellow
strains which stand a good chance of supplanting
the blue and white ones.

Some further illustrations of the application
of this theory of the evolution of color in flowers
will appear in our subsequent studies. For the
rest, the reader who is interested in speculations
of this character will be able to make application
for himself, and to test the theory as to its details,
in particular if he enters the fascinating field of
plant development.

Flowers offer the most inviting
field for the amateur, even while
they still hold their full attraction
for the practiced experimenter,
and one can hardly proceed far
with flower experiments without
becoming interested in the
phenomena of color variation.

HOW TO OBTAIN VARIATION
AMONG FLOWERS

THE DOUBLING OF THE KOREAN
BALLOON-FLOWER

IN illustrating the possibilities of flower
development, the case of the Korean balloon-
flower (Platycodon) will perhaps answer
as well as another.

For some time I had been working with
these flowers, to increase their beauty of form,
size, clearness, and intensity of color, and the
closer and more graceful placing of blossoms
on the stalk. As to all of these qualities,
the existing balloon-flowers left much to be
desired.

The method of work was that which has
already been outlined so fully in connection with
other flowers. The essentials, as the reader is
aware, are first the careful examination of the
entire colony to discover the individual that is the
very best of all as to the particular characters in
question.

95

96 LUTHER BURBANK

If the three or four different qualities,
improvement of which is desired, are not com-
bined to best advantage in any single individual,
then it is sometimes necessary to select an indi-
vidual for each quality, and to carry forward
three or four lines of experiment at the same
time.

It will be recalled that in developing a special
variety of small sweet canning pea, with the
qualities of uniform ripening, small seed, and of
seeds of uniform number and equal size in the
pod, I was enabled to find these qualities exhib-
ited in such combination that the experiment
went forward rapidly, so that in the course of
six generations I had developed precisely the
variety of pea desired.

But it will also be recalled that half a dozen
other lines of experiment were carried forward
at the same time, using the same group of peas,
that led finally to the production of as many
quite different varieties, characterized by large
size of seed, by lozenge-shaped seeds, and the
like. And these secondary experiments were
carried out without in any way interfering with
the primary one. It was merely that, in search-
ing among the different vines, I could not fail
to notice individual plants with interesting char-
acteristics, and nothing more was required than

OBTAINING VARIATIONS 97

to select these from the others and save their
seed.

So in such a case as that of the balloon-flower,
where it is desired to increase three or four quite
different qualities — in this case size, beauty of
form, manner of placement of blossoms, and
intensity and clearness of color — it does not so
very greatly matter whether in the early genera-
tions one finds the different qualities combined
in a single individual, or whether, as is more
likely, he finds one individual that is most grace-
ful, another that has blossoms placed on the stalk
in the best manner, and a third that shows to
best advantage as to intensity and clearness of
color.

It is much more probable, in practice, that the
second alternative will be the one actually pre-
sented. Indeed, it is altogether unlikely, when
new qualities, such as these, that have not hith-
erto attracted the attention of the cultivator of
the plant, are in question, that one will find a
single individual that surpasses all its fellows as
to each quality, though this is sometimes the case.

In fact, with the balloon-flowers, it was neces-
sary to save seed of three or four individuals and
search among their progeny in turn the follow-
ing season, and make additional selections that
involved a number of individuals.

Vol. 7— Bur. D

98 LUTHER BURBANK

But when selection has been carried to a stage
where we have one race of balloon-flowers pre-
senting plants that are uniformly of graceful and
attractive form, and another race that has the
flowers arranged in a satisfactory way on the
stalk, and a third race that produces flowers of
a brilliant white color, the materials are in hand
for an amplification of the experiment along
lines with which the reader is already familiar,
through which the desired combination of these
traits in a single race may be effected with almost
absolute certainty.

THE COMBINATION or QUALITIES

The method in question consists, of course, in
cross-pollenizing the best individuals of the three
new races. Of course, one cannot blend three
strains in a single cross-pollenizing experiment.
But one can cross-pollenize specimens of each
one of the three with each of the others, making
the cross reciprocal in all cases to make quite
sure. Each of the new hybrid races will thus
blend, in one way or another, the traits of two
of the parent forms.

Selection being made to find the best types
among these two cross-bred races, the ones
selected will, of course, be interpollenized, and
their offspring, representing the second genera-

OBTAINING VARIATIONS 99

tion from the three parent forms, will combine
all the hereditary factors of their three special-
ized ancestors.

Among these second-generation hybrids there
will be found, in all probability — if large num-
bers of specimens are grown — some individuals
that will combine in superlative degree the quali-
ties of gracefulness of plant of one grandparent
with the satisfactory arrangement of flowers of
the second grandparent and the clear whiteness
of blossoms of the third grandparent.

It is, then, an obvious procedure to save the
seed of this individual, and while we must expect
wide variation among the plants grown from
that seed, there will almost certainly be some
among them that will reproduce the combined
good qualities of the parent, and further selec-
tion along precisely the same line — called "line
breeding" — will result in fixing of the type, so
that we shall have the variety, hitherto existing
only in our imagination, which we have all along
been seeking to produce.

Moreover, not alone shall we have produced
a type which combines all the best qualities of
the different members of the original balloon-
flowers, but this new race will almost certainly
present these characters in markedly accentu-
ated form. The perfected balloon-flower will

100 LUTHER BURBANK

be more graceful in form than the most graceful
one of the original colony. It will have its blos-
soms much more artistically grouped on the stalk
than any balloon-flower that has hitherto been
seen, and the color of these blossoms will be
clearer and more brilliant than those of any
individual member of the original colony,
whether blue, white, or intermediate, as may
readily be demonstrated by comparison if the
original colony has been preserved, and is now
represented by unselected progeny.

Of course, in these experiments, the unselected
members would usually have been destroyed,
but the worker who experiments on a smaller
scale may find it desirable to preserve the
old colony, or some members of it, if for no
other purpose than to find encouragement
in making such a comparison as that just
suggested.

The results, as I have said, are sure to be
encouraging if you have carried out the experi-
ment in the way just outlined. Nothing more
is required than the use of your eyes and reason-
able judgment in selecting the best specimens;
care in the preservation of the seeds; cultivation
of the seedlings in the way we have elsewhere
fully described; and persistency in following up
the experiment.

OBTAINING VARIATIONS 101

It has often been pointed out that in such
experiments there may not be very much encour-
agement in the first generation or two. Some
forms of plant, and in particular those that have
not been very much under cultivation, or that
are represented by only one or two species, may
hold fixedly to their type and show at first only
a slight range of variation. In such cases you
must be content to go forward by very slow
stages, making but the shortest step ahead with
each generation for the first two or three years.

But even where progress is as slow as this in
the beginning, the time will almost surely come
when the effect of what I have several times
referred to as the momentum of variation begins
to be felt. Some season, to your surprise and
delight, you will discover that the plants are
varying much more widely than they have done
hitherto.

Instead of having to examine your seedlings
with the utmost care to determine which ones are
largest and most vigorous; and then in turn to
examine with equal care the blossoms — when
they appear — to determine which are largest and
most brilliant, you will find that some few seed-
lings will jump ahead of the others as if they
belonged to another race, bringing to your mind
the familiar tale of Jack's Beanstalk, or the less

SELECTED CHILEAN IRIS

Note how widely this flower differs
in form and general appearance from
the iris shown in other pictures. It
belongs to a different species, growing
upright three feet or more in height,
and thriving in very dry soil, while the
Japanese species thrives only in very
moist soil.

OBTAINING VARIATIONS 103

familiar story of Darwin's Hero morning-glory,
which appeared suddenly after several genera-
tions of selection.

When the seedlings which thus practically
select themselves have come to blooming time,
your delight will be enhanced as you discover
that the blossoms they bear are markedly larger
and more brilliant than any you have seen before.

Now all your disappointment and discourage-
ment of the first day is forgotten. Now your
enthusiasm is reanimated and accentuated.
From this time forward you carry on the experi-
ment with renewed zeal, and you feel confident
at last that the coveted goal is well within sight.

PLANTS THAT TEND TO VARY

Of course there are other plants that give
encouragement from the very outset. Such* is
the case with almost any of the familiar culti-
vated plants, of which there are many species
and varieties that have long been given attention
by the horticulturist.

Suppose, for example, that you were to plant
all the seeds taken from the seed pods of a single
dahlia. Perhaps you have done this on occasion,
not with any thought of making new experi-
ments or developing a new variety, but merely
in the hope of reproducing the characteristics of

104 LUTHER BURBANK

the best and most beautiful dahlia among the
number in your garden. In that case you have
doubtless been subjected to bitter disappoint-
ment. For when the carefully nurtured seed-
lings came finally to blooming time, instead of
presenting flowers closely similar to those of the
parent form, they have shown, in all probability,
the widest range of variation — not one of them
perhaps has been similar to the parent. Nor,
perhaps, were any two precisely alike. Among
them you could discover resemblances to all the
other dahlias in your garden and, indeed, to a
large proportion of those that you had seen
pictured in the seed catalogues.

In a word, your dahlia seeds show that they
contain the racial strains of a great variety of
ancestors, and they present a variation that is
truly disconcerting to the gardener whose sole
desire was to produce a lot of dahlias of uniform
character.

In one case, recorded by Darwin, an experi-
menter listed no fewer than eighteen different
varieties of the dahlia grown in the first genera-
tion from the seed of a single plant, and of course
there were all manner of intermediate forms. In
the listed eighteen only six corresponded pretty
closely to certain named or catalogued varieties.
It would perhaps more truly present the record

OBTAINING VARIATIONS 105

if we were to say that there were not eighteen
different varieties merely, but as many varieties
as there were individual plants.

But while such an experience as this is utterly
disconcerting to any amateur whose only thought
is to produce a bed of flowers of uniform color
or character, the same experience would offer
precisely the opportunity that the developer of
new varieties is seeking. Now, it is not a case of
hunting here and there throughout a company
of seedlings for one that differs by a shade from
the others. It is a case of selecting two or three
or a dozen individual plants that present fea-
tures that attract the experimenter ; and selecting
their seed to be planted the following year in
individual plots, that the experiment may be
carried forward, generation after generation,
just as before so far as principles are concerned
— but very differently as regards results, inas-
much as now there is the most striking departure
in each successive generation from the character-
istics of the parent form.

How wide the departure may be within a few
generations is well manifested by the dahlias,
since these plants, as we have already learned,
have all been developed in the space of about a
century from wild originals. Moreover, by no
means are many generations represented as

106 LUTHER BURBANK

might be supposed, inasmuch as the dahlia is
propagated usually from the tuber, and it is only
now and again that an experimenter has taken
the plant in hand to raise it from the seed and
separate out new varieties.

That a plant which in its wild form is an ordi-
nary sort of composite — not very different from
the Black-eyed Susans and allied sunflowerlike
plants that abound by every roadside — could be
developed in a comparatively short series of
generations into the extraordinary flower with
solid heads, and presenting the gorgeous and
variegated colors of the dahlia of to-day, is in
itself an object lesson in the possibilities of plant
development that is nothing less than inspiring.

UNEXPECTED RESULTS

Not only may plants be led along the line of
some desired variation, but there is an element
of chance in the enterprise that adds very greatly
to its interest.

There is always a certain allurement about the
happening of the unexpected. It is highly grati-
fying to select a plant for some desired quality
and to have it respond to selection in such wise
that a variety presenting this quality is finally
produced. But it is doubly gratifying to see
here and there, quite unexpectedly, the putting

OBTAINING VARIATIONS 107

forth of a flower of an unpredicted color, or the
development of a form of which one hitherto had
no conception.

In a field of cultivated poppies, for example,
where there were millions of specimens, all of
substantially identical color, so that the field
made a blazing sheet of yellow, I have come upon
a single blossom of purest white.

To find this white blossom, isolated among the
millions, is an experience that repays one for
years of earnest effort and makes amends for
almost any antecedent disappointment.

It was such a chance discovery as we have seen
that gave the world the wonderful new race
of white Watsonias. Quite possibly the white
flower that Mr. Arderne found among the colony
of reddish pink ones may have been the only one
of its color among a million, or perhaps ten
million, of its fellows for miles around. But this
single atypical individual chanced to be discov-
ered, and its progeny to-day are found by thou-
sands, even by hundreds of thousands, in the
gardens and greenhouses, not alone of its native
home in South Africa, but of all parts of Europe
and warmer regions of America.

The reader will recall that I have raised these
white Watsonias by hundreds of thousands.
Their strains were mingled in the quarter million

108 LUTHER BURBANK

bulbs of this species that I was obliged to destroy
in a single season.

Such are the possibilities of multiplication of
a plant. Such is the geometrical ratio at which
the offspring of a single individual increase if.
given encouragement. Boundless, then, are the
possibilities that lie before the plant developer
who discovers a single specimen of a beautiful
aberrant type.

What we wish to illustrate at the moment,
however, is not the possibilities of multiplication
of the plant, but the interest that attaches to the
development of unexpected variations. And
that the possibility of finding a new form in your
flower garden almost any morning will give
perpetual interest to your task, and will come
to be a compelling incentive that will take
you to the garden as steel is drawn to the
magnet.

To illustrate the possibilities from the case
directly in hand, let us recall the new race of
balloon-flowers, the evolution of which we have
just traced. This experiment began with the
ideal of a balloon-flower of better form, more
graceful placement of flowers, and individual
blossoms larger and of more brilliant color.
These ends were in due course attained, and the
steps have been traced briefly through which

OBTAINING VARIATIONS 109

the new race of perfected balloon-flowers was
evolved.

Now it remains to add that when the experi-
ment was approaching completion, and a new
race of balloon-flowers in many ways satisfac-
tory was actually in being, I discovered one day
among the blossoms one that had a perfectly
regular second row of petals, instead of the usual
single row, or the irregular so-called double,
which had sometimes appeared. Here was an
unexpected variation, which was something not
specially counted on or considered, but, needless
to say, was hailed with delight, and marked for
further education.

If we ask why this second row of petals
appeared, the answer can be only a conjecture.
Doubtless some condition of altered nutrition
stimulated the plant to this abnormal produc-
tion. It is customary to speak of such an anom-
aly as a "sport" or mutation. But doubtless
these words beg the question. They name a con-
dition, but do not in any way explain it.

It is an observed fact, however, that sudden
variations analogous to this may be stimulated
by a change of climate or a change of soil, as
when a plant is brought from another hemi-
sphere, or by a surplusage or a shortage of food.
It is familiarly known that in a beehive the larva

110 LUTHER BURBANK

that would otherwise grow into an ordinary
worker may be made to develop into a queen,
that is to say, a mature female, by special feed-
ing. In somewhat the same way a plant that has
an excess of nourishment may tend to take on
exceptional growth, and one manifestation of
this might be a disturbance of the equilibrium of
the floral envelope, with the production of an
unusual number of petals.

It is known, on the other hand, that a shortage
of food supplies or disadvantageous conditions
of climate may hasten the maturing of a plant,
and cause it to fruit earlier than it otherwise
would do. And any disturbance of equilibrium
of this sort may lead to anomalies in the precise
character of the flower.

Possibly the reason why the petals of the
flower are most likely to be altered as to number,
and also as to color, is the fact that these are
about the newest of all the plant structures. We
have seen that the petals are not themselves
essential to the fertilization of the plant — they
are only advertisements to attract insects. They
were developed late in the evolutionary history
of the plant, and their variability is an additional
evidence of their modernity. The fact that so
many of our cultivated plants have become
"double" is in itself sufficient proof of the tend-

OBTAINING VARIATIONS 111

ency of the petals to be modified under conditions
of change of climate and nutrition to which the
cultivated plant is subjected.

But from our present standpoint, what per-
haps is of greatest interest is the fact that when
petals have once shown a tendency to such modi-
fication, this character is heritable, and the prog-
eny of the plant will reveal some members at
least that show the same characteristic.

Moreover, the "momentum of variation" to
which I have so frequently referred will make
itself felt in the tendency of these variants to
take on still wider variation. In other words, the
plant that has developed an extra petal or row
of petals has acquired a tendency that will urge
it to the production of still greater modifications
of the floral envelope.

In the case of the balloon-flower, the plant
that had developed a second row of petals, when
its progeny were carefully examined, was found
to have transmitted the anomaly to a certain
number, and among the progeny of these there
presently appeared one that had a third row of
petals. So in the course of comparatively few
generations there had been produced a race of
balloon-flowers that had trebled the number of
petals that hitherto had been the recognized
complement for flowers of this race.

A JAPANESE IRIS

Our iris experiments, as mentioned
in the text, have largely had to do with
the Japanese iris. We raised great
quantities of seedlings at Sevastopol a
few years ago. The combinations of
colors are beautiful beyond description,
and they vary in all shades of the rain-
bow. Sometimes the double ones take
on handsome and unusual shapes.
These are typical specimens of a more
usual form.

OBTAINING VARIATIONS 113

Multiplication of petals may result, as we
have already noticed, from the transformation
of stamens into petals, or it may come about
from the springing into being of new petals de
novo, rather than as modifications of any pre-
existing part of the flower. The latter appears
to be the case with the new rows of petals of the
balloon-flower.

At the present stage the flower has a triple
corolla, constituting a very striking modification.
The ultimate limits of its variation can be abso-
lutely determined only by further series of
experiments.

STIMULATING VARIATION

The modification of the balloon-flower has
somewhat exceptional interest, because there is
only a single species of the genus Platycodon, to
which it belongs, anywhere in the world.

In other words, this genus is what is called a
monotype, and it is a well-recognized fact that
flowers belonging to a genus having only a single
species, and even to genera having half a dozen
species, are relatively little subject to variation.
Rightly considered, this is almost axiomatic;
because the very fact that there are many species
in a genus proves that the representatives of that
genus have been variable; else they would not

114 LUTHER BURBANK

have developed so many different forms, since
all members of a genus have sprung from the
same ancestry within comparatively recent
times.

The balloon-flower has, no doubt, been isolated
under climatic conditions that have not greatly
changed for a long period and hence it has main-
tained its specific identity, and the type has
become thoroughly fixed. And this fact gives
added interest to such an experiment as that just
outlined, which shows how marked may be the
developments that can be produced by selective
breeding, even with a flower that tends very
strongly to maintain fixity of type.

But no flower is so fixed that it does not vary
to some extent.

There was no other color until last season,
when a plant bearing large red blossoms ap-
peared among a few thousand seedlings which
had been grown from my long-selected varieties.

There is material at hand, then, through which
cross-fertilization may be practiced, with the pos-
sibility of giving the flower still greater impetus
to variation.

And indeed, even when these crosses have been
made, there will still remain possibilities to invite
the plant experimenter. For, although the bal-
loon-flower stands in a genus by itself, there are

OBTAINING VARIATIONS 115

of course other genera that are not very distantly
related in the Campanula family, to which the
flower belongs. The balloon-flower is often
spoken of as the Chinese bellflower, and with
entire propriety, inasmuch as its nearest relatives
are the European and American bellflowers, of
which there are several familiar species, the best
known, perhaps, being the one called popularly
the harebell or bluebell, and the Canterbury bell.

It is quite supposable that it might be possible
to combine the balloon-flower with one or another
of these European or American bellflowers.

And in that event it is not to be doubted that
the hybrid race would show great new possibili-
ties of variation and, by combining ancestral
traits that have not been blended since remote
geological periods, if at all, we should develop
among the progeny of the balloon-flower races
that would, in all probability, differ so radically
from the parent form as scarcely to be recogniz-
able as having any relationship whatever with the
plant with which our experiment began.

All of this, of course, is taking liberties with
the future. In the case of the balloon-flower,
such hybridizations have not as yet been success-
fully carried out. But in suggesting the possible
results of such potential hybridization, we are
merely drawing analogies from almost number-

116 LUTHER BURBANK

less experiments with other races of flowers, and
have every warrant for drawing such conclusions
as those just suggested.

It may be added that there are yet other pos-
sibilities of stimulating variation by chemical
treatment of the developing ovaries of the flower
itself; or by subjecting the plant to unusual con-
ditions of temperature; but experiments of this
type, reference to which has been made in an
earlier chapter, have not often fallen within the
scope of my own work, and as yet have been
carried out only tentatively by others. They are
mentioned here only as suggesting that there are
other possibilities so various and so complicated
as to give full assurance that no single line of
investigation will ever reach a stage where it loses
interest because it has brought the investigator to
the end of the road.

IMPROVEMENTS IN THE MUCH
IMPROVED IRIS

AND A FEW OTHER OLD FAVORITES

IF YOU are disposed to undertake a series of
practical experiments along the lines sug-
gested in the preceding chapter, it is by no
means necessary for you to send to distant coun-
tries for the material.

Of course, the professional plant developer is
always on the lookout for plants from all parts
of the planet and even of other planets if avail-
able. But the amateur need not be deterred by
the difficulty of securing such materials. He
may go into his garden and begin experiments
with the first flower he chances to find there.

Any old-fashioned flower garden, such as
adorns the dooryards of millions of homes in
America, will furnish abundant material for all
the experiments that any amateur need care to
undertake.

Let me name almost at random a few of the
Common garden flowers that offer interesting

117

118 LUTHER BURBANK

opportunities for development, and any one of
which will serve quite as well as another for the
commencement of your tests of the possibilities of
plant development. Take, for example, the
familiar iris, known sometimes as the rainbow
plant. There are specimens of it, in one variety
or another, growing in almost every garden. It
makes its own way if given the slightest oppor-
tunity, and its unusual flower with the graceful
recurved fringed petals has retained its popu-
larity generation after generation, notwithstand-
ing the coming of many new favorites.

My own work with the iris has had to do
largely with a Japanese species known as Iris
Icevigata. On an acre of damp ground that I
have at Sebastopol, great quantities of these
flowers were raised a few years ago. The com-
bination of colors was beautiful beyond descrip-
tion, varying in all shades of the rainbow.
Among the seedlings were numbers that pro-
duced double flowers, and sometimes the double
ones took on handsome and unusual shapes; in
other cases the anomalies of form were grotesque
and even monstrous, rather than beautiful.

Some of the seedlings produced almost ten
times as many flowers as others, the individual
blossoms being of equal size. Some were tall and
lanky and could hardy support themselves when

A FEW OLD FAVORITES 119

in bloom. Others were short and compact. The
range of variation was from dwarfed forms of
eight inches to giants of four feet or more.

And that the variation was due to heredity and
not to any environmental conditions was shown
by the fact that the dwarfs and giants might
stand side by side in the same soil and subject to
precisely the same conditions of moisture.

There was not much demand at that time for
new varieties, so the entire lot of hybrid Japanese
iris was ultimately sold as a mixture, without
names or numbers, not taking the time to
sort out and fix different types by selective
breeding.

In addition to the Japanese form, I have raised
a great number of other species, including one
interesting form in which the seed pods turned
out in a curious way and exposed the orange or
scarlet seeds. This is a species known as Iris
foetidissima. This anomalous form was grown
extensively to produce a race that would have
seed pods and seeds that would have better form
and open more fully.

It is not necessary to go into details as to the
score or more of other species that I have grown,
as they all reveal more or less similar tendencies
to variation, and suggest over and over the same
possibilities of development.

120 LUTHER BURBANK

It does not matter very much, then, what par-
ticular variety of iris is growing in your garden.
Probably there are plants that bear purple flow-
ers, others with yellow ones, and yet others that
are white. This obviously gives you opportunity
for hybridizing, and there will be abundant in-
terest in watching the results of the blending of
different colors, or even of different species.

If, at the same time that you are crossing the
iris of different colors, you save also seed from
other plants, or from different flowers on the
same plants, that are not crossed, you will be able
to check the results of your experiment, and will
find yourself launched at once into an investiga-
tion that offers fascinating possibilities. It
should be explained, however, that the cross-pol-
lenizing of the iris presents complications which
will not be solved unless you make a very careful
inspection of the flower.

The stigma of the flower has a little lip under
the unique petaloid pistils, very different in ap-
pearance from the organs of most other flowers.
If you examine it closely you will see that the
little shell-like lip that projects is adjusted in
just the right way to scrape pollen off the back of
a bee as it enters the flower, or similarly from the
head of a humming bird. The arrangement is
such that the bee or humming bird will come in

A FEW OLD FAVORITES 121

contact with the pollen of an individual flower
only after it has passed the pistil, and the protect-
ing sheath prevents the deposit of pollen as the
insect or bird leaves the flower. Thus it is in-
sured that self-fertilization will not take place.

While the flower is complex in this regard,
nothing more is necessary than to study its
mechanism attentively, pulling to pieces two or
three blossoms to see just how the pollen must be
deposited. After that you will experience no
difficulty in cross-fertilizing the iris, and the re-
sults of your work are sure to be of interest.

FOUR-O'CLOCK AND COLUMBINE

The familiar four-o'clocks are all natives of
America, but most of them had their original
home in the subtropical and tropical portions of
the two American continents. There is one, how-
ever, that is native to California, and various
species made their way to the gardens even far to
the north a century or more ago, and are now
grown everywhere.

The most striking peculiarity of the four-
o'clocks (Mirabilis) is their tendency to combine
different colors in the same flower in peculiar
patterns.

We have seen a great deal of color variation
among flowers. We have seen numberless in-

122 LUTHER BURBANK

stances in which blossoms of the same species may
be in one case red, in another pink, in a third yel-
low, and in a fourth white. We have seen also
some instances of the mingling of different colors
in the same flower, notably with some of the
dahlias. But our attention has been yet called to
no flower that mingles the colors in quite so anom-
alous a way as is characteristic with the four-
o'clocks. For these blossoms, apparently unable
to decide between different colors, have hit upon
a compromise of arranging the colors in definite
stripes, which give the tubular corollas a very
curious and characteristic appearance.

In a lot of seedlings, supposedly of the same
variety, the stripes may come in various widths of
white, crimson, and yellow. Even when the seed
is saved from a single plant, there will be great
variation among the seedlings, in some the wide
white stripes predominating, in others the crim-
son, and in yet others the yellow. Again, some of
the flowers may come pure white, or yellow, or
crimson, or pink, quite without stripes; or per-
haps half of the blossoms on a given plant will be
one color and half another.

It is obvious that a plant showing such wide
variation does not necessarily call for hybridiza-
tion to stimulate variation, that is in respect to
color. The mingling of hereditary strains is

A FEW OLD FAVORITES 123

already sufficiently complex in this regard and
you will find quite sufficient occupation in at-
tempting to sort out new races of a good color or
combination of colors, and in fixing a dozen of
them so that they will come reasonably true to
type. If you succeed in accomplishing this, in
the course of a few seasons, you will have per-
formed an experiment that you will find full of
interest, and your task will not have been carried
out without giving you very suggestive sidelights
on the problem of heredity.

It is, in any event, a very curious anomaly that
a plant should so have assorted its hereditary
factors that they adopt this compromise. And
your investigation, which endeavors to determine
how accurately the tendency to striping is de-
pendent on particular combinations of hereditary
factors, will not only prove interesting, but may
lead to valuable revelations. The entire problem
of the study of heredity of color, notwithstanding
the attention that has been given it, still bristles
with unanswered questions. Your experiments
with the old-fashioned four-o'clock may serve to
give you answers to some of them.

A somewhat simpler but perhaps no less in-
teresting problem in color heredity may be
taken up in connection with the equally famil-
iar columbine.

SEEDLING JAPANESE IRIS

This is one of a multitude of variants
among the seedlings of the Japanese
iris, which is almost as variable as the
dahlia.

A FEW OLD FAVORITES 125

There are thirty or more species of the genus
Aquilegia, or columbine, and examples of one or
two of the more common ones are perhaps to be
found in your garden. At least you can get
seeds from which to grow them of almost any
seedsman.

The columbines have long attracted my atten-
tion because of their numerous species, and their
wide range of color variation; also because of
the curious shape of the flower and the tendency
of the spurs to vary greatly in length, as well as
in their tendency to open out in some cases, and
in others to remain partially closed. There is,
indeed, one old cultivated variety which has lost
the spurs altogether.

Long ago I carried on some interesting ex-
periments with this spurless kind of columbine,
crossing it with many others, especially with one
known as the ccerulea, which has very large
flowers of beautiful shades of blue. The hybrids
of this spurless form with the other species pro-
duced beautiful large flat clematislike flowers,
some of them three or four inches in diameter.

Perhaps the most interesting feature of the
experiment was that the hybrids were entirely
spurless. This shows that the condition of spur-
lessness, which is an anomaly presumably of
recent origin, inasmuch as the spurs are a char-

126 LUTHER BURBANK

acteristic feature of the flowers of the wild col-
umbines, acts as a dominant factor in heredity.
This, of course, is what should be expected if it
be true that the newly developed characteristics
of a plant are dominant over the older ones.
But the case of the columbines furnishes another
interesting corroboration of this interpretation
of Mendelian heredity.

In the course of other experiments with the
columbines numerous other species were brought
into the combination through successive hybridi-
zations, until my columbine colony carried the
strains of more than a dozen recorded species.
A most beautiful lot of hybrids resulted. Their
various members revealed nearly all the colors of
the rainbow. These were introduced to the
trade as mixed varieties, as it did not seem to be
worth while to fix the different types. On the
contrary, the variety of blossoms seemed to be
considered an advantage.

But even if it had been desired to fix these
beautiful new types, it would have proved ex-
ceedingly difficult to do so. When you have
two or more species of columbine in combina-
tion, the hereditary complications are compa-
rable to those in the gourd family, to which we
have had occasion to refer. It seems as if every
member of a fraternity differs from all other

A FEW OLD FAVORITES 127

members, and you cannot be at all sure as to
what results you may attain by sowing seed from
any individual plant.

But these complications result in part from
the fact that the different columbines are so
easily crossed by the bees. This is a case where
there is no difficulty in effecting hybridization;
the difficulty is to prevent crosses that are not
desired. If the plants are shielded from the
visits of the bees, and careful hand-pollenizing
is effected, there is no great difficulty in combin-
ing the different forms in such a way as to get
very definite results, and the hybrid forms may
be fixed by careful selective breeding.

Of course, when you deal with a spurless form,
if the individuals that you use are themselves
hybrids of the first generation of a cross between
a spurred and a spurless variety, their progeny,
when they are crossed with a spurred variety,
will be in effect second-generation hybrids and
only half of them will be spurless. But this,
again, merely illustrates the familiar segregation
of characters and the reappearance of the reces-
sive trait — in this case the spurred condition-
in a rather definite proportion of the second-
generation progeny.

Another anomaly among the columbines that
offers good opportunity for experimental tests

128 LUTHER BURBANK

is furnished by the double varieties. I used to
observe that if you crossed a double and a single
one, you are about as likely to get a double as a
single. Here, again, it would appear that the
double condition of corolla acts as a Mendelian
dominant factor, and that some of the strains
were themselves mixed.

All in all, then, the columbine offers most
interesting possibilities for the experimenter who
likes to test for himself the principles of hered-
ity. In the matter of color, there is the wid-
est variation, some of the familiar forms being
blue, others red, yellow or white. The curious
spurs that characterize the flower, and the fact
that one variety lacks them, furnish tangible
features that may be tested, and the single ver-
sus the double corolla constitutes a third feature
that is also susceptible to definite observation
and record.

So the experimenter who will work with a
small number, differing as to characteristics of
color and spur and doubleness, has opportunity
for watching the interplay of hereditary forces;
observing the dominance of certain hereditary
factors, and the recessiveness of their opposing
factors; and finally the segregation of the dif-
ferent characters and their reassembling in new
combinations in the second generation, that will

A FEW OLD FAVORITES 129

test his knowledge of the principles of heredity
to the utmost, and at the same time will give him
definite ideas about the practicalities of plant
development that will be at once interesting and
valuable.

Meantime the experimenter may introduce
problems of far greater complexity if he so de-
sires by combining larger numbers of the plants
somewhat at random, allowing them to be cross-
fertilized by the bees. In this way he may
secure, as I have done in some experiments,
columbines of the most wonderful variety. In
some of the mixed hybrid colonies the blending
of hereditary factors was so complex that among
ten thousand plants there would be perhaps not
five hundred that could be classified as approxi-
mately identical with one another, or as conform-
ing to a specific type.

In other words, there would be perhaps nine
thousand five hundred individual plants, each
of which might be said to constitute a distinct
variety.

In the course of these experiments there were
made perhaps ten thousand careful hand-pol-
linations between different specimens of these
variant hybrids, and, needless to say, plants
were secured with exceptional blossoms of
many kinds.

