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This book is due on the date indicated below
and is subject to a fine of FIVE CENTS a
day thereafter.

FEB 0 8 1991

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THE FRUIT OF THE BUR-
BANK PLUM

The famous "Burbank" plum was
grown by Mr. Burbank on a tree intro-
duced from Japan. It is now grown
in enormous quantities, under the most
diversified conditions of soil and climate
all over the world.

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HOW PLANTS ARE TRAINED
TO WORK FOR MAN

BY LUTHER Bl'RBANK Sc. D

SMALL FRUITS

YOLU M E IV

EIGHT VOLUMES • ILLUSTRATED
PREFATORY NOTE B i' DAVID STARR JORDAN

P. F. COLLIER & SON COMPANY
NEW YORK

Copyright, 1914

By The Luther Burbank Society

All rights reserved

Copyright, 1914

Bi The Luther Burbank Society

Entered at Stationers' Hall, London

All rights reserved

Copyright, 1915

By The Luther Burbank Society

Entered at Stationers' Hall. London

.1// rights reserved

Copyright, 1921
By P. F. Collier & Son Company

manufactured in- u. s a

CONTENTS

PAGE

Plums from Eastern and Western

Sources 7

The Greatest Plum of All — The

Prune 25

Four Burbank Prunes and the Work

Behind Them 53

Plums and Prunes Without Stones

and Seeds 75

Planning an Ideal Plum or Prune 95

New Plums and Prunes in the Process

of Making 115

What the Burbank Plums and Prunes

Have Earned 161

Achieving the Impossible — The Plum-
cot 181

The Thornless Blackberry and Others 209

The Raspberry and Some Odd Crosses 233

1— -Vol. 4 Bur. 1

2 CONTENTS

PAGE

Designing a Strawberry to Bear the

Year Around 261

The Sunberry — A Production from

the Wild 287

A Dozen Other Delightful Berries . 313
Great Opportunities in the Grape . 349
Inedible Fruits which May be Trans-
formed 373

LIST OF ILLUSTRATIONS

The Fruit of the Burbank Plum

Frontispiece

PAGE

The Late Shipper 14

Prune D'Agen Fruit 28

The Sugar Prune ...... 32

The Splendor Prune 36

Prune Drying in California ... 40

The Standard Prune . ;. t.i r.3 u 44

The Conquest Prune . .. m m ■» 48

One of the Plumcots . . w ... :. 60

A Superior Plumcot . . r. . ,. 68

Plumlike Plumcot ...... 104

Purple-Leaved Plum with Fruit . 118

Globe Plum Fruits 128

Firm Sweet Plum Fruits .... 134

The Apple Plum 140

Another View of the Apple Plum . 148

3

4 LIST OF ILLUSTRATIONS

PAGE

A Seedling Crimson-Leaved Plum . 156

An Example of Uniform Ripening . 164

A Good Root System 174

The Odd Plumcot 182

Cherry Plumcot 186

Sweet Plumcot 190

One of the New Plumcots . . . 194

Cluster of Apex Plumcots . . . 198

Another Plumcot 202

The Burbank Plumcot .... 206
Thornless Blackberry and the Rec-
reant Seedling 212

One of the New Thornless Black-
berry Clusters 220

The Familiar Blackcap Raspberry . 236

The Primus Berry 242

The Phenomenal Berry .... 250

An Interesting Hybrid . . . . 256

A Sample Seedling Strawberry . . 264

An All-Summer Bearer .... 270

Everbearing Strawberries .... 274

LIST OF ILLUSTRATIONS

Another Perpetual Variety
Yet Another Hybrid Variety

sunberries

Leaf Variations in a Hybrid
Hawaiian Raspberries
The Buffalo Berry .
Interesting Hybrid Berries
A Near View of Two Boxes of

Seedlings

Grapes of the Concord Type
Seedling Syrians ....
A Mammoth Cluster
Unproductive but Meritorious
Small Cluster of a Fine Seedling
The El^eagnus or Goumi Berry .

Berry

PAGE

278
282
290
306
316
322
330

342
352
356
360
364
368
380

PLUMS FROM EASTERN AND
WESTERN SOURCES

Material from the Orient

CLEARLY to apprehend the conditions of
the problem that confronted me when I
first undertook on a comprehensive scale to
put my ideas as to plant development into execu-
tion, it is desirable to note very briefly the char-
acteristics of the different races of plums that
were brought to the Santa Rosa melting pot.
Let me outline them.

Reference has already been made more than
once to the Japanese seedlings. The plums from
this source, like those from every other, typify in
many respects the people among whom they were
developed. Modified to meet the needs of an
island people occupying a relatively small terri-
tory which nevertheless compasses many degrees
of latitude, the Japanese plums differ a good
deal among themselves as to their hardiness. But
in general they are rapid growers, with early and
abundant bearing qualities, and unusual adapta-

7

8 LUTHER BURBANK

bility to wide ranges of climate. The fruit is
unique in form. It averages large in size, with
a high percentage of flesh to stone, and with both
skin and flesh of high color.

The brilliant purple, crimson, pink, and yel-
low shades shown by some of the modern hybrids
are a tribute to the Japanese members of their
ancestral stock.

But while the Japanese plums have these
signal merits they are not without their faults.
Many of them are small and most of them lack
flavor, and freestone qualities had not been de-
veloped in the slightest degree. Many of them
lack timeliness of bearing; others bloom so early
that the crop is often destroyed by late spring
frosts or heavy rains.

Moreover the Japanese often eat plums that
are hard and green, preserving them by pickling ;
therefore they have sometimes neglected to ap-
preciate the sweetness and flavor of the fruit.

These, obviously, are defects that the plant
improver must bear constantly in mind when he
sets out to separate and recombine the traits of
his company of plums.

The Chinese, near neighbors of the Japanese,
developed plums of a different type. The Jap-
anese plum is known as Primus triflora; it per-
haps originated or was developed in Korea, south-

ORIENTAL PLUMS 9

ern Siberia, and northern China. But the Chi-
nese apricot-plum, known to the botanist as
Prunus Simonii, must have originated in some
semitropical climate. It has form and color sug-
gestive of a tomato. It perhaps originated near
the native home of the apricot, to which fruit it
appears to be somewhat more closely related than
to other plums.

The fruits of China, apparently, have not been
greatly modified for many centuries. They
therefore tend to fixity. Indeed, they furnish a
typical example of the way in which the conserv-
atism of a race may be stamped upon its fruit.
Or is it that people and plants alike are con-
servative because of the climatic conditions that
environ them?

In any event, the Chinese plum, when com-
bined with other species of plums, brings to the
union characteristics that are highly important.

Thus the Chinese plum has a delightful aroma,
it is of unique form and rich color, and the stone
is very small in proportion to the flesh.

On the other hand this plum is chiefly adapted
to arid, semitropical climates; the fruit is likely
to remain bitter, and it may crack so badly as to
be utterly worthless.

Fortunately the merits may be retained, and
the faults eliminated, in the hybrid progeny.

10 LUTHER BURBANK

Materials from Europe and America

The more common European plum manifests
no less markedly than the Oriental one the tastes
of the people by whom it has been developed.

European fruit growers have had in mind
many and diverse qualities of fruit, and they
have developed diversified races of plums. The
original species from which the best of these
have grown is known as Primus domestica.

Doubtless at a time sufficiently remote this
plum was of the same ancestral stock with the
Japanese and Chinese species. But many cen-
turies of modification to meet the tastes of the
Caucasian races have so altered it that it
would be difficult to say what were its original
characteristics.

The Western races, carrying the plum with
them to different regions, developed widely dif-
ferent tastes and inclinations, and the plums that
were ultimately grown to meet the tastes are of
course equally diversified in quality. Some are
large and some small; some exquisitely sweet,
others relatively sour. Some are adapted to
eating while fresh; others are most useful for
drying or for canning.

In a word, the races to which the western plum
has catered are of complex lineage; they live in

ORIENTAL PLUMS 11

widely varying climates and under greatly
diversified conditions.

The Caucasian lives everywhere and his fruits
have adapted themselves to his condition.

Summarized in a few words, the advantages
of the European plums are: wide diversity as to
colors, qualities, and flavors, and adaptability to
a wide range of climate.

The faults of the European plums are these:
the stone is quite generally too large for the size
of the fruit; the fruit itself in most cases is too
juicy — sometimes absolutely watery — and there
is a wide range of textures to be avoided, includ-
ing stringiness, brittleness, and sponginess.
Moreover, large size and exquisite quality are
seldom combined. The green gage, the stand-
ard of excellence among the hardier European
plums, is quite small, and the tree is unpro-
ductive. And the large European plums are
quite often lacking in texture and flavor.

Size and quality are not correlatives in the
case of these plums.

It must be especially noted, however, that it
is the European plum, in some of its varieties,
that has the qualities of large sugar production
that permits it to dry readily in the sun without
fermentation. This variety of plum, known as
the prune, has been the means of building up a

12 LUTHER BURBANK

great world industry. At the moment, how-
ever, we are chiefly concerned with the plums
in general rather than with this particular
race.

There remain the American plums — that is to
say the plums that were found growing in Amer-
ica at the time of European discovery.

There are several quite distinct species of
these indigenous plums. They grow far to the
north, and perhaps their most important char-
acteristic is their hardiness. Some of them re-
sist the scorching heat of tropical America;
others thrive and bear in the short seasons of the
snowy north. With hardiness of tree has been
developed a strain of productiveness. Various
wild plums often cover the ground in the fall
with layers of ripened fruit.

Notwithstanding this, however, the crop is
uncertain, some of the thriftiest trees proving
unproductive in certain seasons, and the fruit is
always inferior in size.

Many of the American plums are of fine
quality, even in the wild state. Yet their faults
are almost as numerous as their virtues. The
trees are generally small, not usually large
enough to make good commercial orchard trees.
In form, too, the trees are defective. And the
fruit, notwithstanding its excellent flavor, is

ORIENTAL PLUMS 13

often soft and watery, quite lacking shipping

quality.

In the Melting Pot

Obviously, then, the plums of each country
offer certain good qualities and present certain
defects.

To take the characteristics from the plums of
each country and combine them in different
varieties; to eliminate the faults as far as pos-
sible; to select and test the best among the
millions of seedlings produced from the various
combinations; to redistribute these fruits when
produced and thoroughly tested, sending them
back greatly improved, their good qualities re-
tained and others added — this has been the work
of the last forty years in the attempt to produce
an ideal plum.

Having for working material plums in which
different combinations of qualities have been
developed for the most part unconsciously from
different races, our task was a consciously
scientific selection.

We must strive to produce, in a few decades,
changes comparable to those that had been
wrought in the course of centuries through un-
conscious selection by many peoples under
widely diversified climates and conditions. Con-
scious systematic selection was to amalgamate

THE LATE SHIPPER

This is a cross between the Chinese
apricot plum and a Japanese plum.
The Chinese parentage is shown in the
short, thick, applelike stem, clinging
to the fruit, and yellowish flesh. The
influence of the Japanese parent is
shown in the form of the fruit and in
the stone, which inclines very strongly
to the Japanese type. (Natural size.)

ORIENTAL PLUMS 15

all the best qualities of plums and plumlike
fruits; those that bore the imprint of the con-
servatism of the Chinese race, the insularity of
the Japanese, the diversity of the European, the
nomadism of the Persian, the hardiness and
variability of the American.

The best was to be taken from each, and the
good qualities developed in five widely varying
geographical territories were to be assembled,
combined, sifted, and selected to produce fruit
having the stability, novelty, variety, piquancy,
hardiness, beauty and shipping qualities, and
adaptability to new conditions and uses of the
races that had left their imprint in varying
measure on the ancestral stocks-
Viewing the work in retrospect, I assuredly
can have no cause to regret that it was under-
taken, yet it has been a most laborious task.

Doubtless the time expended on the plum has
been at least as great as that devoted to any
other single line of my investigations. The
labor, especially in grafting, budding, testing,
and selecting, has probably been greater than
that devoted to any other plant origination,
with the possible exception of the spineless
cactus.

Roughly speaking, I might perhaps say that
the plum experiments represent, first and last,

16 LUTHER BURBANK

something about one-tenth of the total expendi-
ture for my experimental work.

In importance, up to the present time, judged
by results, the work with the plum may repre-
sent perhaps one-sixth of all my work ; in extent
and variety, perhaps one-tenth of the total. In
commercial value, up to the present, perhaps the
plums may be credited with one-third; but they
will rank by no means so high when the final
ledger is balanced, for there are very numerous
other productions, among them the cactus, that
loom large in prospective value.

So in the end perhaps the economic rank
of the plums, among the total of my plant
productions, will not be more than one-
twentieth.

Yet when I state that from among the almost
countless new varieties that have been developed
through these forty years of experiment, sixty-
seven have so far been thought worthy of intro-
duction, and some thousands of races are still
undergoing tests, some inkling of the work in-
volved will be gained. And when I add that the
Burbank plums now make up about one-third
of the total export of the plums from California
year by year, and that my proteges are as
popular in South America, Europe, Asia,
Africa, Australia, and New Zealand, and in

ORIENTAL PLUMS 17

numerous other remote regions of the globe, as

they are in the State where they originated,

something of the economic importance of the

experiments in plum development will be

revealed.

Specific Results

Some glimpses have been given in earlier
chapters of the methods of experimentation
through which particular races of new plums
have been developed; and fuller details of the
methods and results will be given in subsequent
chapters of the present volume. Here let me
briefly outline some of the earlier results of my
effort at hybridizing the diversified races that
were brought together for the purpose of these
comprehensive experiments.

I have said that some notable results were
obtained almost from the outset.

As illustrating this, it may be recalled that,
whereas the first hybridizations between the
Japanese seedlings and plums of European and
American stock were made in 1888, there were
no fewer than six varieties of hybrids in my
orchard in the season of 1893, only five years
later, that were considered worthy of introduc-
tion and that were able to take rank at once as
superior in some regards to any plums at that
time known.

18 LUTHER BURBANK

Two of these, named respectively the Dela-
ware and the Hale, were hybrids of a double
oriental stock, one parent being the Kelsey, a
Japanese plum introduced by the orchardist
whose name it bears, and the other my Japanese
Satsuma.

A third was a hybrid between a Japanese
plum named the Sweet Botan, or Golden, and
the Robinson, an American plum of the Chicka-
saw race.

Two others were crosses of the Robinson and
Abundance.

The sixth was a cross between the Kelsey and
the Burbank, its ancestral strains being there-
fore Japanese. This plum was first named Per-
fection, but it was afterward renamed the
Wickson, in honor of Professor Edward J.
Wickson of the University of California.

All these are exceptional plums, but the
Wickson was preeminent in virtue of its com-
bination of good qualities. The tree grows up-
right, largely in vase form. It branches grace-
fully, and it is productive almost to a fault. The
fruit is large and handsome. From the time
when it is half grown to a few days before
ripening it is pearly white in color, but all at once
numerous pink dots appear, and in a few days it
has turned to green flushed with crimson with a

ORIENTAL PLUMS 19

heavy white bloom. The stone is small and the
flesh of fine texture, firm, sugary, and delicious.
It will keep two weeks or more after ripening;
or it can be picked when hard and white, and will
color and ripen almost as well as if left on
the tree.

The general excellence of this fruit may per-
haps best be gauged by the statement that last
year more than one hundred carloads of this
variety alone were shipped from California to
the eastern markets.

Difficulties Overcome

But while these notable successes attended the
earliest hybridizing efforts, it must not be sup-
posed that the experiment was carried out with-
out difficulty.

In fact it was not easy to effect the cross
between the Japanese plums and the European
varieties. Some varieties refused to combine;
and probably not more than one in a hundred
of these crosses proved in any way satisfactory.

When a hybrid is produced, the traits of the
Japanese plum usually seem prepotent in most
of its characters, though in many cases the bal-
ance between the two is good.

Whereas the hybrids of the first generation
sometimes produce fairly good fruits, as a rule

20 LUTHER BURBANK

their fruit is rather soft and acid. The full pos-
sibilities are revealed only in later generations,
and in particular after other species and varie-
ties of plums have been brought into the com-
bination.

As rapidly as possible the hybridizations were
extended, until forty-three races of plums had
been used. In successive generations the various
strains were intermingled until they were complex
far beyond computation or accurate recording.

The original seedlings were used as stocks for
grafting the cions of new seedlings year by year.
To this day they stand in the original rows, al-
though little is left of the original trees except
the trunk and the bases of the branches. Each
season, the grafts that have been proved to be of
no value are removed and cions from new seed-
lings are put in their place.

Most of the trees have borne from ten to
twenty sets of grafts.

Details given in other chapters will enable the
reader to follow in imagination the process of
blending and selection through which, on the
average, year by year a better and better com-
bination of qualities was effected among my
plum proteges.

Almost as a matter of course, there ultimately
appeared individuals that far surpassed most of

ORIENTAL PLUMS 21

the earlier hybrids in one or many desired
qualities,,

The Quartet of "Best" Plums

And in the course of years there were found at
least three new varieties, all of the most complex
ancestry, that excelled any of their forerunners.

The three new claimants, which stand as the
finest products of plum development up to date,
have been named the Santa Rosa, the Formosa,
and Beauty.

These with the Wickson may be listed as un-
qualifiedly the best products of the experiments
in plum hybridization up to date — a quartet of
plums of matchless quality.

It must be understood, however, that there are
unfulfilled possibilities of future development
among the newer hybrids. Selection has gone on
year after year until the plums that remain are
all of almost infinitely complex ancestry and of
fine individual quality. New crossings between
the almost numberless varieties, or even new
seedlings without further crossing, may result
any year in producing a better plum than any
hitherto produced. Indeed, this is to be ex-
pected, for in a sense the work is only begun.

Even by hastening the time of fruiting
through grafting seedlings on small branches in

22 LUTHER BURBANK

the way already detailed, it is impossible to test
any given seedling as to its fruit possibilities in
less than two or three years. So there are only
twelve to fifteen generations at most between my
first hybrids and the seedlings of the present
year.

It is not to be supposed that all the possibili-
ties of the multiple ancestry will be realized in
any given individual within that comparatively
short number of generations.

So, notwithstanding the notable results of the
experiments up to the present, I have every ex-
pectation that the real greatness of my plum
colony is yet to be revealed.

Meantime it is gratifying to record that
unprejudiced witnesses in many parts of the
world have declared the members of the quartet
just named to be each in its way without a rival,
Each of the four has certain points of excellence,
to meet the requirements of a different market.
But, as a group, the four stand in a class by
themselves.

And in token that this is not a matter of
accident, let me recall that in the production of
these four plums selection has been made, in the
course of successive generations, from not fewer
than seven and a half million seedlings. Perhaps
this bald statement will serve, in connection with

ORIENTAL PLUMS 23

what is elsewhere told of methods, to give a
fairly vivid impression of the work involved in
the attempt to develop a perfect series of plums
for all purposes.

We must strive to produce, in a
few decades } changes comparable
to those that had been wrought in
the course of centuries through
unconscious selection by many
peoples under widely diversified
climates and conditions.

THE GREATEST PLUM OF
ALL — THE PRUNE

Forty Years in Search of a
Perfect Prune

IT not unfrequently happens that a visitor
from the East or some foreign land expresses
a particular desire to see a fresh prune. And
when the fruit is shown the visitor usually ex-
presses surprise at its appearance.

"Why, that looks just like a big plum."

"Taste it," I said.

"It tastes exactly like a plum, too."

"There is every reason why it should," I an-
swered ; "for it is a plum. Not only so, but you
may have eaten any number of prunes in New
York or Bombay, as the case might be, even
though you supposed that you had never seen a
fresh one. The prune is an excellent table fruit
and my best varieties are very good shippers.

"So a fair proportion of the best plums that
are sold in the eastern market are really prunes.
Yet, of course, they are called plums when sold

25

26 LUTHER BURBANK

to be eaten fresh. And this is proper enough,
for every prune is a plum, even though every
plum is not a prune by any manner of means."

It is rather curious that this elementary bit of
botanical information should not be more widely
known. But my experience tells me that com-
paratively few persons living away from a prune-
growing district realize that the fruit with which
they are so familiar in the dry state was neither
more nor less than a plum before it was dried.

In fact a prune might be spoken of as an edu-
cated plum — and educated in a particular way.

In a sense all plums of the present day are
educated. Each one has been brought, by selec-
tion, in the course of centuries to a point where
it is a highly edible fruit. My famous quartet of
developed plums, named in the preceding chap-
ter, are assuredly educated in a high degree.
Each of them is large in size, attractive in color,
delicious in flavor, and of such firm quality of
flesh as to bear shipping to distant markets.

Yet no one of them has the particular kind of
education that is absolutely essential for a prune.

Neither Wickson nor Santa Rosa nor For-
mosa nor Beauty plums would have the slightest
value as additions to the orchard of the prune
grower. The smallest and the poorest prune in
the orchard would be preferred.

THE PRUNE 27

Yet the qualities that these educated plums
lack are very few. Or, stated otherwise, the
points of education that the prune has acquired,
over and above other plums, are few. But they
are absolutely essential.

The qualities in question are simply these:
A capacity to produce a large percentage of
sugar and store it in the juices of the fruit; and,
secondly, a capacity to produce a skin covering
having a peculiar quality of cracking in just the
right way when the fruit is plunged into an al-
kali bath. Granted these qualities, any plum is a
prune, lacking them, no plum is a prune of value.

As to the varying degrees in which the qual-
ities may be attained by different races of prunes,
we shall have more to say in a moment.

Going Back to the Blanket

In order to get a clear view of the matter, it
will be well for us to make inquiry as to just how
the prune came to take on the particular kind of
education that now gives it distinction. By so
doing we shall perhaps be enabled to understand
better why it is that the prune finds it so easy to
lapse back from the standards its forbears have
established.

If I had been engaged in a forty-year-long
quest of a perfect prune, without quite attaining

PRUNE D'AGEN FRUIT

This is the common French prune,
originally brought to California more
than fifty years ago, and grown almost
exclusively until the appearance of the
new Burbank prunes. It is a small,
sweet fruit with a tough skin, growing
on a weak tree of comparatively poor
bearing qualities. Millions of pounds
of this prune are now grown and great
capital is invested in its production,
curing, marketing, etc. (Natural size.)

THE PRUNE 29

the ideal, it is chiefly because this fruit shows
such a propensity to forget what it has learned
and to revert to the standards of the ordinary
plum.

And the reason, stated in a word, is that the
traits that now specifically characterize the prune
have been acquired in comparatively recent gen-
erations; whereas the main characteristics that
make the ordinary plum an edible fruit have been
traditional in the family for untold centuries.

When I find our almost perfect prune lapsing
back in the next generation to a condition that
robs it of all value as a prune, I am reminded of
the story of a young Indian who was taken from
his tribe and given every advantage that the
Government could furnish him.

Years were spent in teaching him the studies
of the modern curriculum, mathematics, history,
literature, language, and even a smattering
of art.

At twenty-one he had a better education than
many of our presidents, and his future was con-
sidered very promising by those who had to do
with his training.

Ten years later this educated Indian was one
of the most worthless of his tribe.

He had simply "gone back to the blanket stage
of existence." The pull of past heredities was too

30 LUTHER BURBANK

strong for him. The transitory influence of a
few years of education could not efface the ra-
cial instincts that had been implanted through
thousands of generations of breeding of a more
primitive sort.

And so it is with the prunes. Through
extreme specialization in recent times they have
developed certain properties that were not of
value to their ancestors, and, like the Indian,
they are very ready to throw these off and revert
to their blanket stage of existence.

So when we combine a prune with some fine
variety of plum, or even cross two varieties of
prunes, in the hope of getting a larger and more
productive prune, we very commonly secure a
fine fruit — a fruit sometimes that is in many
ways superior to either parent — but a fruit that
is not a prune at all in the technical sense ; a fruit,
in short, lacking the refinements of large sugar
content and peculiar quality of covering; being,
therefore, a mere plum — in a word, a blanket
Indian.

And all this tends to show that we are right in
assuming that the peculiar property of deposit-
ing a large quantity of sugar in the fruit is one
that was not inherent with the ancestors of the
prune until man undertook the education of the
fruit and trained it for that particular purpose.

THE PRUNE 31

Remote Sugar-Producing Ancestors

Nevertheless all that we know of heredity
suggests that the effort on the part of man to
develop such a trait as this would not have been
successful had it not chanced that there were
among the ancestors of the prune some races
that possessed a tendency toward the peculiar
property of producing very sweet fruit. There
is nothing anomalous in that supposition, how-
ever,, for it is well known that many tropical
fruits tend to have a high sugar content.

Such is the case, for example, with the date,
the fig, and the pineapple.

The orange, also, in some of its varieties, is a
very sweet fruit, and there are numerous others
among the fruits still confined to the tropics that
show the same quality.

Indeed, in general it may be said that fruits
growing in the tropics tend to have a high sugar
content, the reason being, perhaps, that in hot
climates this is necessary to insure preservation
of the fruit long enough to permit it to serve its
purpose in protecting the seed during its growth
and preparation for germination.

But as fruits migrate to temperate zones, they
tend to give up this habit of sugar production.
All pulpy fruits, to be sure, develop a certain

THE SUGAR PRUNE

The Sugar prune is a nearly per-
fect fruit, surpassing the Splendor in
almost every respect, including vigor
of tree and productiveness. Both are
extremely large, freestone, of extra
fine quality and have a larger propor-
tion of flesh to stone than other prunes.
The Sugar prune is now grown exten-
sively in South America, Australia,
New Zealand, and many other countries
besides California. It is a stupendous
bearer. (Natural size.)

l_Vol. 4 Bur.

THE PRUNE 33

amount of sugar, but the percentage is relatively
small with most fruits of temperate climates.
The contrast in this regard between the average
wild plum and such a fruit as the fig or the date
is very striking.

But we have seen illustrated over and over
that a habit once ingrained in a race is with very
great difficulty shaken off altogether, so it is not
strange that, under exceptional circumstances or
conditions of soil and climate, an individual plum
tree might show reversion to the state of some
ancestor and produce a fruit much sweeter than
other plums.

Such an individual, if its fruit came to the
attention of the orchardist, would be likely to be
preserved and propagated; and in the course of
time, through selection among the seedlings of
this tree, a race of sweet plums would be
developed.

But is is only under conditions of artificial cul-
tivation, in all probability, that such a race could
be preserved.

For, of course, the production of a large
amount of sugar must draw on the energies
of the tree, and if this increased sweetness
of fruit did not prove beneficial to the tree
itself, natural selection would presently weed
it out.

2 — Vol. 4 Bur.

34 LUTHER BURBANK

So, we may fairly assume that it is only within
the comparatively recent period since the plum
was under cultivation that the development of
a race of sweet plums, which we now term
prunes, has taken place.

Just the Right Skin Texture

As to the other characteristic prune trait, that
of developing a skin of such texture that it will
crack in precisely the right way when put into the
alkali bath, this may fairly be assumed to be an
even more recent acquisition.

Yet here, again, we may assume that there
were ancestors of the plum that developed char-
acteristics of skin of which this is perhaps a remi-
niscence. And it is not very difficult to conceive
how this may have come about.

The wild plum quite commonly grows along
watercourses and by lakesides. It may chance
that plums growing along the shores of the Med-
iterranean, or perhaps by some inland body of
salt water like the Dead Sea, were covered on
occasion with salt spray from dashing waves or
saturated with the brine when they fell to the
earth.

In such case, varieties that chanced to en-
dure this treatment best would be the ones pre-
served, and in due course a race of plums having

THE PRUNE 35

the right texture of skin to stand this treatment
would be developed.

This particular quality of skin would doubt-
less be subordinated when the plant migrated to
regions away from the salt water and crossed
with other races. But here as before the latent
trait would be preserved as a submerged heredi-
tary factor, ready when the occasion arose to
make itself again manifest.

But how, it may not unnaturally be inquired,
would man himself discover the value of the
alkali bath in preserving the prune?

Granted that a prune had been evolved
through artificial selection that had a sufficiently
high sugar content to make it a drying prune,
how chanced anyone to hit upon the particular
method of drying that is now employed, an es-
sential preliminary of which is the submersion
of the fruit in the alkali bath?

The question is doubly pertinent because even
to this day in France the use of this method is
by no means universal. In many cases the prune
is still dried with the aid of artificial heat, the
fumes and smoke of wood or charcoal taking the
place of the alkali bath in giving the right qual-
ity to the skin and aiding in preservation. So we
may assume that the simpler method of using an
alkali bath is of very recent origin.

THE SPLENDOR PRUNE

The fruits of the Splendor prune
are so placed on the tree that it will
bear an immense load without break-
ing. The heavy fruits are borne on the
strong wood, near together, but far
enough apart to obtain a good distribu-
tion of weight. Not so extensively
grown as others on account of its habit
of clinging to the tree instead of fall-
ing when ripe. The fruit is of ex-
quisite quality.

THE PRUNE 37

Not unlikely the discovery was made al-
together by accident.

Many of us can recall that in our boyhood
daj^s it was customary in New England to make
lye for use in the manufacture of soft soap by
percolating water through barrels filled with
wood ashes. The lye thus made is closely similar
in composition to the fluid that is now used in
preparing the prune. It seems a reasonable con-
jecture that the discovery of its value in this con-
nection may have resulted from observation that
plums which chanced to drop into a bucket of
lye, when removed and thrown aside were more
resistant to decay and dried sooner than other
plums.

Such a chance observation would have sufficed
to give the clue to some ingenious person, and
the value of lye as an aid in making the plum
into a dried fruit would thus come to be under-
stood.

But whether or not this was the manner of
discovery, the fact remains that the lye bath is
an essential part of the process of curing the
prune. Therefore the quality of skin that adapts
the fruit to respond properly to this treat-
ment is one of the absolute essentials that
the fruit developer must have constantly in
mind.

38 LUTHER BURBANK

How Sugar and Lye Cooperate

It may seem rather curious at first glance that
a high sugar content should be essential to the
preservation of the prune, when we reflect that
sugar is a very fermentable substance. Everyone
knows, for example, that starch is transformed
into a form of sugar before it is fermented in the
manufacture of alcohol. How, then, does the
sugar in the prune prevent the fermentation of
the fruit and insure its preservation?

The answer is that sugar ferments only under
influence of certain living microorganisms, and
that these microorganisms cannot work in a too
concentrated solution of sugar. There are myr-
iads of the microbes spread broadcast everywhere
on the wind, and of course they find lodgment
on the skin of the prune as on every other ex-
posed surface.

But the alkali bath to which the prune is
subjected, destroys these germs at the same time
that it cracks the skin of the fruit.

Other germs would find lodgment, however,
and set up fermentation, were it not that the
cracked skin permits a very rapid evaporation of
the water content of the fruit. This quickly
brings the sugar content to a degree of concen-
tration that makes it a powerful antiseptic — that

THE PRUNE 89

is to say a germicide that destroys any micro-
organisms that enter it.

But unless the prune has at least 15 per cent
of sugar in its pulp, it will take too long to desic-
cate it sufficiently to give the sugar the right
degree of concentration. And unless the condi-
tions are very exceptional, even when the plum
has a sugar content of more than 20 per cent, it
still will not dry rapidly enough to escape fer-
mentation unless its skin cracks in just the right
way.

A difference of the hundredth of an inch in the
average interval between the cracks may make
all the difference between a satisfactory prune
and a nearly useless one.

Of course in the pure dry air of many re-
gions of California, under a cloudless sky, a very
sweet prune will often dry perfectly without the
aid of the alkali bath ; but it would not do for the
prune raiser to depend upon these conditions as
a general thing. He must control his prune, for
he cannot control the weather.

Difficulties in Schooling the Prune

It is obvious, then, that the plant developer
must always bear in mind the two particular
features of the fruit's education he has to con-
tend with.

PRUNE DRYING IN
CALIFORNIA

This is a typical scene in the Cali-
fornia prune district. In the fore-
ground are seen piles of trays not at
present in use. In the background
the trays, covered with prunes, are laid
out on the ground while the fruit
dries in the sun. Before drying, the
fruit is sterilized and the skin properly
cracked by dipping in a lye bath.
These prune - drying establishments
quite often occupy many acres each.

THE PRUNE 41

But it is also understood that there are many
other features that cannot be ignored.

A prune tree, like any other plum tree, must
be a good grower and a full annual yielder. The
fruit must ripen early in the season while the
days are long and warm. It must drop from the
tree in exactly the right stage of ripeness that
the orchardist may not be put to the trouble and
expense of picking it. The fruit should have a
small stone and if possible a free stone — over-
looking for the moment the question of entire
stonelessness which will doubtless be required of
the prune of the future.

Again, the trade demands a glossy black
prune, for — owing, perhaps, to the fact that the
French prunes, especially those cured in the
smoke, are black — the average purchaser is prej-
udiced against the prune of lighter color even
though it be of better quality.

When we consider how many of these traits
are different from those required in the ordinary
plum, and hence have been developed in recent
times under conditions of artificial selection, it
will be obvious how largely the task of the prune
developer must be carried out in opposition to
the main stream of heredity ; and it will not seem
strange that forty years has proved none too long
a time in which to develop the perfect prune.

42 LUTHER BURBANK

If I were to attempt to make a guess — it, of
course, would be only that — as to the number of
generations that have elapsed in the history of
the prune since the qualities that chiefly charac-
terize it were developed, my estimate would be
something like this:

The tendency of the fruit to drop promptly at
the right time has been in vogue for perhaps only
five or ten generations out of the thousands of
generations since plums were brought under
cultivation.

The quality of producing sufficient sugar in
the right form for drying may have been devel-
oped during perhaps the last twenty-five gen-
erations; but it has been brought to its present
high precentage during the most recent half
dozen generations.

The condition of the skin which allows it to
crack in just the right way has without doubt
been cultivated for only a few generations.

But on the other hand the fairly edible flesh,
not having a high sugar content, has been
the heritage of the plum for thousands of
generations.

So we can readily understand that the plant
developer may secure among many thousands of
seedlings, nearly all of them producing plums of
fair quality, perhaps only one that may show the

THE PRUNE 43

qualities that specifically characterize the prune
even in a minimum degree.

The progenitors of the seedlings may have
been prunes of fair quality; but the seedlings
themselves have gone back to the blanket stage
of plum development.

The chances against securing even a single
fruit that combines all the desired qualities
among any given lot of seedlings are so small as
to be almost disheartening.

Indeed when the plant developer brings
together two strains, each carrying its galaxies
of more or less antagonistic characters, it is not
altogether unlike scattering the letters of the
alphabet in a whirlwind and expecting them to
fall together in some chance eddy in such a way
as to spell out some specified word.

Marking Progress

I was not unmindful of the difficulties of the
project, but nevertheless the obvious need of a
better prune than California growers had been
able to secure by importation appealed to me
from the time of my first coming to the State;
and when I undertook plant experimentation
on a large scale, the development of the prune
was one of the things that first engaged my
attention.

THE STANDARD PRUNE

The Sugar prune had no real rival
until the Standard was produced.
This is a cross between the Sugar
and the Tragedy prune. It combines
the good qualities of both parents,
and has the very important quality of
being a freestone, the stone being so
loose in the cavity that it may be heard
to rattle when the ripe fruit is shaken.
In exquisite flavor when dried, no fruit
of any kind surpasses it. (Natural size
of well- grown specimens.)

THE PRUNE 45

This work began about 1885, when I was
growing seedlings of the European plum,
Primus domestical from which practically all the
prunes have been developed.

I have told in an earlier chapter of the suc-
cess that ultimately attained the effort, through
the development of the sugar prune. Here I
wish to tell a little more at length of some of the
tentative efforts and partial successes that paved
the way for the final realization of an ideal.

As already told, these experiments were con-
ducted by hybridizing the French prune with the
larger and handsomer but less sugary variety
known as Pond's seedling, and in California
often called the Hungarian prune. The little
French prune was selected as the parent tree and
many thousands of blossoms were pollinated
from the Hungarian. This was in 1885.

Four years later, at the meeting of the Cali-
fornia State Horticultural Society, I had the
pleasure of exhibiting fruit of seventy different
varieties of these crossbreed seedlings.

During the next winter a purchaser of the
commercial part of my nurseries, being ignorant
of the value of these crossbred prunes, destroyed
sixty or more of them. Fortunately, however,
cions from several of the most promising had
been grafted on older trees.

46 LUTHER BURBANK

Among these selected grafts were two that
gave much promise. These were advertised in
"New Creations" of 1893.

The Giant Prune

In 1895 one of the new prunes was introduced
as the Giant. It was so well received that
four years later it was placed on the lists of
fruits recognized by the American Pomological
Society.

The Giant is a well balanced cross between its
two parents the French prune (d'Agen) and the
Hungarian. Fruits average 1V2 to 2 ounces each
and are of a sweeter and finer texture than the
Hungarian but not so firm and sugary as the
prune d'Agen. The large size, handsome ap-
pearance and rare keeping qualities place this
among the best canning, shipping, and market
fruits; but, unfortunately, the Giant follows its
pollen parent the Hungarian in having a low per-
centage of sugar; so it does not cure well as a
prune.

Here, then is a specific illustration of the tend-
ency to revert to the characteristics of the plum
and to give up the special qualities of the prune.

The Giant is a valuable fruit, excellent for
shipping and especially good for canning. When
placed in boiling water the skin immediately rolls

THE PRUNE 47

away from the fruit, leaving the rich honey-
eolored flesh ready for the can.

The plum has made its way to distant terri-
tories, and is now grown extensively in Australia
and New Zealand, being especially prized for
canning purposes.

In California it has proved a favorite and it is
greatly superior to its staminate parent the Hun-
garian prune, especially for shipment.

But it is sold as a plum and not as a prune.

The Pearl Prune

Obviously, then, this was not the fruit I was
seeking. But my experiments continued and
after a few more generations of crossing and
selection, I found among the seedlings one
that produced a fruit in many respects more
promising.

This fruit was introduced in 1898 under the
name of the Pearl prune.

The Pearl prune originated as a seedling from
the French prune. It is usually a little larger
than its parent, but somewhat more flattened in
form. The skin and flesh are pale amber and so
translucent when ripe that the stone can be seen
through them.

It is really a delightful prune, of exceeding
high flavor, delicious aroma, and melting flesh,

THE CONQUEST PRUNE

At last, through successive selections
and recrossings, a nearly perfect stone-
less prune, which was named the Con-
quest, appeared. It was the result
of crossing a partially stoneless plum
with the French prune. This fruit, as
here shown, has the good qualities of
the French prune, and yet is almost
entirely stoneless. It was introduced in
1912. It is exactly like the common
French prune in quality, and very
much like it in appearance, though
larger, and the tree is more vigorous
and productive. Some growers object
to it because, being stoneless, it does not
weigh as heavily when dried. (About
one-eighth larger than life size.)

THE PRUNE 49

surpassing even the true Green Gage plum. No
prune excels it for attractive fragrance. When
cured it produces one of the most delicious of
prunes; but it requires care in handling, since
it does not cure well in the open air. Its chief
fault is that it is not very productive, although
healthy and vigorous.

It was sold to a New Zealand firm for intro-
duction in the Southern Hemisphere in 1898.
I myself introduced it in the Northern
Hemisphere.

The New Zealand nursery company recom-
mends it for that country in a recent catalog as
follows :

"Pearl : — Raised by Luther Burbank. A seed-
ling of the well-known French prune, which it
surpasses in size of fruit. It is very handsome,
flattened ovoid in form, white, semitransparent,
with a heavy bloom. In honeyed sweetness, com-
bined with a peculiarly attractive fragrance and
flavor it excels all other prunes or plums. It
requires care in handling, and will not cure well
in the open air. It is especially recommended for
market and home use when fresh."

The following quotation from "The Plums of
New York," written in 1910, shows how
this variety was regarded in New York at
that time :

50 LUTHER BURBANK

"The variety now under notice is one to be
pleased with if it came as a chance out of thou-
sands ; its rich, golden color, large size, fine form,
melting flesh, and sweet, luscious flavor place it
among the best dessert plums. In the mind of
the writer and of those who have assisted in
describing the varieties for 'The Plums of New
York,' it is unsurpassed in quality by any other
plum. The tree characters, however, do not cor-
respond in desirability with those of the fruits.
The trees, while of medium size, and seemingly
as vigorous and healthy as any, are unproductive
here. In none of the several years they have been
fruiting at this Station have they borne a large
crop. If elsewhere this defect does not show,
the variety becomes at once one of great value.

"The fruits of Pearl are said to cure into
delicious prunes — to be readily believed by one
who has eaten the fresh fruits. This variety
ought to be very generally tried by commercial
plum growers and is recommended to all who
grow fruit for pleasure."