Vol. 7— Bur. E

130 LUTHER BURBANK

A similar line of experiment is open to anyone
who has the smallest plot of ground in which he
can grow a few scores of columbines.

CAMPANULA AND COREOPSIS

If you were to seek experiments of a still sim-
pler character, you might do well to consider the
beautiful campanula, known familiarly as the
bluebells of Scotland.

These are hardy flowers, growing wild in great
profusion, even far to the north. On a botanical
trip to Canada many years ago I was delighted
to see great fields of campanula as far north as
Alberta. They are said to grow even in Siberia.
So whatever the location of your garden, you
will probably have no difficulty in raising blue-
bells. The plants, to be sure, are somewhat sub-
ject to the attacks of fungous pests and insects,
but aside from this difficulty they are easily
grown. It goes without saying that a flower
that has become famous as the "bluebell" is gen-
erally blue in color. Yet it is by no means
unusual to see specimens that are pure white.
And it is this variation that gives opportunity
for some simple experiments in crossing.

Nothing more is needed than to secure plants
of the ordinary blue variety and others that bear
white blossoms. The campanulas are easily

A FEW OLD FAVORITES 131

crossed, and you will have opportunity to test
the color variation in heredity in some of their
simplest relations. There are, to be sure, many
species of Campanula, and it is true that the
garden varieties are likely to have been hybrid-
ized. I have, for example, raised seedlings from
C. rotundiflora, white variety, without securing
any white ones, all returning to the original blue
color. It will be necessary, therefore, for you to
test your varieties by raising plants of uncrossed
seeds at the same time that you are making the
cross-pollinations. But this complication will
only add interest to the experiment.

The many tribes of Coreopsis give opportunity
for experiments of equal interest. These plants
are composites, and in hybridizing them it will
be necessary to use the method detailed in our
story of the dahlia, washing away the pollen
before applying pollen from the other flower.

The different members of the family vary in
color from deepest purplish crimson to light
yellow and white. There are numerous species
under cultivation, and there are wild ones grow-
ing as roadside weeds that are readily accessible
The variability of the different races makes them
an interesting race with which to work.

My own work with the tribe has included a
good many species, the most important of which

132 LUTHER BURBANK

is the one known as the Coreopsis lanceolata.
The experiments were undertaken to make the
plants more compact in growth as well as to
increase the size of the flowers and their abun-
dance. There was no great difficulty in doubling
the size of the flower, and in the course of four
years, working with seed purchased in the com-
mon market, varieties were produced that were
considered well worthy of introduction. These
were distributed by several leading florists.

The developed varieties had exceptional value
because of the large size of the flowers and of the
small center, also because of the strong stems,
making it a good flower for cutting. A fault of
most of the annual varieties is that they have
small, weak stems.

As to all of these matters, the amateur can
work by crossing and selection. The wide range
of color variation affords a ready guide in cross-
ing experiments, and the ease and certainty with
which the plants can be grown from seed adds
greatly to their utility from the standpoint of the

amateur.

SHOOTING STAR AND SALVIA

A really fine plant that offers opportunity for
improvement, yet which has been little worked
with, is the Shooting Star, sometimes called
American cowslip, a member of the primrose

A FEW OLD FAVORITES 133

family, classified under the genus Dodecatheon.
There are sixteen or eighteen species described
in botanical literature, yet so great an authority
as Asa Gray thought that all the Dodecatheon
in the world should be classified as one species.
There are remarkable variations in size and color,
however, yet the varieties are sufficiently fixed to
offer good opportunity for experiment, and at
the same time are closely enough related so that
they may readily be crossed.

The flowers of the various types show the
widest variation — dark purple, crimson, rose,
white, spotted, cream color, and yellow. There is
opportunity for selecting individual colors and
their fixing through selection; and, on the other
hand, for the combination of colors to produce
new shades.

The plants are handsome, and furnish admira-
ble material with which to work, not merely by
way of gaining experience, but also with the pos-
sibility of producing worthy new varieties.

SALVIAS

The Salvias are members of the mint family.
There are many species, showing a wide range of
variation. The commonest one is known for its
brilliant red flowers borne in such profusion as
to make splendid masses to group along walls or

A NEW EVENING PRIMROSE
—THE AMERICA

This is a new variety which orig-
inated on my place some fifteen years
ago and which is now widely grown.
The flowers are far larger than any
(Enothera ever before seen. A single
petal of America will cover the whole
flower of any other kind. These
gigantic flowers look like pocket hand-
kerchiefs thickly strewn over the
foliage.

A FEW OLD FAVORITES 185

as borders. There are other salvias, however,
that have charming light blue flowers. The plant
in the ordinary gardens is grown, of course, only
for its flowers, yet there is a species, known as
Salvia sonomensis, or Salvia ramona, that is,
abundant on some of the hillsides in California,
and that is to all intents and purposes identical
with the cultivated sage. Its foliage has the
exact flavor of that of the cultivated plant. I
have at times thought of growing it to see if there
could not be developed from it a sage that would
be more valuable for seasoning than the one
under cultivation. The common sage runs into
numerous varieties, some woolly-leafed, some
golden-leafed, and some with tricolored leaves.
It is possible that by crossing this plant with
the wild variety, great improvement would be
made in the unique quality for which its leaves
are prized. From the present standpoint, of
course, our interest in the salvias concerns their
flowers. I have done much experimenting with
various members of the family, both in the way
of selection and of combination. The plants are
variable, even within the same species, and the
various forms run more or less together, so that
it is difficult differentiating them botanically
But the contract between the species bearing blue
flowers and the familiar garden plant with its

136 LUTHER BURBANK

scarlet blossoms is striking enough to challenge
the attention even of the least observant.

The fact that the various species can readily
be combined, while at the same time they show
such variation as to color of blossoms, gives them
obvious interest from the standpoint of the ama-
teur plant experimenter. It should be noted,
also, that there are some salvias with white leaves,
one of these having foliage so thoroughly covered
with a white thick woollike growth that the leaves
make excellent penwipers. The experimenter
who works with one of these varieties could
develop interesting modifications of leaf through
selection, and, of course, crossing methods could
be utilized to accentuate the variation.

Another plant that is exceptionally interest-
ing because of the work that has been done with it
in recent years is the familiar evening primrose
(OEnothera).

Mention has been made in another place of the
work of Professor DeVries, which furnishes the
foundation for his celebrated theory of mutation.
It will be recalled that Professor DeVries found
specimens of evening primrose that departed so
widely from the form of their parent as to seem
to constitute new species. The question whether
these mutations were of unexplained origin, or
whether they were really due to hybridization, is

A FEW OLD FAVORITES 137

still perhaps an open one. But, in any event, the
use made of them by Professor DeVries called
particular attention to this plant, and has given
it a place quite apart among flowers of field and
garden.

There are many species of evening primrose,
and the tendency to vary among them is marked.

I have experimented with the primroses, cross-
ing them quite extensively. One form received
from the mountains of Chile has given some in-
teresting results through selection, in that it now
produces blossoms, a single petal of which would
cover the entire blossom of any of the other prim-
roses under cultivation. The flower itself is
sometimes six inches or more in diameter. A bed
of these plants reminds one of a lot of handker-
chiefs spread out on a lawn, as the blossoms are
somewhat square with rounded corners. A new
crop is produced each morning throughout the
entire summer.

The plant itself is somewhat trailing, and
about two feet to two and one-half feet in diam-
eter. It is a perennial, though it commences to
bloom quite early in the season.

This large-flowered variety has been produced
by most rigid selection for size, form, and white-
ness and substance of flower, and it far surpasses
all other members of the genus in size and beauty.

138 LUTHER BURBANK

This Chilean race has been crossed with the com-
mon CEnothera acaulis, or Tarcucacifolia, and
produced a large number of intermediates, from
the best of which selection has been made. These
hybrids seem to come absolutely true in the sec-
ond generation, so far as foliage is concerned,
being in all cases intermediate between the two
species. This is perhaps what would have been
expected in a member of this race, in view of the
observations of Professor DeVries. The plant
seems to have an exceptional propensity to form
new fixed types.

This, of course, is precisely the characteristic
that gives the plant interest from the standpoint
of the amateur experimenter. So a plot may
very well be set aside in the flower garden for
some evening primroses of two or three species.
Crossing will sometimes be effected by the in-
sects, if the experimenter does not care to take
the trouble to hand-pollenize the plants, and the
production of some interesting new forms may
be expected.

Only two other common plants from among
the almost numberless ones that might be selected
are named as offering advantageous material for
selection by the amateur experimenter. But
these are about the commonest of all, and in some
respects among the most beautiful and interest-

A FEW OLD FAVORITES 139

ing — the goldenrod, and the aster. These plants
are almost universally associated when growing
wild in the field, and their blossoms form so
beautiful a contrast that the two may very well
be transplanted to the garden together.

I have experimented extensively with the
goldenrods, as well as with a collection of the na-
tive asters. And while the two plants are so very
different, the fact that they blossom together late
in the fall and harmonize so beautifully in the
landscape, makes it worth while to work on the
two in combination.

The goldenrods are of so many species and so
variable that they tax the skill of the botanist.
To differentiate between them accurately is a
task lying far beyond the skill of most amateurs
But, for that matter, it is my observation that the
different species hybridize so freely when grow-
ing wild that the specific lines are thoroughly
broken down.

Any botanist who pretends to fix hard and fast
lines beween the different species of goldenrods,
and does not take account of the hybrids, which
are even more numerous in many localities than
the parent forms, will not gain a very adequate
idea of the goldenrods as they actually grow.

Any species of goldenrod will serve the pur-
pose of the experimenter. But, of course, it is

140 LUTHER BURBANK

desirable to have a number of species, and it is
obviously worth while to make careful selection
in deciding which ones to transplant to your gar-
den. I have spent many days on a few acres of
ground, searching among the multitudes of
goldenrods and asters for the most beautiful
individual specimens. From these selected seed
was collected, or the roots themselves dug, to
furnish the basis for further experiment.

Some of the wild forms seem almost perfect,
yet when taken under cultivation and care-
fully selected they even prove susceptible of
betterment.

The hybrids, in my experience, are not as vari-
able as might be expected. One can seldom be
sure, in working with the goldenrods, that one
is working with pure species.

But such complications, of course, give added
interest to the work of the plant developer after
he has the fundamentals of the method fairly in
hand. And I think of few problems that would
be more interesting than to attempt to untangle
some of the hereditary complications among the
goldenrods. The fixing of types by selection;
the improving of the best existing ones ; and the
development of new types by crossing — these are
all methods that offer opportunity for fascinat-
ing experiments.

THE TIGRIDIA AND SOME
INTERESTING HYBRIDS

NEW CHARMS IN FAR-AWAY FLOWERS

BOUT a quarter of a century ago I com-
menced cultivating and crossing all the
Tigridias, or Tiger Flowers, that were then
offered by any seedsman or nurseryman any-
where in the world.

I also secured all the species of the allied genus
Ferraria that I could obtain and cultivated them
for the purpose of crossing them with the tiger
flowers. The Tigridias are natives of subtropical
and tropical America, ranging from Mexico to
Peru and Chile. The Ferrarias are from the
Cape of Good Hope, and are represented by
a number of species.

Both tribes belong to the Iris family, and the
two forms are so closely related that by some
botanists they are regarded as properly falling
within the same genus.

My own experiments, which show the ready
hybridization of the various Tigridias and Ferra-

141

142 LUTHER BURBANK

rias, suggest this close relation. Yet the fact that
they are indigenous to different continents shows
that they have been separated for a very long
period of time, although of common ancestry.

The students of geological botany tell us that
there must have been a great mass of land in the
Southern Hemisphere at one time on which races
of plants developed and subsequently were iso-
lated on the land masses that are now known
respectively as South America, Africa, Austral-
asia and New Zealand. At that remote period
the Tigridias and Ferrarias were doubtless of one
stock, and the fact that their descendants of to-
day retain such elements of affinity as to puzzle
the botanists and to serve well the purposes of the
hybridizer gives another illustration of the won-
derful pertinacity with which the characteristics
of a plant are sometimes transmitted through
almost numberless generations without radical
transformation.

It is little wonder that the earlier biologists,
before the coming of Darwin, when confronted
with such observed cases of affinity between races
that must have been separated for countless
thousands of years, were strong in their faith in
the fixity of species.

Yet the facts of variation, even within a few
generations, are too obvious to escape attention.

THE TIGRIDIA 143

And the compromise has been found, as every-
one knows nowadays, in a recognition of the fact
that time is long, and the further fact that natu-
ral selection may be instrumental in maintaining
the fixity of a race, provided the environing con-
ditions are unchanged, just as it may sometimes
be instrumental in somewhat rapidly changing
the form of a race when the environing condi-
tions have altered.

From the outset I found that the various tiger
flowers throve in my grounds, particularly in the
sandy land at Sebastopol, and in sandy beds
especially prepared for them at Santa Rosa.

As before said, I began at once crossing and
hybridizing the various species and varieties,
and of course carried out selection among the
seedlings and made new crossings, according to
my usual custom. The type species with which
the experiments began was the Tigridia pavonia,
of which there are numerous varieties. Another
form known as the conchiflora or Shell Flower
was utilized, and subsequently the T. buccifera,
a form more recently introduced from Mexico.

An especial effort was made to introduce also
into the combination the strains of a plant of yet
another genus, the Herbertia platensis. This is
a tall-growing plant bearing close resemblance
to the Tigridias, and by some botanists classified

HYBRID TIGRIDIAS

The word "tigridia" or tiger flower,
would suggest a striped flower, whereas
this flower is spotted. The word
"leopard" or "panther" would have
been more appropriate, and the term
"jaguar flower" would have been still
more significant, inasmuch as the
tigridias come from South America,
the home of the jaguar. The specimens
here shown are hybrids of a very
interesting type.

THE TIGRIDIA 145

with them. It has pale blue flowers marked with
yellow, and the specimens are of a slightly dif-
ferent structure from those of the Tigridia,
though the bulb and general growth of the plant
are similar.

It was particularly desired to introduce strains
of the Herbertia, because this is a very strong-
growing plant, and its vigor and health would
be of great service in giving hardiness, the one
thing that the Tigridias more especially lack.

In particular, the bulbs of the tiger plant are
difficult to keep over winter, and especially sub-
ject to decay from exposure to air and to the
attacks of aphids when stored.

But I was never able to effect hybridization
between any of the Tigridias, either pure bred
or hybrid, and the Herbertia. The experiment
was made over and over, and in every case it was
without result.

Meantime, however, there was no difficulty
whatever in crossing the ordinary cultivated
strains of tiger flowers among themselves and
with some of their South African relatives. And
the results of such hybridizings were manifest
almost from the outset.

One of the most striking modifications shown
gained greatly in vigor of growth, in hardiness,
and in resistance to disease.

146 LUTHER BURBANK

The colors of the new flowers are all conspicu-
ously brightened. The striping is usually crim-
son on white, crimson on yellow, or yellow on
crimson. In addition to presenting these stripes,
which are quite unlike any marking of the other
Tigridias, the hybrid flowers generally retain the
dotting at the center that characterizes the tribe
in its original form. But these dottings are
greatly increased in size. In some instances, on
the other hand, the dottings are partially or
entirely eliminated.

The original types of these very striking new
forms of tiger flower were readily fixed so that
they breed quite true from the seed.

The hybrid plants thus perfected exceed
greatly the size of any plants that could
have been developed by mere selection without
crossing.

The new tiger plants, although still lacking
something of hardiness, were greatly improved
in this regard over their ancestors, as most of
the old Tigridias are quite subject to insects and
disease. The hybrid forms are much more re-
sistant. There is also a greater power on the
part of the new plants to stand sunshine. The
old Tigridias sometimes withered under the in-
fluence of the sun. This might not at first
thought be expected of a tropical plant, but it

THE TIGRIDIA 147

should be recalled that the growth of vege-
tation in tropical regions is so luxuriant that
low-growing plants of this order are not usually
subject to the direct rays of the sun through-
out the day.

The bulbs of the tiger plant are elongated and
tunicated, and multiply by division somewhat
after the manner of the hyacinths, tulips, and
the allied races in general. It goes without
saying that the bulbs of the new tiger plants
were improved in proportion to the stalks and
flowers.

The bulbs of the new hybrid Tigridias were
doubled in bulk, and in some cases quadrupled,
as contrasted with the parent forms. Like the
somewhat similar bulbs of the gladiolus, they
may best be kept in the ground over winter
here in California, instead of being taken
up and stored as is necessary in colder
climates.

The development of the bulbs of the Tigridias
has not been at all a matter of accident. At all
stages of the experiment in hybridizing and
selection, I have paid the most careful attention
to the condition of the bulbs, selecting always
those that were largest, firmest and soundest.
And the reason for this was not merely that such
bulbs usually produce the best flowers, but also

ANOTHER HYBRID TIGRIDIA

None of the tiger flowers are striped,
which seems to make their name inap-
propriate, as already suggested; never-
theless, there does seem to be something
tigerlike about this richly caparisoned
and oriental-seeming flower. It is
rather curious to reflect that the spots
on the flower are intended to make it
conspicuous, whereas the striped coat
of its namesake is calculated to make
the animal invisible in the jungle.

THE TIGRIDIA 149

that it is worth while to improve the size and.
quality of the bulbs quite on their own account.

The particular reason for this is that the bulbs
of the Tigridia are edible. When cooked like
potatoes, or made into a stew, they constitute a
really delicious vegetable.

To my taste the bulb of the Tigridia is at
least the equal of any vegetable under cultiva-
tion. It is also highly nutritious. I am not sure
that it has an equal among the vegetables of our
gardens in its combination of nutritiousness and
appetizing flavor.

These very qualities lead to its destruction by
all kinds of animal and insect life, like the
Lilium Brownii, which has no bitter principle,
containing sweet and nutritious matter, and
which also is attacked and appropriated by in-
sects and other creatures.

As yet the Tigridia is too tender to gain a
place in the vegetable garden on a footing with
the potato and allied bearers of bulbs and tubers.
But when, through further breeding experi-
ments, it has been rendered more amenable to
general cultivation, its bulb being at the same
time still further increased in size, it may
come to be valued for its edible bulb quite
as highly as for its beautiful and spectacular
flower.

150 LUTHER BURBANK

MULTIPLICATION BY BULB DIVISION

The habit of storing nutritious matter in its
bulb, and the further habit of producing col-
lateral bulbs from which new stalks will grow,
so that the plant multiplies indefinitely in this
way, is characteristic, as everyone knows, of a
large number of plant families, many of which
have come within the scope of our studies.

The phenomenon of bulb division, indeed, is
so familiar to everyone who has experimented in
the vegetable or flower garden as to take its
place among those familiar matters of fact that
call for no comment.

tYet if we consider the matter thoughtfully it
will be clear that this habit of putting forth
offsets from a bulb as the basis for the develop-
ment of new plants is an altogether extraordi-
nary phenomenon — quite as mysterious, indeed,
as the production of the seeds that bear the com-
plex hereditary factors and transmit the quali-
ties of a race of plants from one generation to
another.

There is no fundamental difference between
the production of new plants by bulb division
and their production by seed, except that in the
latter case there is opportunity for the union of
two different racial strains, one borne by the

THE TIGRIDIA 151

pollen and the other by the ovule. This, to be
sure, is a difference that has all-important prac-
tical bearings, inasmuch as the union of two dif-
ferent hereditary strains gives opportunity for
the blending of hereditary factors and their re-
combination, thus compelling variations that fur-
nish the basis for natural or artificial selection,
through which new races are developed.

All this needs no explanation here, as our
earlier studies have made it perfectly familiar.
But we may now emphasize the fact that the
bulb that produces a new plant carries the
hereditary factors of the parent plant substan-
tially as they are borne by the ovule or the pollen
grain that the same plant puts forth on its aerial
stalks, and exactly as the bulb of any plant — in
fact, the bulb of any plant is only a fat under-
ground bud.

If the ovule could develop without being fer-
tilized, or if the pollen could grow into a plant,
the result in either case, we may reasonably
assume, would be a reproduction of the plant
similar to the parent form, just as the aphids
and the bees when parthenogenetically pro-
duced, and in a few instances of plants, for
example, the violet. Yet there are slight differ-
ences even between the different pollen grains
and between the different ovules of the same

SEEDLING TIGRIDIAS

The mid species of tigridias, of
course, breed true from the seed. But,
equally, of course, the hybrid forms
cannot be expected to do so. So there
are fascinating possibilities of variation
among the progeny of any hybrid. Yet
even the most widely varying specimen
is at once recognizable as a tigridia.
(Reduced one-half.)

THE TIGRIDIA 153

plant, as demonstrated by the fact that flowers,
for example, of different colors may be borne on
plants grown from a single seed pod.

So if we are to present the matter quite in its
true light we should say that the aggregate pol-
len product and ovule product of a plant must
be considered as representing the personality—
that is to say, the hereditary complex — of the
plant.

No single pollen grain and no single ovule
contains representatives of all the types of hered-
itary factors that are present in the heredity of
the plant as a whole.

Stated otherwise, the pollen grains and ovules
are very specialized and concentrated portions of
matter, each of which contains a similar equip-
ment of the most fundamental of the hereditary
factors, but each of which contains a somewhat
different assortment of the less fundamental ones.

All the plants that grow from the seed of a
Tigridia, for example, will be unequivocally
Tigridias in stem and leaf. But there will be
minor differences among them as to details of
size, as to freedom of flowering, as to precise
size of flower, and as to the exact distribution
of the color markings.

As a matter of course, when the seeds are the
product of cross-pollenizing, the offspring, rep-

154 LUTHER BURBANK

resenting now two parents, will show a still
wider diversity of hereditary traits.

Meantime, turning attention again to the
bulb, we find that this structure represents the
parent form with much greater fidelity. As
nearly as there can be identity between two dif-
ferent living things, the plant that grows from
any offset of the bulb of any given Tigridia will
be identical with the parent form.

A certain amount of diversity there must
always be, because no two living organisms are
absolutely identical.

But for all practical purposes it may be said
that the different plants grown from offshoots of
an original bulb are identical. The process of
bulb division can be repeated a thousand or a
million times, until the original bulb has been so
multiplied that its descendants people the earth.
But from first to last, one bulb will be substan-
tially like another, and all the myriads of plants
that have thus arisen may be said to constitute a
single personality.

All this is such familiar matter of fact as to
excite no comment.

Yet, rightly considered, it is a fact of the most
mystifying kind and one that must excite
wonderment on the part of anyone who gives it
serious consideration.

THE TIGRIDIA 155

That the multitudes of hereditary factors that
exist in the germ plasm of so complex an organ-
ism as a flowering plant should be grouped in
each successive bulb that develops as an offshoot
of the original bulb of that plant in precisely the
same combination, predetermining the produc-
tion of a future plant identical with the original,
is a fact that becomes increasingly mysterious
the more carefully we consider it.

In particular, the mystery is great if we have
kept in touch with modern ideas as to the segre-
gation of the germ plasm and the body plasm of
the living organism. There is a current notion,
supported by high scientific authority, that the
very earliest division of a fertilized egg cell, in
the case of an animal or plant, results in the sep-
aration of the infinitesimal fleck of protoplasm
into two different parts that are fundamentally
different, one carrying the body plasm from
which the structure of the new individual is to
grow, and the other carrying the germ plasm
that is to convey the potentialities of future
offspring.

New studies in the biological laboratory have
shown that this idea, that the first division of the
egg cell results in such a segregation of body
plasm and germ plasm, cannot be accepted.
Nevertheless, it is obvious that in the case of all

156 LUTHER BURBANK

higher organisms, whether vegetable or animal,
the germ plasm may be a thing apart. As
finally segregated, for example, in the ovules
and pollen grains, it constitutes a concentrated
aggregate that transmits the hereditary factors
from generation to generation in a sense inde-
pendently of the bodily characteristics of the
individual plant itself.

You may, for example, determine that a given
flower and the seed that grows from it shall be
of exceptional size and vigor by cutting off all
other flowers so that the energy of the plant shall
be concentrated on a single one. But in so doing
you merely give added vigor to the new genera-
tion ; you do not alter its fundamental hereditary
characters. These are predetermined by the fac-
tors in the germ plasm that have been brought
from earlier generations and of which the indi-
vidual plant is only the carrier.

All this, then, suggests the isolation of the
germ plasm; and the newest theories of heredity
have tended in some cases to emphasize the idea
that germ plasm and body plasm are things of
a somewhat different order.

Yet the phenomena of reproduction by root
division or by the putting out of new bulbs, fur-
nish a striking demonstration that the germ
plasm which predetermines the form of the fu-

THE TIGRIDIA 157

ture plant is present not alone in the pollen grain
and the ovule, but also in the bulb.

Even from the single bud of a bulb, as we
have seen illustrated in several cases, a new plant
will grow that will duplicate absolutely — in the
interpretation just given — the qualities of the
parent plant. And when we were studying
the fruit trees we saw that this is true of any
aerial bud if grown even on a foreign branch.

Root bulb and aerial bud alike contain the
essential germ plasm of the individual of which
they are a part. They nurture potentialities of
a new individual like the parent form.

GERM PLASM AND BODY PLASM

From all of which it follows plainly that the
germ plasm of the plant cannot be thought of
as isolated from the body plasm. It may well
enough be segregated within the substances of
any given cell. But that it is present in connec-
tion with the living cells of the plant everywhere,
from its roots to its remotest stem, is clearly
demonstrated by the everyday methods of prop-
agation employed in orchard and garden.

Such being the case, it is difficult to avoid the
conviction that the germ plasm that is part and
parcel of every cell of the body plasm of the en-
tire plant is more or less subject to the environ-

A BLUE TIGRIDIA

Here is a Burbank tigridia that has
taken on a color variation that is very
striking. It is a complex hybrid,
further developed by careful selection.
It represents the result of one of my
most interesting series of experiments
in breeding the tigridias.

THE TIGRIDIA 159

ing influences that affect the body of the plant.
And from this it would follow, at least as a
reasonable inference, that environing influences
that modify the structure of the plant body must
have an effect in modifying also the germ plasm
in a way to influence the character of the future
plant that develops from that germ plasm.

And as much as this, it should be added, is
admitted by all experimenters, even by those
who deny the possibility of the transmission of
acquired traits in the older interpretation of that
phrase. That altered conditions of nutrition
may modify the condition of the germ plasm in
such a way as to modify the state of the off-
spring has been shown by experiments in
many fields, both with animals and vegetables.
Such being the case, the question of the trans-
missibility of acquired traits is reduced, as I
have elsewhere stated, to a matter of definition.

Nevertheless, for practical purposes, it is un-
questionably true that the germ plasm is enor-
mously difficult to influence, and that under all
ordinary circumstances it will convey its heredi-
tary factors unchanged, or not appreciably
changed, from one generation to another. In
attempting to modify the forms of successive
generations, the method that has hitherto proved
successful, has been, not the modification of the

160 LUTHER BURBANK

individual germ plasm, but the bringing to-
gether of different germ plasms from diverse
organisms through hybridization.

For such union of germ plasms there is ob-
viously no opportunity in the case of the new
plant grown from the bulb.

Hence the fixity of type of plants propagated
in this way — a fixity that is often of the utmost
practical importance, as in the propagation of a
new race of vegetables or flowers, but which, by
the same token, puts the plant thus propagated
outside the field of the plant experimenter.

COMPLEMENTARY MODES OF PROPAGATION

Thus the two methods of propagation that are
available for such a plant as the Tigridia and
for countless others of its kind, are in a sense
antagonistic or complementary in their influence
on the history of the plant itself.

Propagation by bulbs insures spread of the
race and also maintenance of the racial fixity.

Should environing conditions change, it is un-
likely that plants thus propagated could change
rapidly enough to adapt themselves to these
conditions.

But at the same time that the plant is produc-
ing new bulbs it may also, year by year, produce
seeds that are the result of cross-fertilization.

THE TIGRIDIA 161

And this method of propagation is a perpetual
bid for such variation as will make possible a
relatively rapid change in adaptation to a chang-
ing environment.

That vast tribes of plants should have found
it necessary to adopt both methods of propaga-
tion is in itself an evidence of the struggle for
existence that is the basis of natural selection.

In another way, also, the bulb perhaps evi-
dences the hardness of the struggle for existence,
particularly in tropical climates. Everyone
knows that vegetation is exceedingly luxuriant
in the tropics, and it is a matter of observation
that the habit of developing tubers and bulbs is
especially common among the herbaceous plants
of tropical and subtropical regions. (Perhaps
one explanation is that the storing of food sup-
plies in the bulb enables the young plants to
shoot up rapidly without waiting for the develop-
ment of a large root system.

By so doing they may stand a chance of com-
peting with the surrounding vegetation and thus
have a far better chance of reaching maturity
than if they had grown from tiny seeds.

It is probable, therefore, that the generality of
bulbous plants that one would find in any given
locality in their native haunts would have devel-
oped as offshoots of the bulb of an original plant

Vol. 7 — Bur. P

162 LUTHER BURBANK

or as inbred or close-bred. So the bulb has very
fundamental importance in the plant economy.
And it is interesting to reflect that it is cor-
respondingly important from a human stand-
point, inasmuch as bulbs as well as seeds furnish
us our most important food products.

We have seen that many of the plants that are
propagated solely from the bulb or tuber, of
which the potato is the most familiar example,
may give up the habit of seed production alto-
gether under cultivation. But, on the other hand,
it is observed that plants that produce compara-
tively small bulbs in the state of nature may be
stimulated to the production of far larger bulbs
and more abundant offshoots under cultivation.

Making application to the particular case of
the Tigridia, it has already been recorded that I
have found no difficulty in doubling or even
quadrupling the bulk of the bulb of that plant,
as well as greatly increasing the tendency to the
multiplication of bulbs.

It will probably be found desirable to culti-
vate the plant further along these lines until it
finds recognized place in the vegetable garden as
the producer of a food of the finest quality,
while at the same time retaining value as the
bearer of beautiful flowers.

FOUR COMMON FLOWERS AND
THEIR IMPROVEMENT

RESULTS OF WORK ON THE VERBENA, THE

PINK, THE PETUNIA, AND THE

GERANIUM

PERHAPS the most interesting Verbena
ever produced was the one named the May-
flower. I use the past tense because I am
not sure that any representative of the variety
named Mayflower is now in existence. I have
introduced the plant through a prominent horti-
culturist, but he apparently found it difficult to
reproduce it with sufficient rapidity from cut-
tings and so attempted to propagate it more
rapidly from seed.

Unfortunately the verbenas are so mixed, and
the various races so little fixed, that they do not
breed true from the seed. And so when I sent
to the horticulturist for a sample of the fragrant
Mayflower verbena a few years later, I received
a plant that had but a reminiscence of the dis-
tinguishing quality of the original.

163

164 LUTHER BURBANK

In the meantime, however, I had developed
another race of fragrant verbenas, which was in-
troduced in 1901. These are the two stocks from
which a large number, at any rate, of the fragrant
verbenas now under cultivation have been
developed.

My first fragrant verbena, the Mayflower, was
developed after I had worked for many years
with this flower and had grown great quantities
of the seed for distribution. The plant from
which the fragrant race was developed was found
among many thousands, most of which, as is
usual with the cultivated varieties, have a rather
disagreeable odor, if any.

I had noticed, however, that there were some-
times members of the verbena colony that had a
very slight fragrance, especially in the evening,
and so began a careful search among them to find
a plant the flowers of which had the most pro-
nounced perfume.

After a long search among the thousands,
I found at last a plant that was distinctly
fragrant, surpassing in this regard any of its
associates.

This individual was of course carefully iso-
lated and its seeds planted. In due course I had
a number of seedlings among which some were
found that produced flowers more fragrant than

FOUR COMMON FLOWERS 165

those of the parent. The selection was con-
tinued, according to my usual method, through
successive generations, until at last a plant was
found that was as fragrant as could possibly be
wished. The plant in question was an exceed-
ingly large verbena — in fact one of the largest
ever grown. The flowers it bore were of a rich
rosy pink in color, the exact counterpart of the
color of the familiar trailing arbutus or may-
flower of New England.

Curiously enough the fragrance of the new
verbena was also precisely that of the arbutus in
quality, although it was much more intense, as
was readily admitted by all who tested the two
flowers side by side.

It was for this reason that the new verbena
was given the name of Mayflower.

Several perfumers who saw this verbena were
agreed that it would be of unusual value for the
production of a perfume. It was admitted by
all that no verbena with a comparable odor had
ever before been seen.

The subsequent history of the Mayflower has
already been told. It was purchased by a dealer,
and although plants grown from cuttings made
from it may possibly be in existence, I do not
know where they are and do not know how to
trace them.

BURBANK VERBENAS

The reader is aware that we take the
greatest possible interest in common
flowers no less than rare ones. Our
experiments with the verbena, for
example, have been carried out on a
large scale for thirty years. Here are
some sample seedlings showing a
wonderful range of color variations.
Some of these are delightfully fragrant,
having the exact fragrance of the trail-
ing arbutus, but even more pronounced.
These giant, fragrant verbenas are now
grown all over the world.

FOUR COMMON FLOWERS 167

Aside from its fragrance, the Mayflower was
an interesting type of verbena, owing to its size
and prolific blooming habit and the beauty of its
flowers. But seedlings grown from the plant
could not be depended upon to produce flowers
that would reproduce the Mayflower fragrance.
Indeed they could not be depended on to repro-
duce any particular characteristic of the parent
plant.

Seedlings of the Mayflower produced plants
bearing blossoms of almost every color — scarlet,
crimson, pure white, yellow, deep cobalt blue,
and purplish. But not one of the many thou-
sands raised afterward had the delightful flavor
of the Mayflower.

THE MAYFLOWER ACCOUNTED FOR

As might be inferred from its variability, the
fragrant verbena was a very complicated hybrid.
It was the outcome of hybridizing experiments
in which I had utilized all the various races of the
plant under cultivation. I had not only grown
and crossed the ones that are offered in the
seed catalogues, but also secured seeds from
all four of the original species from which the
cultivated verbenas have been developed, col-
lected from wild plants in North and South
America.

168 LUTHER BURBANK

It is quite unnecessary, however, to hybridize
the verbenas in order to secure variation, as all
of those that are under cultivation are themselves
hybrids, and the plant has been cultivated for a
comparatively short period and none of the
familiar forms breed true from the seed.

The ancestors of the cultivated verbena were
semitropical American plants, and it is believed
that there are four chief species that have been
variously hybridized to produce all the forms
now under cultivation. One of these, V. chamce-
drifolia, bears flowers of brilliant red, two others,
V. phlogi flora and V. incisa, have flowers that
are rosy or purple in color, and the fourth, V.
teucrioideSj are pure white.

The hybridized races show the breaking up of
these colors, quite as might be expected, with the
presentation of all the primary colors in many of
their hues and gradations, although pure blues
are not very well represented, and pure yellow is
very exceptional.

But the point of greatest interest in the present
connection is the fact that the white species of
wild verbena, which is acknowledged to be one
of the forms whose strains have been blended
with the others to produce the cultivated
verbena, has what is described as a jessamine
fragrance.

FOUR COMMON FLOWERS 169

The hybridizing experiments that ultimately
gave us the garden verbena were carried out less
than a century ago, but in the meantime the
strains have been so blended that it would be im-
possible for the most part to trace the character-
istics of any given form of cultivated verbena
with certainty. But it is obvious that the hy-
bridizers and those who further developed the
plant by selection were chiefly influenced by form
and color, as has been the case with so many other
flowers, and paid little attention to the question
of fragrance.

The verbena has been made to develop won-
derfully symmetrical clusters, and its flowers
have taken on the most gaudy hues. But in the
main, as already pointed out, the odor even of the
most beautiful specimens is disagreeable rather
than attractive.

Yet one of the wild parents, as we have just
noted, was fragrant; and our previous studies of
heredity give us full assurance that the factors
for fragrance must be retained in some at least of
the hybrid progeny, and will now and again make
themselves more or less manifest. That such is
really the case, my fragrant verbena clearly
enough demonstrates. To be sure, its fragrance
is not that of the original. Some slight chemical
modifications have taken place, doubtless through

MORE BURBANK HYBRID
VERBENAS

Note the wide range of variation
among these hybrid verbenas. Observe
also that the centers, in some cases,
have been filed up and made solid.
The verbena is a plant with which any
amateur may readily work, and this
picture suggests interesting possibilities
of developing new varieties.

FOUR COMMON FLOWERS 171

the blending of the other chemicals that repre-
sent the odoriferous qualities of the other species,
and it is only by rare exception that an individual
appears having just the right combination to
produce an attractive perfume.

But the point of interest is that when such
an individual does appear, as in the case of the
Mayflower, the anomaly is accounted for quite
adequately by a knowledge of the existence
of fragrant species among the ancestors of
the hybrid.

Even if we had no knowledge of the existence
of such an ancestor, we should still be justified
in assuming that a fragrant verbena is really a
case of atavism. It will be recalled that we in-
voked the existence of remote unknown fragrant
ancestors in explanation of the appearance of
our fragrant calla. But there is an element of
added interest in the knowledge that in the case
of the verbena the ancestor responsible for the
quality of fragrance can be traced.

It would constitute a very interesting experi-
ment in heredity, should some one care to under-
take to hybridize a fragrant verbena with an
odorless one and to trace carefully the hereditary
influence of this quality — noting, for example,
whether it acts as a preponent or as a recessive
character, and whether it tends to reappear in the

172 LUTHER BURBANK

second generation in any fixed proportion of the
progeny.

It will probably be found that the condition
that leads to the production of perfume of a
particular type is so complex and itself de-
pendent upon so many factors that it is not
inherited in any simple and readily traceable
relation, and the practical results fully carry
out this view.

One of the distant relatives of the fragrant
verbena is a fine shrub known as Aloysia citrio-
dora. Another, as different as possible in ap-
pearance, is a little trailing plant known as
Lippia repens.

This little trailing plant is very valuable as a
substitute for lawn grass. It requires less than
one-tenth the water required by blue grass, and
only a fraction of the care. It need be mown
only once or twice in a season, and throughout
the summer it will cover the lawn with a dense
foliage, and bear a mass of small blossoms
resembling those of white clover and fully as
attractive to the bees.

Unfortunately the lippia is not very hardy,
and when the temperature goes much below freez-
ing it turns to a brownish color. It is not adapted
to the cold climates of the northern United
States.

FOUR COMMON FLOWERS 173

An allied species is the mosslike Verbena eri-
coides, often called "Moss Verbena," which is an
exceedingly pretty plant growing wild in the
high Chilean mountains. In California it pro-
duces seed too abundantly and hence multiplies
so rapidly that it becomes almost a weed. It is
possible that new and interesting varieties of
verbena may be produced by hybridizing the
familiar cultivated ones with some of the many
wild species that have not hitherto been brought
into the combination.

CARNATIONS, OR PINKS

It is rather anomalous that a plant should bear
at the same time two popular names suggestive
of colors so different as pink and carnation and
the anomaly is not lessened by the fact that the
plant itself bears flowers not only of the colors
suggested but also of the purest white.

Despite the paradox, however, the Dianthus
fully justifies its popular names, for specimens
are of the most vivid carnation and others are of
the most beautiful pink. Meantime the white
ones are just as beautiful.

Our studies of other flowers have made it seem
commonplace enough that a plant should show
such diversity. But the carnation as represented
by one of my hybrid varieties, presents a color

ONE OF THE FRAGRANT
ONES

We take particular delight in devel-
oping obscure qualities of flowers, and
have developed fragrant varieties of
many flowers that are ordinarily odor-
less, as the reader is aware. Our success
in this regard with the verbena has been
very striking, a great number of our
fragrant verbenas having been intro-
duced and widely cultivated.

FOUR COMMON FLOWERS 175

anomaly that has not been shown by any other
flower with which we have made acquaintance;
nor, indeed, as far as I am aware, by any other
flower whatever.

The anomalous plant in question is one that
produces flowers that are snow-white in the
morning when they first open, yet which at noon
are bright pink, and which finally, toward eve-
ning, assume a deep crimson color. Each flower
goes through this process during the first day*
so that each morning one may see on the same
plant carnations that are crimson, a few that are
pink, and freshly opened ones of white, giving
the plant a very striking and unique appearance.

It chances that the plant that bears this curious
flower is a most astonishing bloomer, seeming
indeed to have more blossoms than foliage. So
its tricolor display is indeed a striking one.

The plant that bears these anomalous flowers
is the hybrid offspring of a white carnation and
of a deep crimson variety of Dianthus Chinensis.

The plant itself is about eight or ten inches
high and of quite compact growth, in these
regards closely resembling the Chinese parent.
The foliage appears to be about an even combi-
nation of the characters of the parents. The
flowers, as we have seen, combine the traits of the
blossoms of the parent forms in a very anomalous

176 LUTHER BURBANK

way. Our earlier studies would lead us to expect
that the combination of a crimson flower with a
white one might produce crimson or white or
pink. It would not surprise us to find hybrid
plants of the same fraternity some of which bore
the crimson flowers of one parent, others the
white flowers of the other parent, and yet others
pink flowers blending the two colors.

This would be what we expect of such hybrids,
if not in the first generation, then in the succeed-
ing generations. But that the color factors
should be so blended that each in turn should be
dominant in the same individual flower, the tran-
sition from one to the other being marked by the
appearance of an intermediate color, is an
anomaly for which our studies of color heredity
have supplied no analogy.

We have considered it strange enough that
different colors should be arranged in stripes on
a flower as in the case of the four-o'clock or in
the new hybrid tiger flowers. But the carnation
that is white at first and then pink and then crim-
son seems to suggest an even more curious com-
promise among conflicting hereditary factors. It
evidences anew the curious flexibility of color
schemes as applied to the petals of flowers, and
presents the evidence from an altogether new
angle.

FOUR COMMON FLOWERS 177

It may be of interest to recall, in connection
with this curious manifestation of color heredity,
that the carnation has been under cultivation
from an early historical period. The name Dian-
thus, signifying divine power, is said to have been
given it by Theophrastus three hundred years
before Christ.

The flesh color of the original carnation was
broken up into red and white more than three
centuries ago. Since then multitudes of varieties
have been developed. Yet there is a strong tend-
ency in this flower to hold to uniformity of color
as regards any individual flower. That is to say,
carnations in general are likely to be uniformly
scarlet or uniformly pink or uniformly white.
There are variegated forms, to be sure, but these
are exceptional.

This tendency of the flower to hold to one color
or another may at least be recalled with interest
in connection with the curious tendency of the
tricolored hybrid to give recognition to the dif-
ferent colors of its parents in the same flower in
successive periods of time.

I have produced no other variant of corre-
sponding interest in this tribe, although I have
had twenty-five or thirty species of Dianthus
growing for the purpose of crossing, and have
produced other variants of some importance.

178 LUTHER BURBANK

In general, it may be said that the carnation,
having been worked on by plant experimenters
for two thousand years or more, presents a diffi-
cult problem for anyone who strives to develop
new races of unusual value. It is like working
against the traditions of the ages to attempt to
modify the characteristics of such a plant in any

new direction.

THE PETUNIA

The experiment in which I hybridized the
petunia with the tobacco plant, producing the
anomaly that was described facetiously as
"the petunia with the tobacco habit," will be
recalled as having been described in an earlier
chapter.

Doubtless this experiment constituted my
most interesting earlier work with the petunia,
although I have cultivated it largely and have
sometimes tried to cross it with other species,
notably with the allied plant known as Salpi-
glossis. This plant is regarded by botanists as
very close to the petunia, but I have been unable
to effect a cross with it.

It will be recalled, however, that the petunia
and the tobacco were combined with difficulty,
and it is very possible that a more extended series
of experiments might result in hybridizing more
satisfactorily with Salpiglossis.

FOUR COMMON FLOWERS 179

An illustration of what can be accomplished
by an amateur who devotes attention to a single
plant is given by the work of Mrs. Sheppard, of
Ventura, California, and her neighbor, Mrs.
Gould. The former took up the cultivation of
flowers for the healthful outdoor life on the
recommendation of her physician, and the latter
became interested in the work through observa-
tion of the results achieved by her neighbor.

On the advice of Mrs. Sheppard, Mrs. Gould
took up the cultivation of the petunia as a spe-
cialty. The result has been that some of the
finest strains of petunias that are known have
been sent out of California. One of the largest
and best of these strains is the form known as the
Ruffled Giant.

A great amount of time and skill are required
in raising the best petunia seed, and there is still
opportunity for improvement. It is particularly
necessary to use good taste in the selection and
combination of the colors. It is found to be, on
the whole, easier to produce large flowers than
those having a blending of clear, pleasing colors.
There are few common garden plants that give
better opportunity for work of the amateur, par-
ticularly for one who has gained a certain amount
of skill through previous experiment. The inter-
esting character of the petunia-tobacco hybrid

180 LUTHER BURBANK

will be recalled. Doubtless by sufficient persist-
ency other hybrids having equal or even greater
interest could be produced.

GERANIUM AND PELARGONIUM

Several years ago I brought all the geraniums
that I could obtain from European and Ameri-
can florists and collected also some fine specimens
of a variety from British America, G. macula-
turn. The last-named variety is exceedingly
hardy, growing as far north as Alberta, where
the thermometer sometimes falls 60 degrees be-
low zero in winter. I thought it would be of
interest to hybridize such wild species as this with
the cultivated varieties.

The pressure of other work, however, pre-
vented me from carrying out the experiments on
an expansive scale. However, it is certain that
the experiment of crossing the wild, hardy, and
cultivated geraniums is well worth undertaking.
The wild geranium is a much more promising
plant to work upon than was the original violet
from which all our beautiful pansies have been
developed. Indeed, there are few other plants
among our wildlings that offer better opportuni-
ties for development.

My more recent work with the geraniums has
had to do more especially with the form known

FOUR COMMON FLOWERS 181

as the Pelargonium, a plant that is horticul-
turally distinguished from the geraniums, but
which is obviously closely related.

An interesting story is told of the way in which
the Pelargonium was introduced into cultivation.
A physician, experiencing difficulty in obtaining
plants from foreign countries and knowing that
the seeds of many choice varieties often lie dor-
mant in the soil, commissioned a sailor to bring
him a barrel of soil from the Far East — I believe
from Borneo.

When the soil was received and spread out and
cultivated, numerous plants sprang from it,
among others the one that became the parent of
the now greatly prized race of Pelargoniums.

This illustrates a convenient way of securing
new plants from foreign countries, as I have
found it to be on many occasions. And however
the Pelargonium was introduced, it has proved a
plant worthy of the fullest recognition. It has
obtained such popularity that the old-fashioned
types of geraniums have in many places lost their
vogue.

Hybridizing the geraniums is not at all diffi-
cult when one understands the process. It is only
necessary to understand that the stigma of any
given flower does not mature until after the
pollen of the same flower has been scattered.

182 LUTHER BURBANK

Bearing this in mind nothing more is necessary
than to gather pollen and dust it on the stigmas
of plants that have already shed their pollen.
To make absolutely sure about guarding against
the self-fertilization of the flower, it would of
course be necessary to remove the stamens before
ripening, though this would generally be labor
lost.

Some of my experiments in hybridizing have
been conducted with the idea of producing fra-
grant races of geraniums. The chief difficulty
in this work is that most of the fragrant gera-
niums have been grown for such a length of
time from cuttings that they have for the most
part lost the power of producing seeds. This
makes it obviously difficult to secure seeds from
the plants that are precisely the ones it would be
desirable to use for the purpose.

Nevertheless, I have produced a number of
varieties having fragrance, of very attractive new
qualities.

One of these fragrant varieties is developed
from a compact-growing Australian form which
produces an enormous amount of seed. This
fragrant variety, which I have named Coconut
Geranium, has a most pleasing fragrance and is
unusually hardy and handsome in growth and
foliage. Bearing as it does an abundance of

FOUR COMMON FLOWERS 183

pollen, it was used to pollinate the well-known
Rose Geranium so much used in perfumery and
which never bears seed. But by the use of the
pollen of the Coconut Geranium seeds were pro-
duced on the Rose Geranium by which a whole
new series of variously perfumed geraniums are
now growing.

A line of work that I carried out at one time
involved the crossing of the pelargoniums with
variegated leaves with those having ordinary
green leaves. Among these crossbreeds it ap-
peared that the green-colored foliage was always,
as was to be expected, prepotent or dominant
over the white and yellow variations. The horse-
shoe variations were more readily transmitted,
but there was a varying proportion of marked
and plain leaves among these hybrids.

Also worked at one time in selecting the
geraniums for the production of large flowers
of dazzling brilliant scarlet color, and with a
good measure of success.

It will thus appear that there is abundant
opportunity for improving the geraniums even
by working with the species ordinarily under
cultivation. However, the best opportunity for
work in this line will involve hybridizing experi-
ments in which the exceedingly hardy wild spe-
cies are utilized. It should be possible thus to

184 LUTHER BURBANK

produce new races of geraniums that have alto-
gether exceptional qualities.

The wild species include some that are white
in color as well as those that are pink or white
striped with pink or with reddish veins. So there
is opportunity to have a wide choice as to color
variation. The cross might likely result also in
giving the geraniums enhanced vigor so that new
races of perpetual bloomers comparable to the
best of the pelargoniums would be produced.
Few plants among all the popular favorites have
greater merits than the geraniums, and none, per-
haps, offers better opportunities for interesting
experiments that may be made by the amateur.

A plant which has been worked
on by experimenters for two
thousand years presents a difficult
problem for anyone who strives
to develop new races of unusual
value. It is like working against
the traditions of the ages to
attempt to modify the character-
istics of such a plant in a new
direction, yet by adding new species
to the ancient combinations the
problem may be solved.

EVERLASTING FLOWERS AND
SOME COMMON EXOTICS

THE AUSTRALIAN STAR FLOWER AND PLANTS
FROM ORIENT AND TROPICS

NOT long ago I received a tentative order
for ten million clusters of flowers in a
single lot. The order came from a French
milliner, who stated that unless he could get at
least ten million blossoms he could not afford to
handle them at all. I was too busy with other
things to attempt to fill the order, but the fact
that it was given is worthy of record as illus-
trating the more or less unexpected oppor-
tunities that sometimes happen to the plant
experimenter.

The flower that the French milliner wished
to use in such quantity was one of the species of
Composite known commonly as Everlastings.
These flowers have long been popular because
they retain their form and color more or less
clearly when dried, and thus make permanent
bouquets. In recent years, however, the abun-

185

186 LUTHER BURBANK

dance of fresh cut flowers has caused them to be
much less popular than they formerly were.

Now, however, it appears that a process has
been perfected through which, by chemical treat-
ment, certain of the dried everlasting flowers are
given a degree of permanency and toughness of
fiber that makes them suitable for use in trim-
ming hats. Moreover, the grace and beauty of
the new Australian star flower are qualities not
possessed by any other everlasting. Hence the
milliner's desire to secure them in quantity.

It was not convenient then to undertake to
meet so comprehensive a request.

With the more familiar tribes of everlastings
I have been well acquainted since boyhood, but
it is only in recent years that I have given them
serious attention. They are of many colors-
red, pink, crimson, yellow, orange, and white
Some of them that are annuals in the eastern
States became perennials in California, even
growing and blooming throughout the winter.
The work commenced with a so-called double
Rhodanthe, which varies from white to red in
color.

The seeds that furnished the original stock
were said to represent a double flower, but only
a small proportion of the plants that grew from
them bore flowers that were really double. That

EVERLASTING FLOWERS 187

is to say, there was almost invariably a center
devoid of petals. My work consisted in select-
ing to fill up the center, and make a flower that
is altogether double.

The flowers vary much in size, and the colors
are so variant as to supply good material for
selection. But a difficulty arises in that the plants
produce very little seed. The selective experi-
ments have now extended over a number of
years, and I have been able to increase the size
of the flower, to improve it considerably in the
matter of doubleness, and to isolate to a certain
extent the different colors, although the plant as
yet is not fixed in any of these regards suf-
ficiently to justify its introduction. The im-
provement already shown, however, justifies the
expectation that varieties of these everlastings
could be developed that would show very
marked improvement over all old types.

A Gomphrena has been under cultivation for
many years. It is a low-growing plant, having
globular, crimson flowers. The introduction of
new native species from South America may be
expected to have the usual stimulative effect, in-
creasing the vitality of the plant and giving it
greater adaptability, and even now a new orange
color is appearing among the old crimson and
white varieties.

AUSTRALIAN STAR FLOWER

This is the everlasting flower that a
wholesale Paris milliner found so
attractive that he asked me to raise ten
million sprays of them for him.
Having too many other matters requir-
ing my attention, I could not undertake
the contract, but the fact that the offer
was made suggests the unexpected
commercial possibilities that sometimes
arise in connection with an experiment
in plant development. Seeds of this
plant were sent to me by one of my
West Australian collectors. It was
small and white. By selection it was
made large and pink. It is an everlast-
ing flower, now of rarest beauty.

EVERLASTING FLOWERS 189

The Australian star flower first mentioned in
this chapter most resembles Rhodanthe, but is as
distinct as a rose is from a carnation. The
botanists have not been able to decide as to its
specific name. With the possible exception of
the Rhodanthe, this is without doubt the most
beautiful of all the flowers called everlastings
so far discovered or produced. The beautiful,
star-shaped, white clusters of flowers, produced
in the greatest abundance, are surpassingly
beautiful.

All the everlastings are natives of desert
countries and are mostly from the Cape of
Good Hope and Australia. The "Australia!
Star Flower," seed of which one of my West
Australian collectors, who first discovered it,
sent me many years ago, came to me as a grace-
ful white flower. After a few seasons' growth
here, however, it began to show a tinge of pink
here and there among the numerous plants then
grown. No two botanists have agreed as to its
scientific status.

This work with the Australian star flower has
consisted of increasing the size of the blossom,
making it semidouble, giving a clear, rosy pink
color, and to some extent rendering it resistant
to disease. This has been accomplished by the
usual method of selection, the better speci-

190 LUTHER BURBANK

mens being selected, and finally the best one
being saved for seed. Very great improvement
was made considering that this was a wild plant
never before under cultivation. The selected
varieties do not as yet breed true from the seed,
but all the new ones are wonderfully improved
in form, size, grace, and with the greatly in-
creased blooming qualities a real transformation
has been effected in a flower which even in the
wild state was beautiful.

THE TRIBE OF CRINUMS

In an earlier chapter mention was made of
hybridizing experiments in which certain mem-
bers of the amaryllis tribe were crossed with
certain of the crinums. It is desirable to make
additional reference to some experiments in
which the crinums themselves were variously de-
veloped and crossed with rather striking results.
The hybrid crinums are a splendid group of
bulbous flowering plants in which the bulbs are
in many cases of enormous size, and the leaves
are broad and long, making the plants very
conspicuous.

Some of the leaves, indeed, are of gigantic
size, and the stalk that bears the flowers may
grow to a height of from four to six feet. The
flowers themselves are of variant color, from

EVERLASTING FLOWERS 191

white to rosy pink, and sometimes almost purple.
They are borne in profusion, and their attrac-
tiveness is often enhanced by their fragrance.

The crinums originally came from the tropics,
being indigenous to various parts of South
America and the southern United States. Sev-
eral species are hardy in California. In some
cases these will withstand freezing, so that even
if the leaves are destroyed by the frost the new
growth will put forth in the spring, and they
will bloom as abundantly as if they had been
carefully housed over winter.

Like most other bulbous plants they thrive
best in sandy soil.

Some of the crinums are evergreen under
ordinary temperature; others are deciduous like
most of their relatives of the amaryllis tribe.

The chief objection to the crinums for house
culture is the enormous size of the bulb, and the
tendency to produce a superabundance of
foliage out of proportion to the number of
flowers ; although this criticism does not apply to
all of them.

Fifteen years ago I had probably twenty
species of crinums, most of them having been
brought from the tropics. My object was to
combine the good qualities of the tropical and
subtropical species with those of the hardy ones.

A PLANT OF AUSTRALIAN
STAR FLOWER

It will be seen that this is an ex-
traordinarily prolific plant growing
blossoms by the hundred. This is an
improved strain selected from among
thousands of others of the same species.
A glance at this plant suggests that
the project of supplying ten million
star flowers for the use of a milliner is
not as hopeless as it seems at first
thought.

EVERLASTING FLOWERS 193

No difficulty was experienced in crossing the
various species, and crossing was carried out in
the usual way, different pairs of species being
mated and then the hybrid forms in subse-
quent seasons remated, noting of course at all
stages which combinations seemed to produce
the best results. Complicated hybrids were
finally produced that combined the strains
of many species and the results were highly
interesting.

In the course of a few years I had a strain of
crossbred crinums presenting most of the desir-
able qualities of the different species in combina-
tion. The new plants, in spite of the strains of
tropical species, are very hardy, withstanding the
coldest weather of this region without injury.
They have very large flowers, varying in color
from white and pink to rosy crimson. The petals
are broad, and the flowers in a large number of
cases are fragrant.

The bulbs of some of these hybrids have taken
on extraordinary growth. At four years of age
some of them are from six to eight inches in
diameter, and twelve to eighteen inches in length,
weighing probably from ten to fifteen pounds,
or even more. More recently specimens have
appeared of even larger dimensions. Some of
these enormous bulbs seldom make offsets, others

Vol. 7— Bur. G

194 LUTHER BURBANK

produce from one to twelve or more offsets in a
season, so that they can be multiplied quite
rapidly.

The seedlings from these hybrids produce
plants that as a rule show a combination of two
or more of the species fairly well balanced. The
seed parent of the larger number of my hybrids
is the Crinum americanum, but in some cases
the Crinum amdbile, or the Crinum asiaticum
was the seed parent. It is observed that a
certain small percentage of the hybrids show
a strong tendency to run toward the seed parent
of whatever species. This can generally be de-
tected by the foliage when the plants are quite
small. I have not observed that any of the
hybrids depart so strongly the other way to-
ward the tropical species when used as the
pollen parent.

In the second and third generations the varia-
tions are better balanced through selection, and
become more fixed in desired qualities than at
first, when grown from seed.

On the whole, it is perhaps a little easier to
get valuable new varieties of crinums by cross-
ing and selection than with most other bulbous
plants, especially the lilies — although there are
notable exceptions among the California lilies,
some of which cross very readily.

EVERLASTING FLOWERS 195

Crinum seeds are very curious, in that they
vary enormously in size, almost always, even
in the same capsule. The pale-greenish bulb-
like seeds with irregular corrugations may vary
from the size of a pea to that of an English wal-
nut. When placed in a graded sequence they
present a curious contrast. Yet the plants
grown from the smallest seeds are likely to be
quite as large and of the same appearance and
quality as those grown from the mammoth ones.
The seeds of the crinum thus funish a unique link
between seeds, buds, and bulbs, suggesting the
properties of all these combined.

Another peculiarity of the seeds is that they
contain so much nutriment and moisture that
they may sprout and grow, making plants of
considerable size, without access to any mois-
ture except that contained within the seed itself.
I have known them to sprout when laid on a
shelf, or in envelopes, away from the light and
entirely dry ; also when sent to me by mail from
Australia they sometimes started as seeds and
arrived here in envelopes as small growing
plants.

The crinums have been under cultivation for
a long time, but there are many species that have
not been experimented with, and the opportu-
nity to introduce new forms from the tropics,

A HYBRID CRINUM

These enormous, fragrant flowers
produced by a seven-pound bulb are
one of the results of crossing several
tropical species with our native Florida
species. The flowers have the size,
beauty, and fragrance of the tropical
species with the hardiness of the natives,

EVERLASTING FLOWERS 197

together with the striking character of the plants
themselves, gives them peculiar attractiveness
for the experimenter. The possibility of mak-
ing still wider combinations, as in the case of
the cross with the amaryllis, and further selec-
tions, should of course not be lost sight of.

THE SPECTACULAR IXIA

Another tribe of interesting bulbous plants
are represented by the genus Ixia. These, like
so many other of the bulbous plants, are natives
of the Cape of Good Hope, being closely related
to the gladiolus, and resembling many other
Cape bulbs, including the Watsonias. There
are various species, but they have been so inter-
crossed that the experimenter need pay very
little attention to specific names and distinctions.
The bulbs are inexpensive, and are commonly
grown several in a pot in the house in winter in
the eastern States, but in California they grow
outdoors, and there is no occasion to transplant
them, except for propagation.

A single bulb will spread by putting out new
bulbs, which in turn make offshoots in the samet
way, until a large and beautiful clump of plants
is often developed. The Ixia, indeed, can
never be seen at its best except when grown in
this way.

198 LUTHER BURBANK

The flower stems are thrown up in great
abundance on long, slender, stiff, wiry stalks,
and the graceful upright or drooping flowers are
of every color except blue — crimson, yellow, and
white being the characteristic colors.

The variety of Ixia known as the Wonder has
double flowers that are exceptionally handsome.
The group of ixias make so striking an appear-
ance that they almost compete with the giant
amaryllis on my grounds in May for first place
in their appeal to the average visitor.

The two plants are utterly different, but each
in its way is most individual and striking; the
Ixia being characterized by gracefulness and
fragile beauty, the other by its massiveness. The
flowers of the Ixia are only about two inches in
diameter ; those of the others eight to ten inches,
yet the massed effect of the Ixia is so striking
that it competes in interest with the larger
flower.

I have worked in a more or less desultory way
on the Ixia for the past fifteen years. The vari-
eties under cultivation are so varied as to their
ancestry, and hence have so strong an inherent
tendency to variation that it is not necessary to
cross them. Even the double variety is prob-
ably at least half a century old. My work of
improvement was for the increase in size and

EVERLASTING FLOWERS 199

brilliancy of color of the flower; and, of course,
here as always, attention is paid to gracefulness
and abundance of blooming, and vigor and gen-
eral health of the plant.

The improvements in all these regards have
been quite striking, athough I have not consid-
ered any individual variety worthy of introduc-
tion under a special new name.

Notwithstanding the amount of work that has
been done with them, the ixias will well repay
the attention of the amateur who cares to work
with them, especially in mild climates.

ORIENTAL POPPIES

In an earlier chapter an account was given of
the blue poppy. An account has also been
given of the development of the new colors in
the flower usually called the California poppy,
more properly known by the somewhat forbid-
ding name of Eschscholtzia. Very little has been
said, however, about the experiments with the
well-known annual and perennial poppies, which
have produced results of considerable interest.

The poppies in question are the opium poppy
(Pap aver somniferum) and oriental (Papaver
orient alis).

The opium poppy is, as everyone knows, a
commercial product of vast importance in the

200 LUTHER BURBANK

Far East. It has been under cultivation iti
Europe to a greater or less extent for several
centuries, and flowers have been greatly im-
proved by the European growers, the varieties
developed being of almost every shade of color,
some flowers being single and others double.

From time to time charming varieties have
been sent out in recent years, including an inter-
esting single one known as the Miss Sherwood,
a variety having blossoms with a white center
and crimson edge, the petals being beautifully
fringed.

There are other varieties of this poppy known
as Pseonia and Carnation Flower poppies that
are double and are exceedingly handsome in
color.

The oriental poppy has very large flowers,
always single and crimson with shadings of
scarlet in color in a state of nature, and in
almost all cultivated varieties — the color being
unusually well fixed. The plant is a perennial
with rough, hairy leaves, and stems. The flowers
are borne on single stems, instead of branching
from a main stalk as in the opium and most
ether poppies. The oriental species has prob-
ably not been under cultivation as long as the
other, but some varieties have been developed,
some of them semidouble, and the colors have

EVERLASTING FLOWERS 201

been modified so that there are dull white, scar-
let, and yellowish varieties, as well as the more
usual crimson.

These varieties, however, seem not to be well
fixed — they do not come true from the seed—
and the best varieties so far produced quite'
generally appear to be lacking in vitality —
possibly from overzealousness in selection by
division, the only way of maintaining and multi-
plying any special variety.

My own experiments have more largely had
to do with hybridizing the orientals and the
opium poppies.

Rather curiously I found that the pollen of
the opium poppy was ineffective when used on
the oriental, yet when a reciprocal cross was
effected, the pollen of the oriental being used
on the opium poppy, seed was produced, and
a great number of hybrids were soon under
observation.

In the hybrid colony, comprising more
than thirty thousand of these plants, there was
as little variation in color as is usual with
the oriental poppy. None of the hybrids
Were double, but they had several interesting
qualities.

One striking peculiarity was that the hybrid
poppies produced in some cases enormous seed

A HYBRID EVERBLOOMING
POPPY

Here is a specimen of a cross between
the opium poppy and the oriental
poppy. The anomalous results of this
combination, of great interest to stu-
dents of heredity, are related in the
text. (About one-third natural size.)