Other Partial Successes

Another prune developed somewhat earlier
was named the Honey prune.

This was one of my earlier seedlings and not
a hybrid. It was of better quality and hand-

THE PRUNE 51

somer than the Green Gage, the standard of
excellence at that time. The tree was not re-
markably productive, but the variety has been
welcomed as a home fruit in several localities of
California. It was not considered worthy of
general introduction, but a few trees were sold
to local growers who were interested in this
variety and felt that it met the demands of
their locality.

A seedling of the prune d' Agen which I called
Miller, was sold to Leonard Coates of Morgan
Hill, California, in November, 1898. This he
introduced in 1908 as the "Improved French
Prune." Later the name was changed to
"Morganhill."

The introduction of this prune as described by
Mr. Coates himself furnishes an illustration of
the length of time it usually takes for the public
to become accustomed to a new fruit. In a letter
Mr. Coates says:

"We did not attempt a system of advertising
in the start, but rather tested it thoroughly for
some ten years or so. It is very hard to introduce
any new fruit as so many have been put on the
market without real merits. Fruit growers, how-
ever, appreciate to a considerable extent the
value of selecting good varieties of fruit to prop-
agate from. It seems that the chief introduc-

52 LUTHER BURBANK

tion of pedigreed stock has taken place since our
present nurseries were located and advertised on
letter heads, etc., as specializes in pedigreed
stock.

"The Miller prune which we now call Morgan-
hill has been coming under the head of pedigreed
prunes. We called it in the first description 'Im-
proved French.' Very few people had enterprise
to buy these trees at any increased figure and now
we are propagating them at the same price as
any kind of prune tree. About half the people
seem to ask for pedigreed prunes and the others
simply say 'French prunes.' "

This, then, suggests a measure of success. It
constituted at least a good beginning.

Successes more unqualified were to follow ; but
the work just described was instrumental in lay-
ing the foundation for the later improvements —
improvements that culminated in four prunes,
one of which is already revolutionizing an entire
industry, while the others have intrinsic values at
least as great.

An account of these perfected prunes will be
given in the succeeding chapter.

FOUR BURBANK PRUNES AND
THE WORK BEHIND THEM

Revolutionizing an Entire Industry

A BRIEF outline of the story of the sugar
prune was given in a chapter of an earlier
volume.

The preceding chapter gives further details of
the quest of a perfect prune.

The present chapter will treat more of results
than of methods, and to present somewhat in de-
tail the characteristics and merits of the four
nearly perfect prunes that have been produced
as the result of my long quest.

While some of the details here presented ap-
peal rather to the orchardist than to the general
reader, yet the story as a whole will be found not
without popular interest. The fact that the
growing of prunes is an industry of great signifi-
cance, and that the fruit is everywhere an impor-
tant commercial product would furnish ample
excuse, were excuse needed, for entering some-
what more into detail as regards the specific

53

54 LUTHER BURBANK

qualities of my quartet of prunes than has been
done in the case of most other of my plant
developments.

The Splendor Prune

Another prune of the same parentage with the
Giant (referred to in the preceding chapter),
namely, the Hungarian prune, crossed with
prune d'Agen, was advertised at the same time,
under the number "A. P. 318" in "New Cre-
ations" of 1893. This was purchased by Stark
Brothers of Louisiana, Missouri, who procured
the entire stock for $3,000, and named it
"Splendor."

This prune is very much larger than the com-
mon French prune, is oblong, has a rich violet-
purple skin, and the flesh is exceedingly sweet,
and black when cured — a great advantage. The
American people have been educated to black
prunes and generally prefer them to those of
lighter colors, following the fashion set by the
French smoke-dried prunes. The Splendor fully
answers the desire on the part of the buyer and
consumer for a "black" prune, of large size and
superior quality.

Splendor prunes, when cooked, require little
sugar, containing about five per cent more sugar
than the French prune, its quality and flavor are

FOUR BURBANK PRUNES 55

superior, and it has a perfectly free stone smaller
than is usual with prunes.

It ripens here two weeks earlier than the
French prune.

The tree is even more productive, it is a more
constant bearer, and is sturdier than its French
parent; it is a well proportioned one, requiring
but little pruning. The fruit is borne in clusters
commencing low down on the body of the tree.

Many thought that this excellent prune would
soon completely displace the prune d'Agen.
Surely if quality and productiveness were all that
were demanded by the grower, this would have
occurred.

But Splendor has one peculiarity which places
it at a serious disadvantage for general commer-
cial purposes as a drying prune; the fruit clings
to the tree when ripe, where it gradually dries
into a delicious, sweet prune.

As prune growers like to have the prune fall as
soon as ripe, to save trouble in harvesting, the
clinging of the Splendor to the tree is considered
a more or less serious fault. However, it is quite
commonly planted wherever the German prune
thrives, and gives excellent satisfaction, except
for the extra trouble of picking.

It is shipped East as a fresh plum from sec-
tions of California in large quantities and is un-

56 LUTHER BURBANK

usually well adapted to shipping, on account of!

its large content of sugar, making a fruit which

carries well.

The Sugar Prune

The Splendor was the best prune I had hereto-
fore produced, but it clearly left much to be
desired.

It was with intense satisfaction that I was able
to offer in "New Creations" of 1899 a prune that
at least approached the realization of my ideal.
This was another seedling of Petite d'Agen.

It was christened the Sugar prune, as it con-
tained when cured 23.93 per cent of sugar — more
than any prune or plum ever before known.

For fourteen years I had labored to produce a
large, early, productive, handsome, easily cured,
richly flavored prune with a high percentage of
sugar. The prize appeared in 1893, and by 1899
I had tested it sufficiently to warrant its intro-
duction. Numerous growers had ordered $50 to
$500 worth of wood for grafting — regardless of
the quantity — even before grafting wood was
offered.

I had worked diligently and unceasingly,
watching for the slightest indication of variation
in the direction desired. Finally through
systematic crossing and careful selection, my
cherished desires were realized — after years of

FOUR BURBANK PRUNES 57

persevering effort and patient waiting — in the
Sugar prune.

In this, at last, I found a prune possessing the
best qualities of all the prunes combined in one;
and several of these qualities were intensified.

The Sugar prune had no rival until the advent
of the still newer prune, the Standard, which I
introduced in 1910.

When the selection of seedlings was made
from which the Sugar prune originated, about
one-half were at once discarded. Only those
were saved which had the customary indications
of good fruiting — large leaves, prominent buds,
and strong, heavy wood with short joints.

Grafts from the young seedlings were placed
upon Japanese plum stocks. This was done be-
cause there was no other stock at hand at that
time. It proved to be a costly experiment, be-
cause more than half of these new, promising
seedlings died before bearing fruit. Some of
the grafts did not start at all ; some made a short
growth and died the first season; some grew a
few seasons and died. Fortunately, however,
some thrived as well as on their own roots.

The grafts that bore the first fruits of the
prune which was later named "Sugar," made a
fair but not a good union with the Japan plum.
Although the first fruits of this variety were

58 LUTHER BURBANK

borne on Japanese plum stock it is not recom-
mended that Sugar prunes be grafted upon such
stock. Roots of the peach and myrobalan plum
make better stocks. Almond roots are also
highly commended by some orchardists.

The seedling bearing the Sugar prune yielded
its fruit the second year after grafting.

At that time I had the French Robe de Ser-
geant and German and Italian prunes growing
on my Sebastopol place, and it was with these
that the Sugar prune was compared. It proved
to be superior in all respects to any of them.

Some of the fruits from the other grafts of
this same lot of seedlings bore good plums but
not good prunes. The fruits of the others had
various faults, such as cracking, too large pit,
clingstones, poor drying qualities, late ripening,
scant foliage, or susceptibility to disease.

Several years are always required for the
merits of a new fruit to gain full recognition,
but the Sugar prune has gained pretty steadily
in popularity. More and more growers are
working their orchards into this variety, and it
is taking the place it deserves, high among the
leading prunes of commerce, especially as the
tree is a tremendous grower and bearer and is
also a good shipper and is proving to be one of
the most acceptable fresh fruits in the eastern

FOUR BURBANK PRUNES 59

markets as well as extremely profitable when
cured.

The growers at Vacaville, California, the most
important early fruit shipping center, became
more enthusiastic as they saw the fruiting of
these trees, the ease with which the larger prunes
can be harvested, and the greater price per ton.
About 2,500 new trees of this variety were
planted in Vaca Valley in 1913.

Growers there received $17 to $25 per ton
more for Sugar prunes in 1913 than for French
prunes grown on the same farm at the same time.
One of the growers reports that his French
prunes averaged fifty-seven to the pound last
year — when cured — while his Sugar prunes
averaged thirty-nine per pound. The larger
prunes always bring the best prices.

Not only did the Sugar prunes bring excep-
tional prices, the whole crop was dried perfectly,
while the French and Imperial prunes, ripening-
later, were caught by the rains and many of
them spoiled. The Imperial prune often dried
to almost nothing but skin and stone.

One pound of green Sugar prunes makes
seven and one-half ounces of dry fruit. It con-
tains six per cent more sugar than the French
prune and is far superior to it in flavor. It is so
much more productive that it may be grown for

ONE OF THE PLUMCOTS

This remarkable fruit was produced
by hybridizing the Japanese plum and
the apricot. Most plant breeders held
that so wide a cross was impossible, and
this successful combination was not
effected without difficulty. The story
is told in detail in the text. The hybrid
product is virtually a new species, of
which there are now many varieties.

FOUR BURBANK PRUNES 61

less than half the cost of producing the French
prune.

The Sugar prune has a great advantage over
the other varieties in ripening early in August,
two weeks before the French prune, and about
a month earlier than the Imperial. It ripens at
a time when the weather is hot and dry, so that
it can be cured bright and glossy in a short
time and before there is any danger from
fall rains.

A month or so later, when the last of the older
varieties are maturing, the weather is often
cloudy and foggy, or sometimes even rainy and
in any case the days are much shorter, so that
curing is carried on under difficulties, often (as
in the cases just cited) with serious loss.

In 1912, prune shippers estimated that rain
damaged the crop of French prunes in this
county 25 per cent. The Sugar prunes were all
cured and packed before the rains, so there was
no loss of this variety.

Progress of the Sugar Prune

The fruit of the Sugar prune is usually even
in size and very large, averaging thirteen to fif-
teen to the pound fresh, which is at least two to
three times as large as the French prune grown
here under the same conditions.

62 LUTHER BURBANK

It has excellent curing qualities, standing the
lye bath better than most other prunes.

The tree is very far superior to the French
prune tree in every respect; better growing,
better bearing, better foliage, better form. It re-
quires less careful but abundant pruning; and it
will carry and mature more than double the
quantity of fruit.

The wood is somewhat brittle, but the chief
cause of the breaking of the limbs, which some-
times occurs, is prolific bearing. It must be
thinned when the fruit is about half grown, to
prevent damage to the tree.

I have found that a very satisfactory and
simple device for doing this is to tap the limbs
gently with a piece of ordinary three-quarters
inch rubber hose five to six inches long, fastened
on the end of a bamboo pole. The hose causes
no injury to the branches, and, by striking just
hard enough, the fruit can be made to fall evenly
and leave the amount desired.

The need of thinning, however, may be largely
obviated by proper winter pruning.

When this variety was first offered, grafting
wood was sold at $10 per foot. That the invest-
ment was a profitable one even at that price is
shown by the following quotation from a letter
written by one of the first purchasers:

FOUR BURBANK PRUNES 63

"I was one of the first to introduce this fine
fruit into our locality, the first year the grafting
wood was placed on the market. I bought seven
feet of wood for $70. The same was grafted
into Tragedy prune trees, using one bud for each
cion. The following fall and winter I sold about
$600 worth of buds and cions from the ten trees
which I had grafted with the Sugar prune cions."

The Best Prune — the Standard

Preeminent as are the qualities of the .Sugar
prune, there is always room for improvement.

I endeavored to make such improvement by
the usual method of crossbreeding.

About 1897 I combined the Sugar prune with
the Tragedy. There were only twelve or fifteen
seedlings from the cross. But these were care-
fully grafted upon older trees, on larger
branches where they would be in less danger of
injury. This, of course, made the bearing of
fruit a year later than if they had been placed
upon the smaller branches. But it seemed worth
while to wait for fruits of such high promise.

The whole tree was given over to each of the
seedlings. Nor was this exceptional solicitude
unavailing. For among these carefully nurtured
cions was one that bore a fruit that surpassed
even the hitherto matchless Sugar prune.

64 LUTHER BURBANK

After a period of trial, in which it met the
severest tests, this superlative prune was intro-
duced as the "Standard."

It is rather curious to record that, with a single
exception, all the remaining cions of this patri-
cian sisterhood have proved wholly worthless as
prunes. But that, of course, was a matter of no
consequence. It sufficed that one cion came to
fruitage with a paragon of prunes.

The Standard prune far surpasses the Sugar
prune in quality. It also has a stone that is en-
tirely free from the flesh, being the first prune
ever produced that combined superior qualities
of flesh with this desirable characteristic.

In the opinion of a number of the best known
growers, it is the best prune ever produced. The
trees are enormous and never-failing bearers,
and good, healthy growers, better than the
French prune though not as strong as the Sugar,
Well-grown fruits measure nearly six inches
around one way by four and a half inches the
other.

On old standard orchard trees the size may
average larger than this, but when the crop is not
too heavy the fruits are really enormous.

The skin is purple with a heavy blue bloom
flesh honey-yellow, fine-grained, juicy, yet
firmer than most drying prunes, and very sweet

FOUR BURBANK PRUNES 65

The stone, which is free, is only five-eighths of an
inch in cross section and very thin.

The Standard is without doubt the best com-
bination drying and shipping prune ever pro-
duced. It ripens with the French prune in Sep-
tember. It has been kept fully a month in good
condition in a basket in an ordinary living room
during our warm fall weather. It can be suc-
cessfully shipped after it becomes dead ripe to
any part of the United States.

And the final test as a prune is that when
dipped in the ordinary lye solution the skin
cracks properly, so that the result is a big,
quickly dried prune of superlative quality.

The following comparison of the French and
Standard prunes, made by O. E. Colby of the
University of California, gives a good idea of
the value of the Standard prune :

Average
The Standard French Prune

Average weight in grams 49.7 23.6

Number per pound 9.1 19.1

Flesh, per cent 96.5 94.2

Pit, per cent 3.5 5.8

Sugar, per cent 18.9 18.5

In case anyone wishes to change a prune
orchard over to a more profitable variety,
whether for drying or shipping fresh, I would
strongly recommend the Standard for grafting.

3 — Vol. 4 Bur.

66 LUTHER BURBANK

The Standard was offered to orchardists in my
catalogue of 1911-1912. The trees were sold at $3
each, and thousands of trees have been distrib-
uted, but it will be a good many years before
the real value of this superior prune is fully
appreciated.

Clinging versus Freestone

One of the most striking individual peculiar-
ities of the Standard prune is its freestone qual-
ity, already referred to. The development of
this character is of such interest and importance
that it calls for more than passing mention.

At first, it is very probable, all fruits were
clingstones. The stone was probably firmly at-
tached to the flesh from the time of the forming
of the meat to the final decay of the fruit. The
stone in fruit acts as a support to the flesh, to
which it is attached and around which it grows.

The clingstone feature was evidently an
advantage to the fruit, as plum and prune seeds
will not germinate if thoroughly dried, and the
clinging meat in most of the fruits keeps the
seed moist for a longer time, thus helping tc
conserve its vitality until the proper season for
germination.

Where the flesh is attached to the pit, the cir-
culation between the pit and the surrounding

FOUR BURBANK PRUNES 67

flesh is less interrupted, probably an advantage
to the development of both.

The clingstone is thus the more normal
condition of fruits. Most fruits are cling-
stone until brought under cultivation. All fruits,
both wild and cultivated, are clingstone
until toward the time the ripening process
commences.

That many cultivated fruits are freestone is
no doubt the result of artificial selection to meet
a very natural demand.

Nuts furnish analogies that help us to under-
stand the relations of seed stone and fruit. The
case of the almond, which was perhaps more
nearly the parent form of stone fruits, is partic-
ularly instructive. In place of the rich surround-
ing meat which we see in peaches, apricots, and
plums, the almond has a leathery skin, which is
inedible. This generally clings to the stone per-
sistently in the wilder forms, but with the best
cultivated almonds the nut drops readily from
the husk or outside covering.

Similar to the persistency with which the flesh
of the plum clings to the stone is the attachment
of the husk in the walnuts and the chestnut, in
each of which the husk separates with more diffi-
culty in the wild than in the best cultivated
varieties.

A SUPERIOR PLUMCOT

This delicious plumcot, as yet unin-
troduced, possesses marked freestone
characteristics, a quality very unusual
among the Japan plums that figure
among its ancestors. Apricot parent-
age is indicated by the smooth stone
and by the shape and ridging of the
fruit. The flesh, by its red color,
shot with yellow, indicates plainly the
Satsuma plum, modified by apricot
influence. As an example of mixed
inheritance, therefore, the fruit has ex-
ceptional interest. The fruit appeals to
any palate.

FOUR BURBANK PRUNES 69

From the standpoint of protection and repro-
duction of the almond, the clinging husk is an
advantage rather than an objection. The seed
of the almond will germinate after being thor-
oughly dried. It needs no flesh to tide it over,
as do the pulpy stone fruits. But for man's use
the clinging husk is a disadvantage, and the cling-
stone habit has been eliminated in all the best
cultivated varieties of the almond.

In the plum a similar change has been devel-
oped by selection. The meat does not cling to
the stone in many cultivated varieties. In the
almond the quality of the meat has been greatly
improved, while the husk or immediate covering
has not been improved in any respect, as no use
is made of it.

Even a freestone fruit does not start as a free-
stone, but the flesh tends to leave the stone as
the fruit approaches maturity, very much as a
leaf ripens away from its supporting stem in the
fall when it has performed its annual function,
or the fruit parts from the tree when it is fully
ripe. The flesh parts from the stone by a nat-
ural process. This leaves the stone either "free"
or partially free.

Some individual trees among a lot of seed-
lings— chestnuts in particular — will hold their
leaves persistently all winter (this persistence is

70 LUTHER BURBANK

especially common with crossbred chestnuts)
even when thoroughly dead and dried, giving an
untidy appearance to the tree, while the leaves of
other seedlings fall at once and leave the branches
clean and free.

This is a similar process to the parting of the
flesh from the pit in fruits, both being ripening
processes.

There is every gradation between the com-
plete attachment we call "clingstone" and the
"freestone" condition. In some fruits there is
a single point of attachment; in others the
flesh adheres over a part of the surface while
the remainder may be wholly free from the
stone.

There is also another form of partial separa-
tion found in some fruits where the flesh clings
tenaciously to the stone until fully ripe, when it
parts readily, while in others it may separate
from the fruit and be shaken about within it even
before thoroughly ripe.

There seem to be two forms of variation, one
in the time of attachment and the other in the
persistency of attachment.

This persistency of attachment varies greatly;
in some fruit it would be possible by a little work
to cut around the stone and in others the flesh is
attached so closely that to remove the stone satis-

FOUR BURBANK PRUNES 71

f actorily you must have sharp tools and use them
with discretion.

The old hereditary tendencies make it difficult
to change plum and prune heredity so that it will
produce freestones instead of clingstones. Never-
theless this has been accomplished with several
varieties, including the Standard prune.

Of late the canners have preferred the cling-
stone peaches mostly, perhaps because they have
a firmer flesh that does not fall to pieces when
cooked, as the freestone peaches generally do.
The pit is very easily removed with a sharp in-
strument made for the purpose. With this
exception, fruits are generally more valuable
when they are freestone.

The Conquest — A Stoneless Prune

But what if the fruit had no stone at all?

That would, indeed, be the ideal condition.
And this ideal is met in the fourth member of my
quartet of best prunes — the Conquest.

This, the newest of my prunes, was first
offered in the catalogue of 1911-1912.

The work of producing the stoneless prune
parallels that of the production of the stoneless
plum, a preliminary account of which has already
been given, and fuller details as to which will
appear in the succeeding chapter. Here it is

72 LUTHER BURBANK

necessary to mention only such aspects of the
work as refer specifically to this prune.

The Conquest was produced by crossing a par-
tially stoneless plum in my orchard with the
French prune.