EVERLASTING FLOWERS 203

capsules, five or six times as large as the ordi-
nary seed capsule of either parent species. Yet
in other plants the seed capsule would be smaller
than that of either parent. In still other cases
twin capsules are produced uniformly, and with
a certain number there was produced a mere
rudiment of a capsule. But the most striking
of all were the numerous plants that produced
not even an intimation of a capsule, the flower-
ing stem ending abruptly like the end of a lead
pencil.

All in all the hybrids showing this extraordi-
nary variation in the seed-bearing capsule —
ranging from enormous enlargement of the cap-
sule to its entire obliteration — make a very
wonderful and interesting study in heredity.

It is of further interest to note that, although
these hybrids were raised from seed of an annual
poppy (hybridized, however, by a perennial),
yet without exception every member of the
entire company of thirty thousand is a
perennial.

The flowers themselves vary greatly in size,
some of them being seven or even eight inches
in diameter, while the smallest are perhaps only
four or five inches. Some are beautifully
crimped, others have flat petals, there being the
most striking variations in form.

204 LUTHER BURBANK

Even the specimens that have unusually
large, plump seed capsules may produce no
thoroughly well-developed seeds. In a gallon
of the seed pods, from which one might expect
perhaps two quarts of plump seed, I usually
obtain perhaps from one hundred to three
hundred or four hundred grains mostly of
shrunken ill-shaped seeds. Yet these shriveled
seeds when sown produce good plants. Even
seeds that seem so abortive that it is incredible
they should germinate, may produce perfectly
healthy seedlings.

STRIKING VARIATIONS IN THE SECOND
GENERATION

The second-generation poppies produced from
these seeds were among the most remarkable
companies of plants that I have ever seen.
All who saw them agreed that they were the
most variable lot of plants of a single fraternity
that they had ever observed.

The diversity was so great that it might be
said that there were no two plants among the
thousands that were even approximately identi-
cal. No two could be found in which differences
could not readily be observed in the foliage.

Some of the peculiar forms of leaf were these:
{I) Long, smooth strap-shaped leaves some-

EVERLASTING FLOWERS 205

times not more than half an inch wide and a foot
or more in length ; sometimes smooth and some-
times villous; dark green or light green. (2)
Short and stubby leaves, trifoliolate, either vil-
lous or glaucous. (3) Leaves resembling those of
the oriental poppy. (4) Leaves like those of the
opium poppy. (5) Nondescript leaves, vari-
ously suggestive of the leaves of primrose, cherry,
dock, wormwood, dandelion, and scores of others.

It is interesting to note that the blossoms of
the second generation varied somewhat less than
the leaves, although much more diversified than
the blossoms of the first generation. Some were
double and of various shades of the opium
poppy. The range of color included almost
black, deep crimson, purple, light crimson, sal-
mon shades, pink, white, and various combina-
tions of these colors. Yet on the whole color
variation was not greater than that ordinarily
found in the opium poppy.

The second-generation plants seemed not to
have the vitality shown by those of the first
generation. There were exceptions to this, how-
ever, individual plants manifesting a vitality in
excess of the average of the first-generation
plants.

Most of the second-generation hybrids that
produced double blossoms proved to be annuals

STILL ANOTHER HYBRID
POPPY

The selected poppies sometimes
attain very extraordinary size. This
blossom measured almost a foot across.
Few flowers afford greater interest for
the amateur gardener than these spec-
tacular hybrids, which are now grown
in all countries where flowers are appre-
ciated. (A little more than one-fourth
natural size.)

EVERLASTING FLOWERS 207

or biennials, partaking thus of the characteristic
of the parent from which they derived their
doubleness of blossoms. This is perhaps what
might have been expected. It is notable, how-
ever, that the quality of annual or biennial
growth should have reappeared in these hybrids
of the second generation, the first-generation
hybrids having been, as already noted, all
perennials.

But, on the other hand, some of the second-
generation hybrids were perennials, and have
continued to live and thrive, bearing large quan-
tities of blossoms each season.

Thus the perennial and annual habit ap-
peared, in the case of these two poppies, to be a
pair of unit characters of which the perennial
habit was dominant and the annual habit reces-
sive; there being a characteristic segregation in
the second generation.

As to habit of blooming, there was another in-
teresting anomaly. The opium poppy, a strict
annual, blossoms only for a short period — for
a few weeks at most. The oriental poppy,
although a perennial, also blooms but a short
time. The first generation hybrid poppies
bloom persistently. There is not a day in the
year when some of these hybrids are not in
bloom, spring, summer, autumn, or winter —

208 LUTHER BURBANK

blossoms can always be gathered in quantity
from them.

The hardiness of the hybrids has not been
fully tested. I should not be surprised to find
that they are largely as hardy as the oriental
poppy, but the California climate does not sub-
ject them to a severe test.

THE THIRD-GENERATION HYBRIDS

In the third generation a large number of the
hybrids reverted toward one or the other of the
original parents. But even those that resembled
one of the parents or the other strikingly, re-
tained also traits of the other parent.

All these unique hybrids present such inter-
esting characteristics that it will be worth while
to record that the opium poppy that was used as
the original parent was of the Miss Sherwood
variety, but that later other opium poppies of
every shade and color that could be obtained
were also used. Perhaps in all twenty-five or
thirty selected varieties of opium poppies of
various colors and different forms were used as
seed parents. The progeny, however, as far as
I could observe, varied little more than these
from the Miss Sherwood crossing, and was not
greatly influenced by the different type of
opium poppy used. However, the variation was

EVERLASTING FLOWERS 209

so great in any event that it would be difficult
to judge as to this.

In general, the minor colorings and doublings
of color seemed to have less effect in the heredity
than the more fixed original foliage and flowers
of the wild plants. The hybrids show double-
ness and selected colors very slightly, except in
a few cases in the second generation, when there
was a tendency to return toward the original
forms.

The size of the pollen and length of the pol-
len tubes may conceivably have something to do
with the failure to effect hybridization when the
oriental poppy was used as the pistillate parent,
but this is only conjectural. Also, the opium
poppy has been so long under cultivation, and
has become so adaptable, that it probably is
more pliable and more ready to receive strange
pollen.

The relative sterility of the first-generation
hybrids may be judged from the fact that al-
most five thousand seedlings produced ten or
twelve gallons of capsules, but that there was
only about a quarter of a teaspoonful of seed to
each gallon of capsules.

As these seeds were shrunken and much
smaller than ordinary poppy seeds, however,
the actual number of seeds was proportionately

210 LUTHER BURBANK

large. Still the total number was only a frac-
tion of what would have been the output of
poppy plants of normal fertility.

All in all, this experiment of hybridizing the
oriental and the opium poppies, with the pro-
duction of relatively infertile hybrids showing
Mendelian heredity as to some traits and a
blending of characters as to others, and a fur-
ther segregation and recombination of charac-
ters in the second generation, constitutes an
unusually interesting experiment in heredity. I
have made many other experiments in breeding
the various poppies, but none perhaps that ex-
celled this one in interest and importance. The
best of these new hybrids have now been grown
both by division and from seed for sixteen
years and are unusually vigorous and have
flowers of wonderful sizes and various colors,
mostly crimson.

THE HYBRID LARKSPUR AND
OTHER TRANSFORMATIONS

INTRODUCING A MISCELLANEOUS
COMPANY

A/L the members of my hybrid larkspur
colony are descended from a single
individual.

That individual, in turn, was the select and
peerless member of a company of some five thou-
sand or more, all of them of equally aristocratic
lineage, and each one of them worthy to show
itself in any larkspur company. But the usual
rigorous method of selection was also applied.
The one individual that came nearest meeting
all expectations was preserved. The rest were
sent, with sundry thousands of other plants of
diverse species, to the bonfire.

The selected individual, of course, became the
progenitor of a new colony of larkspur. Some
of these improved upon their ancestors, and
many interesting varieties were isolated through
selection.

211

212 LUTHER BURBANK

The original parent form from which the one
best larkspur was selected as the progenitor of
new races was of the species known as Delphin-
ium hybridum, or hybrid larkspur. As the
name implies, this plant is itself of hybrid ori-
gin, but it has been cultivated a long time in
Europe, being unusually popular in England,
and ranks as a true species, or at least as a good
• horticultural variety.

There are numerous other species of larkspur,
sixty or more altogether. Some are annuals
and some perennials. Our native California
species are among the most beautiful. One
of these, named nudicaule, is a perennial grow-
ing along the sides of streams and in shady
canons, although on occasion even mounting
to the tops of high rocks. It bears flowers
of a bright orange red, sometimes varying to
yellowish, that are very showy. The plant
is easily cultivated either from seed or by
division, as indeed are nearly all perennial
larkspurs.

Another species is D. cardinale, a large,
strong plant growing in the southern part of
, California, the flowers of which are bright red
and yellow, though quite different in general
appearance from those of the one just named.
Yet another larkspur that is of interest is D.

THE LARKSPUR 213

decorum, an extremely variable form growing
usually on overflowed land.

The flowers of this wild species vary almost
as much as do our hybridized and cultivated ones^.

Growing side by side in a bed of wild lark-
spurs of this species may be found plants bear-
ing flowers varying from deep blue, pale blue,
dark rosy pink, pale pink and yellow, to almost
pure white. The flowers of these are quite
large and showy, but the colors, although so vari-
ant, are seldom brilliant. This is one of the spe-
cies the seed of which requires time and patience
to induce germination.

The larkspur known as D. californica is a
giant species, often found in canons toward the
coast. It towers to a great height, sometimes
reaching seven or eight feet, but the flower is
insignificant when compared with most other
species, both in size and color. They are pur-
plish blue or dingy white in color.

The combination of this species by crossing
with some of our cultivated ones has not re-
resulted in producing anything of value.

There are several other native species of this
State and some of them are mentioned in detail,
chiefly to show the variation among them, sug-
gesting the possibility of interesting develop-
ments when the various forms are combined. I

IMPROVED HYBRID
LARKSPUR

Few of our flower productions are
more popular than this improved
hybrid larkspur. This picture suggests
that the flowers amply justify their
popularity. They are the product of
hybridization, as their name suggests,
combined with careful selective breeding.

THE LARKSPUR 215

have utilized them all more or less in experi-
ments, and in addition have grown nearly all the
larkspurs that are ever offered by seedsmen or
florists. As already stated, my chief experi-
ments began with the use of the hybrid larkspur
as a seed parent, but of course the hybridizing
experiments soon blended the strains of many of
the other species, until the larkspur colony, like
so many other flower groups, is of such conglom-
erate ancestry that the precise proportions of
the different strains in any given race are not
traceable.

Needless to say, selection has been carried for-
ward along with the hybridizing experiments,
these two methods always being complementary.
Particular attention has been given to size of
flower, vigor of plants, and resistance to insects
and disease, as well as that of multiplication by
division, at the same time that compactness of
growth and brilliancy of color of flower have
been carefully regarded.

One of the worst faults of the hybrid larkspur
is that it tends to grow too tall, with a stalk that
does not well support it, so that it requires to be
staked. But my hybrid larkspurs have been so
selected that they are compact in growth, and
usually able to support themselves even in a
moderate gale.

216 LUTHER BURBANK

All the characteristic larkspur colors are rep-
resented among the new varieties, and in addi-
tion there are combinations of color that have
never before been seen, I think, in the larkspur.
Some of the individual flowers are considerably
over two inches in diameter, and some of the
largest are very double.

The color yellow is not common with the
larkspur, its characteristic colors being red, blue,
and white. There is one yellow species, a native
of southern Asia. From this I have developed
varieties with pale yellow flowers. The best o£
the selected varieties, as descended from the
original one chosen among the first five thousand,
is known as Burbank's hybrid, and has been
given full recognition by seedsmen, florists, and
gardeners. There is still opportunity for fur-
ther development among the larkspurs, how-
ever, and improvements may be expected which,
if not spectacular, have at least a fair measure
of interest.

No plant is ever so fully developed that it does
not hold possibilities of improvement.

A rare lemon yellow larkspur has been lately
discovered near Bodega Bay, California. How
this should have been so long overlooked is a
mystery, even though it occupied only a small
space in its native location.

THE LARKSPUR 217

AN ALMOST ENDLESS VARIETY

The great family of composites presents an
almost endless variety of flowers, of which we
have seen some striking examples, most notable
among these being perhaps the daisies and the
dahlias. But now and again a new form makes
bid for popularity, and there is still an indefinite
amount of material among our wild plants
from which garden plants might be developed.

Yet the old favorites are not necessarily sup-
planted. Indeed, there are some of them that
have perennial interest, holding their charm de-
spite all competition.

One of these is the marigold, of which there
are various species that find favor not only be-
cause of the ease with which they may be culti-
vated, but also because of the length of time
during which they bloom, the abundance of
blossoms, and their good keeping qualities after
being picked.

The marigolds most commonly cultivated fall
into two distinct groups, one spoken of as the
African marigold and the other as the French
marigold. In addition to these there are native
species, among others a very interesting one
sent me from Arizona, by Professor Lemon,
whose name it bears. This native form is a

MORE HYBRID LARKSPURS

The hybrid larkspurs are very
pleasing in form, and the compact
clusters in which they grow are
peculiarly attractive. But their other
good qualities are enhanced by the wide
range of color variation, of which a
faint suggestion is given in this picture.
The range of colors is striking, and all
of the colors are pleasing. (One-third
life size.)

THE LARKSPUR 219

shrub about four feet in height, and in the fall
it bears a mass of beautiful single golden flowers
about the size of the French marigold.

This is one of the handsomest shrubs of this
sort, and although I think it has not yet been
introduced, it deserves a place in every garden,
if — as has not yet been proved — it will stand the
colder climate.

My experiments with the marigold were
mostly conducted many years ago, chiefly along
the lines cf crossing the French and African
races and this new Arizona perennial species.
In addition to their practical horticultural re-
sults, the experiments gave some interesting
illustrations of hereditary influence.

In particular it was observed that when the
double marigolds were crossed with the peren-
nial single species, above mentioned, all the
hybrids were single, as would naturally be
expected, for most wild plants have their tend-
encies in all directions more fixed by endless
uniform environment instead of the ever-
changing environment of cultivated plants.

It is interesting to recall that precisely the
opposite result was produced in hybridizing the
poppies. In that case the union of an annual
and a perennial poppy produced hybrids, all of
which were perennials and for the same reason;

220 LUTHER BURBANK

the oriental poppy had not been under cultiva-
tion as long as the other.

One of the best marigolds with which I have
worked is called the Lemon Ball. It is of the
African type, and produces great lemon-yellow
blossoms in abundance, blooming throughout
the entire season. The best specimens are com-
pletely double, but if the seed is saved from the
most double blossoms, almost half of the seed-
lings will bear single flowers, or those not per-
fectly double.

It is obvious that the factors for singleness
and doubleness tend to be segregated and that
the strains of the double marigold have not all
been isolated in such a way as to produce double
flowers uniformly. This should also be expected
for the reasons above mentioned.

This, of course, could be done by careful
selection.

More recent experiments have to do with the
general improvement of the marigolds, and I am
also experimenting with a new species from
Chile with reference to its possible value as a
potherb for its fragrance and flavor. It is a
tall, slender shrub with innumerable pale, straw-
yellow flowers — almost white. Like one or two
other species of the genus it has a most delight-
ful fragrance and flavor. As regards quality

THE LARKSPUR 221

and intensity of flavor, it surpasses all others,
but apparently has no other merit. Whether it
will prove a sufficient value for introduction in
the vegetable garden is still problematical.

A less familiar member of the Composite
family which, however, has gained rapidly in
popularity in recent years is the plant known as
cosmos. This is a Mexican species that is now
making its way into the flower gardens every-
where. It is related to the plant known as the
black dahlia (Bidens atrosanguinea) botanically,
yet the relationship is not so close that the two
can be combined, at least I have not been able to
cross them.

A peculiarity of the cosmos, due doubtless to
its recent importation from a subtropical region,
is its habit of blooming only very late in the
autumn. This is sometimes regarded as a merit,
but as the plant is very tender, there is danger
that its blossoms will be destroyed by early
frosts. So the most important work done with
the plant in recent years is the production of
early-blooming varieties. The effort has been
so far successful that there are now varieties
that bloom in midsummer. The fact that this
modification has been brought about within a
comparatively few plant generations illustrates
the pliability of the cosmos.

EDUCATING THE CALENDULA

Even the flower at the left has
multiplied its petals many times; and
the middle flower and the one at the
right show successive stages of the
filling up of the center with ray
flowers.

THE LARKSPUR 223

It is, in fact, one of the most variable and pli-
able of plants — comparable in this regard to the
dahlia.

Such being the case, it is not surprising that
it has been found possible to develop new shades
of color, as well as much larger and finer flowers
than those of the original species. Forms with
wider petals, and others with twisted petals and
other variations of the corolla, have also been
developed. Even a double cosmos has been pro-
duced. But the species is comparatively new in
the flower garden, and offers therefore, rather
exceptional opportunities for the experimenter.

The amateur who is looking for a plant that
has not been carried to anything like its limits
of variation may advantageously pay attention
to this graceful, attractive, and rapid-growing
composite.

The extreme heat and long days of the sum-
mer even in high altitudes in the United States
makes possible the cultivation of a large number
of flowers that were originally of tropical habi-
tat. Among these no others are more familiar
or have retained their popularity more steadily
than the tribe of plants of the genus Ipomoea,
which numbers among its representatives plants
of such diversity as the morning-glory, the moon-
flower, the cypress vine, and the sweet potato.

224 LUTHER BURBANK

THE BRILLIANT MORNING-GLORY

It is not difficult to account for the popularity
of the morning-glory. A vine that grows with
the greatest rapidity and that bears flowers of
striking and brilliant color in the greatest pro-
fusion, day after day, for weeks together,
covering our arbors or pergolas in a few
weeks' time, has merits that are not duplicated
exactly by those of any other flower under
cultivation.

The morning-glory has not been very exten-
sively worked with, but it has shown a very
marked tendency to variation, and, as usual
with plants under cultivation, has broken up
into numerous varieties, showing in particular a
wide range of color variation. One of the most
remarkable of the varieties is the Japanese
morning-glory, some forms of which have
double flowers of very curious structure. The
single varieties of the Japanese type are of rela-
tively immense size and of the most wonderful
color. But they do not produce so abundantly
as the common morning-glory, do not climb as
well, and seem to lack the vigor of the more
ordinary form.

My own experiments with the tribe have had
to do with the crossing of several related forms.

THE LARKSPUR 225

The plants can quite readily be crossed, and
the seed germinates readily. These experiments
have not been carried far enough to produce any
very striking results. It is obvious, however,
that the morning-glory offers good opportuni-
ties for improvement, and the ease with which it
can be cultivated makes it a plant that should
appeal particularly to the amateur. The wide
range of color variation, together with the fact
that the colors are fairly fixed in certain varie-
ties, make possible crossbreeding experiments
that can readily be checked.

Possibly also it may be feasible to cross the
common annual morning-glories with the moon-
flowers or with various other members of the
genus. The moonflower itself, which produces
large white flowers in great abundance, has
been greatly improved by selection.

There is also an interesting Brazilian morning-
glory (Ipomcea setosa) with a vine that grows
with great rapidity and bears a rosy purplish
flower, and a perennial tree morning-glory, a
native of Texas, which bears very large light
pink flowers in abundance. Indeed the number
of species from which selection can be made is
rather large, and variation among them suffi-
cient to give the experiment in hybridizing ex-
ceptional interest.

Vol. 7— Bur. H

A CALENDULA OF REAL
DISTINCTION

This specimen is approaching the
limits of variation in the direction
toward which it has been specialized.
Note the fringed character of the ray
flowers, and their exceedingly sym-
metrical distribution, like shingles on
a roof.

THE LARKSPUR 227

Another vinelike plant from South America
that has made its way into every garden is the
Tropceolum, commonly known as the nasturtium.

There are at least forty species of this tribe,
mostly climbing natives of Peru and Chile. One
of these, T. tuberosum, produces spicy roots that
are highly prized as food and the seeds of the
annual varieties are sometimes used in pickles
and salads. The seeds of the form familiar in
our gardens are often pickled and it is probable
that table products of greater value could be
developed from these plants if attention were
paid to breeding them with that idea in mind.

Some of the nasturtiums are exceedingly
tender to the slightest chill, but they may grow
in the hottest and driest soil.

My work with the nasturtiums has been
mostly with specimens sent from South America
by my collectors, representing eight or nine
species. Some of these have bulbs that sometimes
remain dormant in the ground for two or three
years, and then sprout and grow very fine vines.

The common nasturtium of our gardens, T.
majus, is one of the most readily grown of our
annuals and has been so long cultivated and so
thoroughly crossed that the colors of the flowers
are exceedingly variable. In recent years very
good work has been done, particularly by Cali-

228 LUTHER BURBANK

fornia cultivators, in the improvement of the
climbing nasturtiums, and in particular by cross-
ing the ordinary form with the one known as
T. minus.

Both the parent forms and the hybrids have
run into numberless colors, clear lemon-yellow,
flesh color, deep crimson, purple, scarlet, deep
yellow and white, the colors being variously
blended, and the foliage of the plant being some-
times most beautifully variegated. Even the
form of the leaf has been changed, so that there
now are ivy-leaved strains of nasturtiums.

The nasturtiums offer great interest for the
amateur experimenter, as they are very readily
hybridized, and as their range of variation, even
without crossing, is so great as to afford the
widest opportunity for selection. Indeed, cross-
ing has been so fully carried out that for ordinary
purposes selection will answer far better than
further crossing. It is exceedingly difficult even
to keep the colors of the various nasturtiums
separate. The seed of a pure white variety quite
commonly may produce various colors. And it
is more difficult to fix these colors than is the case
with most other flowers. But of course such
difficulties only enhance the interest of a
really earnest experimenter, and develop his
enthusiasm.

THE LARKSPUR 229

STAMPING PERSONALITY ON A FLOWER

An illustration of the way in which the per-
sonality of the experimenter finds expression in
the plants that he cultivates was furnished me
a number of years ago by Mr. Peter Barr, a
well-known horticulturist who specialized with
the narcissus and daffodils.

On visiting my place a number of years ago,
he related an experience that may be taken as
typical, yet which the amateur who has not
experimented extensively might regard as rather
extraordinary. The story has been told in an
earlier volume, but it may be briefly repeated
here.

Mr. Barr stated that among the thousands of
seedlings, the whole stock of which he purchased
of two specialists in England, he could always
tell at once, on seeing the blooms, which of the
two specialists had developed any individual
plant, even though the varieties had been mixed.

One of the breeders produced very large,
coarse flowers, gigantic and broad, and lacking
in delicacy of contour. The other produced
seedlings of graceful and exquisite form.

And these contrasting characteristics of the
different daffodils, Mr. Barr assured me, typified
the personalities of the two breeders by whom

230 LUTHER BURBANK

they were developed. One of these was a per-
son of little refinement, notwithstanding his love
of flowers; the other was a cultivated banker of
artistic temperament. The tastes and propensi-
ties of the two men made themselves felt in all
the flowers they produced; which of course was
inevitable, when we reflect that the plants were
produced by selection, and that each man
naturally selected the type that appealed to him.

The incident is here mentioned not as some-
thing exceptional, but as typical. Almost as a
matter of course, one could draw correct infer-
ences as to the personality of a plant developer
from observation of the varieties that he has
developed — provided always, of course, that his
selections have been made along the line of his
own tastes, and not to meet some specific com-
mercial demand.

There should be for the amateur an added
stimulus in the reflection that he is thus putting
the stamp of his own personality upon the plants
with which he experiments. The flowers of your
own garden may thus come to have an individu-
ality that represents you as fully as you are
represented by your costume or by the books you
gather on your shelves. And surely the possi-
bility of developing a flower garden that has
such individuality, differing from any and every

THE LARKSPUR 231

other flower garden in the world, should give
the pursuit of the amateur florist unique interest.

SOME INTERESTING NATIVES

More than once the possibility has been sug-
gested of introducing to the garden species of
plants that grow in the wilds and that offer inter-
esting possibilities of development. Two or three
other tribes of these interesting wildlings may be
here referred to. To name all that are worthy
of consideration would take many volumes, for
there are more than ten thousand species of
flowers indigenous to the United States, and of
these only something like fifteen hundred have
at one time or another been placed under
cultivation.

Two or three familiar ones may be named, in
addition to those that have already been referred
to, as offering exceptional attractions.

There are, for example, the Gilias, repre-
sented by many species. I have cultivated
twenty or more wild ones at one time, selecting
for brilliancy of color, for size of flower, for
compactness of growth, or for some other desired
quality.

On occasion I have carefully examined at least
ten thousand different plants in order to select
the individual with which to begin improvements.

THE VARIEGATED
NEGUNDO

This variety of "Box Elder33 is
prized for the color of the leaves—
and very justly so. It is the only
hardy tree known which produces such
beautifully variegated foliage, which
retains its beauty all summer, even
in our sunny climate. This was in-
troduced from my place' some thirty
years ago.

THE LARKSPUR 233

The gilias vary greatly in color, so that they
are very interesting flowers with which to work,
and the colors may very readily be fixed in the
course of four or five generations. So also may
the qualities of compact growing, size of flower,
and the like. The plants, therefore, are encour-
aging ones for the amateur who is anxious to get
results.

The familiar milkweeds have been referred
to in another connection with reference to the
peculiar arrangement of their pollen masses,
which are so adjusted as to entangle the feet
of bees.

The amateur will find it peculiarly interesting
to cross-pollenize these flowers. It will be advan-
tageous to work with a magnifying lens of con-
siderable power. The curious form of the flower
and the unique arrangement of the pollen masses
give the work of cross-fertilizing these plants a
unique character, and these flowers are in general
among the most puzzling of all flowers for the
amateur.

There is possibility of developing, among the
milkweeds, plants of commercial value. I have
cultivated a number of unclassified South Amer-
ican species. For two or three years the work
of selecting the best seedlings among a large
number was carried on, until several races among

234 LUTHER BURBANK

several species were pretty sharply defined. The
best of these are now being crossed, the object
being to get varieties of more beautiful blossoms
for garden culture, and also to secure varieties
that will be of value in producing a fiber that
has something of the quality of silk.

Even now tons of milkweed seed pods just
before they are ready to open are dried in the
Mississippi Valley and shipped to Japan, where
they are used to make a kind of cloth, which is
even more beautiful than the finest silk, but not
as durable on account of the short fiber. In the
Philippines there is a remotely related plant, the
Kapok, which supplies a fiber much used for
filling pillows and the like.

It is considered within the possibilities that a
variety may be produced that will be of value for
the production of rubber, as the juice of some
species has excellent rubber qualities.

The native varieties of milkweed are generally
exceedingly hardy and as they are perennials
may be worked on season after season. There
is great variation as to vigor of growth, size of
leaves, compactness of plants, and color and
form of leaves, as well as regarding the size,
color, and abundance of blossoms. The seed
pods, with their white, silklike fiber, also vary
greatly. And there is corresponding variation

THE LARKSPUR 235

as to the amount of latex or milk produced by
the various individual plants.

All in all, then, there is scarcely another tribe
of plants that shows a wider range of interesting
qualities for observation of the experimenter.

Another wildling offering attractions of a
different character is the so-called painted cup,
or Indian's paintbrush, classified by the botanist
as Castilleia.

The most familiar form of this plant is the one
known for its brilliant scarlet color. But the
tribe is exceedingly variable, and the different
members present flowers that range from scarlet,
crimson, orange, yellow, and purple to pure
white. Some are variegated. Individual plants
growing on the same cliff along the ocean shore
may show the widest range of variation in the
color of their blossoms. All colors are sometimes
combined in the flowers of a single plant.

In other cases one will find a small patch of
yellow flowers in one place, and in the neighbor-
hood another patch of orange or white ones.

The only color that is missing is blue. It
would thus be an interesting quest for some plant
developer to see whether he could develop a blue
painted cup, somewhat as I was able to develop
a blue poppy. Even failing in this, the oppor-
tunity to study heredity of color, and to isolate

236 LUTHER BURBANK

races of painted cup of one color or another,
and fix them so that they would come true from
seed, would require a number of seasons.

The fact that the painted cup does not always
prove easy of cultivation suggests that it is a
plant worthy the attention not merely of the
beginner but also of the amateur who has gained
experience, and who is willing to try his hand at
difficult problems of plant development.

As before said, it would be possible to extend
almost indefinitely this list of interesting flowers
that invite development. But the ones named
may serve by way of introduction, and the
amateur may readily extend the list by looking
about in almost any garden or by rambling
almost anywhere along country roads or in
neighboring fields.

The material lies everywhere
about us, and despite the activi-
ties of large numbers of flower
lovers, there are hundreds of
species readily accessible that have
never come under the hand of the
cultivator, and which therefore
have the attraction of entire
novelty.

ORNAMENTAL PALMS AND
CLIMBING VINES

VIEWS ON ARTISTIC TREATMENT

VISITORS from the East are often sur-
prised to find palms growing thriftily at
Santa Rosa and also in nearly all parts of
the State. The average resident of northern
latitudes associates the palm with tropical con-
ditions. And while it is known to everyone that
these trees grow in southern California, it seems
a matter for wonderment that they should be
found so far to the north as the region in. which
my experiment gardens are located.

In fact, isothermal lines make little or no dif-
ference in California, as the winds from the
Pacific, deflected by the mountains, determine the
climatic conditions, and produce quite unpredict-
able results. Thus it is that oranges are sold by
the carload from northern California before they
are even colored in the southern part of the State.

And again, the palm is a relatively hardy tree,
in comparison, of course, with tropical plants in

237

238 LUTHER BURBANK

general. And whereas the date palm does not
thoroughly perfect its fruit, for the most part,
except in regions where the summer is very long
and hot, this tree may withstand extremes of
temperature that are widely removed from any-
thing experienced in the tropics, and other palms
generally perfect their fruit wherever they can
be grown.

Indeed, so hardy are some of the palms that
the question arises whether it may not be pos-
sible by selective breeding and adaptation to
develop races of palms that will thrive even in
the middle latitudes of the eastern United States,
and far to the north of their present limits on
the Pacific Coast. The fact that most of the
palms now growing in California have been
introduced within comparatively recent times,
and that they have gradually made their way
northward, is suggestive of the possibility of
much wider extension of their habitat.

A difficulty in the attempt to carry out any
project in selective breeding calculated to give
the palm additional hardiness or any other qual-
ity is found primarily in the fact that this tree
does not mature its fruit until from ten to
twenty-five years of age. But in recent years
an effort has been made by the Department of
Agriculture and by several private individuals,

ORNAMENTAL PALMS 239

to introduce races of date palms that will bear
marketable fruit, and study of the palm that has
been undertaken in this connection will doubt-
less lead to important results. Even now it has
been demonstrated that just as good dates can
be grown here as in the Sahara.

It appears that the palm, notwithstanding its
relative fixity, is subject to considerable vari-
ation, and that this is particularly true of the
date palm fruit, as might be expected consider-
ing that this tree has been under cultivation from
prehistoric periods, and because it has been
selected for the fruit alone.

The most delicate and delicious date fruits are
not the ones that can be secured for export, so
that these varieties can never be seen on the
American market until they are grown here. All
the best date palms, unlike most other palms, are
grown from suckers which come up from about
the roots of the tree.

To be sure, the Oriental peoples, for whom
the date has supplied a most important food
product from the earliest periods, have probably
paid very little attention to selective breeding.
Still the broad general fact that "like produces
like" has been matter. of common knowledge
from remotest antiquity, and it can hardly be
doubted that a certain amount of more or less

240 LUTHER BURBANK

intelligent selection of the trees that bear the
best fruit, with attempts to raise seedlings from
these trees and thus secure races of good fruit
bearers, has been practiced generation after
generation.

Moreover a certain amount of cross-pollen-
izing between allied races of palms has doubtless
taken place without the agency of man, and
so it is all but certain that the different palms
under cultivation bear mixed racial strains, some-
what as do the different races of orchard
fruits and cultivated plants of temperate
climates.

It is quite to be expected, then, that the palms
grown from the seed should show a good deal of
variation.

That such is really the case is made obvious to
anyone who attempts to raise them. The date
palm, for example, may readily enough be
grown from the seed, for the seeds germinate
readily, though slowly. But the tests have
shown that the progeny of a date palm bearing
fruit of the best quality cannot be depended upon
to transmit the characteristics of the parent with
a high degree of certainty.

So it is necessary to grow the young trees
from suckers if the strain of the parent is to be
perpetuated accurately.

ORNAMENTAL PALMS 241

The experts of the Department of Pomology
at Washington and several private individuals
have imported rooted suckers, obtained from
female trees known to produce fruit of excel-
lent quality, distributing and planting them in
various regions of the southwestern United
States.

The trees that grew from these suckers have
proved to be pistillate, as expected, and pro-
duced fruit equal to that of northern Africa.
Considerable difficulty was first experienced in
securing suckers from the best trees, even private
individuals not being allowed to own them in
the original country. As to the date palm, the
progress already made in the improvement of
the fruit indicates beyond the shadow of a doubt
that still further improvement will be made in
many directions. It is probable that the colony
of fruit bearers thus introduced will spread
indefinitely, until the date palm becomes an
important economic tree in warmer portions of
America, as it has already done in parts of
California.

It is even more important with the palm than
with other fruit-bearing trees that propagation
should be carried out in this way, because when
the plants are grown from the seed only half of
them will be bearers of pistillate flowers.

242 LUTHER BURBANK

The pollen-bearing trees will of course bear
no fruit, and while there must be here and there
one of these in the palm grove — one staminate to
about twenty-five pistillate trees — it would be
an obvious waste of space to give over half
the ground to sterile trees. Yet there is no
way of determining whether an individual tree
is a male or a female until it comes to the age
of blossoming; and the palm is a tree of
slow growth that matures only after many
years.

But trees grown from suckers will be of the
same sex as the parent trees; hence the double
utility of propagating by this method.

PALMS FOR ORNAMENT

From the standpoint of the present chapter,
however, the fruit-bearing qualities of the palms
are not so much in question as their ornamental
character. Considered merely as ornamental
trees, there are members of the genus Phoenix,
to which the date palm belongs, that are more
attractive than this famous fruit bearer. And in
general the character of the form and foliage of
a date palm is carried with sufficient certainty
from parent to offspring by the seed to make it
perfectly feasible to raise palms from the seed
ornamental purposes.

ORNAMENTAL PALMS 243

Even where the seeds are planted in rows,
with the expectation of producing colonnades of
palms, along roadsides or for borders, the palms
may be grown from the seed without danger that
they will vary sufficiently to interefere with the
symmetry of the row, provided the seed are
gathered from the same tree, or at any rate have
come from the same general stock.

If, however, the seed be imported from dif-
ferent regions, there is probability of variation
even among trees of the same species.

The usual method, in California, is to germi-
nate the seed in a hothouse, growing the young
plants in pots at first, and then removing them
to boxes that they may be more readily trans-
planted, as they make hard, slender, wiry roots.
They are as easily grown as kernels of corn,
though requiring much longer periods of time.
Occasionally, however, when quite small, they
are planted in nursery rows, and it is sometimes
desirable and safe to transplant them after they
have obtained a growth of twenty or thirty feet
in height, and a diameter of trunk of one or
two feet.

In such a case, it is best to cut around the
roots of the tree some time before removal,
making a ball of earth that is to be removed with
the tree. This treatment induces the palm to

244 LUTHER BURBANK

throw out new roots, giving added firmness, and
making provision for the rapid absorption of
moisture and nourishment after transplantation.

A box being constructed around the soil, the
palm may be removed to any distance.

Sometimes a single palm thus transported is
of such size as to require an entire flat car. But
unless the precaution is taken to cut back the
roots and allow them to stand for some time
before removal, as just suggested, there is dan-
ger that the palm will die after transplantation,
because the loss of its long roots makes quick
adaptation to the new conditions impossible.

The Phoenix canariensis is a thoroughly hardy
palm in this climate, and the handsomest of the
hardy members of the tribe.

It is therefore the one most used for planting
for ornament in California, though the Chamce-
rops eaccelsa from Japan is as hardy and next
most common. The Canary palm grows with
great rapidity after the plant has the first five
or six leaves, although like all other palms its
early growth is slow. An ordinary specimen of
this species, transplanted into good soil in this
region when it has four or five leaves, will grow
to a height of fifteen feet, with a corresponding
spread of branches, and develop a trunk eighteen
inches in diameter in six to ten years.

ORNAMENTAL PALMS 245

No other palm with which I am acquainted
will make more than about one-half this growth
in the same time and under the same circum-
stances.

There is considerable difference in appearance,
however, and in rapidity of growth of different
strains of palms of this species. Yet the seed-
lings are unusually true to type, so that long
rows of the Canary palms may be grown from
the seed with full assurance that they will not
vary sufficiently to break up the general uni-
formity of the row.

Palms of the genus Chamcerops are also very
hardy. I have never known one of them to be
injured by frost anywhere in California, even
when quite young.

There are several species of this genus. I have
grown them from the seed somewhat extensively,
and have noted a wide variation among the dif-
ferent species, some making large trees while
others are dwarfs, some of which, in this region,
never attain a height of more than three or four
feet. One exceedingly thorny species may be
multiplied by division readily, as it throws
up suckers abundantly around the old plant,
unlike most other palms. Some accidental
hybrids have appeared among the species of
Chamoerops.

246 LUTHER BURBANK

VARIATION AND DEVELOPMENT

Notwithstanding the considerable variation
among the different strains, there is almost no
discoverable variation in seedlings of a species
of this genus of palm when grown from seed of
the same tree. The species most commonly
grown in California is C. excelsa. This is a
species that in China and in Japan is one of the
most useful of trees, its foliage being used for
thatch, the rigid leaf stalk for braces, and the
woolly substance about its trunks for cordage
and other purposes.

Moreover this is the palm from which fans are
usually made, the undeveloped, immature leaves
being used for this purpose.

The palms of this genus usually bear the
staminate and pistillate flowers on different
trees, but it is not unusual to find a few staminate
blossoms on pistillate trees, or, contrariwise, a
few pistillate blossoms on staminate trees.

If the attempt is to be made to hybridize the
different species with the hope of developing
hardier races, the matter of fertilization of the
flowers becomes obviously important.

It will be worth while, then, to select the trees
with reference to those that tend to mature their
fruit while young.

ORNAMENTAL PALMS 247

But the work of developing a race of hardy
palms will necessarily be a slow one, requiring
the cooperative labors of successive generations
of plant experimenters. And whereas it is prob-
able that in the course of a century or two hardy
palms will be developed, so that the question of
selection of ornamental palms will be of interest
even to residents of the middle and perhaps even
of the northern regions of the United States,
at the moment the matter can have practical
interest only for a limited number of people,
and we need not consider it more at length
here.

It suffices to say that the methods of hybrid-
izing and selection that have proved successful
with other plants will doubtless be found to have
full application to the palm ; and to add that the
actual work in this field has been begun only in
a tentative Way.

The method of hybridizing is simplicity itself
—as simple as crossing two varieties of corn.

Meantime, however, the palm exists as an or-
namental tree of the very greatest value in Cali-
fornia, and the interest shown in it by tourists
justifies the expectation that, in the near future,
efforts of a comprehensive character may be
made, probably under Government supervision,
to develop races of palms that can be grown far

248 LUTHER BURBANK

to the north of the present limits of this tree in
the eastern United States.

A drive along Grange Boulevard in Los
Angeles, or from Palo Alto to Stanford Uni-
versity, for example, and inspection of its rows
of palms, alternating with pepper trees, gives
the visitor from the East a mental picture of the
possibilities of this race of trees for ornamental
purposes that should certainly stimulate a spirit
of emulation. Interspersed among pines — their
ancestors of prehistoric times — they will be
particularly appropriate and look especially
well.

The ornamental value of palms for roadsides
and borders, and artistically placed here and
there on the lawn, is admirably supplemented by
a background of vines growing on walls or over
rustic arbors or pergolas.

And of course there are numerous vines, as
everyone is aware, that flourish abundantly in
regions where the palm cannot be grown. So
the picturesqueness of effect that can be gained
by the use of vines sometimes better than in any
other way is available for the residents of north-
ern climates, even far toward the Arctic Circle,
almost as fully as in the subtropical regions.

Among the vines that are so thrifty that they
will grow in almost any soil, and so hardy as to

ORNAMENTAL PALMS 249

resist the coldest winters, the various species of
the genus Ampelopsis take foremost rank. Of
these the Japanese Ivy, sometimes known as Bos-
ton Ivy (A. Veitchii] and its varieties, is prob-
ably the best known and the most extensively
grown. For the purpose of covering brick and
stone walls it is perhaps the most beautiful of all
vines.

This vine has a close rival, however, in the
native species familiar everywhere in the Middle
and Eastern States as the Five-Leafed Ivy or
Virginia Creeper (A. virginica) . This vine,
however, does not cling to flat, smooth surfaces
as does the Asiatic species.

The strains of this vine differ materially in
different localities, there being one in particular,
named the Engelmanni, which clings to walls
and trees better than the ordinary varieties.
Vines of this variety are also far ahead of others
in their rapidity of growth and in the beauty of
their foliage, and especially in their autumn col-
oring. Some varieties hold their foliage nearly a
month longer than others.

These variations should be borne in mind in
selecting plants for the covering of walls or
making of arbors. The wild Ampelopsis vines
growing in Colorado are, in my opinion, much
superior to those of the Eastern States.

250 LUTHER BURBANK

I have raised thousands of seedlings of both
species of Ampelopsis just named, and many
specimens of other species known respectively as
A. Tieteropliyla and A. arbor ea, and have crossed
some of them.

The Japanese Ivy and the Virginia Creeper
have now been crossed, and it is expected that the
combination will produce varieties of value, giv-
ing opportunity for the development of new
races or ornamental vines to add to the compara-
tively limited number now available. The work
is being carried forward on a large scale, and it
is probable that the Ampelopsis and the grape
may be brought into combination.

Meantime, I have more lately developed a new
variety of Virginia Creeper through selection
that has much larger foliage than the ordinary
varieties, and that is also a much more rapid
grower, with the habit of holding the foliage to
a late period in the autumn. As the plant is
readily propagated by cuttings, such a new race
as this may be distributed indefinitely.

These vines are grown chiefly for their beauty
of foliage alone, although the grapelike berries
of the Virginia Creeper are not without some
decorative value.

There are other vines that in some respects
rival the Ampelopsis as climbers for the covering

ORNAMENTAL PALMS 251

of walls and arbors, and that have the added
merit of producing beautiful flowers. Notable
among the vines that have this double attractive-
ness are the various species of Clematis.

There are several native species of the
Clematis, and some of the species have been
brought sufficiently under cultivation to develop
a tendency to vary widely. Nearly all are rapid
climbers, and produce beautiful flowers in great
abundance. In addition some have feathery seed
pods that are scarcely less attractive arid inter-
esting than the blossoms that precede them, mak-
ing an artistic contrast with the foliage for a
considerable period. So all in all the clematis
must be ranked among the most beautiful of
vines.

My own work with the members of this class
of plants has been largely with the types that are
known horticulturally as Jackmanni lanuginosa,
These have large blue and white flowers, some-
times inclined to red and pink.

This type has been raised very extensively
from the seed for many years, and, by selection,
several varieties were produced that bore very
handsome double flowers of peculiar form, vary-
ing in color from blue, pink, and ashy gray to
pure white. Some of these new varieties also
have exceedingly large broad petals with the

252 LUTHER BURBANK

flowers of unusually rounded outline, not unlike
the form of a dahlia.

Several of the best of these were introduced
through dealers. The clematis is somewhat sub-
ject to a disease usually ascribed to the same
cause that destroys lilies and many other plants
in cultivated soil. It is probably bacterial, and
is associated with thrips, millipeds, and eel-
worms, which probably serve to disseminate the
germs.

Subsequently I began a series of hybridizing
experiments, using the Clematis cocdnea as the
original seed parent.

This species is herbaceous and has scarlet flask-
shaped flowers, with the sepals slightly opened
by the curling outward of their tips. The sepals
are thick and fleshy, although not leathery, giv-
ing the flower almost the appearance of a fruit.

This species is not variable, about the only
diversity noticeable being a slight variation in
the size of the flowers. It produces seed freely,
and to the pistils of cocdnea was applied the
pollen of various other species; among these
being C. crispa, known as "Blue Bells,"
C. Davidiana, C. Fremonti, C. ligustidfolia,
C. Douglasi, C. verticillaris, C. ocddentalis,
C. Fortunei, C. Viticella, and others, no attempt
being made to keep the various crosses separate.

ORNAMENTAL PALMS 253

The hybrid progeny showed a very wide varia-
tion, especially as regards color of the flowers.
There were blue, crimson, scarlet, and white
flowers, and sometimes all of these colors ap-
peared on a single plant.

There was also much variation within certain
limits in the form and texture of the flowers,
which in general were of a much larger size than
those of the seed parent, and more spreading
and widely open in form. Some of these had
thick sepals and some had thin ones.

Perhaps the most striking peculiarity was that
the interior of the sepals often had a frosted
appearance, due to the presence of a filament
network of papillae. There is something of this
appearance occasionally in flowers of C. coccinea
and C. crispa, but it was greatly accentuated in
many of the hybrids. In general habit and their
herbaceous stems, the hybrids seem almost uni-
formly to follow the seed parent.

The flowers were produced in great abun-
dance, and the colors were not only most beauti-
ful but showed combinations never before seen in
the clematis. The bell-shaped flowers are for the
most part white on the inside, but exteriorly they
are crimson, pink, orange, blue, or purple. The
beautiful frosty throats give the flowers an ap-
pearance that is unique.

254 LUTHER BURBANK

Among the hybrids a few of the most beautiful
forms were selected and placed, without specific
names, with a florist for introduction. Some of
my earlier clematis introductions had been given
names more or less suggestive of their peculiari-
ties of flower, including "Ostrich Plume" and
"Snow Drift." Another "Waverley," etc.

I have stated that the earlier varieties were
subject to the clematis disease. In the later ex-
periments the endeavor was made to produce
varieties that would be immune to disease, as well
as those that would show exceptional hardiness.

Several years ago, while on a trip in northern
Canada, I found patches of clematis on half-
woody slopes, growing in a region where the
thermometer sometimes goes fifty or even sixty
degrees below zero in the winter — regions where
the deep wells do not thaw out altogether during
the entire summer, always having a thick coat oi
ice about their walls.

The hardy clematis found in this region bears
dark blue flowers that are fully three and a half
inches in diameter, being about as large as those
of the cultivated varieties known as the blue Jack-
manni, the blossoms of which also resemble it in
color. There are two or three wild species in
the same region, namely C. Fremonti and C.
ligustidfolia, plants that bear rather inconspicu-

ORNAMENTAL PALMS 255

ous flowers of a greenish white color, but having
long, feathery seed coverings that give them
interest, and being in addition strong growers.

These have already been named among the
species of clematis that were used in hybridizing
experiments.

It was to be expected that plants having
strains of such hardy species in their heredity
would develop some varieties of great hardiness.
And in this the expectations were not disap-
pointed. A more extended series of experiments
than I had planned to undertake would be neces-
sary to fix the new varieties, and to make sure
as to which of them are the hardiest.

There is still opportunity for fine work iu this
direction. The clematis is such a beautiful vine,
and there are so many species available, and
among these species such amazing variety of
form of vine and flower, that the opportunity for
extensive breeding experiments with this type is
most inviting.

In raising the seedlings my practice was to
sow the seed quite thickly in boxes in the green-
house, as soon as it ripened in the fall, forcing
the plants throughout the winter, and transplant-
ing them in the open field in the early spring.
The seedlings would quite often make vines from
eighteen inches to two feet long the first season,

256 LUTHER BUKBANK

but would rarely bloom the first year. In the
second season they would almost invariably do so
and the general character of their flowers could
then be determined.

But the blossoms of the first season would not
fully represent the possibilities of their mature
production. For example, plants that first bear
blossoms that are semidouble would in later sea-
sons, when the vines had gained in strength, bear
fully double flowers.

At the time when my first hybrid double
clematis flowers were produced, there was, I
think, but one other double one known anywhere
in the world, this being a form produced in Eng-
land. More recently, however, several good
double varieties of this class have been introduced.

The clematis is a plant that improves with
acquaintance. Existing varieties furnish vines
that are beautiful in foliage, in flower, and in
their picturesque display of seed pods. There is
a great variation among the forms already under
cultivation, but there is still abundant oppor-
tunity for improvement with these; and in addi-
tion wild species may be found that through
hybridization will certainly introduce tendencies
to still wider variation.

What plant could offer greater inducements
to the experimenter?

ORNAMENTAL PALMS 257

BIGNONIA, WISTARIA, AND BELLFLOWER

There are two or three other groups of vines
that must be given at least passing notice.

One of the interesting forms with which I have
done much work is the class of climbing shrubby
plants of North and South America of the genus
Bignonia. By crossing some of the bignonias
with the Tecoma, a plant that grows wild in Vir-
ginia and Maryland, some interesting results
were brought forth.

There was modification of color of flower,
length of seed pods, and vigor of growth of the
plants themselves. But no variety was secured
that seemed worthy of special introduction.

An interesting feature of the hybridizing ex-
periments with the bignonia is associated with the
curious sensitiveness of the stigma of the flower
to irritation. The two lips of the stigma stand
open, like a set trap, and when pollen is sup-
plied they close, traplike, grasping it instantly.
Anyone who has never seen the lips of the stigma
of the bignonia close when irritated by bees or
artificial means would be greatly surprised.

It is necessary in applying the pollen to
be somewhat dexterous, lest the lips of the
stigma close and make the stigmatic surface
inaccessible.

Vol. 7— Bur. I

FLOWERS OF THE TECOMA

There are more than one hundred
species of this genus, natives of
temperate, tropical, and subtropical
America, and also of Asia and Africa.
Owing to the shape of the flowers, they
are popularly known as trumpet vines.
Some species, however, are upright
shrubs or trees.

ORNAMENTAL PALMS 259

Nor may the lips be pried apart. They open
spontaneously, however, after a time, but usually
not until the patience of the operator has been
exhausted. It is a curious and interesting experi-
ment to irritate the stigmatic surface with a grass
stem or twig, which will be grasped as the trap-
like stigma closes, and held as a frog might hold
a stick in its mouth. The same remarks apply
also to the unrelated Mimulus or monkey flower.

Another ornamental vine that offers oppor-
tunities for the plant developer is the familiar
and beautiful Wistaria.

There is a fair degree of variation among the
different types of wistaria, some bearing blue
flowers and others white ones. The plants of this
genus are not only valuable as climbers, covering
walls and arbors with vines that bear beautiful
flowers, but they can also be trained to form tree-
like bushes that are most attractive additions to
the lawn. The Chinese wistaria is ordinarily a
long vine, but may be trained to a bush five feet
across and thrive fully as well. Under this mode
of culture, a certain amount of energy that would
ordinarily go to the production of the vine itself
is saved and utilized for flower production, so
that wistaria bushes thus trained become aston-
ishing bearers of blossoms, like gigantic
bouquets.

260 LUTHER BURBANK

Nothing more is necessary in training the vine
than to trim it to form a head, and then from
time to time to cut out the straggling branches.

The wistarias are difficult to hybridize, because
their flowers are papilionaceous, like those of the
peas and beans. But, with a little care, hand-pol-
lination may be effected, and some very striking
variations should be obtained in the second gen-
eration from a cross, for example, between the
American and Chinese wistarias.

A complex hybrid between these and the
Japanese variety, Wistaria multijuga, which
produces astonishingly long racemes of flowers,
should give results of additional interest.

My own experiments with the wistarias have
consisted of the growing of a great number of
seedlings, both of the Chinese and American
species, selecting among these for plants varying
in form, and bearing blossoms of different
size and colors. The results of these experi-
ments show that the wistaria is quite an
adaptable flower, and one that is certain to
repay more extensive breeding experiments, in
particular those that introduce the element of
hybridization.

Only one other type of ornamental vine will be
mentioned here, the Lapageria, or Chilean Bell-
flower.

ORNAMENTAL PALMS 261

As an excuse for selecting this one among
many tropical and subtropical forms, I may say
that when I first saw the Chilean bellflower I
thought it the most beautiful flower of any kind
that I had ever seen. It has glorious, great,
drooping, bell-shaped, rosy or white blossoms,
which no lover of flowers could fail to admire.
The foliage of the plant is smilaxlike, and some-
what deficient in quantity, but the wonderful
flowers make amends for any defect of foliage.

Unfortunately the plants are very difficult to
raise, needing peculiar soil and much attention.
They are also sensitive to changes of tempera-
ture, and do not bloom at an early age. More-
over they must be kept moist at all times to
insure good growth.

The possibilities of work with plants of this
genus are shown in a remarkable cross said to
have been made by Veitch, of England, between
one of the Lapagerias and the Philesia bucci-
folia, the latter being the pollen plant. The hy-
brid which has been named Philegeria Feitchii, is
of exceptional interest, inasmuch as the parents
belong to different genera. In scientific interest
it ranks with the blackberry-raspberry hybrids.

As illustrating the possibility of the produc-
tion of interesting new forms, I may note that
a collector in Chile sent me a few years ago

262 LUTHER BURBANK

several species of plants allied to the Lapageria,
but unclassified as to species, that very much re-
semble the English Ivy and that show unusual
habits of growth. One of these is said to bear
excellent fruit.

At three years of age, when the first blossoms
appeared, the strongest plants were about fifteen
feet high. Among the thousands of seedlings,
there is enough difference in the form of
foliage, rapidity of growth, and other character-
istics to show that the plant is susceptible of
improvement even in the first generation of
seedlings from wild stock.

Experiments in hybridizing these new plants
with Lapageria, and further experiments in
selection in the hope of securing a new vine that
combines with other good qualities the property
of fruit production, are contemplated.

The clematis is a plant that im-
proves with acquaintance. There
is a great variety among the
forms already under cultivation,
and through hybridization with
wild species still greater variation
may be induced.

LAWNS AND THEIR
BEAUTIFICATION

SOME OLD AND NEW SHRUBS AND
GRASSES

MOST people who see a good Lippia lawn
are surprised to learn that it is not a
grass. At a little distance this looks
very much like any other lawn that is well cov-
ered with grass. But on closer inspection it ap-
pears that the lawn is carpeted with a plant that
is obviously not a grass. It is in reality a spe-
cies of verbena, very much more closely related
to the familiar flower of that name than any
other plant in cultivation.

This anomalous substitute for lawn grass is a
plant which was briefly referred to in an earlier
chapter as a relative of the verbena. It is known
as Lippia repens, sometimes as Lippia canescens.

It is a plant indigenous to Chile, from which
country I received the seed from which the new
and greatly improved lawn plant was developed
a number of years ago.

263

264 LUTHER BURBANK

The value of the Lippias as lawn plants had
been shown by Dr. Francheschi, of Santa Bar-
bara, California, as long ago as 1900, he having
introduced a common form of Lippia repens
from southern Europe, where it had been grown
as a lawn plant by division until it had lost its
power of producing seed, thus making further
improvement impossible.

The opportunity to improve the plant came
when my collector in Chile sent seed of some of
the wild species from the Andes. There was a
good deal of variation among the plants raised
from this seed, and the following season about
ten thousand plants were raised, each one of
which was given a little space in order that its
individual peculiarities as to rapidity of growth,
tendency to spread, and color of foliage might
be studied.

From among these plants about half a dozen
were saved, and the descendants of these con-
stitute several varieties of Lippia that have
marked peculiarities. A single cutting of one
variety will spread on an ordinary soil over a cir-
cle about ten feet in diameter in a single season.
This form would be very valuable for growing
in sunny places, in certain localities along
irrigating ditches, where the soil is subject
to wash.

LAWN BEAUTIFICATION 265

But I have more recently found two far
better substitutes for this purpose. One is the
Mesembryanthemum cequilaterale, which grows
on our seacoasts. This produces an enormous
amount of very heavy foliage, which is hardly
moved even by a strong stream of water.

The other is the vine commonly called trailing
myrtle (Vinca major) . This forms a great mass
of long white roots, and long slender vines with
abundant evergreen foliage, which resists stream
wash by shingling the whole surface so that the
water cannot reach the soil. No plant surpasses
it for this purpose.

Another variety of seedling lippia grows only
half as fast, but has very fine dark green leaves
and lies very close to the ground, making a most
beautiful velvety lawn, while the older lippias
made a very unsightly lawn, though better than
none, for warm dry climates. Unfortunately
none are hardy in the cold northern climates.

A third variety of lippia has pale-green leaves,
is a slower and even more compact grower, and
makes a lawn that contrasts charmingly in color
with a lawn of the other lippias, or ordinary
lawns of blue grass.

A fourth variety has long ropelike runners
growing in all direction, but not filling up the
spaces, and therefore not being suitable for

266 LUTHER BURBANK

lawns. Still another has hairy leaves that give
it a peculiar frosty appearance, whereas the
leaves of other varieties are most often glossy
green.

The foliage of these selected new seedlings
vary greatly in size, the leaves of some being sev-
eral times as large as others. The half dozen
types selected are being used for further de-
velopment, and as might be expected they show
still more variations in the second generation. A
single plant of some of the rapid-growing varie-
ties usually overgrows and covers up perhaps a
dozen of the smaller lippias of the same age.

Add that the new plants, in addition to their
rapid and compact growth, are adapted to dry
soil, requiring not one-tenth the water that blue
grass or other ordinary lawn grass requires, and
keeping in good condition longer than any blue
grass or clover lawn with a fraction of the care
or the expense for watering, weeding, and mow-
ing necessitated by the ordinary lawn and it is
obvious that these developed varieties of lip-
pias constitute an important acquisition.

Curiously enough the lippia lawn makes a
better appearance where it is frequently trod
upon and subjected to treatment that would
injure an ordinary grass lawn, or destroy it
altogether. The plants appear to pay no atten-

LAWN BEAUTIFICATION 267

tion if a path is made directly over them; their
appearance is actually improved thereby.

With some species occasional runners may
grow above the main mass of foliage and
become unsightly, but these are readily cut away,
leaving a smooth velvety surface.

The real difficulty that stands in the way of
the general introduction of the lippias as lawn
plants of altogether exceptional quality, how-
ever, is their relative tenderness to frost. If
selections should result in producing a hardy lip-
pia, the plant will be welcomed everywhere, as it
is already coming to be welcomed in the warmer
regions as one that at least partly solves the
problem of a lawn that will require practically- no
attention, and yet maintain its greenness even
in long periods of summer drought. It must be
added, however, that during the wintertime it
turns brownish, and at that season it is not quite
as ornamental as a blue-grass lawn.

Until the lippia is further developed for har-
diness, however, it could not be used except in
the milder climates, and in the cold regions the
blue grass and other allied grasses and the
clovers must be depended on for making lawns.

Meantime one of these new lippias has been in-
troduced, and named Dixie. This makes a most
beautiful dark green, close-growing lawn.

SPANISH BROOM

This compact, upright, ornamental
shrub is known to the botanist as
Spartium junceum. It is a thrifty
shrub, but unfortunately not very
hardy. In any region where it can be
grown, it should be prized as a garden
ornament. The plant has been greatly
improved here by selective breeding.

LAWN BEAUTIFICATION 269

With all their tenacity in resisting storms,
drought, and constant tramping, these lippias
do not become weeds, as they produce no under-
ground stolons. By simple plowing or spading
they may be more readily removed than the
ordinary lawn grass.

If left all summer without mowing, the lippia
lawn makes a rich bee pasture resembling some
of the low-growing clovers. If mown once or
twice, it has the general appearance of a blue-
grass lawn, being soft and yielding to the tread
like a fine Axminster carpet. The lippias do not
thrive well in the shade, being essentially sun
lovers. The new lippia just described settles the
lawn question for sunny places in warm climates,
as well as the problem of very greatly lessening
the wasting of land by erosion on river banks and
hillsides.

Meantime other experiments are being carried
on with various other plants which give promise
of finally making good lawn plants. Among the
most interesting is a species of trailing Hyperi-
cum, specific name unknown, from the moun-
tains of eastern Chile.

Somewhat similar species of hypericum have
lately been introduced to my gardens from
Russia, Siberia, and central and northern
Europe, which show a similar creeping habit,

270 LUTHER BURBANK

and no doubt will be hardy everywhere. These,
even in the first generation from the wild native
parent, show variation in rapidity and compact-
ness of growth, and from all appearance a few
years' work will give us a lawn plant for all
climates, but probably a little more difficult to
get started.

All the hypericums will stand a great amount
of drought and ill treatment; are unusually
hardy, stand tramping and mowing readily. No
doubt in future there will be produced varieties
that will be valuable as lawn plants for all
climates.

Until the new plants have been perfected,
however, the conventional lawn grass, with Ken-
tucky blue grass at the head of the list, must be
relied on in colder climates. It is not necessary
to refer to the common lawn grasses here in
detail, their general character and qualities being
familiar to everyone, and there having been no
marked development in recent years in the way
of improving them.

It suffices to suggest that care should be taken
in buying seed from reputable dealers that grass
of good quality may be secured and the number
of weeds minimized. Beyond that it is hardly
to be expected that the interests of the amateur
plant developer will extend. For the grasses do

LAWN BEAUTIFICATION 271

not offer opportunities for striking results in the
way of improvement that make them appeal to
the amateur. And, in any event, blue grass in
its best varieties constitutes a lawn grass of
really fine quality, and if properly cared for will
produce a lawn of a very satisfactory character.
Mixtures are seldom better, and not often as
good as the pure Kentucky blue-grass lawn.

As to the matter of soil for the lawn, nothing
specific need be said beyond the statement that
the same sort of preparation is desirable that
would be used in preparing soil for field or
garden crops. Some details as to this will be
given in the succeeding chapter.

It is well here to offer a few suggestive hints
as to such preparation of the lawn which will
insure a proper regulation of the supply of air
and water, upon which the condition of the lawn
so largely depends. What is true about drain-
age and irrigation will have equal application to
land that is to be used for raising flowers or
vegetables or small fruits. These suggestions
are based very largely on my personal experi-
ence at Santa Rosa in preparing the ground for
the experiment gardens on which plants of
several thousand different species, and repre-
senting many families from all parts of the globe,
are grown.

272 LUTHER BURBANK

A PRACTICAL DRAINAGE SYSTEM

Hundreds of persons each season marvel at
the exceedingly varied and prolific crops raised
on the experiment farms — exclaiming, "What a
delightful soil you have!"

Their surprise grows when they are assured
that this productive land was originally almost
valueless for growing plants. It was made fruit-
ful by artificial drainage and irrigation. The
application of the simplest principles of regula-
tion of water supply resulted in transforming a
relatively sterile soil into one of the most fertile
areas of the earth's surface. The method by
which this was accomplished may be outlined as
offering a model that may be followed to advan-
tage in draining similar land anywhere.

Probably half the low-lying soils in the United
States could be made more productive by drain-
age. Even if the soil of your lawns and gardens
is fairly productive, you may advantageously
consider the advisability of introducing a system
of drainage like that which we have employed at
Santa Rosa with striking results.

The soil originally consisted of what is called
adobe, a black claylike soil, said to be of volcanic
origin, and this particular piece cracked so
during the latter part of the dry season, that it

LAWN BEAUTIFICATION 273

was considered unsafe to pasture stock on it, as
it endangered the legs of the animals, the cracks
often being several inches in width and appar-
ently bottomless. No crop had been grown here
for years ; and house lots a mile or more out sold
for about the price I paid for the four acres.

Of course there is nothing novel about the
statement that the drainage of land is important.
The matter has been more or less understood
since the earliest periods. Yet a very large part
of the land of the United States that is given
over to lawns and gardens is left to depend
entirely on natural drainage, and fails to pro-
duce anything like the crops that might be grown
on it, if a more rational provision had been made
for adjusting the water supply.

In California the value of drainage has been
shown in the results obtained even with wheat on
fields drained and those not drained. Only one
or two ditches across a field have made it possible
to produce two or three times as large a crop as
was grown in the same field before the ditches
were made.

In a certain oat field in Wisconsin the yield
per acre was doubled by drainage. The yield
before drainage was only sixteen bushels, but
after drainage it was increased to 32.3 bushels
per acre.

A FRITILLARIA

The Fritillaria is found in many
colors — brown, spotted, striped, green,
yellow — and one beautiful California
species is brilliant scarlet.