The difficulty of getting a stoneless prune was
about equal to the difficulty of getting a satisfac-
tory stoneless plum. If I had crossed with a
plum it would have been a hundred times more
difficult to get the prune characters than it was
to get stonelessness.

In the Conquest the size and quality of the
French prune is retained or even intensified,
together with the stonelessness of the other
parent. This cross brought out both prunes and
plums — some of the largest plums ever seen. At
first they were all blue like the stoneless parent ;
later they took on all the colors of ordinary
plums.

The advantages of the stoneless prune are too
obvious to require elucidation.

To be sure, the new prune is not in every case
absolutely stoneless. A small speck often per-
sists in prunes of best quality. It has been no
great trouble to totally eliminate the stone in a
poor fruit; to combine stonelessness with good
quality of fruit has been extremely difficult. But
continued selection has finally produced a prune

FOUR BURBANK PRUNES 73

of this kind which has the quality of the best

French prunes, together with entire stone-

lessness.

By Way of Summary

Such, then, are the four Burbank prunes that
are the pick of all those that have been developed
on my experiment farms.

The methods used in their production are
similar to those used in the development of the
four best Burbank plums as told in an earlier
chapter. The distinctive qualities of the four
prunes themselves may be summarized thus:

The Splendor prune is large, productive, has
high sugar content, has a small free stone and
ripens early, yet has the fault of clinging to the
tree.

The Sugar prune is very large, productive,
very early, superior in tree form, an especially
good curer, and is both a sure bearer and a sure
seller.

The Standard prune has most superior quality
of flesh, is entirely freestone, and in general is the
best combination drying and shipping prune thus
far produced.

The Conquest prune is similar to the French
prune in quality of flesh, but better, and has the
stone brought down in size to a mere speck, and
the tree is far more vigorous and productive.

74 LUTHER BURBANK

Because of the many characters it is necessary
to combine in producing a successful prune, it is
probable that the work represented by these four
varieties is fully equal to the production of ten
times that number of standard plums — with,
probably, proportionate benefits.

But from the almost numberless varieties, the
result of years of selective breeding, there will
probably arise individuals year by year that will
present new and superior combinations of quali-
ties ; and among these may appear at any time a
prune that may even surpass my best prunes of
the present as markedly as these surpass their
predecessors of a generation ago.

This, indeed, is fully to be expected. Each of
my prune trees, with its colony of selected hy-
brids, may be regarded as a factory admirably
equipped for the turning out of new varieties of
prunes. Even though it were left to be operated
solely by the bees, its mechanism has been so per-
fected, its equipment is so complete, that it can
scarcely fail of its purpose.

PLUMS AND PRUNES WITH-
OUT STONES AND SEEDS

How All Fruits May Become Seedless

A NUMBER of years ago a distinguished
pomologist who was not in the secret of
my newest plant development, visited my
place at Sebastopol in company with the eminent
botanist Professor Hugo de Vries.

Standing by one of the plum trees, de Vries
asked his friend to cut through a plum and ex-
amine the stone.

Then with obvious amusement he watched the
pomologist work his knife carefully around the
center of the plum — to avoid a stone that was not
there.

As he told of it afterward, he declared that
even the boots of the pomologist indicated sur-
prise when the knife cut at last through the
center of the plum without meeting any ob-
struction.

This was a case in which a man's surprise
would be somewhat proportionate to his knowl-

75

76 LUTHER BURBANK

edge of botany and plant physiology. The more
he had studied the subject, the better he would
be able to appreciate what stonelessness in a
plum really means. The more he had worked in
plant development, the fuller would be his ap-
preciation of the labor represented in the repro-
duction of this anomaly.

And my visitor, being both a botanist and
a plant experimenter, was certainly greatly
surprised.

What the Stone Means to the Fruit

The story of the development of the stoneless
plum has been told in an earlier chapter.

It will be recalled that I worked primarily
with a small, partially stoneless plum that was
found in France — a sour, acrid fruit of no in-
terest except for its partial lack of seed covering
I crossed this inedible fruit with a cultivated
plum, and selected and recrossed through suc-
cessive generations until I had segregated the
characters of stonelessness and good quality of
flesh and reassembled them in a single individual.

Further mention of the development of the
stoneless prune, through crossing the stoneless
plum with the French prune, with the ultimate
production of the Conquest prune, was given in
the preceding chapter.

STONELESS PRUNES 77

Here it is not necessary to repeat the details of
the method through which the stoneless plums of
various kinds, including the prune, were devel-
oped. It seems desirable, however, to examine
at some length the relations that obtain between
the stony seed covering and the general and
especial needs of the plant ; and to correlate this
type of seed covering with other type of protec-
tive seed covering that serve the same or a
similar function in the case of other tribes of
plants.

When man takes a plant under his care, some
of its many parts may become of little use, be-
cause of the changed conditions of the artificial
environment.

Thus the wild oat has a pointed, sawlike beard,
which, turning and twisting under influence of
moisture and heat, helps the seed to burrow into
the earth. This is obviously useful to the plant
in a state of nature. But it becomes a useless
piece of baggage when the plant has been tamed
and grown by man, for man will see that the seed
is planted in return for the crop it yields.

The blackberry, domesticated, has no further
use for the thorny armor that was originally de-
veloped to protect it from destruction by ani-
mals that would browse on its leaves and stems or
trample it to death.

78 LUTHER BURBANK

In the same way the cactus, when taken under
cultivation, can dispense with the spines that
were so necessary a protection to it while it grew
in the desert, where, in the old days, buffalo and
antelope, and in more recent times cattle and
horses, would feed on its succulent slabs were
they not carefully guarded.

The apple, pear, and plum, which armed them-
selves with sharp thorns when in the wild state,
have given up the thorns since they came into
the orchard.

Among other families of plants we find that
protection has been secured by the development
of acrid or astringent or poisonous properties,
offensive odors, or imitative colors that serve no
useful purpose except to safeguard the plant
against its enemies. And such protective devices
and mechanisms often become a burden when
the plant is brought under the guardianship
of man.

Of a piece with these protective devices is the
peculiar covering that the plums and their allies
have developed about the seed that grows at the
heart of their fleshy and succulent fruit. This
stone is like an armor-plate covering that success-
fully protects the seed from the action of even
the strongest jaws, or from almost any forces of
nature to which it is likely to be subjected.

STONELESS PRUNES 79

Possibly one reason why the stone fruits have
developed this unusual seed covering is that each
fruit of this family bears but a single seed. The
many-seeded apple does not need to protect its
seeds quite so jealously; but the plum, with its
single seed, can afford to take no chances of the
destruction of that seed.

The case illustrates a familiar principle of
nature. Everywhere it is observed that the more
prodigal the supply of reproductive mechanisms,
the less the seeming care with which they are
guarded. Among forest trees that are fertilized
by the action of the wind, pollen is produced and
wasted by the ton. But in flowers pollinated by
insects, relatively small quantities of pollen are
produced, and its distribution is carefully pre-
pared for by the auxiliaries of color and
fragrance and nectar which guide the pollen-
distributing insects.

The mustard produces thousands of seeds for
each plant, and it does not even take the trouble
to imitate the grains of other plants, in size and
form, as some of the seeds are obliged to do in
order that they may be distributed with the grain
when grown.

The peach, on the other hand, produces but a
single seed for each flower and fruit, and armors
that seed with so strong a covering as to make

80 LUTHER BURBANK

it difficult for the germinating cells to make
their exit when the time comes for their de-
velopment.

Thus these stone fruits conform to a great
familiar principle of nature. Their exceptional
covering has been developed by natural selection
to insure continuance of the species under natu-
ral conditions.

But it is obvious that, now that man has taken
the plant under his care, the species will be
perpetuated with his aid, and hence the extraor-
dinary armor about the seed might well be dis-
pensed with. But as a matter of course the
plant cannot drop all at once a structure that
heredity and environment have worked thou-
sands of years to build up.

Man cannot take the Indian and say to him:
"Be civilized," and expect him in a generation to
drop the tendencies that have become a part of
him through centuries of inheritance.

The hunter cannot take the wolf and by treat-
ing him like a domesticated animal make a dog of
him in a single generation — even though the an-
cestor of the dog was a wolf. And similarly
when the fruit grower takes the plum under his
protection, he cannot hope that this plant will
give up at once the protective device that has
served it so well in the long past.

STONELESS PRUNES 81

Heredity will have its say, and the seed
armor will persist long after it has ceased to
be of real utility.

The Stone Becomes an Incumbrance

And yet it is easy to see that under conditions
of artificial cultivation, the stone is not merely
useless to the fruit; it is a positive incumbrance.

In the first place it puts a tax upon the vitality
of the plant — makes a strong draft on its ener-
gies. A plant is a manufactory for transform-
ing elements of the soil and of the air, under the
influence of sunlight, into grains, fruits, gums,
essential oils, and the like.

Its capacity to produce any one of these is
more or less complementary to its capacity to
produce the others.

When the cultivated plum produces a useless
stone, it has worked to no purpose; and the
energy that goes to build the stone might far
better have been utilized, even from the stand-
point of the plant itself, in the production of
fruit.

For the perpetuation of any given race of
cultivated fruit plants now depend not upon the
character of its seed covering but upon the ap-
peal made by the pulp of the fruit to the palate
of man.

82 LUTHER BURBANK

So the stone not only destroys a part of the
usefulness of the plum for man directly, by its
presence in the fruit, but it is also indirectly
harmful in that it hampers the vigor of the tree
in the production of foliage and larger quantities
of fruit.

Yet when the plant improver attempts to re-
move the stone that has thus come to be an
incumbrance to the plant, he is obliged, as it
were, to swim upstream against the hereditary
current of the ages. Ten, fifteen, twenty years
— these are but moments of time when working
against tendencies that are fixed by thousands
of repetitions under conditions that remained
unchanged for numberless generations, and until
the immediate present.

Bearing this in mind, we gain a more vivid
impression of the difficulties that confront the
plant developer who would endeavor to relieve
the plum of its burdensome stone.

Aid from Nature

But here as elsewhere nature will sometimes
seem to forget for a moment the very funda-
mentals of her plan ; and through such a lapse the
hereditary mechanism of a given organism may
be changed more radically, perhaps, in a single
generation, than it could be changed by almost

STONELESS PRUNES 83

any number of generations of selective effort on
the part of man.

Such a lapse was made, we do not know just
when, in the case of a minor variety of plum that
chanced to grow in central Europe. Through
this momentary lapse in nature's memory, this
plant found itself with a seed for which the cus-
tomary stony covering had been nearly half for-
gotten. Only about half remained of the shell
that to plum seeds in general is as a veritable
armor plate.

The plant that suffered this strange mishap
was, as the reader already knows, a little French
bullace of small significance, known as the sans
noyau. Of course we must not be supposed to
imply that the relative importance of this partic-
ular member of the plum tribe had anything to
do with its mishap. The laws of heredity apply
quite as rigidly to the most insignificant as to the
most important of plants. Indeed, it is scarcely
within man's province to decide as to which
plants are really insignificant and which impor-
tant in the scheme of things.

But at least it may be affirmed that, according
to ordinary human standards, the little bullace
was of a most inferior type. Yet, paradoxically
enough, it became, in virtue of its misfortune, the
most important race of plums in the world.

84 LUTHER BURBANK

For without the aid of this apparently mal-
formed variety, the plant developer would have
had no leverage with which to attack the problem
of relieving the great family of stone fruits of
their now useless and even obnoxious seed
covering.

The malformation of the little bullace, through
which it lost its seed protector, would doubtless
have resulted under conditions of natural selec-
tion in exterminating the species.

But the same transformation which would
thus have worked destruction in a state of nature,
sufficed to make sure that, under the changed
conditions of artificial selection, this particular
plum should become the progenitor of all the
plums of the future.

For we can little doubt, now that the stone has
been taken from a few varieties of cultivated
plums and prunes, that all other varieties will
ultimately be brought into the stoneless coalition.
And the only feasible way to bring this about
will be to interbreed one variety after another
with the descendants of the little stoneless
bullace.

The plums of the future will be diversified in
form and size and quality.

They will draw their chief ancestral traits
from the plums of Japan or China or Europe

STONELESS PRUNES 85

or America, or from a blending of these
strains.

But each and every one of them will have the
little sans noyau for one of its ancestors, and will
owe to that plebeian ancestor the quality of stone-
lessness which will be regarded as one of its best
prized characteristics.

A Retrospective Glance

In this view, then, the stoneless plum may be
considered perhaps the most interesting of
fruits.

Possibly a future even more important than
that just suggested may be in wait for it. It is at
least within the possibilities, as hinted in our dis-
cussion of the peach, that the quality of stone-
lessness may be extended from the plums to the
allied tribes of stone fruits by hybridization.

Conceivably the descendants of the little bul-
lace may include not only the races of cultivated
plums, but even all races of apricots, peaches,
and plumcots and cherries as well.

But even though the view be confined to much
narrower limits, it still remains true that the
stoneless plum is among the most important of
all plant developments. So it may be worth
while even at the risk of a certain amount of
repetition to review the history of this develop-

86 LUTHER BURBANK

ment, and in particular to add a few details that
have not hitherto been presented.

It will be recalled that the little sans noyau,
despite its name, was not altogether stoneless,
inasmuch as each fruit had a covering of stone
more than half way around the kernel ; also that
the fruit itself was only about the size of the
ordinary cranberry, and was harsh, acrid, and
unpalatable.

Yet when this unpromising fruit was crossed
with the French prune, and with numerous other
plums and prunes, some of the crossbred seed-
lings produced fruit larger than the French
prune, and nearly all of the hybrids were su-
perior to the wild parent.

All the seeds of these hybrids were carefully
saved and planted. The seedlings were grafted
on older trees, and a few seasons later still better
ones were obtained; plants bearing larger fruits
and many of them showing the tendency to
abandon the stone.

The first generation hybrid seedlings of this
type, which were quite numerous, had mostly
the French prune for the pistillate parent.
Some, however, were from the reciprocal cross.

Of the latter, the crooked thorny seedlings
which indicated that they were not crossed, or
had reverted to the wild type, were generally

STONELESS PRUNES 87

destroyed even if they bore stoneless fruit.
Those which showed the French prune or
ordinary plum type were grafted into older
trees to bear.

All the seedlings from the cross of the sans
noyau pollen upon the French prune were
grafted and fruited even though many of them
exhibited the thorny, dwarf, ill shape of the
wild parent.

After the first generation the seeds of all were
mixed, as there seemed no object in keeping
them separate. For two or three generations
there were all sorts of trees, the greater tend-
ency being toward the bullace, which, being a
wild type, would naturally be expected to have
its characters more thoroughly fixed.

In the first generation some plums were ob-
tained fully twice as large as the fruit even of
the cultivated parent. But most of these had
stones, and were, moreover, soft, sour, undesir-
able fruits.

All but a few of the more promising grafts
were removed from the trees, and the experi-
ment was continued with the selected ones.

In the next generation there was some gen-
eral improvement in the growth of the seedlings
and the size and quality of the fruit. And in
later generations the quality of the fruit rapidly

88 LUTHER BURBANK

improved — combined with stonelessness — until I
obtained two or three fine plums and prunes.

These were grafted extensively and seedlings
raised and selected for still further improvement.

Some of the earlier results of these experi-
ments were exhibited at the Pan-American Ex-
position at Buffalo, New York, in 1901, and
aroused much interest among fruit growers.
None of these, however, was worthy of introduc-
tion as a commercial fruit.

The plum called Miracle was the first of the
stoneless plums to be introduced.

This is borne on a rather slow-growing tree
and has the size, flavor and appearance of a small
Damson, being about an even balance between
the French prune and the original sans noyau in
most of its characters. Some years it is quite
productive, but it is not an altogether depend-
able bearer.

A representative of the Oregon Nursery Com-
pany, on a visit to my Sebastopol grounds in
1903, was greatly pleased with this variety, and
at once purchased it. It has been advertised and
grown quite extensively. Its flesh is of such
quality as to be chiefly valuable for the making
of jam.

At that time it was the best stoneless plum in
existence. But its chief merit was that it was

STONELESS PRUNES 89

the forerunner of a race of stoneless plums and
prunes which will in time be grown wherever
these fruits are raised.

The Stoneless Prune

The next stoneless variety to be introduced
was the prune named the Conquest, with which
we have already made acquaintance. It will be
recalled that this is one of the quartet of best
prunes described in the preceding chapter.

From 3 per cent to 6 per cent of the bulk
of the French prune is stone. The specks of
stone that remain in the Conquest do not
constitute more than one-thousandth part of
the fruit, which is thus edible practically with-
out waste.

The Conquest was offered in my catalogue of
1911-1912 with the following description:

"There has been known for several hundred
years a wild plum, an unproductive, thorny bush,
which bore insignificant, acid, bitter, wild berry-
like fruits with only half or two-thirds of a stone.
Years ago it was hunted up in Europe with the
plan in view of producing really valuable stone-
less plums and prunes. The labor and expense
incurred in these experiments have been enor-
mous, but among the many thousand varieties,
one really good stoneless prune was produced

90 LUTHER BURBANK

and is here offered for the first time in the his-
tory of this earth.

"The tree is a vigorous, healthy, rapid grower
and unusually productive. The fruit is very
similar to its civilized parent, the common French
prune, in form, size, color, and golden, sweet, rick
flesh. The stone has been eliminated wholly with
the exception of a tiny speck. The fruit is so
very valuable and the tree so very productive
that I have consented to introduce it this sea-
son. It ripens with the common French prune
and is in all respects very much like it in size,
quality, and appearance."

The French prune is nearly oval, but Conquest
is slightly larger and more flattened in form,
like some of the other prunes.

Further Improvement in Prospect

Among the later seedlings I found some very
good fruits which have reverted to the stony
type, one of them in particular being extremely
large and of sweet, rich, superior quality.

Thus, after several generations of plums with-
out stones, those having ordinary stones again
appear. There are others, however, that retain
the stoneless condition, and are of exceptional
size. Every color of the plum now appears in
these stoneless hybrids — white, pale yellow,

STONELESS PRUNES 91

orange, scarlet, crimson, violet, deep blue, almost
black, striped, spotted, variegated, and mottled
in every way imaginable.

They ripen from the middle of June until
Thanksgiving, and while some varieties are no
larger than a cranberry, others are larger than
any other plum now generally cultivated, except
perhaps the Climax, the Wickson, and Kelsey.

After a time, no doubt, varieties may be pro-
duced with solid flesh throughout, as many seed-
lings now have indications of such a condition.
The best stoneless plum thus far produced has a
strong tendency toward this condition.

I am often asked how the present plum with
stones and seed will be replaced by the stone-
less variety.

Will the ordinary varieties be supplanted
within a few years?

There is no probability of that. It will be a
long time before our present orchards are re-
placed by trees bearing stoneless fruit. Long
years of selective breeding have been required to
give the plum its good qualities. To hold to
present standards of quality and make the fruit
stoneless as well, will require a great amount of
time, patience, and effort.

Of course, with modern methods it can
be done in a much shorter time than in the

92 LUTHER BURBANK

past, but it must take a long time gradu-
ally to replace one and then another and
another.

The replacement of the ordinary plum by the
stoneless plum will come about gradually, some-
what as the red potato was replaced by the white
potato in California. Twenty-five years ago
nothing but the red potato could be obtained in
any of the markets of this State. Even my own
brothers questioned whether the Burbank could
make headway against it. To-day more than
five million bushels per year are grown in this
State and red potatoes are not to be found.

The Outlook for Seedless Fruits

It will be remembered that there have been
seedless raisins grown for a century or more, yet
everyone knows that seedless grapes are by no
means universal.

The well-known Washington navel seedless
orange has made a new world market for this
fruit. Yet the bulk of the oranges in the mar-
kets of the world have seeds. There are good
seedless lemons, limes, and grapefruits; but they
are very gradually finding their way into the
markets.

The change from stone to stoneless fruit will
come about by imperceptible steps. The change

STONELESS PRUNES 93

will be so slow as hardly to be noticeable. Poorer
varieties of all fruits are gradually replaced
by the better; so gradually that the change is
scarcely noticed.

Odd forms are constantly coming up in na-
ture— like the little, deformed bullace that was
the parent of the new stoneless plums. Some-
times their inherent prospective value is recog-
nized— oftener not. A hornless animal appeared
as a sport or sudden variation in Argentina half
a century or so ago. Possibly this freak may
have appeared a hundred times before. But in
this instance some one having imagination
noticed the mutant and fostered it, and we
now have hornless stock from that Argentine
variation, not only of the original but of nearly
all breeds.

Among fruits, changes no less marked are
constantly arising, and as time goes on these
will be more and more recognized, and appreci-
ated and used. As a greater knowledge of plant
improvement is becoming disseminated, more
pronounced changes for the better will be made
— the elimination of stones and seeds being one
of the most important of the many improvements
required.

The appearance of the stoneless plum, not as
a chance sport, but as the product of an arduous

94 LUTHER BURBANK

series of hybridizing experiments, may be taken
as a sure augury that the conception of an age of
stoneless fruits is not illusory — however long its
coming may be delayed.

Man cannot take the Indian and
say to him: feBe civilized" and ex-
pect him in a generation to drop
the tendencies that have become a
part of him through centuries of
inheritance.

PLANNING AN IDEAL PLUM
OR PRUNE

The Requirements and How They
May Be Met

WHEN I was in the nursery business a
man came to me on one occasion and
wanted trees for his orchard. I
showed him my stock, but it did not suit him.
He wanted trees that grew six feet high before
branching. I had nothing answering that de-
scription, so he bought elsewhere.

In a year or two his tall trees were sweeping
the ground, quite as might have been expected.
So the orchardist came to me to find out what
he should do.

Naturally I told him he should have com-
menced right by getting trees of the right form
at the outset. Now there was nothing for him
to do but to cut his trees back to the right
height, and let them start anew, thus losing
two years of growth. He did not like this
prescription, but presently had to follow it. Of

95

96 LUTHER BURBANK

course, his trees were never as good as though
they had been given the right start; but their
new condition was an improvement on the
old one.

This misguided orchardist was simply acting
on the mistaken idea that was everywhere cur-
rent until quite recently — the idea that it is
necessary to run a tree into the sky so that other
crops can be raised under it, and that teams
can be driven close to the trees in cultivating.
Nowadays the orchardist adapts the implements
of cultivation to the tree, instead of adapting the
tree to the implements.

Or, what is better, he adapts the trees to the
land and makes the orchard pay better and with
less labor, without attempting to raise any other
crops in the orchard.

It has been discovered that skyscrapers in
the orchard do not pay. A tree should be
of such form that the fruit may be picked
conveniently. It should not be necessary to use
stepladders to gather the fruit from the lower
branches.

In the case of the prune, in particular, a low-
branching tree is especially to be desired, that
the prunes may not get bruised in falling, for
even as tough a fruit as a prune may be injured
in falling from a tall tree.

IDEAL PLUM OR PRUNE 97

Planning the Plum Orchard

The old way of planning an orchard was to
look over a catalogue and order half a dozen of
this or half a dozen of that, especially if the name
sounded good, without asking any questions or
gaining information as to whether the varieties
selected were adapted to the region where they
were to be grown.

And the old way for the grower or nursery
man was to accept the form of the tree as it
tended to grow, with little or no attempt to
change it.

But the new way is for the intending orchard-
ist to select his varieties with the utmost care,
paying careful heed to questions of soil and
climate, and introducing only such fruits
as are adapted to the conditions that must
be met. And as to the trees themselves, when
they begin to grow, the modern plant im-
prover is by no means content to leave every-
thing to nature. He takes a hand from the
outset, and largely determines the form of
the tree.

Moreover, the up-to-date orchardist will look
beyond the existing form, and recognize that it
requires both imagination and labor to produce
the ideal tree.

4 — Vol. 4 Bur.

98 LUTHER BURBANK

Building an ideal plant of any kind is like
building a house. Each must be planned in ac-
cordance with a clearly conceived idea. But
there is this great difference: In the case of the
plant you must wait for nature to supply you
with the material with which to build.

Plant building is architecture — but architec-
ture with limitations. It is always slow and very
often it is extremely disappointing, yet it has its
encouraging surprises as well. Times without
number I have been ready to give up an attempt
to secure an improvement on which I had worked
unsuccessfully for years, when, just as patience
was at the breaking point, nature would seem
to have a generous mood and, as it were, throw
the desired characteristic into my lap.

What the blue print means to the architect, the
conception of the tree or fruit or flower wanted
should mean to the plant improver. It
represents a precise ideal toward which to
work, and it gives standards of comparison
by which progress may be checked as the work
progresses.

In the case of the plum it is possible to present
the ideal to the mind with great accuracy. Of
course it may not be possible to attain results
strictly in accordance with the plan. But usually
the ideal may be at least approximated if it has

IDEAL PLUM OR PRUNE 99

been intelligently conceived, and if it is persist-
ently borne in mind.

Specification for an Ideal Plum

Let us now note specifically and in sequence
some of the practical points to be considered in
planning our ideal plum.

In so doing we shall find that there is a certain
amount of overlapping, or perhaps we had best
say interference, of qualities. A plum that is
best for one purpose may not be best for another.
We must bear in mind the different purposes
to which a plum is put, and endeavor to make
our plan comprehensive enough to cover all
of them.

There are certain qualities, to be sure, that are
desirable in every variety of fruit. Large size,
for example, and frost-resisting quality are sel-
dom or never disadvantageous. Yet even this
must be qualified, for, in case of a prune, drying
becomes more difficult as the fruit enlarges, and
unusual size may be a disadvantage. But for
plums in general we aim at a tolerably definite
combination of qualities — size, form, color, flavor
and hardiness — and endeavor to associate these
in the same fruit.

Taking up our ideal plum tree part by part,
let us first consider the root.

100 LUTHER BURBANK

This is of great importance. A great difficulty
of the French prune is that its root system is ordi-
narily inadequate. It is usually necessary to
graft this prune on other roots. Peach stock is
sometimes used to advantage both for this and
for other varieties of plum. But there are some
plums that do not graft kindly on the peach, and
it is necessary in such cases to make a double
graft, using first a cion of some plum that grafts
well on the peach, and then grafting on this the
cion of the desired variety.

This is obviously a rather tedious procedure.
Fortunately it has been discovered that the
myrobalan plum furnishes good roots on which
almost all plums may be grafted, and this stock
is becoming very popular. The roots of the
apricot are also sometimes used successfully. On
deep, dry soil, almond stock often gives the best
results with certain varieties.

But, of course, there will be great advantage
if the plum can be made to grow a good set of
roots of its own. It should be recalled that an
abundance of roots is always closely correlated
with abundance of foliage. One may tell at once
in the orchard whether a tree has a good system
of roots by observation of the foliage. And the
close dependence of the roots on the foliage is a
matter of common observation.

IDEAL PLUM OR PRUNE 101

Many orchardists fail to realize how com-
pletely the roots are governed by the amount of
foliage. And even when this is realized the ob-
served conditions are not always correctly inter-
preted. If the foliage did not govern the roots,
our orchard trees would be of all sizes and of all
degrees of vigor, whereas now, when grafted on
seedlings of varying degrees of vigor, the trees
are uniform.

As to the stem of the tree, this should come
up straight as a flagstaff, and should branch
sturdily, the branches coming out not quite at
right angles but turning slightly upward.
Branches should not turn down, nor should they
be crooked. Moreover, the branches should not
tend to grow too long and slender.

Many seedlings tend to take on a bushy
growth, which is undesirable. Others are too
slender. Some have a general irregularity of
growth, which is particularly objectionable.
Brushiness invariably indicates a lack of pro-
duction; it suggests a reversion to some inferior
ancestral type. And it may fairly be pre-
dicted that the tree will show similar reversion
as to fruit, producing a small fruit of poor
quality.

Brushiness is indicated by slender, too abun-
dant, poor branches instead of sturdy branches.

102 LUTHER BURBANK

Slender branches can never be correlative with
large fruit — they have not requisite strength.

That is one of the many reasons why I select
seedlings with large branches, and those having
prominent buds and large, thick leaves. These
are all indications of a bearer of large fruit.

Large branches and large fruit are associated
together through the effect of past heredity; just
as, contrariwise, small fruit and small leaves and
branches are the hereditary traits that are simi-
larly associated with small fruit.

Of course, it is not always possible, in the
present stage of orchard development, to secure
a tree of perfect growth and form.

This is true not alone of plums but of other
orchard fruits. Some of our best varieties of or-
chard trees, like the Bartlett pear, have branches
too slender and upright, and do not carry the
fruit well. The Bellflower, though a fine apple,
makes a weeping growth. The Newtown pippin
makes too slender and upright a growth. On the
other hand, the Gravenstein apple makes a very
fine, spreading tree, and the popularity of this
varietjr may be to some extent associated with
the almost perfect form of the tree itself.

But it is one thing to observe that a tree is
imperfect, and quite another thing to take the
trouble to improve it.

IDEAL PLUM OR PRUNE 103

We know that the branch system should re-
semble a vase in form, avoiding brushiness,
woodiness, or overgrowth. But many orchardists
who are well aware of this will not take the
trouble to prune the tree in such a way as to
encourage this development; nor will they con-
sider the matter of selecting a variety that tends
to grow in the right way without pruning.

As to the leaf system, it is always desirable
that the foliage of a fruit tree should be large,
thick and abundant. Such leaves indicate ability
for large sugar production.

In the case of cherries it is particularly desir-
able that the leaves should hang over the fruit
to protect it from the weather and from birds.
With the plum this is not so necessary. Still the
question of foliage should always be considered.
Other things being equal, seedlings should be
selected that show large, thick leaves.

Blossoms and Fruiting

It is almost axiomatic to say that plum seed-
lings should bear perfect blossoms in reasonable
abundance.

The blossoms should be borne on the larger
wood of the tree rather than on the tips, because
the fruit is held better where it has the support
of the older wood. Moreover, if the fruit is borne

PLUMLIKE PLUMCOT

This is the plumcot named "The
Bearer." At first view, the fruit
gives the impression of a Japanese-
American hybrid plum, but the short,
thick wood, the prominent buds, pecu-
liar bark, and especially the fuzz, indi-
cate apricot parentage. The apricot
characters are prominent in the tree;
but the fruit is, on the whole, distinctly
plumlike in general appearance.

IDEAL PLUM OR PRUNE 105

at the tips of the branches, these are brought too
near the ground.

The time of flowering should be given careful
consideration in connection with the climate
where the orchard is to be located. Many fruit
trees bloom so early that in mild climates the
late spring frosts injure them. In general, late-
blossoming trees have an important advantage.

It should be understood that a tree that
blossoms late usually matures its fruit early,
whereas one that blossoms early will usually
bear late fruit. This is, of course, precisely the
reverse of what might be expected, unless we
bear in mind the reasons for the difference. A
moment's reflection makes it clear that late bear-
ing and early fruiting should be correlative,
being adaptations to a climate where the summer
is brief.

The bearing season of the plum may be short
or long according to the use to which the fruit is
to be put.

Fruit that is to be gathered wholesale for the
market should have a short season, the major
part of it ripening at the same time. On the
other hand, fruit for home use or a local market
should have a long season.

But even more important is the matter of
"every year bearing." A tree that never makes

106 LUTHER BURBANK

a failure — one that bears annually and does not
have any off years — is the kind of : tree that is
needed. The orchardist naturally wants a tree
that can be depended upon to give him a crop.
A tree that sometimes balks after starting a lot
of fruit, because the temperature or conditions
of moisture are not just to its liking, is not the
kind of tree that endears itself to the fruit
grower.

It must be understood, however, that fullness
of bearing has no necessary association with
hardiness. The two qualities are quite distinct.
A tree may have one quality and quite lack
the other. It may be able to thrive under
adverse conditions, but not to bear under adverse
conditions.

The ideal tree, of course, is one that will not
only thrive but will invariably produce a fair
crop of fruit whether the season is hot or cold,
dry or rainy. A fine practical test of fullness
of bearing is supplied when a frost comes just
after the blossoms have dropped, while the
miniature fruit is fully exposed.

A tree that will stand this test may generally
be depended on as an every-year bearer.

Nowadays the plant developer has this matter
of every-year bearing in mind, and varieties of
plums have been developed which conform to

IDEAL PLUM OR PRUNE 107

this business principle. Our fathers pretty gen-
erally supposed that a fruit failure about every
second or third season was to be expected. Now
we know that the right variety of fruit can be
depended on to give a crop each season.

In selecting stock for your prospective plum
orchard, bear this point very carefully in mind,
and choose only such varieties as have the in-
herent tendency to bear fruit with regularity.

Size and Quality of Fruit

It was just noted that a prune may be so large
that it dries badly. This is not likely to be the
case, however, if the prune ripens early and has
a high sugar content. And as to plums in gen-
eral, large size is, of course, a foremost merit.

There are other fruits that sometimes tend to
grow too large. This is true of certain pears;
also of some peaches. But the plum has not as
yet been developed to anything like the maxi-
mum size, notwithstanding the very great im-
provement of recent years. A good many of
my newer plums are giants in comparison with
the standard plums of a generation ago. But
no one complains that they are too large. On
the contrary, their unusually high price in the
market is due in considerable measure to their
large size.

108 LUTHER BURBANK

In selecting the ideal plum there is no reason
nowadays why you should not secure one that
bears fruit that is at least two inches in diameter
on the average.

In form the plum should approach the globu-
lar. This is best in most fruits, for the reason
that the spherical form is the most compact, and
therefore the one best adapted to handling and
packing.

The suture in the plum is a mark of recogni-
tion, but of no value to the fruit in any way. It
is mostly due to the fact that one side of the
plum grows slightly larger than the other.
But this is a matter that concerns the
pomologist rather than the fruit originator or
grower.

The same is true of the ridge on the plum
stone. It is a mark often used as a distinguish-
ing character between different varieties, but
which has no practical significance.

The plum should be of some attractive color,
red, yellow, or even a brilliant white. Green
fruit is never attractive. It would appear that
the birds and man have combined forces to
produce red and yellow fruits by selection,
because these colors are enticing, and we have
come to associate them with superior qualities
of fruit.

IDEAL PLUM OR PRUNE 109

The skin of the plum should be thick and firm,
especially if the fruit is to be shipped to a distant
market.

For home use or a near-by market a thin-
skinned plum may be quite as satisfactory.

The bloom of the plum adds to its appearance,
and its condition may be a test of freshness. The
bloom evidently had originally a protective func-
tion, possibly shielding the fruit from the sun, or
otherwise protecting the juices from top rapid
chemical change.

The bloom may be developed on a fruit by
means of selection where it is especially desired
for any reason. It is obviously only a minor
characteristic of the perfect plum.

The flesh of the plum should be firm, par-
ticularly if the fruit is to be used for shipping
purposes. The texture may be shown by cutting
the fruit with a dull knife. For home consump-
tion, plums that are very watery are often con-
sidered a great treat. I have some splendid
watery plums now growing — fruits that almost
melt in the hand. But these have not the texture
to stand the trip to market and keep in good
condition.

The orchardist must bear this difference
clearly in mind, and let the choice be determined
by the use for which the fruit is intended.

110 LUTHER BURBANK

Nearly white is usually the most suitable color
for the flesh of the fruit. Yellow flesh is also
admissible, and sometimes pink or crimson.
The plums with crimson flesh, as we have else-
where learned, are all descendants from the
Satsuma plum which was one of my earliest
importations from Japan.

Plums show almost every possible combina-
tion of flavors. Appearances are sometimes
deceptive as to the eating qualities of the fruit.

As an instance, one plum that I have named
the "Fraud" is extremely beautiful to look at,
but its flavor is that of vinegar. There is, of
course, a great range of variation between differ-
ent plums — even aside from those that rank
as prunes — in the matter of sugar content.
Some are very sour and require a great amount
of sugar when cooked; others require almost
no sugar, except possibly to bring out their
flavor.

Taste and aroma are so closely associated that
they may be said to be almost identical. They
simply represent the same thing as interpreted
by different organs of sense. It is obviously
desirable that a market fruit should have an
attractive aroma, for both market man and
customer often judge the fruit by this quite as
much as by the taste.

IDEAL PLUM OR PRUNE 111

Closely associated with the flavor of the plum
is the matter of a chemical content that will resist
fermentation. A fruit that is too juicy and does
not contain enough sugar will ferment very
easily, as we have seen in connection with our
studies of the prune. Some plums are peculiarly
subject to fermentation, particularly if bruised
in any way.

Plums that contain plenty of sugar are, as we
have seen, more resistant to fermentation.

This is one reason why prunes have gained in
popularity for shipment in the fresh state to the
eastern plum market. There is a good field for
investigation as to the particular qualities, in
addition to sugar content, that tend to make a
fruit resist fermentation. In general it is ob-
served that insipid fruits decay first.

Highly flavored acid fruits as well as very
sweet ones tend to resist fermentation.

But the precise chemical conditions that have
to do with this very important property of re-
sistance to decay have been but little investi-
gated. All that the prospective orchardist can
do at present is to select varieties of fruit
that have been shown to have good marketable
qualities.

Finally, there is the matter of the stone. In the
case of the very soft plum, the stone may serve

112 LUTHER BURBANK

a useful function in giving support to the fruit.
But the stone may be somewhat smaller than it
commonly is and still give adequate support.
In the development of stoneless plums it will be
necessary to bear in mind that the removal of
the stone to some extent takes from the fruit its
natural support, and the plant developer will
select with intent to increase the firmness of the
pulp of the fruit.

Where the stone is retained it should be free,
particularly in the case of the plum. The ad-
vantages of a freestone fruit are obvious to
every fruit eater. Varieties of plums have been
developed in which the stone becomes practically
detached from the fruit on ripening.

There is now no reason why the orchardist
should not include freestone among the qualities
that he demands of his ideal plum.

If to these qualities of root and branch and
leaf and flower and fruit we add the one com-
prehensive requisition that the texture of tree
and fruit alike should have the indefinable qual-
ity that makes it resistant to disease, we have
perhaps summarized in broad and general out-
lines the most essential qualities of the ideal
plum.

It may properly enough be said that no plum
hitherto developed can measure up to the maxi-

IDEAL PLUM OR PRUNE 113

mum or ideal standard as to each and every one
of these qualities. The production of a variety
that will meet these requisitions remains for the
plant improver of the future — perhaps of the
not distant future.

Meanwhile it will, I think, be admitted by
those best competent to judge that there are
some of my hybrid plums, notably, for example,
the Wickson, the Formosa, and the Santa Rosa
plums, and the Sugar, Standard, and Conquest
prunes, that, in their respective fields, make a
fair approximation to the ideal standard. There
are plums in the orchard that excel all these in
some respects, but have not as yet all the qual-
ities in combination.

Building an ideal plant of any
kind is like building a house.
Each must be planned in accord-
ance with a clearly conceived idea.
But there is this great difference:
in the case of the plant you must
wait for nature to supply you
with the material with which to
build.

NEW PLUMS AND PRUNES IN
THE PROCESS OF MAKING

Some Suggestions on Which Others
May Build

ON one occasion a well-known nurseryman
who had bought a large number of fruit
trees from me stopped before a tree in my
orchard and tasted the fruit with the air of an
expert.

"That's the best plum I ever tasted," he said,
as he looked at the tree with admiring eyes. "At
last you have a perfect plum. It has just the
right amount of fruit on it; the taste is perfect!
Sell me that tree and I will make a fortune
from it."

"It's not for sale," I was compelled to answer.

Thinking I wanted a fancy price, he started
to figure what he could pay.

I interrupted to tell him the faults of the fruit.
It could not be shipped; it would not bear with
any degree of certainty. He had chanced to see
the tree on the very day in the year when it was

115

116 LUTHER BURBANK

on exhibition at its best. We had had a week of
cool weather and all the plums had ripened
slowly together on the tree; they had responded
to ideal weather — and produced a beautiful fruit
of superior flavor. But conditions are not al-
ways ideal by any manner of means — and this
plum could not stand adversity.

The next year the would-be purchaser saw
the same tree — coming, in fact, for the further
observation of it — and found the fruit worthless.
For three days we had had unusually warm
weather, and the fruit lacked quality. My esti-
mate of it had been verified.

This is related to illustrate the need of caution
in judging a new fruit. The work is not over
when the plum is produced; the fruit must be
tested under varying conditions and in successive
seasons.

But, of course, there is no great difficulty hi
applying the final tests. That requires only
patience and open-mindedness. The real diffi-
culties were encountered at an earlier stage of
the experiment.

What some of these difficulties are, and how
they may be overcome, will be told in the suc-
ceeding pages. We have considered the ideal
plum somewhat attentively from the standpoint
of market man and consumer. Let us now regard

NEW PLUMS AND PRUNES 117

the same subject from the standpoint of the
plant developer and orchardist.