LAWN BEAUTIFICATION 275

There are at least two bad effects to be
expected from an oversupply of water. They
are:

(1) An oversupply makes certain areas so
soft that they cannot be cultivated at all or at
least not until late in the spring.

(2) Air, which is essential to plant growth,
cannot enter the soil supplied with a super-
abundance of water.

Air is as necessary to the roots of plants as
water and it is upon this principle that all sys-
tems of cultivation and drainage are based.

The complicated chemical changes in the soil
for the growth of the plant cannot take place
unless there is sufficient of both air and water.
Roots cannot exist where there is a super-
abundance of water in the soil.

There are several systems of drainage which
will not be discussed here. I consider under-
drainage with common drain tile is the best sys-
tem for ordinary conditions, and it is with this
system that I have had most experience. The
discussion is given mostly from the viewpoint of
results on my own grounds.

Small, well-burned drain tile was used on my
Santa Rosa grounds carefully laid with a slope
of one foot to forty feet and it has proven emi-
nently satisfactory in every respect for twenty-

276 LUTHER BURBANK

five years. The soil is a heavy adobe and was
almost worthless before it was drained.

The good results of the drainage were scarcely
apparent the first year, but the benefits were
multiplied each year until now the soil is
easily cultivated and bears enormous crops,
while before draining no crop of any kind could
be raised.

This system consists of one main line of four-
inch tile with laterals of two-inch tile every
forty feet. The laterals gather the surplus water
quickly after a heavy rain and the main tile
carries it to a small stream near by.

The laterals do not need such a large capacity
as most people think. It must be remembered
that they work both day and night, and Sundays
as well as week days and a very small tile will
carry a great amount of water in the course of
twenty-four hours.

It is a good plan to have the tiles flushed now
and then, and if they are not too large they will
be flushed during heavy rains when filled to ca-
pacity. This flushing serves to keep them clean
and the flushing produced naturally when small
tiles are used is sufficient reason for recommend-
ing the smaller sizes rather than larger ones
which are more expensive and generally less
efficient.

LAWN BEAUTIFICATION 277

The general impression is that cracks should
be left, and sand put in the cracks. The real way
is to surround the joints with clay; then they are
permanent. The worst thing to do is to put sand
or gravel or straw about the cracks. A tile four
feet deep will drain twice as wide an area as
a tile two feet deep. About four feet is the
best general depth where a lower outlet is at
hand.

The strength of the entire system depends
upon the weakest section. Therefore it is neces-
sary in laying the tile to examine carefully each
piece, and to see that they are well burned, but
not sufficiently to make them impervious. The
system must be laid upon the proper grade, for
if the line sags, sediment will collect and retard
the flow of water.

It is best to make a silt basin at the point
where the branching tiles unite. This is formed
by digging down a foot or two, and bricking or
cementing up a barrellike receptacle, the en-
trance pipe from the main system being a little
lower than the exit pipe, so that the silt may
settle.

In the twenty-five years since the tile system
was laid at Santa Rosa, the tile itself has never
been exposed or in any way touched or examined.
It continues to perform its function perfectly.

278 LUTHER BURBANK

Drainage is really a science in itself, and there
is not enough space here to give a full discussion
of it. There are a number of good books
upon the subject, however, and the names of
these will be found in the chapter on reference
literature.

Before the system is installed, some com-
plete treatise on drainage should be thoroughly
studied.

In some cases it is possible to secure the aid of
a person who has had experience in laying drain
tiles, and where this is possible it is the best plan.

SUPPLYING WATER

Irrigation is closely allied to drainage. The
two systems are for a similar purpose — to regu-
late the amount of moisture in the soil for plant
growth.

Irrigation is needed in locations where there
is not sufficient rainfall to insure the growth of
certain crops. In many places also where the
rainfall is sufficient but not well distributed, irri-
gation will be profitable, especially in seasons of
unusual drouth.

For large tracts such as orchards and extensive
seed and vegetable gardens, the common prac-
tice is to run water in large ditches with a system
of smaller ditches throughout the field.

LAWN BEAUTIFICATION 279

If such a system is properly constructed and
cared for, little is wasted because it is placed very
close to the point where it is needed.

For small areas, sprinklers are generally used.

The fault with most of the common sprinklers
used to irrigate small areas, such as lawns and
small gardens, is that they do not distribute the
water evenly. Most of them cover a circular
space and there is always some part of the soil
which has too much water or too little. One of
the most important points in irrigation is to have
the water distributed evenly.

Some flat or fish-tail sprinklers distribute
water quite evenly, but the newer system of over-
head irrigation known as the Skinner system is
by far the best for all areas of any size.

This consists of a number of one-inch galvan-
ized pipes with nipples placed along the sides
about twelve to twenty inches apart. These
pipes with the nipples inserted are mounted upon
supports about six feet above the ground. The
pipes are connected with the water supply and
the water turned on when needed.

Depending upon the pressure, this system will
distribute water evenly for a space of from
twenty- five to fifty feet on either side of the pipe.
The pipe may be located between two beds so
that it may be turned on its support and distrib-

DIERAMA PULCHERRIMA

One of the most beautiful and, with-
out doubt, the most graceful of all the
African bulbous plants. It is closely
related to the humble Ixia, but towers
six feet above it. The flowers are much
larger than in the picture, and much
more brilliant in color. (About one-
fourth life size. )

i

LAWN BEAUTIFICATION 281

ute the water on either side. When advantage
can be taken of the wind, the water will be
thrown almost twice as far as when there is no
wind,

This system has been somewhat modified to
adapt it to small areas where irrigation is not
needed often. Instead of mounting the pipes
upon permanent stakes, they are carried from
one place to another as irrigation is needed and
placed upon temporary supports or movable
stands.

For greater convenience in handling the pipes,
the temporary supports are only about four feet
high. On the top of these is nailed a curved piece
of sheet iron in which the pipe rests. The mov-
able stands are made of galvanized pipe in tripod
form and can be made by any plumber.

The sprinkler pipe is attached to the water
supply by a rubber hose and the system operates
in the same way as when in a permanent location.

The Skinner system is patented, but it is
not expensive to install. The pipes can be pur-
chased at any hardware store but the nipples and
the tool for drilling the holes in the pipe for the
nipples are patented and must be purchased
separately. Many of the seed houses, that handle
tools in addition to seeds, sell this irrigating
system.

282 LUTHER BURBANK

When this system is to be used on a lawn the
supports can be made more or less ornamental.

The cost of irrigating lawns by this method is
far less than by the use of circular sprinklers, for
both time and water are saved and the lawn is
supplied with a more even distribution of
moisture.

There is another plan of irrigation which is
known as the underground pipe or tile system.
This is not often used because the first cost is too
great. In some cases, however, it has proven to
be satisfactory.

The part of any sprinkler system that deteri-
orates most rapidly is the rubber hose. When it
can be replaced by iron pipe it should always be
done to save expense.

Where hose is used it is usually necessary to
purchase a new supply each season. Its first cost
is two or three times less than that of a galvan-
ized iron pipe, but the pipe usually lasts from
ten to twenty years. There are several other
systems of irrigation of lesser importance, but it
is not necessary to describe them here.

THE MENACE OF WEEDS

However well the soil may be prepared for
garden or lawn, and whatever the attention
given, cultivated plants of every description

LAWN BEAUTIFICATION 283

are perpetually menaced by the rivalry of
weeds.

A weed may be said to be a plant out of its
proper place so far as the economy of man is
concerned.

This does not mean, however, that it is out of
its proper place in the economy of nature. Na-
ture has a use for weeds, and in fact they have
done much good for man.

When crops were first cultivated, farmers
stirred the soil in order to destroy the weeds.
They did not then fully realize that stirring the
soil aided the growth of the crops. They did
discover, however, that when the weeds were
destroyed much better crops were produced, and
thus the weeds forced farmers to stir the soil and
allow the air, so necessary to the plants, to circu-
late among the roots.

Now that farmers have learned the real reason
for cultivation at the proper times, whether there
are weeds present or not, the destruction of
weeds assumes a different aspect.

Weeds are a detriment in many cases from the
fact that when proper precautions are not used
they take possession of areas of land so that it is
impossible to grow useful crops.

There are two general classes of weeds, an-
nuals and perennials.

284 LUTHER BURBANK

Annual weeds reproduce themselves by seeds
which mature each season, usually in great abun-
dance. Perennials, in cold climates, although
most of them produce seeds, also perpetuate
themselves by storing food and living matter
under the ground where the life of the plant is
protected until spring. Many perennials have
underground stems which are sent out in all
directions. From each node a new plant may
grow under the proper conditions.

It is obvious that such weeds are most difficult
to destroy because, although they may be pre-
vented from bearing seeds, they distribute them-
selves over large areas.

The handling of annual weeds is summed up
briefly in one sentence: Prevent the production
and the introduction of seeds. But with the
perennials not only must the introduction and
production of seeds be prevented, but the entire
plant must be uprooted and destroyed.

When perennial weeds have taken possession
of an area of land, they may generally be brought
wholly under the control by thorough weekly
cultivation during one or two seasons. This
often means that one or more crops must be
sacrificed. Every weed on the entire area must
be destroyed as soon as — and with some kinds
before — it appears above the surface.

LAWN BEAUTIFICATION 28.5

The vitality and food provided by perennials
in most cases does not keep the plant alive more
than one season. The plant depends upon its
store of food being replenished by another
growth each season. If the leaves cannot develop
above the ground, so that raw mineral food col-
lected by the roots can be digested and stored
again underground, the plant cannot grow the
following season.

Thus it is that by cutting off the plants con-
tinually for an entire season as soon as they
appear above ground they will die out and not
appear again on that area unless, of course, the
seeds are again introduced.

Most weeds are provided with greater facilities
for reproduction and distribution than cultivated
plants. Most weeds also have some special means
for distributing their seeds over large areas.

Many of them, such as cockleburs (Xanthium),
sand burs (Cenchrus), burdock (Arctium) and
sticktights (Bidens), have burs surrounding each
seed which are made up usually of many hooks
or spines. These seeds attach themselves to the
clothing of persons and to the various domestic
animals, and are thus transferred from one lo-
cality to another.

Many of the weed seeds such as thistles, wild
lettuce, dandelions, etc., are provided with a

LARKSPURS WITH WONDER-
FUL COLORING

The colors are far more beautiful
than can possibly be reproduced on
paper.

LAWN BEAUTIFICATION 287

feathery portion which assists their carriage by
the wind.

Other seeds are borne in pods which, when
dry, open with a suddenness which throws the
seeds great distances.

Some seeds are borne in fruits which are
relished by birds and animals. The seeds in this
case are usually small and are provided with a
hard coating so that they are not destroyed by
digestion in the bird's or animal's stomach, but
are carried great distances and on reaching the
ground are usually in best condition to ger-
minate.

Most weed seeds have the ability to retain their
vitality for a long time. Farmers who have
plowed fields deeply have sometimes noticed that
a certain weed which was present the year before
plowing disappeared entirely for two or three
years only to reappear again later. This was
due to the fact that the seeds were placed by the
deep plowing several inches below the surface,
and when the soil was plowed deep again they
were brought nearer the surface. In some cases,
seeds have been known to retain their vitality for
twenty years or more.

Although weed seeds are provided with many
more contrivances to secure a wide distribution
than those here mentioned, this is not the only

288 LUTHER BURBANK

provision for their perpetuation. Living as they
do among many discouragements and difficulties
it has been necessary for them to provide protec-
tion for the plants themselves against unfavor-
able weather conditions and against animals.
Some weeds have the ability to withstand long
and severe droughts while others are able to grow
where there is a superabundance of moisture.
Some are able to withstand extremely low
temperatures.

Protection against destruction by animals is
afforded by spines, thorns, bitter juices, and
poisons.

Understanding these provisions of nature for
the production and perpetuation of weeds it is
quite apparent that prompt and efficient methods
must be used by farmers and gardeners in de-
stroying them on first appearance.

A few mustard, thistle, or dandelion plants
which seem harmless because there are so few,
may spread to such an extent that in a few years
it will cost thousands of dollars to rid an infested
area from the pest which, if destroyed while still
few in numbers, would have cost only a few
dollars or dimes.

Weeds are much like a leak in a boiler or a fire
let loose. They are easily attended to at first,
but lead to destruction if proper attention is not

LAWN BEAUTIFICATION 289

given in the beginning. Never is the old saying
"A stitch in time saves nine" better exemplified
than in the case of weeds.

As has already been intimated, many fields are
infested with weeds through the introduction of
the seeds in the seeding of the crops to be grown.
Weeds that thrive particularly well with certain
crops sometimes produce seeds so like the seeds
of the crop in size and appearance that it is often
practically impossible to separate them.

In many sections a weed known as corn cockle
(Agrostemma) is a pest in wheat fields. So
nearly do the seeds of the corn cockle resemble
the kernels of wheat in weight and size that for a
long time it was almost impossible to separate
the cockle seeds from the wheat. This, of course,
caused millers a great deal of trouble, for the
corn cockle seeds have a black shell about them
which discolors the flour. Finally a special
machine was constructed for the removal of
cockle seeds.

The perennial morning-glory, commonly called
the devil's-shoestring, has often palmed seeds off
for wheat among screenings fed to poultry, being
about the same size and has established itself on
much of the best soils in California.

The darnel (Lolium) commonly called cheat,
infests grain fields in some sections and so well

Vol. 7— Bur.

290 LUTHER BURBANK

have the seeds masqueraded that many farmers,
thinking their seed was thoroughly clean, later
found this weed and have believed that the seeds
changed into wheat, barley, oats, or whatever the
grain happened to be.

This mimicry, of course, is developed by evolu-
tion. That is, those seeds which are most nearly
like the seeds with which they are mixed are over-
looked in cleaning and remain to perpetuate the
race. After many generations of this sort of
natural selection, the seeds constantly tend to
approach the grain seed in form, size, weight,
and color.

Seeds do not change their botanical characters
as farmers sometimes suppose, but, having a
hard coat, may lie in the ground until a wet
season when the grain is destroyed and the weed
takes its place.

Many States have long maintained official seed
inspection for purity. Now there is a United
States law of similar nature. These laws have
been so well enforced that there is not so much
danger now of infesting land with weed seeds as
was the case a few years ago.

Farmers who make a practice of buying grain
for seed from their neighbors or other persons
who have not had their seeds examined by in-
spectors are likely to have their fields infested

LAWN BEAUTIFICATION 291

with noxious weeds. From a small sample, the
quantity and kinds of weed seeds may be de-
termined. This is especially true of alfalfa,
clover, and lawn grass seeds.

If the sample contains weed seeds, it had better
be rejected, for there are always weeds enough to
contend with without sowing more.

Grains, clovers, and grass seeds are far more
apt to have foreign seeds mixed with them than
any other class of seeds as they are usually har-
vested by the wholesale, weeds and all, and it
is only by careful screening that the other seeds
can be removed. With seeds of hoed crops, such
a condition does not exist.

It is impossible,, of course, to give here a com-
plete description of all the different kinds of
weed seeds, but pictures are given in the natural
color of some of the most common ones. By
comparing the seeds with these pictures it will
usually be possible to determine the kind of
weeds that are found in your locality.

Of course, one must always expect to find a
few foreign seeds in a sample of grain, but re-
member that the weed seeds cost the same price
per bushel as the oats.

In orchards, especially in California, the two
worst weeds are wild morning-glory and a new
species of perennial amaranthus.

A BEAUTIFUL HYBRID
LARKSPUR

It is difficult to see how this hybrid
larkspur could be improved upon as
to the symmetrical development of its
flower cluster, and the uniformity and
excellence of its individual blossoms,
nearly all of which, it will be seen, are
in full bloom at the same time. But
there are almost numberless varieties
of equal merit among our hybrid lark-
spurs. (Nearly one-half life size.)

LAWN BEAUTIFICATION 293

Both of these produce many long and persist-
ently sprouting roots. The morning-glory sends
its roots to great depths and has taken possession
of many acres of the best land. This, of course,
greatly reduces the production of crops and the
value of the land.

The overrunning of a field is due to the fact
that the owner of the land was careless in not
destroying the morning-glories when they first
appeared. This weed spreads in all direc-
tions like a fire and its spreading is increased
by ordinary cultivation, as small portions
of the roots are carried by the cultivator to
other locations where they soon grow into new
plants.

It is extremely difficult to exterminate the
perennial morning-glory in orchards and vine-
yards because the ordinary cultivating machinery
does not run close enough to the rows. The only
way to exterminate this weed is to spend all the
time and labor necessary for one whole season in
cutting off the plants before they appear above
the surface. This may be done with a cultivator
made with sharp knives that run under the sur-
face. It will be necessary to go over the ground
regularly at least once a week. If this pest is
allowed to produce any foliage it gives the plant
a new start.

294 LUTHER BURBANK

The common amaranthus produces an enor-
mous amount of small black seeds. It is an
annual and is often called careless weed, because
it is seldom found in abundance except on land
that has been carelessly cultivated. Thousands
of seeds are produced by a single plant and they
come up during summer and thrive especially
well on rich fertilized soils.

The common amaranthus, however, is almost
harmless when compared to the new perennial
species which has lately been seen in many public
grounds, and is rapidly spreading to farms and
gardens. This new weed, unlike the annual,
sends down long slender roots deeply into the soil
and if cut off, no matter how deeply, will imme-
diately sprout with redoubled vigor.

But this is not the worst.

Like the annual, its sole object seems to be to
produce enormous quantities of seeds. This new
pest trails instead of growing upright and begins
to produce seed almost as soon as the plants
appear above the ground. This seed production
is continued perennially as long as the plant lives.

The only method of destroying this is to cut
off the first plants which appear, and apply a
small quantity of salt or sulphate of iron on the
cut portion of the root, at the same time burning
every portion of the plant removed.

LAWN BEAUTIFICATION 295

Mustard, wild radish, and wild lettuce, though
annuals, are often difficult to exterminate as they
are abundant seed producers. The best method
of exterminating these is to destroy each plant
before it has time to ripen seed.

Usually it is possible partially to rid the land
of them by plowing it thoroughly early in the
spring and growing some cultivated crop.

Sheep sorrel or redweed, sometimes called
"shamrock," is another most persistent weed,
very hard to exterminate if once established,
especially in lawns and moist shady places. It is
a persistent producer of runners, as well as seeds
that are projected a great distance when ripe.

It seeds abundantly when the plants are quite
young. As the seeds ripen they are projected
with great force in all directions. This is best
exterminated by unremitting destruction with
the hoe before the plants produce seeds.

There are numerous other smaller and more
insignificant weeds such as shepherd's purse, sev-
eral senecios, chickweed, and others which are
not as persistent as those already discussed, but
which should be kept well under control by
thorough cultivation if good crops are to be
produced.

It should be borne in mind that weeds are
enormously prolific, and that their seeds go

296 LUTHER BURBANK

everywhere. It does not suffice to keep your
garden weeded and your lawn well mown. It is
necessary also to pay heed to the weeds along
neighboring roads, for their seeds will be no re-
specters of your boundary lines.

You will be taking steps toward enhancing the
beauty of your lawn next season, and will be
lessening your work in the flower bed and vege-
table garden if you use scythe and hoe freely on
the weeds growing along the roadside everywhere
in the neighborhood of your grounds.

No effort that you could bestow would have a
larger influence toward the beautification of
your next season's lawn, and the lightening of
your labors in next season's garden than that
devoted to the destruction of this season's crop
of weeds, wherever found.

FLOWERS; AND THE DISPOSITION OF TREES

Probably color is the most attractive thing
about flowers. Usually solid colors are more
attractive, but harmonious combinations are
almost as valuable.

A graceful form probably comes next in
attractiveness.

Size and abundance of bloom next. Size does
not always happen to be an advantage. Some
flowers, as the heaths, are attractive because of

LAWN BEAUTIFICATION 297

the smallness of the blossoms. In this case the
small size really adds gracefulness to the plant.
Where the blossoms are small more are needed
to make a good effect, so improvements on
flowers with small blossoms should be made
along this line where needed.

Everyone must be his own judge of harmony
in the colors of plants. Most persons have a
natural sense of harmony to direct them to the
combination of colors desired.

White is harmonious with all colors. A deep
red is not harmonious with blue, except some-
times with a pale blue. The sense of distinguish-
ing harmonious combinations of colors has been
more developed since aniline dyes were intro-
duced. This is principally because with the ani-
line dyes almost any shade of color can be made.
Before their introduction the unusual shades
were not often seen, some of them never before.

All the prismatic colors are beautiful and
attractive in their proper place. The delicate
shades of each of these colors are even more
pleasing to the average educated mind. Red is
the most insistent color. Yellow and orange are
next. White is insistent. Black is insistent.

In selecting flowers the aim should be to select
those that are striking, harmonious, pleasing,
and new in respect to color. In order to be able

THE BOTTLE-BRUSH BUSH

This is a shrub from New South
Wales; a rather tender plant, but
thriving outdoors at Santa Rosa. It
belongs to the myrtle family.

LAWN BEAUTIFICATION 299

to select flowers for color one must be thoroughly
familiar with all of the colors in each variety
now in existence. Now that there are thousands
of people seeking for new varieties where there
was one before it often happens that two or more
persons will develop new varieties almost ex-
actly alike at the same time. For this reason,
it is perhaps better to work with plants that are
not so common.

Each new flower should be developed for
some definite purpose. Red is an appetizer even
to the birds. They will always eat the red fruit
before that of any other color. Red flowers are
good for the dining-room and orange or yellow
will serve the same purpose almost as well.
Delicate shades are needed for the parlor, draw-
ing-room, sleeping rooms, and libraries. A pale
blue is very good, and pinks and combinations of
pink, rose and white are especially pleasing. It
is also desirable to have a bright color occasion-
ally in these rooms where more quiet flowers are
kept. This gives a dash and spirit that is
needed.

Practically all colors blend well with gray or
brown as a background.

Flowers banked around the foundation of a
house represent an unconscious exhibition of
advanced civilization.

300 LUTHER BURBANK

Vines give a peculiar grace to architecture,
softening too angular lines, and subduing unat-
tractive colors. Green vines blend with any
color.

Flowers harmonize with all surroundings and
subdue undesirable forms and colors. Borders
of flowers break the hard angles between a build-
ing and the ground. Perpetual bloomers and
perennials are especially good near buildings.
The tall ones should be placed close to the build-
ings and the small ones in front. The smaller
flowers are better on the lawn, in borders, or
near the street. It is not well to put too many
plants in bunches in front of the home. A single
tall plant here and there sometimes lends an
artistic effect. Usually when tall plants are
placed near the sidewalks or the roads, it is best
to have those with thin foliage.

Colors should, of course, be those that attract
and please the inhabitants. It is never, however,
well to have a predominance of red. Flowers
about the house serve to keep those living there
in good spirits, adding a cheeriness that tends to
keep people happy. White is always a good
color. Blue is appropriate but must be accom-
panied by red or yellow, otherwise it gives a
cold effect. Purples and deep crimsons do not
always blend as well as other colors.

LAWN BEAUTIFICATION 301

HEDGES AND TREES AND SHRUBS

The larger trees should generally be in the
rear of the house. Fruit trees should be back
of the house or to one side. The trees that shed
their leaves should be on the south and east sides
of the buildings to shade in summer and to allow
the sun free access during the winter. This
leaves the evergreens for protection and orna-
ment during the winter.

Trees with plenty of summer foliage should
be planted on the southwest to protect the house
from the hot sun in the summer. On large
estates oaks and elms and the larger trees
may well be planted even in front of the home.
Evergreens, especially tall ones, should usually
be set out rather sparingly. Do not put them
too close to the house, as they keep out the
sunlight and make the house cold and dark.
A number of evergreen shrubs are, however,
always desirable for winter decoration of the
place.

Palms are pleasing in a warm climate, but
must not be crowded, for they will not be able
to exhibit their grace and beauty and will suffer
from lack of light and air. Usually the best way
is to plant an abundance of trees and shrubs,
later removing those that are not needed. Some-

302 LUTHER BURBANK

times it takes great courage to cut out part of
the trees, especially if some of them have become
favorites, but it will be to the detriment of the
place as well as other trees if the thinning is not
done at the proper time. Evergreen trees and
evergreen shrubs should be allowed to grow
close to the ground.

It may be of interest to add the names of a
few of some desirable ornamental trees and
shrubs, though wholly incomplete, and many of
those here mentioned are only suitable for mild
climates.

Trees for ornament : Arbor Vitses, Big Tree,
Lawson Cypress, California White Fir, Silver
Cork Fir, Maidenhair Tree, Silver Pine, Doug-
las Spruce, Tideland Spruce, White Ash, Bass-
wood, Birches, Kentucky Coffee Tree, White
Elm, American Holly, Magnolias, Oaks,
Maples, Walnuts, Palms, Dracaenas, Laurels,
Cypresses, Lindens, Junipers, etc.

Shrubs for ornamental planting and lawn
decoration: Black Alder, Andromeda, Jap-
anese Barberry, Button Ball, Spanish Bayonet,
Chokeberry, Flowering Dogwood, Inkberry,
Jersey Tea, French Mulberry, Wild Roses,
Strawberry Bush, Sumach, Sweet Shrub, Wax
Myrtle, White Fringe, Wistaria. These are
all hardy in most or all of the Eastern States.

LAWN BEAUTIFICATION 303

To mention those suitable for mild climates
would take many pages.

Shrubs for windbreaks, hedges, barriers : Black
Alder, Arrowwood, Mountain Ash, Barberry,
Chokeberry, Coral Berry, Flowering Dogwood,
Wild Grapevines, American Hazelnut, Huckle-
berry, French Mulberry, Russian Olive, Osage
Orange, Sassafras, Waxberry, White Fringe,
and Witch Hazel.

For street planting it is necessary to select
carefully such trees as will not grow too large,
and generally those which will not bear fruit or
nuts or shed too many leaves, and evergreens
are not often the best, especially where shade is
desired. There are many trees well adapted 'to
this purpose. For wide streets and roads the
American Elms, Maples, Linden, Tulip tree,
Weeping Birch, etc. For subtropical climates,
Palms, Dracaenas, Magnolias, Grevilleas, Pep-
per Trees, Laurels, Umbrella Trees, Camphor
Trees, Eucalyptus, Acacia, and innumerable
others.

THE FIELD AND FLOWER
GARDEN

SOME PRACTICAL HINTS FOR THEIR
BETTERMENT

MANY have thought that decreased yields
are always due to the exhaustion of
certain chemicals from the soil. This is
not always the case. In fact, it is seldom
that decreased yields are due to the lack of
plant food.

Plant origination, the highest type of work
with plants, has shown the underlying principles
of soils and their use. The results of fifty years'
work in getting best results from the soil are here
summed up in such a way as to show the under-
lying principles of crop production.

These principles are applicable on every farm,
and may be applied in increasing the yield of
any crop.

Years ago farming and gardening were "hit
or miss" performances. Farmers tried methods
because some one else had used them, and but

305

306 LUTHER BURBANK

few of them knew the reasons for any of the
operations.

In order to understand how to select soils and
how to secure the best results from them, one
must know the underlying principles of produc-
tive ability of soils and the methods used by
plants to secure food from them.

Farming is now considered a manufacturing
process. As a matter of fact, a farmer uses more
kinds of raw materials and produces more kinds
of finished products than any other manufac-
turer. It is just as necessary that he select his
raw materials with extreme care as it is that the
manufacturer of machinery select the most
durable kinds of wood and the strongest kinds of
metal.

Farmers have sometimes been criticized for
not using more fertilizers, but this is not always a
just criticism. Fertilizers are valuable in some
cases, but often a better physical condition of the
soil would make it possible for the plants to se-
cure enough food materials to increase the yield
materially without adding fertilizers, and too
often the crop produced would not repay for
the purchase of fertilizers.

Profit in crops depends upon the location of
the crops grown, the use to which the crops are
put, and the cost of fertilizing when fertilizing is

THE FLOWER GARDEN 307

necessary. There are other things which affect
the profits, but these are the underlying factors.

No definite rules can be given about handling
the soil, for each one must work out his own
practice according to his own conditions.

The value of soil depends upon its texture, the
elements it contains, the exposure, location, nat-
ural drainage, the availability of the elements
required to keep up its productiveness, etc.

A well-drained alluvial soil of fine texture is
the most productive for average crops. Further-
more, it is usually most durable in its productive-
ness. That is, its valuable qualities continue to
manifest themselves year after year.

Other things being equal, a field located in a
comparatively level valley or plain is more val-
uable than one on the side of the hill. Often the
soil on the side of a hill is rather thin and there
is always the danger of washing. Rains come
and carry the most valuable part of the field into
the valleys below.

Of course, hillside fields are valuable for some
crops. In some cases, where the soil is rich, even
better results are obtained on the hills than in
the valleys. This is especially true in California
and the semiarid sections.

North and east slopes are usually best for late
crops, but the south and west slopes are always

308 LUTHER BURBANK

better for early crops. A slope toward the sun
even of only one or two inches to the rod makes
a difference in earliness of a week or more. This
has been proven by many experiments.

The northern and eastern slopes hold the
moisture longer, but do not warm up so quickly.
For this reason they are able to withstand
drought better, but never yield as early crops as
the southern or western slopes.

A clay subsoil a foot or more below the surface
with a sandy surface layer is the ideal soil for
fruit trees. In fact, such a soil is good for most
any crop. If the subsoil slopes sufficiently to
drain off surplus water, such a soil will always
produce good crops.

CHEMISTRY AND PHYSICS OF THE SOIL

Plants secure their food from the soil through
minute hairline appendages on the roots, known
as root hairs. The roots thus serve only as
canals. The root hairs collect the food.

Because of the extremely small size of these
root hairs it is plainly seen that any food used by
the plant must be thoroughly dissolved before
being taken up. These root hairs are deciduous
like the leaves, and are only active to any extent
where the leaves are in existence and active. All
food taken up by the roots is secured in solution

THE FLOWER GARDEN 309

and this makes it necessary to keep the soil
properly supplied with moisture.

The presence of the proper chemical elements
and moisture, however, is not the only thing that
is needed for the root hairs to do their work well.
Air must be present in the soil or it will be im-
possible for the root hairs to secure the necessary
food for the plant.

The air in the soil must mostly come from the
surface so it is obvious that it is always necessary
to keep the surface of the ground in such a condi-
tion that it will admit air. Thorough cultivation
and deep plowing keep the soil in a loose
condition.

Knowing that the plant's roots must have
plenty of air, one enjoys stirring the soil deeply
for he knows that by this method the crop will be
increased.

Cultivation must be frequent because the sur-
face of many soils has a tendency to become
rather hard and compact, especially after heavy
rains.

We may consider that there are minute tubes
leading from the surface down into the soil.
When the tops of these tubes are closed by hav-
ing the soil bake it is easy to see that the supply
of air is cut off. Stirring the surface, then,
makes a connection with the outside air.

310 LUTHER BURBANK

Cultivation also goes far in keeping insects
and diseases under control. Many insects' eggs
and Iarva3 and many disease germs are found in
the soil. When the field is stirred frequently,
these are brought to the surface and exposed to
the hot sun and many of them are thus destroyed.

Soil is of a very complex composition, and
furthermore it is continually changing. A worm
burrows into the soil and on his way replaces and
rearranges thousands of soil particles.

As the root hair penetrates among the particles
of soil it affects a change.

The passing of moisture from one particle to
another makes changes which are of extreme im-
portance from the standpoint of fertility.

Because of this ever changing condition, it is
necessary to pay close attention to cultivation in
order to keep the conditions as near uniform as
is possible.

A soil that is not given the proper care as to
cultivation often holds its valuable food elements
like a deposit in a bank that bears no interest.

Every business man knows that it is an ex-
tremely bad policy to allow resources to lie idle,
but farmers too often do not consider the ele-
ments in the soil as resources.

There are three important ways to make avail-
able the supply of plant food in the soil: One

THE FLOWER GARDEN 311

is by stirring the soil so that the air makes it
possible for the root hairs to secure the elements.
Another is by supplying sufficient air and
moisture so that the elements in the soil will be
dissolved. And the third is by applying fertil-
izers, which supply the plant foods needed, in an
available form.

It does not always follow that when the yield
of a certain piece of land is small, that land
needs fertilizers. It is very often the case that
the poor yield is due to poor seed or shallow
culture, or other cause. If great care is taken
in selecting seed from the highest yielding
fields year after year, one will then know that
when the small yield comes it is due to some-
thing else.