The first step in plum improvement obviously
involves propagation by seeds. In my own work
great effort is made to secure seed of the best
varieties at the outset.

As we have seen, seedlings from cultivated
fruits always show a wide range of variation.
Such variations offer opportunity for selection.

An Outline of Methods

The simplest method of working for improve-
ment is to select the best seedlings thus obtained,
without attempting pollenizing experiments.

An extension of the method calls for cross-
fertilization within the species — followed again,
of course, by selection.

A yet bolder method, and one calling for more
time in the work of selection, may be used — that
of hybridizing individuals of different species.

Finally the method may be so elaborated that
several of the best varieties of different species
are intercrossed to form new varieties. The
plum "Combination," as an instance, combines
the characteristics of three widely varying
species and of numerous varieties within these
species. Most of my recent plums carry the
strains of many diverse species.

PURPLE-LEAVED PLUM
WITH FRUIT

This is the so-called "Oval Crimson3*
variety of purple-leaved plum. It is a
fruit of very attractive appearance and
of good quality; which is by no means
usual with the fruit of the purple-
leaved plum. As a rule these plums
are prized for their ornamental foliage
rather than for their fruit. (Life size.)

NEW PLUMS AND PRUNES 119

This perfected method has been little used by
other plant originators, but its practicability and
value are demonstrated by the results.

The wide range of results attainable when
these methods are used is shown by the fact that
I now have plums the flavor of which is very
similar to the following fruits: peach, apricot,
apple, pear, lemon, orange, banana, pineapple,
and berries of various kinds.

In addition to these, there are flavors that can-
not be described because they are unique — due
to new combinations or blends.

Although the flavor of a fruit is only one of its
important attributes, it sometimes determines
the value or lack of value of a new variety, and
it is always an important factor. In many cases
I have produced new varieties of plums which
were good in every respect except the flavor, and
because of this one defect they were destroyed.

Plums in my present colony are of every
imaginable color and quality and ripen at all
seasons from the earliest to the latest. Some
trees have green foliage and some have purple.
The trees also differ in growth in almost every
imaginable way. Some are adapted to cold
climates, some only to warm. Some require
much moisture. Some will thrive under semi-
arid conditions. A few give promise of being

120 LUTHER BURBANK

adapted to such a variety of climates that — like
the Burbank plum — they may be grown practi-
cally throughout all the plum-growing regions
of the world.

And the explanation of this diversity is found
in the wide range of ancestral strains that have
been blended to produce this versatile company.

Europe, Asia, and America have furnished the
foundation materials upon which have been built
the seventy or more varieties of plums, prunes,
and plumcots that have already been sent out
from my experiment grounds since the first im-
portation of Japan plums in 1885.

The Asiatic plums have been the most used,
forty-three of the varieties introduced being de-
veloped from them.

Fourteen introductions were developed in part
from American, and twelve in part from Euro-
pean species.

Native Raw Materials

The influence of foreign blood in our plum
family has often been mentioned. Let us now
give recognition to the contributions of the native
stock.

The native plums of America, although
usually of a good flavor, are not nearly as large
as the Asiatic species, and not as large as the

NEW PLUMS AND PRUNES 121

American cultivated plums, and no larger than
the wild ones from Europe.

But they possess the important characteristic
of hardiness. For this reason, it has been neces-
sary to use them in many cases to combine
with more tender species in order that the
new varieties might become standards in the
colder sections of the United States and other
countries.

Six important American species have been
used in these experiments: They are known as
the American plum (Prunus americana), the
Wild- Goose plum (P. hortulans) , the Chicka-
saw plum (P. angustifolia) , the western Sand
Cherry (P. Besseyi) , the Beach plum (P. mart-
tima), and the California wild plum (P. sub-
cordata).

These were the native wild plums of the
Middle, Eastern, and Western States and the
Rocky Mountains south to the Gulf of Mexico.
Most of them are unusually hardy. Cold does
them no harm even in the northernmost part of
the central division of the United States.

As to quality of fruit, these wild plums differ,
but all the cultivated varieties have attractive
flavors, and these flavors have been blended vari-
ously in no fewer than fourteen new varieties
that I have thought worthy of introduction.

122 LUTHER BURBANK

Anyone who has experienced the delightful
flavor of my plums, Gold, Shiro, Geewhiz,
Duarte, or America, will be interested to know
that these new varieties (along with ten
others) are American plums, reconstructed
through combination with other species, but
owe their flavor largely to their wild American
ancestors.

To develop the earliest plum in existence from
six species of later plums seems an impossibility.
Yet this is what happened when the Wild- Goose
type was combined with five other late-ripening
species. The plum introduced from this com-
plex combination has been aptly named "First."
It was the first introduced variety in the
making of which the Wild-Goose had a part,
and the first plum to ripen of all those grown
in California at the time of its introduction
in 1901.

If the Wild-Goose plum is mentioned, the
Chickasaw should not be overlooked; for al-
though it has not served in the production of any
introduced varieties, its hardiness has con-
tributed valuable attributes to many varieties
still in the proving orchard.

But perhaps the greatest interest attaches to
the story of the little Beach plum. In its wild
state this is not much sought ; for its fruit varies

NEW PLUMS AND PRUNES 123

from the size of a large pea to that of a small
hazelnut, and it is inedible unless cooked. Yet
this little plum has some flavor; it makes jams
and preserves of good quality.

The results produced on my grounds with this
species are so important as to indicate that the
Beach plum is highly valuable to use in the de-
velopment of new plums for cold climates. I
have produced four important varieties in which
it is one of the parents.

The story of these ennobled Beach plums is
so interesting and suggestive that it is worth
telling somewhat in detail.

The Ennoblement of the Beach Plum

Perhaps the most astonishing result produced
by hybridizing the little Beach plum is the fruit
to which I have given the provisional name Giant
Maritima.

This is a second-generation hybrid from an
improved hardy Beach plum pollenized with one
of the hybrid Japan plums.

In 1895, the first year this seedling bore, the
fruit was one hundred times larger than its seed
parent, the maritima. In 1896, the fruit was
even larger than in the previous year, and in
1899, as the tree gained in age and strength, the
size was still further increased.

124 LUTHER BURBANK

In that year some of the fruits were measured
and found to be eight and a quarter inches in
circumference.

The Beach plum from which this remarkable
hybrid was developed is a native of the Atlantic
coast of North America, growing on the sands
and among rocks near the seashore from Labra-
dor to North Carolina. It is known botanically
as Prunus maritima.

It is one of the hardiest and toughest of all
known wild plums. It is a low, compact bush,
rather than a tree, with rough, even thorny,
branches, and small dull green oval leaves. The
flowers are small, but are produced in great pro-
fusion, making it almost worthy as an orna-
mental plant. The fruits, as before stated, are
small, usually less than half an inch in diameter;
and they are quite commonly bitter, being almost
or wholly inedible unless cooked.

The Beach plum for many years has been
known to possess some horticultural possibilities,
especially hardiness, productiveness, and general
"staying" qualities under the most trying condi-
tions. The value of these characteristics was dis-
covered soon after my general plum experiments
were started, and every effort was made to cross
it with some of the larger and finer species. For
several years this cross could not be effected,

NEW PLUMS AND PRUNES 125

mostly because the Beach plum blossoms very
late, long after all other plums have shed their
bloom.

Finally, however, very late blossoms of the
latest plums of other species were cross-fertilized
with some of the earliest Beach plum blossoms,
the crosses being made both ways.

In the meantime I had been growing seedlings
of the Beach plum by the hundred thousand. By
continuous selection I had produced varieties
bearing fruits nearly an inch in diameter, of a
pleasing form and color, of delicious flavor. The
trees, moreover, had almost incredible produc-
tiveness together with increased size and vigor.

Although my most enthusiastic friends often
laughed at these extensive experiments with
what they called my "huckleberry plum," and
some of the best fruitgrowers made sport of the
insignificant fruit, I saw in the little Beach
plum great hardiness, late blooming, enormous
productiveness, and the ability to withstand
adverse conditions, and was sure of some meas-
ure of success.

Several crosses were finally made between the
improved maritima and the best cultivated varie-
ties of other American and Japanese hybrid
plums. No really good fruits were obtained in
the first generation, but some excellent varie-

126 LUTHER BURBANK

ties, both in productiveness and quality, were
produced in the second, third, and fourth
generations.

Usually the first-generation hybrid maritimas
make a much stronger growth than their wild
parents, sometimes attaining four to six feet in
two years, while the wild Beach plum on a good
soil rarely grows more than three to three and
one-half feet high in the same time.

The wild tree has short branches, black bark,
and small leaves. The first generation hybrids of
these with the American and Japanese plums
have longer, smoother, and larger leaves, lighter
colored wood, and longer and more slender
branches.

These hybrid seedlings are easily distinguished
the first season, as the Beach plum has red roots,
while those of the hybrid vary, most of them
being lighter. Beach plum seedlings, no matter
how young, from seeds crossed with other varie-
ties, show various shades between the pale yellow
or brown root of the European and Asiatic varie-
ties and the red root of the wildling, and if there
were no other test this would be amply sufficient
to prove them hybrids.

Such, then, was the parentage of the Giant
Maritima, which first bore fruit, as already noted,
in 1905 — fruit over two inches in length. When

NEW PLUMS AND PRUNES 127

I first came across this enormous fruit on a tree
with the Beach plum foliage and blooming habits,
the branches literally hanging in ropes of gigantic
fruits, I could hardly believe my own eyes.

The fruit begins to ripen here early in July,
and when ripe it is a deep crimson, covered with
a thin pale bloom. The flesh until fully ripe is
very firm and solid, but it breaks down quickly
when ripe. It is honey-yellow, with a pale green-
ish tinge. The quality is good. The fruit is
fragrant, and as large as the Kelsey, Wickson,
Climax, or any other plum known in 1905.

It is found necessary to thin the green fruit
carefully, otherwise the tree would be crushed
with its weight of fruit. It has been grafted into
numerous older trees, and appears to be a strong
grower. Having originated from such an un-
usually hardy wild stock on one side, it will no
doubt produce a crop of fruit almost anj^where.
In itself, however, this will never prove of much
commercial value, as it lacks firmness of texture.

The Beach Plum in Other Combinations

The wild Beach plum was also crossed with
my Combination plum, which has in its ancestry
plums of almost every type. The resulting seed-
lings were not as good as had been anticipated,
but two were very much liked by a well-known

GLOBE PLUM FRUITS

It will be seen that the flesh and
the skin of this plum are almost
uniform in color. This is a very
unusual characteristic. The plum is
a complex hybrid, and the red flesh
betokens a Satsuma ancestor. Although
named, this plum has not as yet been
introduced.

NEW PLUMS AND PRUNES 129

California fruit grower, and were sold to him
in 1908.

One of these was given the name "East." It
is a prolific variety. The fruits are globular,
pale yellow, half covered with a crimson bloom
and numerous indistinct dots. The flesh, pearly
yellow in color, is of good quality, though prob-
ably inferior to some of the best Japanese hybrid
plums. The fruit ripens here from August first
to fifteenth.

This was tried at San Jose for several years,
but found to be too soft for shipping. It is,
however, a desirable variety for home consump-
tion. It has never been offered to the public.

The other plum from this cross is known as
"Pride." It also proved to be of little value
as a shipping plum. It ripens too quickly,
so that it will not stand shipping any great
distance.

Pride is apple-shaped, which is usually a de-
sirable form. It is a good grower, an excellent
bearer, and ripens about July 20th. The skin of
the fruit is a deep red with a whitish bloom. The
flesh is a dark red — showing a Satsuma cross —
and of excellent quality.

Besides these, nearly two thousand other
promising maritima hybrids are now being
grown from these crosses. Many of them are

5 — Vol. 4 Bur.

130 LUTHER BURBANK

excellent in habit, productiveness, and hardiness.
As yet only one of them has been sufficiently
tested to warrant their introduction.

Tribute from the Sand Cherry

Another native American plum which is as
hardy as the Beach plum is Prunus Besseyi,
commonly known as the western Sand Cherry.
Although it is called a cherry, it is really a plum
and has been successfully crossed with the plums,
as pointed out in an earlier chapter. It is thor-
oughly hardy in the Central and Northern States
and is found most often in Minnesota and the
Dakotas.

My work with this variety has not been so ex-
tensive as with the Beach plum, but has resulted
in the development of one new plum which has
been thought worthy of introduction. It was
offered in my catalogue of 1911-1912 under the
name Epoch, and is described there as follows :

" 'Epoch' should be one of the hardiest of
all known plums, as it is a cross of the western
Sand Cherry and the American plum, both
being about as near 'Arctic' plums as can be
mentioned.

"The tree is a compact grower, dwarf, with
dark brown wood, which always, without fail,
produces ropes of fruit, each fruit one and a half

NEW PLUMS AND PRUNES 131

inch in diameter, beautiful crimson, with shades
and dots of yellow. Flesh pure deep yellow,
firm, with a rich cranberry flavor, but sweeter,
and when ripe very good. Ripens August 15.
The youngest, as well as the oldest, trees literally
cover themselves with fruit, which keeps remark-
ably. Probably the most productive and best of
all the 'Iron Clad,' extremely hardy dwarf
plums."

As this variety has not been introduced long
enough to get reports from growers in various
parts of the country, it is not possible to say just
how valuable it will prove to be. Its hardiness,
however, is well established, for it has been grown
in North Dakota, where the young trees have
endured a temperature which no other plum had
been able to live through.

This work of developing hardy fruits for the
colder sections is being pushed by other workers.
Professor N. E. Hansen, of the South Dakota
Experiment Station, has been working for many
years, especially in crossing the Sand Cherry
with some of my best hybrid plums and with
other varieties. He has been successful in pro-
ducing several good hardy varieties.

It is to be hoped that others will enter into this
work, as hardy plums are much needed in many
northern regions of our country.

132 LUTHER BURBANK

The California Wild Plum

Almost every imaginable flavor is to be found
among the California wild plums (P. subcor-
data). Some are quite sweet, some are sour,
others are distinctly bitter. A few are delicious.
The fruit usually is small and round, about the
size of the wild plums of the Mississippi Valley ;
and of brilliant red color, or sometimes yellow,
and rarely purple.

Strange as it may seem, the best fruit is pro-
duced abundantly where the trees are growing
on rather poor, almost desert soil.

The trees in different localities (and the same
is true in a measure of each tree in the same
locality) seem to have an individuality of their
own, a somewhat characteristic condition with
our California wild trees and shrubs. Some of
these plum trees grow large and tall, with a
straight, upright habit. Others form spreading
bushes of low, compact growth that often bear
abundantly when only a foot or two high,
bending to the ground with their burden
of fruit.

Under cultivation this plum has improved,
and some selected seedling varieties are of very
superior quality. Some of these plums when
cooked have a flavor closely similar to that of the

NEW PLUMS AND PRUNES 133

best cranberries, which they resemble also in
color.

When crossed with the Japanese, American,
and European plums, a large and handsome
fruit is developed, the form being usually nearly
globular, but sometimes oval. The trees of these
crosses are also greatly improved over the wild
ones in form, size, and symmetry of growth.
They are always hardy and vigorous, and are
as a rule exceptionally prolific.

For jellies and canning these hybrid fruits
are probably superior to any other class of
plums, and, a few of them are most excellent
when eaten uncooked. In particular one which
I have recently distributed under the name
"Nixie" is valuable for use in any form.

The California wild plum has also had an im-
portant part in the production of the new varie-
ties known as Combination, East, and Glow, all
plums which exhibit the superior quality of the
wild parent.

Thus have the native plums of the United
States been used in producing new varieties.

The European species, though used to a
slightly less extent, have produced results of
even wider value.

The early settlers — either because they did
not expect to find plums in America, or because

FIRM SWEET PLUM
FRUITS

The surface dotting of the American
varieties and the shape of the Japanese
plums are shown in this attractive fruit,
which is a complicated hybrid, the result
of repeated crossing and selection. The
native plums of America have had an
important share in producing some of
my most prized varieties.

NEW PLUMS AND PRUNES 135

they were attached to their own varieties —
brought plums from Europe, known botanically
as Prunus domestica.

The plums, like the settlers who brought them,
found the adopted country hospitable. They
thrived and multiplied. Seeds sprang into new
varieties in the fence corners and some of them
bore better fruit than the colonists had seen in
Europe.

It was natural that these new varieties should
spread while the less valuable ones were neg-
lected. When a farmer journeyed from Ply-
mouth to the home of a friend near Boston and
saw there a plum better than the one he had
brought from Europe, he secured grafts and gave
the better variety the preference on his own farm.

Thus by the exchange of grafting wood, new
varieties of plums were distributed among the
pioneer farmers of the new land.

The Share of Europe

To-day there are at least a hundred improved
varieties of the European type of plum, all of
which, up to the last few years, originated from
chance seedlings in the gardens of the first
settlers. Among the best of these are the
Washington and the Jefferson, both superior
varieties.

136 LUTHER BURBANK

It appears that some at least of the European
plums originated in southwestern Asia. At all
events, a plum that is thought to represent the
original wild form has been found growing in
the region about the Caucasus Mountains and
the Caspian Sea.

It is known that the plum was one of the
fruits and the dried prune a staple food of the
Huns, Turks, Mongols, and Tartars, who main-
tained in this region a crude horticulture from
a very early period. Here, even at the present
time, plums are commonly grown and prunes
are an article of trade.

The European plums have many unusually
good qualities, including strong, vigorous, pro-
ductive, hardy, upright trees with strong wood
and branches capable of carrying heavy loads of
fruit. Furthermore, they are not much subject
to disease.

The fruit is not used so much for shipping long
distances when fresh as some of my new Japa-
nese hybrid plums. Some of the newer seedlings,
however, such as the Splendor, Giant, Sugar, and
Standard bear fruit which is shipped fresh in
large quantities from California to New York
and by sea to foreign countries every season.

For the most part the consumers of the large
cities do not know that the big, sweet, luscious

NEW PLUMS AND PRUNES 137

plums that they purchase in June and July are
of the same varieties sold in the dried state as
prunes.

The European plums have been used in the
production of eight of my introduced prunes and
have contributed to these the characters neces-
sary for drying and shipping.

The European plums produce new forms
readily from seed, so that it is scarcely neces-
sary to cross them with other species to obtain
seedlings with rather distinct new characters.
Furthermore, it is difficult to make productive
varieties when crossed with other species. My
experience has been that they do not cross read-
ily with the Asiatic plums, Prunus triflora, Pru-
nus Simonii, and Prunus foment os a, nor very
readily with any of the native American plums.

On the other hand, the common European
plum crosses readily with the French species,
Prunus cerasifera, the Cherry plum or myrob-
alan, often producing most valuable new
varieties.

This French Cherry plum is a small, slender
tree. It is usually quite productive, but no seed-
lings of large size or superior quality have ever
been produced directly from it, and the fruit of
its seedlings are not only lacking in quality but
in size and firmness of flesh.

138 LUTHER BURBANK

The only variety I have introduced which is
a seedling of this plum is a cross with the Asiatic
Prmius triflora. This hybrid is called Doris.
There is blood of the French Cherry plum, how-
ever, in some hybrid plums, including my well-
known Shiro and a few others.

The European plums have also contributed
largely to the production of new races of fruit
trees that are highly ornamental. A whole race of
plum trees beautiful enough for lawn decoration
has sprung into being in my open-air laboratory.

The French plum with purple leaves, Prunus
Pissardi, formed the basis for the development
of these ornamental fruit trees. The methods
used in developing these hybrids are the same as
with the others, and results are similar, although
the fruits have not proven so generally valuable
as certain varieties raised solely for fruit.

The main use of the purple-leaved plum is for
decorative purposes, but the fruits of the two va-
rieties introduced are good enough for home use
and in some cases are sold in near-by markets.
This refers more especially to the very early
purple-leaved plums, the Vesuvius, Othello, and
Thundercloud.

The story of the stoneless plums, which also
owe their origin to European stock, has been told
elsewhere and need not be repeated here.

NEW PLUMS AND PRUNES 139

The unique form of the Apple plum, the de-
lightful Bartlett pear flavor of the Bartlett
plum, the appetizing color of the Santa Rosa,
and the large size and remarkable shipping
qualities of the Wickson would not have been
developed had it not been for the use of the Jap-
anese species, Prunus tri flora.