Expensive fertilizers are sometimes added
when a thorough stirring of the soil, drainage, or
irrigation would accomplish the same result.

Soil that is producing fruit crops needs less
fertilizing than that producing grain crops. The
fruits contain such a large percentage of water
that the essential elements of fertility are ex-
hausted from the soil very slowly.

On the other hand, grain contains a large per-
centage of the essential elements of soil fertility
and it is necessary to add fertilizers to grain
fields much more often than to orchards.

A SELECTED NIGHT-BLOOMING
CEREUS (C. strictus)

This very fine specimen is the result
of careful selection from large numbers
of seedlings. The flowers of this
variety are nearly nine inches in
diameter. They open early in the
morning and are completely withered
by ten or eleven o'clock. It will be
noted that two of the blossoms on the
right-hand stalk have withered and that
they are marked with strings to indicate
that their seed is to be saved for future
experiments.

THE FLOWER GARDEN 313

Now that the fertilizer manufacturers are
under government supervision it is safe to use
any good standard fertilizer on the market.
Many experiments have been conducted to de-
termine the right element in which the soil is
lacking and supply that alone.

The analysis of soils has often proven of value,
especially in scientific researches, but it is not
practical for the average farmer to have a chem-
ical analysis made of his soil to determine what
kind of fertilizer should be used.

In practically every case good barnyard
manure gives excellent results. In the same
way a fertilizer purchased in the market usu-.
ally gives the results desired. Because of the
complexity of the soil and the complexity of the
requirements of the plants so far as different
elements are concerned, it is plain to see that
it seldom or never happens that any one
element is wholly eliminated from the soil
at a time.

Sometimes an element which appears to be
exhausted from the soil is merely in an unavail-
able form. The addition of other elements in
such a case, although they do not seem to be
needed, may produce the required results be-
cause they assist in changing the unavailable
elements to an available form.

314 LUTHER BURBANK

Nitrogen usually has the most immediate and
pronounced effect upon crops when it is applied
in fertilizers. Nitrogenous fertilizers always
produce quicker results, and when it is desired to
get early crops, these are the ones to use,
especially in the early part of the season.

Nitrogen is quite often in the form of am-
monia in the fertilizer. Ammonia is very
volatile and escapes into the air rapidly if not
properly incorporated. A commercial product
that has a strong odor indicates that the am-
monia is escaping into the air.

Use a fertilizer when it is absolutely necessary,
but make sure first that some cheaper process,
such as cultivation, irrigation, drainage, or
rotation of crops, will not accomplish the same
result.

The physical condition of the soil in practi-
cally every case is more important than the chem-
ical condition, that is, it has a more direct effect
upon the crops.

INCREASING CROPS BY ROTATION

Many flower lovers have been dismayed at
having a favorite collection of lilies almost en-
tirely destroyed by insects. Such a disappoint-
ment can generally be prevented by moving the
lily bulbs.

THE FLOWER GARDEN 315

Great fields of grain have produced smaller
yields year after year until it was finally impos-
sible to grow a profitable crop at all.

The remedy is rotation.

Each grower must be his own doctor, however.
There is no short cut to profitable crop yields.
They are obtained by the man who understands
the bad effects of growing the same crop on one
field year after year, and who knows that these
effects can be avoided by making a change in
crops.

Every horticulturist and every agriculturist
should study what follows carefully. It tells
why failures come, and why rotation forestalls
such failures.

There are at least four important reasons why
rotation of crops is necessary.

In the first place, insects which often gather
in great numbers about certain plants are de-
stroyed, or at least their number is reduced when
other crops are grown on the land. This is
because certain insects are adapted to depend
upon certain plants for their nourishment.
Lilies and amaryllis are often almost completely
destroyed by such insects as mites, small centi-
pedes, wire worms, eelworms, etc.

Absolutely new, uncultivated soils seldom are
troubled. It is mostly in gardens where plants

316 LUTHER BURBANK

from various quarters are grown that difficulty
occurs.

These pests gather around the lower part of
the bulb and if the bulbs are left in the same
place several years the insects often destroy them
completely.

Although this is not generally known, it is the
common cause for the destruction of lilies.
Many have had beautiful lily beds exterminated
and have been unable to determine the reason.
Often by transferring the bulbs to another loca-
tion, if thoroughly disinfected before replanting,
they can be saved.

If gladiolus bulbs, for instance, are planted in
the same place year after year, they do not thrive.

Usually there are fewer and fewer bulbs as
the seasons progress, rather than more, and those
that are produced are much smaller than the
bulbs originally planted. The plants are also
sooner or later destroyed.

The third year the crop is almost a complete
failure. It is especially necessary to practice
rotation of crops with gladiolus and lilies.

The same thing is more or less true with most
other bulbs, as most of them have a bitter poison
or protective principle that repels these insects.
Some of them, of course, are not quite so sus-
ceptible to the ill effects as others.

THE FLOWER GARDEN 317

Various bacterial and fungous diseases also
attack plants that are grown in one place year
after year. These organisms, although they may
not be entirely destructive the first year or two,
gradually multiply and become a greater pest
from year to year.

When trouble arises from this source the
remedy is to rotate the crops or, in other words,
move the crop infested to another location.

Fungous diseases are especially destructive in
potato fields. The potato scale, blight, and wart
are well-known diseases which can often be
wholly or partially controlled by the proper
rotation and the planting of uninfected seed.

The third cause for failures is the unfavorable
condition of the soil produced by the toxic sub-
stances thrown off from the growing plants.
Plants, like animals, give off waste matter which
is not only useless but poisonous to the plant
itself, and often to other plants of similar
nature.

These toxic substances are often less poison-
ous, and in some cases are beneficial, to other
crops. It is obvious that when waste products
from a certain crop have accumulated in the soil
for a number of years, that soil is not as well
suited to the crop as formerly. A change of
crops practically always results in a more profit-

318 LUTHER BURBANK

able yield because the waste products of the first
crop are often not injurious to the second one.

The fourth cause, which is far less common
than the others, is exhaustion from the soil of
certain elements necessary to plant growth.

It is very seldom indeed that any one of the
elements necessary to plant growth is wholly
absent from any kind of soil. It does happen
sometimes, however, that an element is not
present in available form. The plant's roots, of
course, cannot take up certain elements that are
in such a form that they cannot be absorbed.
When the supply of material in the form that can
be used is exhausted, the plant does not thrive.

Quite often the failure of crops when it can be
definitely attributed to the condition of the soil
is due to an unfavorable physical condition rather
than an unfavorable chemical condition.

Rotation of crops often has an important and
essential effect upon the physical condition.
When alfalfa, cowpeas, clover, or some other
legume is grown, the roots grow deeply into the
soil and when another crop follows, the fissures
or canals opened up by these deep growing roots
are used by the roots of the new crop, besides
storing considerable nitrogen. In this way it is
much easier for the following crop to permeate
the soil where there is plenty of moisture. The

THE FLOWER GARDEN 319

roots can develop much more quickly and with
less effort than if the deep-rooting crop had not
been grown on the soil before it.

It is quite evident that the addition of barn-
yard manure has almost as much beneficial effect
upon the physical and bacterial condition of the
soil as upon its chemical condition.

The effects of rotation are most astonishing as
shown by the results attained especially in Cali-
fornia when grain follows a corn crop. There is
usually fully twice the yield secured from the
small grain crop following a crop of corn than
when small grain follows a crop of small grain.

No doubt, the cultivation given the corn dur-
ing the summer has much to do with putting the
soil in the proper physical condition for plant
growth. This cultivation destroys more of the
microscopic organisms which are injurious to
plant life, and releases elements which otherwise
would be unavailable.

With the present varieties of plants, it will
probably always be necessary to practice rotation
of crops. But when plants are developed whicK
are resistant to the various conditions which have
been mentioned, rotation will perhaps not be so
necessary.

Already certain plants have been developed
which are resistant to numerous diseases and

320 LUTHER BURBANK

insects. Varieties of grapes are grown which re-
sist the attacks of phyloxera, and apples which
are resistant to the attacks of aphis are well
known.

Peaches and almonds which are not subject to
curl leaf have been developed.

Plums which are not affected by the brown rot
and plum pocket are now on the market, also
cherries, pears, walnuts, and perhaps chestnuts,
which are resistant to blight.

Because of the value to be secured from crops
which need not be rotated, too much emphasis
cannot be placed upon the importance of devel-
oping new plants for this purpose which are
resistant to the various pests.

It will almost always be found that in fields
badly affected with some disease or insect there
are one or more plants which are not affected as
seriously as the rest of the crop. By selecting
such plants and perpetuating them by seeds or
division, a new variety may eventually be pro-
duced that is resistant to the particular disease
or insect which caused the damage.

If resistant plants were developed many old
field and garden soils which have become worth-
less for certain plants could be made to produce
profitable crops. Such soils are quite often thor-
oughly infested with numerous insects and dis-

THE FLOWER GARDEN 321

eases and the failure of crops is due more to this
than to the lack of proper chemical elements.

It is possible to get resistant varieties of vege-
tables, grains, flowers, and trees and the process
is the same in all cases.

Nature practices rotation of crops in the
forest. A forest of hardwood trees is almost
always replaced by softwood trees. After these
have grown on the land for some years, they are
replaced by hardwood trees. And so the rotation
continues.

This is not intended to be a complete discus-
sion on the rotation of crops. It is the principles
which underlie the practice that are of the most
fundamental importance.

It is impossible to suggest any definite kinds
of rotations which will be applicable under all
conditions. Each person must familiarize him-
self as much as possible with the underlying
principles and determine the rotation that is
needed under his own special conditions.

The physical condition of the soil
in practically every case is more
important than the chemical con-
dition; that is, it has a more direct
effect upon the crops.

Vol. 7— Bur. K

THE ALMOND AND ITS
IMPROVEMENT

CAN IT BE GROWN INSIDE OF THE
PEACH?

IN THE early years of my experimenting,
soon after commencing the importing of
plants, I had crossed the Japanese plum with
the almond.

The cross was made without very great diffi-
culty, and the results were exceedingly interest-
ing. Each species was fertilized with the pollen
of the other, and here as elsewhere it appeared to
make no particular difference in which way the
cross was made.

The hybrid seedlings partook somewhat of the
character of the earliest of the hybrids produced
by crossing the plum and the apricot. Most of
the seedlings outgrew either parent, their en-
hanced vigor suggesting that of the hybrid wal-
nuts. But, on the other hand, some of them
almost refused to grow at all, being perma-
nently dwarfed, and in this regard suggesting

323

324 LUTHER BURBANK

a certain number of the second generation of the
walnut hybrids.

This wide diversity of form and vigor in the
first-generation hybrids is a rather unusual phe-
nomenon. As a rule, we have observed that first
generation hybrids are somewhat uniform in
character, and that the tendency to wide diversity
appears in the second generation. Attention has
more than once been called to the fact that the
discovery that such is the tendency among
hybrids was the one that put me on the track
of most of my successful plant developments.

At the time when these experiments in hybrid-
izing the Japanese plum and the almond were
commenced, there were few, if any, other plant
experimenters anywhere in the world who had
fully grasped the principle that variation occurs
in the second generation, and that it is by raising
large numbers of second-generation hybrids from
which to make selection that the development of
new and useful varieties of plants may best and
most rapidly be carried out.

This principle is so familiar to-day that horti-
culturists and botanists who refer to it very com-
monly overlook the fact that the recognition of
the principle is very recent.

Thirty-five years ago I found it impossible to
convince most well-known horticulturists, bot-

THE ALMOND 325

anists, and biologists — with many of whom I had
some spirited discussions on the subject — that
the great individual variations occur in the second
and a few succeeding generations.

To-day all these men, in common with horti-
culturists and biologists in general, acknowledge
that these variations and recombinations do
occur.

Indeed, nothing more is necessary than the
most casual inspection of the new varieties that
have been developed at Santa Rosa in the
intervening period to establish the validity of
what was generally regarded as a heretical view
only thirty-five years ago.

And yet the case of the first-generation hybrids
between the Japanese plum and the European
almond, showing the wide diversity just re-
corded, suggests that it is not always easy to lay
down rules of thumb. Observation of the phe-
nomenon of plant development in the field may
present complexities that make the sifting out of
principles difficult. No one whose first hybridiz-
ing experiments happened to be performed with
chance hybrids of the plum and almond, and who
saw among his first-generation seedlings all the
range of forms from dwarfs to giants, would
have been likely to conclude that the first-gen-
eration hybrids are generally uniform in char-

THE ALMOND AND ITS
RELATIVES

Here, reading from left to right, are
shown the peach, the almond, and the
nectarine. The peach and nectarine
are regarded as variant examples of
the same species. The almond crosses
readily with either, producing interest-
ing hybrids.

THE ALMOND 327

acter and that variation takes place in the second
generation.

Looking back now, and being able to check the
observation with knowledge gained through
noting the effect of hybridizing many hundreds
of other species, it is interesting to make in-
quiry as to why the first-generation hybrids of
the plum and almond showed such anomalous
diversity.

The answer may probably be found in the as-
sumption that either one parent or the other was
itself a hybrid. Perhaps both parents were
hybrids. The fact that almonds are known to
cross with the peach and the nectarine — to which
reference will be made more at length presently
—lends color to this assumption. And of course
there is no question that the Japanese plums are
largely hybridized. In a word, then, the hybrids
produced by cross-pollenizing the Japanese plum
and the almond were probably in reality second-
generation hybrids having the strains of other
species than the almond and the Japanese plum
in their heredity.

Be this as it may, the facts as to the curious
diversity among the plum-almond hybrids have
more than passing interest.

It should further be recorded that the diver-
sity in size was matched by the wide range of

328 LUTHER BURBANK

diversity in minor characteristics. The bark and
leaves varied extensively among the different
hybrids; on some trees the buds were round and
plump, and on others long and sharp. Many of
the trees produced somewhat abundant blossoms,
and the individual blossoms varied widely in color
and in size.

But there were other trees that produced no
blossoms whatever under any circumstances.

These would form great clusters of buds, but
instead of bursting into flowers the buds would
drop off and later ordinary branches would come
out in their stead.

In the case of buds already opened to form
flowers, the blossoms not only varied as to size
and color, but they showed the most astonishing
diversity as to their essential fructifying organs.
Some of the blossoms had numerous pistils and
no stamens. Others had numerous stamens and
no pistils. In yet other cases there were blos-
soms having stamens and pistils, but absolutely
without petals.

In no case was fruit formed. The blossoms one
and all were sterile.

An attempt was made to fructify the blossoms
by pollenizing them with pollen from each of the
parents. But this effort was futile. The ovaries
were seemingly incapable of maturing.

THE ALMOND 329

It would appear, then, that the Japanese plum
and the almond, as represented by the particular
specimens that were used in these hybridizing
experiments, were just at the limits of affinity
that permitted cross-fertilization, but imposed
sterility on the offspring. The parents were a
shade more widely removed from each other
genetically than were, for example, the plum and
the apricot or the Persian and California
walnuts. This fact, and not the mixed ancestry
of either parent, may have accounted for the
diversity of form of the progeny.

As the plum-almond hybrids were sterile, it is
obvious that the experiments through which I
had hoped to develop new varieties and perhaps
new species of fruits could go no further in this
direction. It is of course possible that individual
plums and almonds or different varieties of the
two races might be found that would combine to
produce fertile offspring. This supposition finds
support in the fact that my earliest crosses be-
tween the plum and the apricot were also sterile ;
whereas later ones produced the fertile plumcot,
as the reader is aware.

So it is obviously worth while to continue the
experiments of hybridizing the plum and the
almond, and there is reason to hope that interest-
ing and valuable results may be attained.

SELECTED ALMONDS

It has been suggested, not without
plausibility, that the almond represents
somewhat closely the primitive type of
stone fruit, from which all our other
stone fruits have been developed. Be
that as it may, the leathery covering of
the present-day almond is something
strikingly different from the pulp of
the peach or plum or apricot.

THE ALMOND 331

My own experiments, however, although they
have been repeated occasionally and have never
been quite lost sight of during the thirty-five
years that have intervened since the first tests
were made, have produced only the anomalous
results just related. Yet even these, in addition
to their scientific interest, may be thought to
point the way to more practical developments.

At least they prove that there is no barrier
between plums and almonds that may not be
partially broken down.

THE ALMOND CROSSED WITH PEACH AND
NECTARINE

Since the almond can be crossed with the plum
it may reasonably be expected that mating would
be effected with its closer relatives, the nectarine
and peach, with even greater facility.

In fact, it has been observed that the almond
crosses with the nectarine so readily that it is
practically impossible to prevent cross-fertili-
zation when the two trees grow in the same
neighborhood. The bees appear to visit them
indiscriminately, and to effect hybridization so
commonly that it is impossible to raise fruit from
the seed with any degree of certainty when there
has been an opportunity for cross- f ertilization ;
this, however, does not very commonly occur

332 LUTHER BURBANK

as the almond blooms long before the peach.
The same thing is true, as might be expected,
of the peach; which, as we have elsewhere
seen, is scarcely separable botanically from the
nectarine.

Most varieties of almond blossom very early
in the season, before nectarines or peaches are in
bloom. But where the trees are blossoming at
the same time in the same neighborhood the bees
are almost certain to mix them indiscriminately.

It is not unusual in California where almonds
and peaches are growing in the same orchard,
and where peach seeds are planted, to have sev-
eral of the seedlings exhibit marked character-
istics of the almond ; or, contrariwise, to find that
a number of the almond seedlings show the char-
acteristics of the peach.

This, of course, is perhaps sometimes annoy-
ing to the practical grower, but it suggests in-
teresting possibilities for the plant developer.

Wishing to see just where the experiments
might lead, I have crossed the almond with the
nectarine, using great care to make sure that the
experiment was not vitiated by accidental pollen-
izing. In some cases I have used the old and
generally useless method of tying a sack over the
flower, which I do not usually consider necessary
in pollenizing if properly performed.

THE ALMOND 333

Hybridizing experiments of this type were car-
ried on somewhat extensively for at least fifteen
years. I have thus produced a hybrid almond-
nectarine that has an absolutely smooth skin, with
nothing of the roughness and tomentose condi-
tion usually found in the almond. The hybrid
reproduced the color and quality of the flesh of
the white nectarine parent as well as its smooth
skin. And as the almond quality of seed and
stone was fairly reproduced, the combination was
a very curious one — to all intents and purposes a
smooth-skinned peach, with white flesh, bearing
at its core an almond nut.

This hybrid, it may be noted incidentally, is a
most remarkably vigorous grower.

An allied series of experiments of equal in-
terest was inaugurated by hybridizing the Lan-
guedoc almond and the Muir peach, using, as in
the other case, the utmost precaution to prevent
foreign pollenization.

Many seedlings were grown from this cross
and a large number of them have been under
observation for years.

The most notable thing about these hybrid
seedlings from the outset was the tendency of
many of them to take on rapid growth. Some
of them grow several times as fast as the average
seedlings of either parent. This tendency of

SOME MAMMOTH SPECIMENS

At the left, a selected specimen of the
common almond; in the center, the
Palestine almond; at the right a speci-
men of the Big Fat almond — the
latter obviously well named. Note the
characteristic texture of the shell, which
does not vary greatly in these speci-
mens, but which differs markedly from
that of all other stone fruits.

THE ALMOND 335

hybrids to rapid growth is something that we
have seen manifested in many other cases. It is
a rather common result when species that vary by
just the right amount are hybridized. The
hybrid walnuts furnished the typical illustration
of this on the most spectacular scale.

The fruit of these almond-peach hybrids varied
widely on different trees. Sometimes the fruit
was leathery like that of the almond, but in other
cases it was edible and quite peachlike. In a
few cases the pulp was so fully developed that
it might be considered a fairly good peach. The
seed covering was usually in the shape of an
almond and smoother, thinner, and generally
more elongated than the peach stone. It was
hard-shelled and corrugated, but had not the
texture of the peach stone. The meat within was
generally sweet or slightly bitter.

Thus the fruit of this hybrid might be said
to be fairly intermediate between the fruits of
the parents, yet on the whole the flesh of the
peach and the stone of the almond, respectively,
tended to be prepotent. This is what would be
expected, when we recall that the flesh is
the specialized modern development in the case
of the peach, and that the seed is similarly
specialized and developed in the case of the
plmond.

336 LUTHER BURBANK

We have found occasion to believe that pre-
potency or dominance is conditioned on newness
of development 5 the case of the peach-almond
hybrid gives a measure of support to this
theory.

But while the specific qualities of peach and
almond, representing their specialized develop-
ment in comparatively recent times, thus tend to
be segregated along Mendelian lines, yet the
traits in each case are of such long standing that
they do not Mendelize in the clear and satisfac-
tory way that we have seen manifested in some
other cases — for example, the color of the black-
berry, and its thorns.

There is, to be sure, a very marked segregation
in the second generation, illustrated by the most
astonishing variation among different second-
generation hybrids in the matter of size, rapidity
of growth, and almost every quality of flower and
fruit.

This variation was so marked, indeed, as to
rob the seedlings of the value they might other-
wise have had as stock for grafting. The large-
growing specimens have value for this purpose,
but the diversity among the seedlings is so great
that they cannot at present advantageously be
grown with any hope of producing dependable
stocks.

THE ALMOND 337

In the matter of the fruit, the second-genera-
tion hybrids are equally variable. There are
some specimens that tend to reproduce the
almond qualities and others that tend to repro-
duce the peach qualities. And as might be
expected there are yet others that combine the
quality of the two fruits. The best of these bear
fruits that are obviously peaches, even peaches of
good qualities, yet that have at their center what
would be at once recognized as an almond nut,
with characteristic shell and seed.

In a word, these are almonds grown inside the
peach — a combination of obvious interest.

But this anomalous fruit, notwithstanding its
interest, did not present commercial possibilities
that could at the moment be realized. The
peaches that thus bear almonds are not generally
so far of the best quality as compared with recog-
nized varieties of the best commercial peaches.
Neither, on the other hand, were the almonds
borne by these peaches of a quality to enable
them to compete in the market with the best
varieties of commercial almonds.

There is no reason to doubt that a continuance
of the experiment in which selection was made
among the best specimens of this hybrid fruit,
together with further hybridization in which the
strains of the best peaches and the best almonds

MEATS OF SELECTED
ALMONDS

These are the meats of the almonds
shown in the preceding picture, ar-
ranged in the same order, with the
common almond at the left and the
Palestine almond in the center. Al-
though these almond meats differ so
radically in form, it will be seen that
they retain the characteristic almond
quality throughout, just as we saw in
the case of the shells in the preceding
picture. (Nearly twice life size.)

THE ALMOND 339

were successively introduced, would result in pro-
ducing a peach-almond that would have flesh
equal to the best varieties of peaches and a nut
equal to the best almonds.

Even now there are certain apricots that bear
delicious nuts. Inasmuch as the apricot is
already in this condition, there is no reason why
the peach should not do the same. The apricot
seeds of California are now nearly all shipped to
France to make almond oil.

At the time when the experiments above re-
ferred to were carried out, however, it was not
clear that a fruit combining the qualities of the
peach and the almond would have great commer-
cial value. The peach industry and the almond
industry are so entirely different that the inaugu-
ration of altogether new methods would be neces-
sary to make them operable in combination.

Hence the hybridizing experiments were not
carried beyond the third generation, and the
hybrid trees were thereafter used as stocks for
grafting of cions that gave greater commercial
promise, even though less interesting from a
scientific standpoint.

A NEW PEACH-ALMOND CROSS

A subsequent series of experiments was under-
taken, however, to which reference has been made

340 LUTHER BURBANK

in another connection, in which the almond was
combined with the purple-leafed peach.

It has already been recorded that the first-
generation hybrids of this cross bore green leaves
exclusively, but that purple leaves appeared in a
certain proportion of the hybrids of the second
and subsequent generations.

In this cross, the purple-leafed peach was used
invariably as the pistillate parent. There is
every reason to suppose, however, that the
results would have been the same had the cross
been made the other way.

Among the second-generation seedlings were
not only some with red leaves, but others that
showed a combination of colors varying from the
pure green almond leaves through different
shades to the crimson leaf of the peach.

There was thus exhibited a pronounced tend-
ency to segregation of colors in certain cases,
and a combination of the colors in others.

Selection being made among the trees with the
purple leaves, this characteristic, as might have
been expected, reproduced itself, and a race
of purple-leafed peach-almonds, was developed.
The fruit of this hybrid is purple-fleshed, and as
to its general characteristics it is a fair com-
promise between the peach and the almond, not
unlike the hybrid form already described.

THE ALMOND 341

This form of peach-almond has considerable
merit as an ornamental tree, and it will probably
prove of value as an acquisition for the garden
and dooryard. Even though a peach that bears
an edible seed has no greatly added commercial
value, owing to the small size of the seed, such a
fruit with large seed of thinner shell, and with
peach flavor, should certainly be appreciated.

IMPROVING THE ALMOND

All this has to do with the production of a
compound fruit in which the almond seed is only
an accessory. It remains to say a few words
about the almond itself as a commercial nut.

The importance of the subject will be obvious
when we record that last year five thousand five
hundred tons of almonds were produced in Cali-
fornia alone. When it is further recalled that
numberless unsuccessful attempts have been
made to establish almond orchards in various
warmer regions of the United States, and that
the failure of these orchards has been due almost
exclusively to a single remedial defect, the
importance of the almond from the standpoint
of the plant developer will be more clearly
understood.

The one great defect of most varieties of
almond is that they bloom so early that their

ALMONDS GROWN IN
PEACHES

These are the stones of various types
of peach-almond hybrids. It will be
seen that some of them show the char-
aracteristic appearance of the peach
stone, where others show the marked
influence of almond parents. All bear
meats that have the characteristic
almond quality, more or less modified.

THE ALMOND 343

blossoms are likely to be destroyed by heavy
rainstorms or frost. A second minor defect is
that many of the varieties of almond do not bear
well unless they are cross-fertilized with pollen
from other varieties.

The latter defect is obviously one that requires
only reasonable intelligence in the planting of
different varieties in contiguous rows, so that
cross-fertilization may readily take place, or the
production of varieties with perfect blossoms.
To overcome the defects due to too early bloom-
ing is a somewhat more difficult matter.

Fortunately, however, there is a rather wide
range of variation among different kinds of
almonds as to time of blooming. It follows that
there should be no great difficulty in producing,
by selective breeding, a variety that combines
desirable qualities of nut production with the
habit of late blooming. The difficulty has been
that until recently orchardists have not recog-
nized the possibility of thus segregating and
recombining characters, and they have "trusted
to luck" in setting out their almond orchards,
so in a large number of cases the profitless trees
were removed or re grafted to prunes.

Latterly, the California orchardists have
learned that there are two or three varieties that
may be depended on, notably the Nonpareil and

344 LUTHER BURBANK

the Ne Plus Ultra, both of which originated in
California from seedlings grown by A. T. Hatch
of Salinas County. These may best be pollen-
ized, in the opinion of experienced orchardists,
by the variety known as Texas Prolific.

Unfortunately neither of the varieties men-
tioned produces nuts of the largest size, but their
certainty of bearing gives them advantage over
varieties that would otherwise be superior but
which cannot be depended upon.

It should not be difficult, except that such an
experiment necessarily takes time, to crossbreed
the different varieties that have individual traits
of exceptional value, and thus to produce in the
second generation, or through successive selec-
tions, varieties that will combine the best quali-
ties. Something has already been accomplished
in this direction, notably in the case of such a
variety as that known as Drake's Seedling, a late-
blooming variety that is prolific and a regular
and abundant bearer, notwithstanding its parent
form was the Languedoc, which has been pretty
generally condemned for irregular bearing.
There is no good reason why the almond should
not bear as regularly and as abundantly as the
apple, peach, or cherry.

As to the shell of the almond, this has been so
specialized through selective breeding that in the

THE ALMOND 345

best varieties it is perhaps as soft and thin as
desirable. If it becomes too soft, it is liable to
injury in shipping, and thus the appearance of
the nuts is marred and their market value
impaired; also being subject to destruction by
birds before it is harvested. Perhaps, however,
selective breeding may advantageously be car-
ried out with an eye to the whitening of the shell
of the nut. At present it is necessary to bleach
the shells after the nuts are thoroughly dried,
first with low pressure steam and then with the
fumes of sulphur. Such bleaching is necessary
to meet the demands of the consumers.

It would obviously cheapen production and
save a good deal of trouble if a variety could be
produced that would have the desired color of
shell in the natural state. Another defect is that
the almond tends to cling to the tree too tena-
ciously, requiring unnecessary labor. All almond
growers would appreciate improvements in these
two respects.

My own experiments of late have been in all
the directions mentioned, and I have good reason
to suppose that I now have better almonds than
any heretofore grown.

It is clear, then, that there are various direc-
tions in which the almond may profit by the
attentions of the plant developer. The steady

346 LUTHER BURBANK

and increasing demand for this nut warrants
the expectation that systematic efforts for its
improvement may meet with an adequate finan-
cial reward. Already the cultivation of the
almond is an industry that exceeds in importance
that of any other nut except the walnut and
pecan. And it is an industry that will increase
in proportion as the efforts of the plant devel-
oper make the almond a more certain bearer of
better nuts. What has just been said will suffi-
ciently indicate the lines along which the plant
developer must work in order to produce these
results.

WALNUTS AND OTHER
EXPERIMENTS

MENDEL'S THEORIES IN PRACTICE

THE hybrid walnuts, already known to the
reader as the Paradox and the Royal were
first publicly announced in my catalogue
called "New Creations in Fruits and Flowers,"
in June, 1893.

The hybrid walnuts themselves were then five
or six years old and the Royal had borne fruit,
so that a photograph of its large-sized nut could
be given. The Paradox, on the other hand,
although it had flowered for several seasons, had
produced no fruit. It was supposed, therefore,
that it would be impossible to reproduce this
hybrid from seed.

In subsequent years, however, the Paradox
proved its capacity to produce fertile fruit,
although it has never been a free bearer. In my
supplementary catalogue of the year 1898 I was
able to offer seeds of the Paradox for sale, and
to make a statement as to the manner of seed-

347

348 LUTHER BURBANK

lings that might be expected to grow from these
seeds. The statement, in view of the date when
it was printed, has somewhat exceptional interest
in the light of later developments, so I quote
it here. It was as follows :

"The six beautiful specimens of this hybrid
growing on my home place have been objects of
admiration to all who have seen them.

"Young trees could have been sold at almost
any price, but, having no time to raise them, we
offer this season's crop of nuts which will be a
great surprise in producing about one-third of a
new type of the broad-leaved Persian walnuts,
one-third of a new type of the California black
walnut, and about one-third combined, as in the
original tree."

The "original tree" in question was, of course,
the hybrid called the Paradox, produced by
crossing the California walnut and the Persian
walnut. So the seedlings, the character of which
is predicted in the paragraph just quoted, would
of course represent second-generation hybrids
from this cross.

I make the quotation here, carefully specify-
ing the date at which the original was printed,
because there is a certain interest in knowing that
tests made prior to this time with the seeds of the
hybrid walnut had clearly revealed to me the fact

THEORIES IN PRACTICE 349

that "about one-third" of the second-generation
hybrids would revert toward one parent, while
another third would revert toward the other
parent, the remainder being intermediate in
character, and in this corresponding to the first-
generation hybrid that was their parent.

This implies a fair understanding of the com-
bination of characters of the two parent species
in the first-generation hybrid, and the segrega-
tion and recombination of these characters in the
second-generation hybrid. It will be noted also
that the distribution of these characters in the
second generation (as predicted on the basis of
rny observation of earlier seasons) was essentially
that which has come to be familiar everywhere
within recent years as the typical distribution of
characters among second-generation hybrids in
what is now known as Mendelian heredity.

To be sure, the figures given are only approxi-
mate, nor have I in any of my experiments
endeavored to keep accurate account of the pre-
cise numbers, the large scale on which I operate
making this scarcely practicable — but the close
approximation of the rough estimate that I
made to the precise figures that have been deter-
mined by more recent investigations, sufficiently
attests the accuracy of the observations on which
the estimate was based.

350 LUTHER BURBANK

And, figures aside, the essential principle of
the segregation of characters, and their redistri-
bution into three essential groups, one represent-
ing each parent, and one combined as in the first-
generation hybrid, is as clearly stated as can be
desired.