Tribute from the Orient

Indeed, the Japanese plum stands as part con-
tributor to forty-three varieties added to Amer-
ican horticulture. These have been sent out
from my farms, and few nursery catalogues list
more than two or three Japanese plums other
than these varieties, although several have been
developed by other workers.

China, as well as Japan, has furnished ma-
terial for the development of highly valuable
plums. The well-known varieties, Maynard,
Climax, Chalco, Santa Rosa, and Formosa, and
many other newer seedlings, have in their make-
up the blood of Prunus Simonii^ the apricot-
plum of China.

This fruit takes its name from Eugene Simon,
who introduced it into France from China in
1872. It was distributed in this country about
1881. It is peculiar in shape, being a large, flat,
tomato-shaped plum, with dark orange-brown,

THE APPLE PLUM

It is difficult for the casual observer
to believe at first that the plum here
represented is not an apple, as it has
the form, color, general appearance,
and rare keeping qualities of the fruit
that suggested its name. It is a
remarkably free grower, having led
to the comment that buds and grafts
of this variety "would probably grow
if fired among the trees from a shot'
gun.3'

NEW PLUMS AND PRUNES 141

hard flesh, purplish-red skin, and a small
stone.

The fruit is sometimes eatable, and sometimes
classed as good when grown in the hot, dry cli-
mates of the interior vallej^s of California. Its
merits and defects were outlined in an earlier
chapter. Here I will only add that it is by no
means necessary to have a perfect fruit to begin
your experiment. I have in many cases devel-
oped the very best of new fruits from two nearly
worthless ones.

In selecting the Simon plum for these experi-
ments, its value for plant improvement was con-
sidered and not its value as a market plum.

As a result of its use, its small stone, delight-
ful aroma, and desirable tree characters have
been imparted to a new race of plums, several of
which have already added millions of crates a
year to the shipments of the principal plum-
growing sections.

Others even more promising are still in the
test orchard awaiting final approval.

Such, then, are the materials that have been
utilized in the development of new fruits. The
native plums of the Middle West, the worthless
wild plums of the bleak coast of Labrador, the
plums of the Pacific slope; those which our fore-
fathers brought from Europe; a worthless, wild,

142 LUTHER BURBANK

half-stoneless plum; plums from Japan, some
with red flesh; other Japanese and Korean va-
rieties with large bright-colored fruits and de-
lightful flavors; the apricot-plum from China,
the purple-leaved plum from France and the
cerasifera, which has been grown mostly for
grafting stocks, have all been freely used.

Although some of these species are insignifi-
cant in themselves, their characters by combina-
tion and careful selection have had a share in
making fruits of the rarest and most desirable
qualities.

And the work, notwithstanding its notable re-
sults, is only at its beginning.

The Mystery or the Bud

In completing this outline of the methods of
plum development, let us now consider a little
more in detail an aspect of heredity which con-
cerns equally all our other cultivated orchard
fruits, and which must seem mysterious to every-
one who gives the subject a moment's considera-
tion. I refer to the familiar but extraordinary
fact that whereas the bud or cion of a given tree
will reproduce the fruiting qualities of the
parent with the utmost fidelity, yet the seed-
lings grown from the fruit may have the widest
diversity.

NEW PLUMS AND PRUNES 143

It has been pointed out that you need not
hybridize the orchard fruits in order to get new
varieties. The seed of almost any plum tree, for
example, will give you seedlings aplenty that
are different from the parent tree.

That a single variety may thus contain the
potentialities of a hundred different types of
future fruit is a mystery to which we have
referred, but to which we may recur without
apology.

When we further reflect that the branch in
question, which carries this amazing heritage,
perhaps grew from a single pea-sized bud in-
serted on the trunk a few seasons ago; and that
the tiny bud in question must have contained,
predetermined within its apparently insignificant
substance, all the potentialities that will be re-
vealed in all the different "varieties" of its
progeny, the mystery becomes still deeper — if
comparison be permitted between the various
aspects of a subject every phase of which
lies almost beyond the bounds of human
comprehension.

But even though we cannot hope fully to
understand, much less to explain, the mysteries
of heredity of which the case of the bud fur-
nishes a familiar yet striking example, we can
not help pondering on the matter. And nowa-

144 LUTHER BURBANK

days we are accustomed to associate function
with structure everywhere in nature, seeking a
physical basis for the observed phenomena asso-
ciated with life processes, it is natural that here
as elsewhere attempts have been made to visual-
ize the conditions that obtain in the germ plasm
of the plant, and to picture in imagination its
actual mechanism.

In our age the telescope, fortified by the
weirdly penetrative spectroscope and aided by the
most sensitive photographic plate, has enabled
the astronomer to reach out into unthinkable
realms and to record not merely the direc-
tion and speed of light, but even the chemical
composition of stars so distant that their light,
traveling 186,000 miles per second, requires ages
to reach the earth.

With the aid of the same instrument, the uni-
verse is proved to be peopled with dark stars,
definitely revealed to us even though forever
invisible; the structure of the universe as a
whole is coming to be understood, and the
course and direction and speed of groups and
streams of stars by millions have been tested
and charted.

In such an age it is not strange if the worker
who turns his eyes in the opposite direction, and
attempts to penetrate the mysteries of the micro-

NEW PLUMS AND PRUNES 145

cosm of the plant or animal cell should have
found means to pass beyond the range of vision
of the microscope and reveal something of the
intimate nature of the events that are taking
place in the world of molecule and atom and
electric particle.

Aid from the Microscope

In point of fact the invasion of the world of
the infinitely little by the modern biologist has
been no less wonderful than the exploration
of the world of the infinite vastness by the
astronomer.

And perhaps it should not seem strange to
anyone who has a philosophical conception
of the underlying harmonies in nature, that
the conditions revealed in the microcosm of
the living cell should suggest in many ways
an epitome of those made manifest in the
macrocosm.

Such, at all events, is the message that the
modern biologist and physicist bring us from the
worlo! of infinite littleness. Making the first
stages of their invasion with the aid of a micro-
scope, they show us that all living tissues, veg-
etable or animal, are composed of cells, and that
within each cell there is a vitally important cen-
tral structure called the nucleus.

146 LUTHER BURBANK

This structure lies at the heart of every germ
cell through which a living organism propagates
its kind.

The pollen grain of the plant, for example, is
the carrier of such a germinal nucleus. The pol-
len grain itself is a structure of almost micro-
scopic size, yet it is colossal in comparison with
the infinitesimal fleck of germinal matter that
lies at its center. Yet the modern microscope
can so magnify this fleck of matter that some-
, thing of the mechanism of its vital parts
becomes visible.

The microscopist tells us that within the ger-
minal nucleus there are to be seen sundry films
of matter, arranged to form a sort of skeleton,
which are readily stained under his manipula-
tion and which he therefore names "chromo-
somes" colored bodies. He observes that the
nuclei in cells of different plants and animals
have these infinitesimal chromosomes arranged
in different characteristic groups, differing in
number in different species, but always the same
for each and every cell of plants or animals of
a given species.

The enlarged vision of the microscopist en-
ables him to assure us that when two germ cells
of the opposite order come together — when, for
example, the nucleus of a pollen grain blends

NEW PLUMS AND PRUNES 147

with the nucleus of the plant ovule — there are
various characteristic dividings and interlinkings
between the two sets of chromosomes within the
two nuclei.

In the blending and rearrangement of these
minute structures, he believes that he is witness-
ing the underlying processes that bespeak the
blending of hereditary potentialities and their
recombination to determine the future possibil-
ities of the new organism that is thus brought
into being.

All this is very wonderful. But it brings us
after all only one stage nearer the confines of
the mystery. The chromosomes within the nu-
cleus, which all biologists nowadays regard as
the tangible carriers of hereditary tendencies or
capacities, are few in number, and, small as they
are, we are forced to conclude that each of them
must be the carrier, not of a single potential trait
or tendency, but of a multitude of such potential
traits or tendencies.

Our practical experiments in plant breeding
have shown us that we deal often with a dozen
or more tangible characters that are grouped
against each other in opposing pairs — definitive
qualities of size or color or flavor of fruit and
all the rest — and it requires but a moment's
thought to see that each of these "unit charac-

ANOTHER VIEW OF THE
APPLE PLUM

In noting the very peculiar apple-
like character of this fruit, it is inter-
esting, by way of comparison and
contrast, to consult the earlier pictures
showing the wide variation of plum
forms, including the inverted pear
shape, the even oval of the Splendor
prune, and the almost spherical form
of other types. (Life size.)

NEW PLUMS AND PRUNES 149

ters" is in reality made up of a multitude of
minor characters.

Heredity carries all of these definitely from
one generation to another; so their potentialities
must be represented within the structure of the
chromosomes ; and there are by no means chromo-
somes enough to supply one for each hereditary
character.

So we are obliged to assume that each
chromosome is in itself a complex structure, and
that within that structure there are subordinate
structures — like the individual bricks and boards
and nails and rivets that go to make the struc-
ture of any piece of human architecture — that
determine by their quality or their arrangement
the specific potentialities of the future organism.
Each chromosome, in other words, must be
thought of not as the tangible conveyer of any
particular "unit character," but as a receptacle
in which several or many factors or determiners
of diverse unit characters — size of flower and
color quality of leaf and fruit and all the rest —
are assembled.

Further Aid from the Physicist

But unfortunately the powers of the micro-
scope do not suffice to reveal these unit struc-
tures within the chromosome.

150 LUTHER BURBANK

What they are like must for the present re-
main only a matter of conjecture.

But that they are definite mechanical struc-
tures of unthinkable smallness, represented by
chemical atoms in specific combinations, we can-
not doubt. And in revealing to us the size and
character of these atoms, the modern physicist
gives us aid in supplementing the vision of the
microscopist and in helping to make it seem at
least a possibility that the definite factors of
heredity have a physical basis within the micro-
scopic chromosomes.

The conclusions that give this assurance are
based on various almost infinitely delicate tests
that are made in the modern physical laboratory.

Summarizing these in a few words, it appears
that the physicist and chemist are now able to
make definite computations as to the size of the
molecules and atoms that make up the structure
of all matter. And the figures they present,
when they have taken a census of the atom, are
such as to give us full assurance that even so
small a structure as the minutest chromosome
within the nucleus of a plant cell contains mol-
ecules and atoms in such numbers as to make
possible an infinite complexity of arrangements
and therefore an infinite diversity of resulting
qualities.

NEW PLUMS AND PRUNES 151

Thus we are told that the smallest particle of
matter visible under the magnifying influence of
the most powerful microscope is of such dimen-
sions that 50,000 of such particles placed in line
would be required to cross the space of one cen-
timeter or about two-fifths of an inch. If we
calculate the cube of this number we find that
125 thousand billion such particles could be
crowded into the space of a cubic centimeter. But
it further appears that, according to a definite
measurement made by Professor Rutherford,
more than 20 billion times that number of helium
atoms would exist in the form of gas in the same
space.

And the commentator I am quoting adds:
"Of course the molecules of gas are widely sep-
arated. So it follows that the smallest particle
of solid matter visible through the most power-
ful microscope contains many times 20 billion
atoms."

"Many times 20 billion atoms" in the smallest
particle of matter that the microscope reveals!
Vastly more than that number of atoms, then,
in each individual chromosome of the group
lying within the nuclei of pollen grain and ovule
— since these are by no means at the limits of
visibility. And each atom has itself specific in-
dividuality. Each group of a thousand atoms

152 LUTHER BURBANK

or so might make up a molecule of a different
type of protoplasm.

So here is material for millions of kinds of
protoplasm, were so many needed.

Here within the infinitesimal germ cell, re-
vealed to us in part by the microscope of the
biologist and for the rest made manifest in im-
agination by the revelations of the physicist,
is material enough to supply tangible carriers
for all the conceivable hereditary factors that
come to make up the most complex organism of
any plant, or for that matter of any animate
creature whatever.

The Germ Cell a Complex Organism

Let us make the illustration specific. Suppose
that the chromosome in the nucleus of any given
pollen grain — say that of a plum blossom — were
of the very smallest size visible under the micro-
scope. Suppose, also, merely for the sake of
illustration, that the hereditary factors for unit
characters that it bears are of a thousand differ-
ent types — representing all details of size and
color and foliage and growth and leaf and blos-
som and fruit of the future tree. We know that
the chromosome really does bear these potential-
ities; I am merely assuming their number at a
thousand individual units for illustration.

NEW PLUMS AND PRUNES 153

In our former views, when we considered the
transmission of complex qualities by the infini-
tesimal pollen grain the thing seemed utterly in-
scrutable and mysterious. But now, with the
aid of the new facts that the physicist has
supplied us, the mystery is somewhat clarified.
He shows that the smallest visible bit of proto-
plasm must contain at least twenty billion
atoms.

So there would be enough of these atoms to
supply no fewer than twenty million to make
up the structure of each individual hereditary
factor.

Now twenty million bricks, of ordinary size,
piled solidly together, would make a mass 100
feet square and 300 feet high.

So the structure of each hereditary factor of
all the thousand in our infinitesimal speck of
germ plasm may be as complex as any building
that could be made with such a pile of bricks
as that — and more complex, no doubt.

Add that each individual atom in our germ
plasm structure is no crude brick, but is con-
ceived by the best informed students of physical
science to be "at least as complex as a piano,"
and we gain a yet clearer conception of the pos-
sible intricacies of the mechanism of each of our
imagined thousand hereditary factors.

154 LUTHER BURBANK

In this view, then, the germ cell may well be
an organism as complex and of as definite a sys-
tem of architecture as the full grown tree into
which it will ultimately develop.

The leaves of a tree — even the leaves of a for-
est— are a meager company compared with the
census of the atoms within the nucleus of a
single germ cell.

An Amazing Microcosm

Nor need we limit our view to the germ cell
that produces a single plant. Let us consider
for a moment the bud from which the branch
grew on which are produced, according to our
illustration, plums, the seeds of which may give
rise to some hundreds of different "varieties" of
fruit.

Do the analyses of miscroscopist and physicist
make comprehensible the fact that the original
bud of the plum tree can contain potentialities
of so many different complex structures?

Another glance at the figures of the physicist
will supply the answer that would have been be-
wildering were it not for what we have just seen
as to the complexity of the germ plasm. It ap-
pears that, according to the estimates of Profes-
sor Rutherford (based on accurate count of the
atoms given out as so-called alpha particles in

NEW PLUMS AND PRUNES 155

the radiation of radium) the mass of an atom is
so inconceivably small that the number of atoms
making up a portion of matter as big as our
plum bud (which we may assume to have the
bulk of about a cubic centimeter) is represented
by the figures 68 followed by twenty-four
ciphers — 68 "octillions," if the figures must be
read.

So the number of atoms that are aggregated
in the tiny plum bud is vastly greater than the
total number of people that have lived on the
earth since the human race was evolved.

To attempt to give tangibility to the idea of
the smallness of the atom, we may borrow an
estimate made by the late Lord Kelvin. It may
be computed that if the tiny plum bud were
imagined to be enlarged in size until it became
as big as the earth, each component atom being
increased in the same proportion, its entire struc-
ture would then be made up of units (magnified
atoms) of about the size of footballs.

If we then reflect, further, that according to
the definite analyses of other physicists, with Sir
J. J. Thomson of Cambridge at their head, each
atom is itself a complex structure — the very sim-
plest atom, that of hydrogen, being composed of
at least 1,700 particles called electrons which are
in reality the unit particles of electricity — we

A SEEDLING CRIMSON-
LEAVED PLUM

One of the most striking of plum
seedlings, being the result of Kelsey,
cerasifera, triflora, and apricot cross.
The magnificent reds of leaves and
fruit make a strikingly handsome
and effective combination that is as
pleasing as it is unusual. This has been
named "Vesuvius." (Natural size.)

NEW PLUMS AND PRUNES 157

shall gain a still more enlightening view of the
complexity of our plum-bud microcosm.

It has been estimated by a French physicist,
Becquerel, that the size of the individual elec-
trons that make up the atom is such that they
may be thought of, not as piled solidly together
within the structure of the atom, but rather as
infinitely separated by comparison, like a swarm
of gnats flying about in the dome of a cathedral.

It is a little difficult for anyone not accus-
tomed to this particular use of the imagination to
follow the conceptions of the physicist. But we
may accept his findings as authoritative, for they
are the result not of one man's work alone
but of tests that have been applied by many
workers.

Making the application to our plum bud, then,
it appears that its bulk is such as to give us as-
surance that it contains (although it actually is
no larger than the smallest pea) a number of
atoms so great that if the atoms were conceived
to be all gathered into 8,000 different groups
(each group representing a different variety of
future plum), there is material enough to supply
at least eight million billion atoms in each group !
And each of these atoms is itself a complex
structure made up of several thousand electric
corpuscles.

158 LUTHER BURBANK

Now we know that each particle of proto-
plasm, the physical basis of all life, is composed
of atoms of carbon, hydrogen, nitrogen, and
oxygen in complex combinations. A single mole-
cule of protoplasm may contain a thousand or
more atoms.

But even allowing a thousand atoms to each
molecule, we have ample material for the con-
struction of something like eight million billion
molecules for each one of our 8,000 groups of
potential plum trees.

Obviously there is abundant opportunity for
the combination of such material into complex
groups, quite adequate to account for the differ-
ent qualities of our various plums — be they ever
so divergent as to form or size or color or flavor.

The Bud as a Walled City

In this expanded view, then, it is no more
wonderful that a pea-sized plum bud can obtain
within its germ plasm the potentialities of hun-
dreds of varieties of future plums than that a
city can comprise hundreds of houses, no two
just alike, all built of wood, brick, stone, and
metal in different proportions and combinations;
just as the germ cells are all built of the atoms
of carbon, hydrogen, nitrogen, and oxygen in
different combinations.

NEW PLUMS AND PRUNES 159

There are far more bricks (atoms) available
to build each different type of germ plasm in our
plum bud colony than are required to build the
largest structure in the man-made city.

The real wonder, as I said before, lies in the
fact that each infinitesimal aggregation of mole-
cules of protoplasm has the capacity to take to
itself stray atoms that are brought into its neigh-
borhood, shape them into its own structure,
somewhat as a bricklayer shapes the bricks into
the walls of a building, and thus increase con-
stantly in size.

It is this capacity of the germ plasm to gather
material and utilize it in expanding its structure
— together with the further capacity to move in
response to environing forces — that is the under-
lying mystery of the entire life process, includ-
ing the interesting aspects of it that we see
manifested through heredhy.

In a word, a fruit bud is a walled city ten-
anted with a multitude of complex structures,
and the mere size of the bud, in our clarified
view, has nothing whatever to do with the won-
der of its composite architecture.

The phenomena of the germ cell have hither-
to appeared peculiarly mysterious simply be-
cause our blunt human senses deal ordinarily
with masses of matter of a more tangible size.

160 LUTHER BURBANK

Now that the microscopist and the physicist
have opened the way for us into the microcosm,
we see that mere size is of no great significance
in the matter, and that there is ample opportu-
nity within the nucleus of the smallest germ cell
for an organization of molecules and atoms that
for all practical purposes may be at once as
complex and as definite as the visible structure
of the mature plant in which the germ cell
sprang or of that other mature plant into which
it will develop.

The work, notwithstanding its
notable results, is only at its
beginning.

WHAT THE BURBANK PLUMS

AND PRUNES HAVE

EARNED

The Opportunity Which Improvement
Opens Up

THE BURBANK plums and prunes have
earned money for everyone except the
originator. Introducers, growers, canners,
and shippers, transportation companies, dealers,
and consumers have made and saved money from
these fruits.

The originator, on the other hand, as nearly
as he can estimate, has received about 50 cents
on each dollar invested in the work of plum
development.

My experiments altogether — nearly one-fifth
of which have been devoted to plums and prunes
— have cost me very nearly $250,000. The in-
come from the sale of new varieties has been ap-
proximately $100,000. Up to 1912 I was about
$150,000 behind on all my experiments. But the
loss on the plums has been less, probably, than

6 — Vol. 4 Bur. 161

162 LUTHER BURBANK

that on a good many other lines of experiment,
and there is reason to believe that varieties not
yet introduced will presently bring a return that
will more nearly balance the account; but
from my books, lectures, and other sources
I have at last, by good business management,
now made the account balance well on the
right side.

Meantime, the sums earned for others by the
Burbank plums and prunes after they have gone
out into the world have been really significant,
from whatever standpoint considered.