The interest of all this hinges solely on the fact
that the statement was published in 1898, based
obviously on observations made prior to that
date ; at a time, therefore, when no one living had
the remotest knowledge of the discovery made by
Mendel more than thirty years before. Mendel
himself died in 1884, and the rediscovery of his
work was not made until a year or two after the
date of my catalogue, just quoted.

And I may fairly assume that there were few,
if any, botanists or plant developers in the world,
at the date of this publication, who had any such
clear conception of the meaning and interpreta-
tion of the prediction contained in the quoted
paragraph as my own original observations had
given me.

In fact, the observation on the seeds of the
Paradox walnut, as here quoted, was made quite
casually.

I did not put it forward as constituting a new
pronouncement in heredity, because it simply
represented a specific application of a general

THEORIES IN PRACTICE 351

truth regarding the tendency of heritable char-
acters to be segregated and recombined in the
second-generation hybrids that had come so
often under my observation that it had become
a commonplace to me many years before the
publication of this catalogue in 1898.

Elsewhere I have stated that the matter had
been the subject of controversy with a good
many of the leading botanists and horticulturists
of the world, and that during the period of per-
haps fifteen years prior to the rediscovery of
Mendel's experiments, I apparently stood in a
minority of one in the belief that such segrega-
tion and redistribution of characters in the sec-
ond-generation hybrids is the usual and all but
habitual method of inheritance.

After DeVries and his fellow workers had
come upon Mendel's earlier publication and
made it known to the world, the matter was no
longer in dispute.

But then the neophytes who had so long
refused to listen to my claim were disposed, after
the manner of neophytes, to become overenthusi-
asts, and some of them at least thought that the
principle of the segregation of heritable charac-
ters in the second generation was one that must
supplant all other principles of heredity, reduc-
ing questions of inheritance to such simple for-

352 LUTHER BURBANK

mulas that the veriest tyro could master them,
and, having them in hand, could go into the field
and create new forms of plant life at will.

And because I ventured to point out that the
essential principles that now came to be spoken
of as Mendelian had been the guiding principles
of my experiments for at least twenty years
before Mendelism was heard of, I was denounced
in some quarters as reactionary, the fact being
quite overlooked that the essential principles
involved had been discovered by me quite inde-
pendently; exploited by me in connection with
many hundreds of species; given publication by
me prior to the rediscovery of Mendel's forgot-
ten paper; championed by me against the oppo-
sition of all the leading authorities of the world;
and that therefore the aspect of heredity in ques-
tion might with full propriety have been named
"Burbankian" instead of "Mendelian," were it
not that Mendel's discovery had priority because
it w;as published so long ago as 1863, whereas my
independent discovery of the principle was not
made until almost twenty years later.

Even at that, however, I had had full twenty
years priority over anyone else except Mendel
in the recognition of the principle.

Therefore, as I just intimated, I have found
it a trifle disconcerting to be heralded as reac-

THEORIES IN PRACTICE 353

tionary and as scouting the essential principles
that I ardently espoused during a period of at
least sixteen years subsequent to the death of
Mendel, during which they had no other
champion.

What I have deprecated, however, in recent
years, is the overenthusiasm of certain alleged
followers of Mendel, who have entertained what
I conceived to be a misapprehension as to the
real significance of "unit characters," and who,
misguided by a narrow range of experiments,
and lacking the breadth of view that comes with
wider experience, have supposed that all herit-
able characters might be classified as fixed and
unvarying entities that are transmitted in
accordance with the Mendelian formula.

Fortunately, many former holders of this
biased and inadequate view have seen its insuffi-
ciency, and already there is a tendency to react
from it, evidenced in the writings of some of the
leading Mendelians; and, coupled with this, the
tendency to take a broader view of heredity and
to understand that there are countless heritable
characters that do not Mendelize in any tangible
or demonstrable way; that "unit characters" are
themselves made up of subordinated characters;
that new "unit characters" from time to time
appear, whereas old ones that at one time Men-

Vol. 7 — Bur. L

354 LUTHER BURBANK

delized are finally so fixed that they blend with
the older structure of heredity and no longer
present the phenomena of "dominance" and
"recessiveness" — in a word, that heredity is a
somewhat larger term than Mendelism, and that
the biologist or botanist or plant developer who
would gain a really clear conception of the situ-
ation must clearly distinguish between the lesser
term and the greater, although at the same time
recognizing that one is an essential substructure
of the other.

So Darwinian heredity, which recognizes the
heritability of whole coteries of characters that
are too profoundly fixed to Mendelize, is again
receiving recognition; and the multitude of spe-
cial studies of the past decade that were inspired
by the rediscovery of Mendel's work and by the
exploitation of his formula will take their place
as interesting additions to the minutiae of the
scheme of heredity, without being supposed by
anyone, except here and there a victim of mental
strabismus, to represent the full measure of the
great mysteries of inheritance.

We have had occasion in successive chapters
to present again and again illustrations of the
type of hereditary transmission that lends itself
to classification under the Mendelian notation.
We shall catch further glimpses of it before we

THEORIES IN PRACTICE 355

are through. Here it seems worth while, in con-
nection with the story of the hybrid walnuts, to
attempt a more comprehensive view of the entire
field of heredity, endeavoring to gain a clear
notion as to just what are the underlying prin-
ciples that determine whether or not a certain
heritable character or pair of characters shall
Mendelize ; and in so doing we may correlate our
earlier studies and secure a clearer notion of the
underlying principles of evolution, and of the
origin and development of species, than could
perhaps have been gained without the aid of the
illustrative cases that have been presented.

NATURAL SELECTION

The principle of natural selection applies to the
preservation and to the weeding out of species.

In the case under consideration, it was the
changed climatic conditions, through which the
Northern Hemisphere was transformed from a
region of tropical heat to one of arctic cold, that
resulted in the destruction of countless species,
leaving only a tithe of the original number to
constitute the flora of the temperate zone in our
own day.

It is easy to see how the altered conditions of
temperature made the struggle for existence
unduly hard for many species, because there is a

356 LUTHER BURBANK

tangibility about the coming of a glacial period
that finds an analogy in the coming of winter in
the regular sequence of seasons. The fact that
a plant which thrives in the summer in northern
regions cannot survive through the winter unless
protected is so familiar as to give us a concrete
example of the destruction of species through
changed climatic conditions in the geological
eras.

But the struggle for existence that goes on all
about us among plants of every species is so
much less tangible that it is not so easily
visualized.

Not unlikely the climate of the Northern
Hemisphere is changing now year by year as
rapidly as it ever changed in any era of the past.

The alteration is so slight within the span of
any single life as to be unappreciable. But when
we look back, aided by the studies of the
geologist, and think of the change of climate
that transformed the flora of the Mesozoic time,
we see things clustered in perspective, and in our
mental vision the picture of the transformation^
from tropical to arctic conditions corresponds
rather to the onset of winter in our annual
experience, than to the true picture of a change
of climate that required not merely centuries but
millenniums.

THEORIES IN PRACTICE 357

In the same way we conceive of the evolution-
ary changes through which new species were
evolved in the past as having been relatively sud-
den. I have already referred to the difficulty
with which the average mind can grasp the idea
that precisely the same sort of change in animal
and vegetable forms is taking place to-day that
has taken place in all other stages of evolution.

It was one of the great merits of Darwin's
exposition of the "Origin of Species" that he
gave detailed illustrations of the struggle for
existence, and brought tangibly before the minds
of thoughtful people the conception that each
race of beings is more or less in competition with
every other race, and that the race that is adapt-
able enough to adjust itself to new conditions
is the only one that stands any prospect of
survival.

The idea of the progression of the normal
increase of living creatures in geometrical ratio
and of the resulting overpopulation of any terri-
tory by the progeny even of a single pair, if
there were no counteracting factors, was of
course received by Darwin from Malthus. But
the application of that idea to all races of animals
and plants, and the logical deduction from its
application which first made possible anything
like a clear understanding of the reason why

HYBRID WALNUTS

The nut of the Paradox walnut has
the outward appearance of the Persian
walnut, one of its parents. The shell
retains, however, a good deal of the
thickness of the black walnut, but this
can be modified by selective breeding in
later generations.

THEORIES IN PRACTICE 359

vegetable and animal races have evolved, was
due to Darwin.

Alfred Russell Wallace conceived the same
idea independently, and must always be credited
with a share in the discovery.

But of course it was Darwin's exposition that
gave the subject general vogue, and the scheme
of heredity that it connotes is with full propriety
spoken of as Darwinian evolution.

The essentials of this scheme of heredity may
be stated in a few words, as follows: Animals
and plants tend to increase in geometrical ratio.
If unopposed, the progeny of a single pair of
animals or an individual plant would soon popu-
late and overpopulate the entire earth. Oppo-
sition to such overpopulation comes from the
rivalry of other animals and plants. The strug-
gle for existence thus induced puts a premium
on the individual animal or plant that is better
able than its fellows to seek means of sustenance.
Such an individual will, on the average, live
longer and produce more offspring than an indi-
vidual less well adapted to its surroundings.

The preservation of these favored individuals
and their progeny may be described in a phrase
as "the survival of the fittest."

The natural processes that determine such'
survival on one hand, and the destruction of

360 LUTHER BURBANK

the less fit on the other, may be spoken of as
constituting "natural selection."

This term, natural selection, has obvious pro-
priety because it connotes a process closely akin
in its results to the artificial selection through
which man determines that certain races of ani-
mals and plants under domestication shall be
preserved, and that others shall be destroyed.
But artificial selection is after all only a phase
of natural selection, in which a man becomes
an active influence or a deciding element in
environment.

Because of man's power to transform the con-
ditions of soil, to supply artificial heat, and to
bring together and hybridize plants and animals
that would not come in contact in the state of
nature, the results of artificial selection, epito-
mizing within certain bounds the results of
natural selection, may be produced with un-
exampled celerity.

Man, for example, eliminates a species in a
few decades, where nature would have found no
way of correspondingly rapid elimination. The
black walnut, for example, has been almost
exterminated throughout eastern America be-
cause man prized its wood for the making of
furniture. But for the presence of civilized man
the black walnut would doubtless have main-

THEORIES IN PRACTICE 361

tained its position for ages to come, just as it
had maintained it throughout the ages of the
past.

Yet we must not forget that on occasion there
may be natural methods of elimination that will
single out a species and destroy it as expedi-
tiously and as certainly as man could accomplish
that end.

A case in point is furnished by the chestnut,
which, as we have seen in a recent chapter, has
been singled out in certain regions of the eastern
United States by a fungoid blight that leaves no
chestnut alive in the regions over which it
spreads. Yet this blight seems powerless to
affect any other species.

Here, then, we have an example of a destruc-
tive agency of an unpredicted kind that gives an
example of the rapid destruction of a species,
through natural selection, because that species
could not rapidly enough adapt itself to a new
condition.

Given time, the chestnut would doubtless
develop immunity to the fungoid pest. But time
was not given it, and hence it was destroyed.

This present-day illustration perhaps gives as
vivid an impression of one of the more tangible
ways of the operation of natural selection as
could be desired. But wfe must suppose that such

362 LUTHER BURBANK

drastic measures as this are rather exceptional
and that in general the processes through which
species are eliminated are more subtle in their
operation, although their ultimate results are no
less striking.

All this has to do, however, with the de-
struction rather than with the evolution of
species.

I have already said that the principles of nat-
ural selection apply with equal force, and seem-
ingly with entire impartiality, to the destruction
and to the preservation of species.

But it is obvious that mere preservation of
species does not necessarily imply also the evolu-
tion of species. Natural selection might give a
dominant position to a particular species, and
preserve it for indefinite periods without essen-
tial change.

But this could only occur in case the con-
ditions of environment themselves remained
essentially unchanged.

It is fundamental to a clear understanding
of evolution to realize that in a changing envi-
ronment, under natural conditions, no species
could be preserved unless it proved adaptable.

Indeed, the more perfectly adjusted the
species might be to its environment at a given
period, the more certainly must that species be

THEORIES IN PRACTICE 363

destroyed should the essential conditions of the
environment change.

The great penalty of specialization is the
danger that attends it from this source. It is
held that the species that were eliminated when
the great climatic change occurred to which we
have more than once referred were those that
were the most highly specialized.

But, on the other hand, a species that is able
to change in such a way as to adapt itself to new
conditions stands at least a chance of being pre-
served, however, widely the environment may be
altered. And, in fact, most species in a state of
nature have a considerable measure of adapta-
bility. Individual variation is the universal rule,
and such variations are accentuated by natural
selection very much as the plant developer accen-
tuates them by artificial selection. So the plants
and animals in a state of nature are plastic
material, and under changing conditions of
environment which represent probably the usual
and normal condition of things, they are con-
stantly, even if slowly, being modified. And of
course such modifications, when they have been
sufficiently added to, alter the character of the
species altogether.

Which is only a detailed and roundabout way
of saying that species are evolved and trans-

364 LUTHER BURBANK

formed into new species under the influence of
natural selection.

But whoever considers this matter attentively
will come presently to realize that in any such
analysis of the operation of natural selection in
the evolution of species as that just suggested
there is an underlying assumption to the effect
that the various modifications of the individual
are transmitted to the offspring of the individual.

Unless such is the case, it is clear that there
could be no such thing as the evolution of new
species. It would avail nothing for the progeny
of an individual that this individual was well
adapted to its surroundings, unless the said
progeny inherit the characteristics that made
such adaptation possible.

There is no logical escape from that conclu-
sion. Whatever our conception of the mecha-
nism of heredity, or of the exact manner in
which the transmission of variation occurs, no
one can be an evolutionist who does not believe
that acquired characters are transmitted through
heredity.

There was a school of biologists who gained
great prominence a few years ago, who denied
the possibility of the transmission of acquired
traits. Throwing logic to the winds, they based
their denials on a metaphysical interpretation of

THEORIES IN PRACTICE 365

certain observed microscopic structures within
the germ cell. These same biologists, while de-
nying that acquired traits could be transmitted,
were at the same time ardent upholders of what
they called Darwinian evolution.

But such a paradoxical contention must of
necessity fail to maintain itself for any consider-
able period. In the last analysis people are able
to put two and two together and discover that
the result is four. And in the course of time
even the most illogical biologists were forced to
see the elemental truth of the proposition that
new characters acquired by an individual organ-
ism must be transmissible, else there could be no
such cumulative change as that which results in
the transformation of a species in new adapta-
tions to its surroundings.

In other words, if acquired characters are not
transmitted, there can be no organic evolution.

But a good many of the former adherents of
this paradoxical view have abandoned their illog-
ical position unwillingly, and even now are only
willing to admit that such acquired characters
are transmissible as are imprinted first on the
germ plasm, and not on the body of the parent
organism.

The contention really reduces the entire
matter to a question of definition. It is virtu-

366 LUTHER BURBANK

ally a distinction without a difference when we
reflect that, at all events in the case of plants,
germ plasm and body plasm are everywhere
associated, so that we must suppose that if there
is really a distinction between the two, it is a
distinction within the substance of the individual
cell, as the plant body contains both body plasm
and germ plasm. Our earlier studies have
shown that we are forced to this conclusion; and
obviously, if this interpretation of germ plasm
be accepted, it is a mere quibble as to whether
the change or modification of an individual plant
involves primarily the germ plasm or whether it
involves the body plasm of the same cell as well.

Of course such mere incidental modifications
of an individual as have to do with injury of
its parts, the laceration of tissues, or the like,
cannot be supposed to have any influence in
heredity.

If such accidental modifications are heritable,
the entire scheme of inheritance would become
chaotic.

The modification that is heritable must be
one that involves the constitution, so to speak, of
the plant ; such modification as would be brought
about by changed conditions of nutrition, or by
an altered temperature. A certain amount of
experimental proof is already in hand that such

THEORIES IN PRACTICE 367

modifications as these may be inherited. And if
the opponents of the theory of the transmission
of acquired traits can get any comfort out of the
claim that such modifications directly affect the
germ plasm, we need not wish to rob them of
that cold comfort.

Details as to the special manner of inheritance
aside, we may accept it, I think, as the only logi-
cal conclusion from a wide survey of the facts of
heredity and evolution, that all modified charac-
ters that affect the constitution of the individual
are heritable. Even the slightest modification
of structure due to altered nutrition, to changed
temperature, or the like, probably makes its in-
fluence felt on the next generation in exact pro-
portion to its value in the great complex scheme
of characters with which it is associated.

But this statement must not be misinter-
preted. It must not be supposed that any minor
modification of an individual can influence, ex-
cept in an infinitesimal way, the inheritance of
the offspring of that individual.

For the new modification will be, in the nature
of the case, only as an alien drop or two in an
ocean of hereditary tendencies.

Or, stated in somewhat more modern terms,
the hereditary factor that represents the new
modification will be as one minor factor among

368 LUTHER BURBANK

thousands or perhaps millions of preexisting
factors.

If we revert to an earlier illustration, in which
we thought of the germinal nucleus as a piece
of architecture made up of multitudes of fac-
tors of heredity, we may think of the new factor
as one added brick in a structure of palatial
proportions, made up of thousands of bricks.

Yet it is by the cumulative effect of such
minor modifications, we may well believe, that
evolution has been brought about, and that in
the long lapse of ages the highest forms of exist-
ing plants have been built up by successive
stages of inheritance from the lowliest single-
celled organisms.

THE STATUS OF MENDELISM

In the large view, then, whereas it will be
recognized that all acquired traits have their in-
fluence in heredity, yet it will also be recognized
that the vast sum of qualities that are of less
recent origin has preponderant influence, and
that the racial characteristics as a whole are
overwhelming in their power as against any
individual modifications.

Yet, to complete our picture, we must recog-
nize also that nature is not conservative, as she
is commonly said to be, but is highly progres-

THEORIES IN PRACTICE 369

sive. It could not be otherwise in a world in
which the natural environing conditions are con-
stantly changing.

The basal law of evolution, as we have seen,
is that the unchanging, the conservative organ-
ism, is doomed. It is only the progressive,
the changeable, the plastic organism that can
hope to maintain itself and perpetuate its kind
indefinitely.

The price of specific life is that the species
shall not maintain its identity.

And this interpretation of the situation gives
a clew, so it would seem, to that important and
interesting aspect of heredity to which we re-
ferred at the beginning of this chapter — the
phase commonly spoken of as Mendelism. The
essential characteristics of this aspect of hered-
ity, as we have pointed out over and over, is
that heritable characteristics are transmitted in
a sense independently one of another, in such a
way that they may be segregated and put to-
gether again in new combinations in successive
generations.

The detail within this scheme of transmission
with which Mendel himself was chiefly con-
cerned, and which absorbed the attention of his
followers until it was found that there was need
of taking a wider view, was involved in the phe-

370 LUTHER BURBANK

nomena of dominance and recessiveness. Men-
del found, for instance, as we are aware, that
when a tall pea vine was crossed with a short one
the hybrids of the first generation were all tall,
because, as he said, tallness was dominant and
shortness recessive. And in the second genera-
tion one-fourth of the vines were short because
the factors for shortness were segregated, ac-
cording to the theory of chances, and one-fourth
of the vines were pure recessives.

The fact of such dominance and recessiveness
between pairs of heritable characters is too ob-
vious to escape attention of any careful practi-
cal experimenter, now that attention has been
called to it. But it is equally obvious that there
are vast numbers of other heritable characters
regarding which no such clear matching as to
dominance and recessiveness is observed to take
place.

And so the early enthusiasts were led finally
to see that Mendelian dominance and recessive-
ness apply only to a certain small number of
hereditary factors in the case of any individual
plant or animal.

They came presently, after much heated argu-
ment, to admit that dominance and recessive-
ness constitute after all only a minor aspect of
Mendelian heredity.

THEORIES IN PRACTICE 371

Yet this aspect of the subject, even if not all-
important, has obvious interest. And the ques-
tion naturally arises as to which ones among the
numberless hereditary factors in the case of any
given organism will "Mendelize" in the main,
and why these factors will thus Mendelize while
others fail to do so.

The answer is found, apparently, in the simple
assumption that the factors that show the phe-
nomena of dominance and recessiveness are those
that are relatively new acquisitions in the germ
plasms of the species under observation. Traits
that have been the common heritage of the an-
cestry for untold generations, constituting the
fundamental structures of the organism, do not
Mendelize. They have proved their merit, and
are accepted as part of the necessary equipment
of the plant, not subject to the testing process
that Mendelism essentially constitutes.

Such fundamental structures are, for example
the root and stem and leaves and stamens and
pistils of a flowering plant. As to their broad
essentials of form and structure, these funda-
mental organs are inherited en bloc, and never
jeopardized by being weighed in the Mendelian
scale.

But the newly acquired characteristics, such
as details of leaf form, or color of petals, or size

THE ROYAL WALNUT

Tliis magnificent tree, one of the
-first seedlings of the Royal walnut,
stands in a dooryard beside the Sebas-
topol road, near Santa Rosa. It bears
mute but eloquent testimony to the suc-
cess of one of our early experiments
in hybridizing forest trees.

THEORIES IN PRACTICE 373

and quality of fruit — these are matters that are
subject to modification because they have not as
yet established themselves as fundamentally
necessary in any detail of form or color to the
species. These fall within the scope of Men-
delian testing.

For hundreds of thousands of years, doubtless,
the progenitors of plants that now have flowers
were provided with roots and stems and leaves,
and with essential reproductive organs, but had
no blossoms. In comparatively recent times the
blossoms were developed. And the modifica-
tions of color of the blossoms in the case of any
given species are, as we have found reason to
suppose, of still more recent origin.

These modern details, then, and their like,
are the ones that are subject to variation and
that are still matter for change and adaptation;
still in the experimental stage, as it were. And
precisely because such is their status, these are
the things that are subjected to the Mendelian
test when they are brought in juxtaposition,
through hybridizing, with forms that differ as
to these details.

And as only the relatively new structures
Mendelize, so it is the newer member of any
pair that assumes prepotency or dominance.
Contrariwise, the older member is recessive.

374 LUTHER BURBANK

Students of different examples of Mendelian
heredity, as applied to animals and plants, have
puzzled long to discover the underlying prin-
ciple that determines which character shall be
dominant and which recessive. But this simple
principle appears to furnish the explanation.

The new trait or characteristic is dominant
over the older one precisely because it is new.

By making it dominant, nature gives it the
best possible chance. It will reproduce itself in
all the immediate progeny of the individual that
possesses it. Thus nature shows anew that she is
progressing. She accepts the new characteristic
and gives it more than an even chance.

But at the same time she is not so foolish as to
renounce the old character without full testing.
She allows it to be subordinated for a genera-
tion, but in the next generation it reappears, iso-
lated, to compete with the dominant character.
And whether in the end the new dominant char-
acter will prove itself and prevail, or whether
the recessive character will reestablish itself, de-
pends entirely on the value for the species of one
character as against the other.

Mendelian heredity, then, is a testing out
process for new characters. It is, as it were, the
skirmish line of the advance guard of evolution.
So long as a character is subject to Mendelian

THEORIES IN PRACTICE 375

transmission, showing the phenomena of domi-
nance and reeessiveness, it is a relatively new
and unfixed character still on trial.

And in proportion as any character has proved
itself and has passed the trial stage, it becomes
blended with the hereditary factors that have
more stable position, just as conscious acts of
the individual become instinctive or reflex when
often enough repeated.

In this view, then, the so-called unit characters
that Mendelize are, as was said before, merely the
fringe to the great fabric of heredity. They serve
the plant developer an admirable purpose, and
it is with their manipulation that he is chiefly
concerned. Their relative insignificance is evi-
denced in the fact that the plant developer can-
not possibly produce major modifications in the
organisms with which he deals.

He does not attempt to make squash vines
into oak trees, or blackberry vines into tomatoes.

He recombines those newer, and hence less
important, structures and qualities of which the
fact of their Mendelizing is adequate proof of
their newness and relative unimportance. If he
would get beyond this and create really new
forms, adding something to the plant that no an-
cestor of the plant ever had, he could hope to do
this only if a term of life were granted him that

376 LUTHER BURBANK

would be measured not in mere years but in
millenniums. For evolution is a slow process,
and the history of the development of natural
species is measured in geological eras.

SELECTION AND MENDELISM

Perhaps it may be worth while to illustrate
this matter a little more in detail, that we may
make clear precisely what manner of thing the
plant developer is doing when he produces a new
race by selection.

We have stated over and over that the process
of hybridizing and the process of selection are
complementary. One supplements the other.
In hybridizing we make possible new combina-
tions of the hereditary factors, and in selecting
through successive generations we isolate certain
definite combinations, and thus produce what
we call new varieties. Now it is frequently
stated by the experimenters who have paid
attention only to a few conspicuous characters
that Mendelize, that all possible combinations of
characters will occur among the second genera-
tion hybrids, provided only enough of these are
produced.

Possibly this statement is correct. But it is
not susceptible of demonstration because it
would not be feasible to produce enough indi-

THEORIES IN PRACTICE 377

viduals in a single generation to put it to the
test. For the number of possible combinations
increases in geometrical ratio, as we have seen,
with the increased number of characters under
consideration. And a really penetrating view
of the situation reveals to us hereditary factors '
in the germ plasm of each individual plant that
would be numbered, could we isolate them, not
merely by tens or scores; not merely by hun-
dreds or thousands; but rather by hundreds of
thousands or millions.

To those experimenters who have been prone
to think of "unit characters" as few in number,
such a statement will perhaps seem anomalous.
Yet there can be no question that it is fully
justified.

In point of fact, what the present day student
of heredity usually speaks of as a unit character
might better be referred to as a "unit complex,"
or by some allied term that would suggest its
complicated character. The word "gene-com-
plex" has been suggested in a similar connection.

It would appear that the real purpose of
selective breeding through many generations is
to remove one after another of the factors that
dominate or mask other factors, so that subor-
dinate or recessive factors may make themselves
manifest.

378 LUTHER BURBANK

No one who has experimented widely will
doubt that it is possible by a series of selections
extending over several generations to accentuate
a given character, say to bring out the crinkled
formation of the poppy petal, or the corruga-
tions in the leaf of a wild geranium, or an added
row of petals in a balloon-flower. And it goes
without saying that, according to the modern
terminology, the character thus isolated must be
represented by a hereditary factor which was
present in each successive generation utilized in
our experiment, but which for some reason was
not enabled to make its influence so potentially
felt in earlier generations as it was in later ones.
And the only logical explanation appears to
be that in each successive generation of the
plants carefully selected and inbred, there was
a new redistribution of factors, always along
Mendelian lines, which isolated, in the case of
the individual we selected, the particular char-
acter which we had under observation more and
more completely.

Whereas, in a simple case of Mendelian

heredity, where one pair of factors is in mind,

Miere is complete isolation of the recessive fac-

f)r in one case in four; in this complex case

liere is isolation of groups of factors, and in

me case among thousands there may occur such

THEORIES IN PRACTICE 379

relatively complete isolation of the factors for
quality we are seeking as will serve our purpose.
Such isolation might occur in the second genera-
tion, but it cannot be counted on to occur until
we have tried again and again, in each succes-
sive generation, using material that is little
less complex because a certain number of
disturbing factors have been segregated and
removed.

We may perhaps illustrate the meaning of all
this a little more clearly if we suggest that each
so-called unit character with which Mendelian
heredity deals is in reality made up of a thou-
sand factors. I do not mean to imply that the
number is just that; it is merely that a thousand
is a convenient round number for purposes of
our computation.

There would be, then, a thousand factors for
color combined to make up what we commonly
speak of as the unit factor for color; there
would be a thousand subordinate factors for
form of flower; a thousand others for texture of
petal; a thousand others for odor; yet another
thousand for hardiness; and so on for each and
every patent characteristic of flower and twig
and stem and root of the plant. In the aggre-
gate, let us say, there are a thousand different
"unit characters," each made up of a thousand

380 LUTHER BURBANK

minor factors, so that the total number of heredi-
tary factors stored in the germ plasm and seek-
ing for recognition, in the case of a single plant,
is a round million.

Each of these million factors has been devel-
oped in the long slow process of evolution, one
after another added, generation by generation,
or era by era, beginning with the time when the
remote primordial progenitor of the plant was
a single-cell organism.

In the course of the ages, development has
taken place along diverse lines, and it has come
to pass that certain combinations of hereditary
factors have been grouped into systems that
have so long been working in harmony together
that they cannot be separated. The members of
one such group determine the architecture of the
root; the members of another group determine
the architecture of the stem; and so on for each
of the patent characters.

But there are other groups of factors that are
less ancient in their origin. There were some
that made their way into the germ plasm of the
ancestors of the plant so recently as half a mil-
lion years ago. There are others that are mere
parvenus of perhaps ten thousand years. And
there are yet others that are upstarts of literal
yesterday.

THEORIES IN PRACTICE 381

Each one of these hereditary factors is striv-
ing for recognition and endeavoring to make
tangibly manifest the condition or quality or
form or constitution of tissue that it specifically
represents.

And, according to the view just presented,
the thousand factors that make up any given
complex stand in such sequential relation to each
other that each successive one controls in a
measure its predecessor in point of time, and is
controlled by its successor. The very newest
factor that has been admitted to the coalition has
a more powerful influence than any other single
member of the coalition.

But meantime this most powerful individual
is after all only one among a thousand.

In a company of a thousand men, some one
man is stronger than any other. But this
strongest individual would be infinitesimally
weak in comparison with the combined strength
of the other 999.

This is the important thing to bear in mind.
The newest member in each of the thousand or
so hereditary "complexes" that we speak of as
unit characters is the most powerful individual
factor. But, inasmuch as the great body of
antecedent factors are using their influence in
unison in another direction, it is inconceivable

382 LUTHER BURBANK

that the influence of the single new factor should
greatly change the aggregate result.

In this view, what we term a species is a com-
pany of organisms in the germ plasm of which
the groups of factors for each main character-
istic have become purely and unqualifiedly reces-
sive, so that they act as a unit in producing a
given character. They thus determine the chief
characteristics of heredity in the Darwinian
sense, which finds its popular expression in the
phrase "like produces like."

Meantime, there are always minor groups of
newer characters that are striving for recogni-
tion, and while these are relatively insignificant
because of their newness and small number as
compared with the whole, yet they are conspicu-
ous and important in the eyes of the plant de-
veloper because they represent precisely those
modifications of form and constitution and
color that mark what we speak of as variations
from type; and because they are so matched
against one another in heredity — in the manner
that we call Mendelian — as to make it possible
for the plant developer to segregate and recom-
bine them variously by hybridizing, and thus to
develop new races from the old stock.

When, however, the plant developer, through
his hybridizing experiments, brings together

THEORIES IN PRACTICE 383

groups of characters in which the old guards,
so to speak, that have control over the funda-
mental characters are in conflict, no union is
possible.

Either fertilization will not take place, or the
offspring will be sterile. Only within narrow
limits, and as regards the new and relatively un-
essential characters, can there be diversity or, at
most, the accentuation of old characters.

Such an accentuation, for example, occurs, we
may suppose, in the case of the hybrid walnuts,
which take on gigantic growth. Both Persian
walnut and California walnut have in their germ
plasm the hereditary factors of large groups of
remote ancestors of the Mesozoic era, when
gigantism was the fashion, but these factors
have for long generations been subordinated by
newer one born in a less favorable era. Now,
however, hybridization brings the two strains
together, arid the two dominant groups of
factors for slow and relatively dwarfed growth
in some way mask or neutralize each other,
enabling the earlier groups to make their
influence felt.

And here, as we have seen, the factors for
growth that have thus been rudely disturbed as
to their hitherto harmonious coalitions, are re-
assorted in the second generation, as united

384 LUTHER BURBANK

groups acting along Mendelian lines, so that
part of the progeny of the second generation are
giants, and part of them are dwarfs, and that all
manner of intermediate forms find recognition
in the case of different individuals.

In no other way known to us could such a dis-
turbance of the coalitions of hereditary factors
have been brought about. So the plant devel-
oper who thus brings together racial strains that
have been long separated, introduces a dis-
turbing element that in its practical effects may
produce such modifications as could only be
produced otherwise through the aggregate in-
fluences of environment for almost numberless
generations.

But let it be repeated that even when the hy-
bridizer effects such a disturbance as this, he can
do no more than to enable subordinated heredi-
tary factors to make themselves manifest.

He is dealing with material that has been
brought together through age-long experiments,
and even though the new combinations that he
effects may be striking ones, he may rest assured
that even his most spectacular achievement is
but a feeble replica of plant developments with
which nature has experimented thousands of
times over in the course of the long evolutionary
ages.

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