As illustrating their earnings in a single field,
we may note that in the season of 1912 there
were 564i carloads of Burbank plums of different
varieties, aggregating 396,133 crates, shipped
from California alone to the eastern markets.
This represented more than one-third of all the
shipments of plums. The average price per
crate received for all Burbank plums was $1.20
as against $1.03 the reported average for other
varieties. The maximum price per crate for any
Burbank plum was $3.25 as against a maximum
of $3.04 for any other variety; the highest aver-
age prices per crate being respectively $1.71.
Millions of crates are now (1920) shipped, and
prices have ranged from $2 to $4 per crate this
season.

PLUM AND PRUNE PROFITS 163

The total wholesale price of the Burbank vari-
eties of plums shipped in this single season was
not far from one million dollars.

If individual varieties are under consideration,
the plum specifically known as the Burbank ex-
cels any other single variety by a large margin;
the figures being, for the season of 1912, for the
Burbank 116,764 crates, and for its closest com-
petitor 98,149, a difference in favor of the Bur-
bank of 18,615 crates. Some of my other new
plums take the lead.

If prices are taken into account, the lead of
the Burbank becomes still more significant, the
highest price per crate for this plum being $1.93,
and its average price $1.12. The total revenue
from shipments of this single variety of plum
was more than $130,000 in 1912.

And all this, of course, refers to the Burbank
plums merely as shipping plums from a single
district. It takes no account of prunes, the
handling of which constitutes an altogether inde-
pendent industry. Nor does it, of course, refer
in any way to the shipment of plums from any
region except California. Yet the Burbank
plums are grown everywhere, and in some re-
mote regions as, for example, South Africa, they
are raised on the largest commercial scale. The
bushmen of Australia are perhaps as familiar

AN EXAMPLE OF UNIFORM
RIPENING

The Red Ball plum shown here
approaches the ideal for extra early
home and market purposes, which re-
quires that the plum not only ripen
evenly throughout its flesh, but that
the individual fruits ripen simultane-
ously. With such a fruit the entire
crop may be gathered at once — an
obvious advantage to the shipper.
(About three-fourths natural size.)

PLUM AND PRUNE PROFITS 165

with the deep yellow, juicy, tender but firm flesh,
and the sweet aromatic flavor of these plums as
are the orchardists of California. They are
equally well known in New Zealand, in England
in France, in Nova Scotia, and in southerr
Canada, and in this country they have become the
standard in all the States except Wyoming.

The total number of nurserymen in America
who list Japanese plums is 150, and of these 142
list the Eurbank; a record not approached by
any other plum.

A More Comprehensive Valuation

But these figures, and any others of like char-
acter that might be collated, serve, after all, to
give only a vague and general idea of the eco-
nomic importance of the new plums.

Statistics having to do with shipments to
the great markets, even were they available
for all territories, would tell but a small
part of the story. The true benefits accruing
from this work cannot be reduced entirely to
figures.

A large proportion of the earnings, for ex-
ample, have been protective — in the nature of
assuring large and regular yields of superior
quality ; thus giving significant returns each year
instead of uncertain yields occasionally.

166 LUTHER BURBANK

Again, even the most elaborate statistics would
entirely fail to present the facts at their true
value, because the identity of a plum is often
lost through the prevalent custom of renaming
varieties. The Abundance plum, as an instance,
has been designated "Botan," "Botankio,"
"Chase," "Yellow Japan," "Douglas," "Oval,"
and probably by other names by the growers and
sometimes also by the nurserymen and dealers.
The Wickson plum has been sold under the
name "Eureka," and similar liberties have been
taken to a greater or less extent with each of the
twenty Burbank varieties that are prominent as
shipping plums.

Therefore the figures based on the records of
distribution, growth, and sale of a variety are
sure to be far below the correct figure.

But most important of all is the fact that a
large part of the entire plum crop is grown
for home consumption or for distribution in local
markets or shipped by sea, of which no record is
available. With the wide distribution of Bur-
bank products over the entire world, in many
cases in countries where no systematic public
records are kept, there are unrecorded benefits,
profits, and earnings to the extent of millions
of dollars annually, of which no accurate esti-
mate can be made.

PLUM AND PRUNE PROFITS 167

And, finally, even if complete up-to-date rec-
ords of the earnings of the Burbank plums could
be collated, the figures would give but a vague
idea of the real importance, from a purely eco-
nomic standpoint, of the work that has been ac-
complished, for the reason that it takes a long
time to introduce a new fruit, whatever its im-
portance, and the best Burbank plums and
prunes have been developed within very recent
years. Of my quartette of "best" plums, only
the Wickson has been on the market long enough
to acquire anything like the reputation and the
vogue that its merits justify. As to the others,
Formosa was introduced in 1906, Santa Rosa in
1907, and Beauty, perhaps the best of all, only
in 1911.

So whereas we find that the Wickson was
shipped from California in 1912 to the extent of
one hundred carloads, there were only two car-
loads of Formosa and fourteen carloads of Santa
Rosa recorded, and of course Beauty is not rep-
resented at all.

Obviously, then, the earning power of these
newest and best plums is a matter for the future.
When the statistics are collated, let us say for
the year 1925, it will be possible to gain a
clearer view of the real importance of these new
productions.

168 LUTHER BURBANK

Of course, orchardists are proverbially con-
servative. Perhaps it is natural that they should
be so, considering that they deal with trees that
require some years to come into bearing. An
orchard cannot be made in a season, like a grain
field, but the rapid conquest effected by the Bur-
bank plum and others of my earlier production
leaves little room for doubt that my newest plums
will make their way no less effectively in the
course of the coming decade.

Fortunately for the fruit grower, he may in-
troduce these new Burbank varieties with less
loss of time than usually attends the introduction
of ordinary plums.

All of the older varieties in an ordinary Cali-
fornia plum orchard require five or six years'
growth before they commence to pay for them-
selves. But most of the new Burbank varieties
will commence to bear heavily in the third or
fourth season, and by the fifth or sixth year they
will have produced as much as the ordinary plum
orchard four or five years older.

Why Plant Creation Is Costly

Since I have spoken of the losses sustained by
the plant originator in developing fruits that
bring such large monetary returns to others, per-
haps I should explain a little more at length why

PLUM AND PRUNE PROFITS 169

it is that the plant developer who experiments as
I have done cannot hope for a quick financial
return for his efforts.

One chief reason why experimentation of this
order does not pay is that it was done so compre-
hensively, thoroughly, and on so large a scale.

Where a man conducts plum improvement, for
example, as an adjunct to a nursery business,
there is no reason why he might not eventually
secure even a single improvement that could
directly pay him for his care and expense in
producing it. There would be no certainty as
to this, to be sure, as the chance of securing a
really good new variety is not better than about
one in ten thousand. That is to say, in handling
ten thousand seedlings, there would be no prob-
ability of securing more than a single good new
variety.

But, on the other hand, sometimes even a small
lot of seedlings may give more than one good
variety, as has been the case several times.

In any event, the nurseryman can carry out a
line of experiment on a moderate scale without
considerable monetary outlay. So at worst he
will lose very little.

But where innumerable crosses are made and
thousands of seedlings are raised each year only
to be destroyed; and where all needed improve-

170 LUTHER BURBANK

ments are worked for together as in the combina-
tion of a great number of species and varieties —
instead of taking a certain established variety
and attempting to make one or two improve-
ments upon it — there must necessarily be a much
greater proportion of expense.

But, so far as my own experiments are con-
cerned, the pioneer work has now been done. I
have elsewhere told how the material has been
gathered from all over the world, until the plums
and prunes of my production carry hereditary
strains in their germ plasm from ancestors im-
ported from five continents.

And I have pointed out that there are thou-
sands of new varieties among my plum trees that
have exceptional qualities, and from the progeny
of which, variously interblended, many new
and important races of plums and prunes will
doubtless be developed in the immediate
future.

The sum total of my work with the plums and
prunes, judged by the record of actual introduc-
tions, comprises the development of only some
seventy new varieties. But it must be understood
that these seventy introduced varieties are only
the pick among thousands, very many of which
were but slightly inferior to the ones chosen.
And, as stated before, the final balance sheet for.

PLUM AND PRUNE PROFITS 171

my work with this fruit cannot be struck for
many years to come.

My plum orchard might be compared, in this
regard, to a large number of modern industries,
manufacturing establishments, for example,
which have a high first cost and which cannot be
expected to pay more than the interest on the
investment for many years, yet which may ulti-
mately show a profit that will pay back the orig-
inal expenditure and even give a balance on the
credit side of the ledger.

Plant Improvements Cannot Be Patented

There is, however, one feature of plant devel-
opment that puts it on a different plane, as re-
gards probable financial returns, from that
occupied by other fields of inventive or creative
industry.

This is the fact that nothing comparable to a
patent can be obtained on new varieties of fruit
trees or flowers, such as the developer of new
mechanical inventions or chemical combinations,
or artistic productions can depend upon to guard
his invention and make it at least probable that
he will share in the profits that accrue from its
introduction. The plant developer must either
introduce his new varieties through direct sales to
nurserymen and planters, or else sell them out-

172 LUTHER BURBANK

right for a comparatively small sum to a whole-
sale dealer. In the latter case he receives a sum
that is never large. In the former case his re-
turns are altogether problematical, and at best
there are only two or three years during which
he has a partial monopoly of the sale of the
product of his labors.

In three or four years, according to the rapid-
ity with which the new variety can be multiplied,
orchardists who have purchased grafting stock
can compete in the market with the original
introducer.

Suppose, for example, that I have a new plum
that I decide to introduce directly. I sell graft-
ing wood by the foot. The highest price I have
ever received for grafting wood, even of the
choicest new variety, is $10 a foot.

This, to be sure, is at the rate of about $800,000
a cord, if you choose to reckon it that way; but
unfortunately you sell only a very small fraction
of a cord. There is not likely to be any very
active demand for a new variety of plants, or
until it has been tested out in several localities.
Meantime, the first purchaser, in making the
test, has grown a large quantity of twigs from
his grafted cions; and with this, obviously, he
can enter the market on an equal footing with
the original producer.

PLUM AND PRUNE PROFITS 173

Thus, a single foot of wood gives enough buds
to graft a strong, vigorous, young tree ; and from
that tree enough wood may be taken next year
to graft nearly an acre of orchard. After that,
of course, the supply is practically unlimited.

Thus the cost of securing a plum or prune
orchard of the very choicest variety is absolutely
insignificant; to say nothing of the fact that the
enterprising purchaser, when he has demon-
strated the value of the new product, can sell
grafting wood to his neighbors in such quanti-
ties as to pay back many times over his original
outlay — even though, as sometimes happens, he
makes the sales at only a fraction of the price
charged by the original introducer.

In this way, it is clear, any orchardist who pur-
chases cions of a new stock may quickly enter
into competition with the original producer or
the firm that has purchased the right. Often
the second man that comes into the field may take
advantage of the advertising done by the first,
and quite possibly make as great a profit as the
producer and the original introducer. And each
local nurseryman may in turn take up the work
of distribution, supplying the local demand.

So the few feet of grafting stock that the
original plant developer sold for a mere fraction
of what it had cost him to produce the new

A GOOD ROOT SYSTEM

The photograph shows a yearling
plum having a sturdy, well-branching
root system that will provide, in suit-
able soil, sufficient nourishment for the
plant above it. The reciprocal relation
between root system and leaf system
should be clearly understood by every
orchardist.

PLUM AND PRUNE PROFITS 175

variety, have within a few years multiplied to
make up the thrifty branches of scores or hun-
dreds of orchards, until everyone who desires the
fruit is supplied, without an additional cent com
ing to the pocket of the originator.

This was what I had in mind when I intimated
in the beginning that the most successful new
fruits, which bring fortunes to a large number of
dealers and growers, may represent financial loss
to the originator.

Incidental Profits from the New Plum

Not to dwell unduly on this aspect of the sub-
ject, however, let me point out a little more in
detail some of the benefits conferred by new
fruits having exceptional merits.

For example, a fruit may make an exceptional
profit for the grower merely because of the fact
that it comes into bearing very early in the sea-
son, before the market is glutted with fruit of
other varieties.

The Burbank, Santa Rosa, Climax, and For-
mosa plums, among others, are striking ex-
amples of this feature, as they come into bearing
very early. Several of these have come into the
market at a time when it is nearly bare of fruit.

Another advantage is secured to the fruit
grower by varieties that are regular and abun-

176 LUTHER BURBANK

dant bearers. Regularity of bearing is a factor
for which I have worked constantly, and it has
been instilled into all my new varieties of plums.
These trees are not constructed on the hit or miss
plan. They can be depended on to give a crop
each year. It requires no argument to show that
the expense of starting an orchard can be paid
much more rapidly by trees that will bear abun-
dantly each season. An enormous crop every
other year would not at all take the place of even
a moderate crop every year. But my new plums
are not only regular bearers, but most abundant
bearers as well.

Sometimes the grower is deceived by receiving
a large price for a variety of fruit that is pro-
duced in such small quantity as to bring a
meager aggregate return.

The wise orchardist, however, will look for a
fruit that will produce abundantly and at the
same time being a good price per basket. The
Tragedy at $2.00 a crate would generally pay
much less than the Burbank at $1.00 a crate,
owing to the difference in the productiveness of
the two varieties. But the Tragedy, even with
its small production, averages (according to the
returns of last year) only 19 cents a crate more
than the Burbank. And of course the Burbank
was one of my earliest introductions. Some of

PLUM AND PRUNE PROFITS 177

my newer plums quite outclass it in selling
value.

All of the most successful of my new plums
are early bearers and produce large and at-
tractive fruit. The purchaser desires a large,
high-colored, handsome fruit, and he is not dis-
appointed if he finds that it has excellent quality
also.

Then, in order that a fruit shall earn money
for its grower, it must be adapted to stand ship-
ment to a distant market. Many beautiful plums
lack this quality and as a consequence never
have been, or can become, valued fruits for com-
mercial shipping by the carload.

But my new plums have been developed with
this need constantly in mind. I have recognized
that a fruit to become of importance for ship-
ping long distances must have a number of
qualities that hitherto have not been required in
fruit. It must be of texture that will not break
down in handling and shipping; it must retain
its flavor, or even have improved flavor if picked
before it is quite ripe; and it must remain firm
and hard, not only throughout the long journey,
but during subsequent days, until it can be placed
among the retail distributors.

Very few plums in existence to-day are wholly
up to these standards of excellence. The Wick-

178 LUTHER BURBANK

son, one of my early introductions, fulfills these
conditions better than any other plum before
produced. But there are several among my pros-
pective introductions that will excel even this.

Often one new character in a plum, prune, or
plumcot doubles its earning capacity. The ship-
ping qualities of the Wickson; the color of the
Santa Rosa; the flavor of the Geewhiz or Nixie;
the bloom of the Plumcot which enables it to be
placed on the market as fresh in appearance as
when first taken from the tree — these are ex-
amples of characteristics that may double the
earning capacity of the fruit.

Incidentally, we must not fail to note that
improved varieties of plums and prunes have
greatly enhanced the earnings of the transporta-
tion companies. Where fruit is shipped by the
carload, it can be handled economically by the
railways, and as transportation is an essential
link between the producer and the consumer,
there is no difficulty experienced by the common
carriers in securing an adequate price for their
work.

Another minor point that might readily be
overlooked is that the Burbank plums increase
the earnings of the retail dealer, who not only
makes a direct profit from their sale, but so
beautifies his exhibit by introducing these large

PLUM AND PRUNE PROFITS 179

and handsome fruits as to attract customers, and
thus facilitates the sale of his less attractive fruit
as well.

Finally, the earnings of the Burbank plums
advantage the ultimate consumer. The new
plums can be produced so much more cheaply
that sooner or later this reduction in cost of
production will rebound to the benefit of the
final purchaser. He gets the fruit at half the
former price. The fruit itself is of greatly im-
proved appearance and quality, yet it costs less
than smaller, less attractive, and less highly
flavored plums formerly cost. So in the end
the consumer shares the profit of the Burbank
fruits with all the other parties concerned.

If in conclusion I revert to the statement that
nobody is made financially poorer except the
originator of the fruit, it is only that I may add
that he also receives an adequate reward in the
knowledge that he is a benefactor of all parties
concerned and a detriment to none.

If he can only pat himself on the back, while
others may pat themselves on the purse, perhaps
his satisfaction after all is not less than theirs.

ACHIEVING THE IMPOSSIBLE
THE PLUMCOT

A Cross Which Man Said Could Never
Be Made

SEVERAL years ago a party of noted
scientists from various parts of the world
were visiting my farms.

I asked one of them — an American, then
known to the public as a compiler of various
books on horticultural subjects — to come over
to another part of the grounds and see one of
my crosses between the plum and the apricot;
one of my first crosses then just ripening.

"There can be no such fruit," my visitor
declared. "The two species are wholly different
in all respects. Everybody knows it is impos-
sible to cross two trees of such widely varying
types as the plum and the apricot."

I was not surprised to hear him make this

statement. For at that time very few biologists

— and in particular few technical botanists — had

quite given up the notion that there are hard and

181

THE ODD PLUMCOT

This fruit, as the reader is aware,
has very exceptional interest because it
is a hybrid produced by crossing species
so widely separated as the plum and
the apricot. The cross was successfully
made only after a long series of
experiments. Now, however, we have
a great number of varieties of plumcots.

THE PLUMCOT 183

fast lines between the different species as com-
monly classified.

This belief has undergone a radical change in
recent years, and the many combinations of
widely different species made on my Sebastopol
farm have had at least a share in broadening and
clarifying the views of the classifiers.

"Well, what kind of a tree do you think this
is?" I asked a moment later.

"Why, a plum, to be sure."

"Please examine more closely, professor," I
requested. "This leaf looks to me more like an
apricot than like a plum!"

"Yes — yes. I see now it is; it is surely an
apricot — the leaf, though differing from most of
the apricots, is certainly an apricot leaf."

"Now look again, carefully — look at the
foliage, bark, branches; and now let us examine
the fruit. Then tell me what you really think
it is."

After a long and thorough examination, I
heard the reluctant decision: "Well, it surely is
what you claim it to be — a cross between the
plum and the apricot. I never thought it could
be made."

I told him I had hundreds of others bearing
fruit of different sizes, shapes, and qualities.

"Show me another — quick! quick!"

184 LUTHER BURBANK

And he saw not merely one other, but a score
or two, to his added mystification.

When the apricot and plum were crossed to
produce an intermediate fruit, the accomplish-
ment was thought by some botanists to savor of
a violation of the laws of nature.

Breaking Down a Barrier

Notwithstanding the general acceptance of
the idea of evolution of species, a reminiscence
of the old special-creation point of view lingered.
Even if existing species have evolved in the past,
they were thought to be fixed in the present; or
at any rate to be separated by impassable heredi-
tary gulfs.

If, by a rare chance, species did interbreed, it
was quite generally supposed that the offspring
must necessarily be sterile.

Therefore, when the statement was made
that I had crossed the plum and apricot and
produced a healthy and vigorous new fruit, it
was met with profound skepticism from most
quarters.

But it was only necessary to bring the skeptics
to the trees themselves and introduce them
to the new fruit to convince them that what
they considered impossible had really been
accomplished. The plum-apricot hybrid attests

THE PLUMCOT 185

its heritage convincingly to any competent
observer.

As we have elsewhere seen, the apricot has
been found difficult to improve, because of its
lack of adaptability — pliability, as it may be
called. The tree thrives, blossoms well, but
rarely fruits in this region, chiefly because of
the tenderness of its blossoms. Partly because
the climate here made it difficult to attempt
the improvement of this tender plant, I
decided to try crossing the apricot with the
plum, which thrives unusually well in this
locality.

Had I known how much time and labor and
patience these experiments were to demand, they
might never have been undertaken. Plant im-
provement of any kind tests purse and patience ;
but the improvement of tree fruits strains both
to the breaking point. Working with vegetables
or flowers, it is possible to get valuable improve-
ments well under way in from three to five years
— after which continued selection makes prog-
ress more rapid.

With tree fruits you have only just begun
after a dozen years of crossing, growing, testing,
and selecting.

Nevertheless it was with pleasurable antici-
pations that I began these experiments which

CHERRY PLUMCOT

This beautiful fruit is a curious com-
bination. The fruit itself is a true
plumcot, whereas the stem and leaves
are distinctly those of the plum. The
coloring and dotting of the skin are
characters that reveal the plum parent-
age; but the other qualities of the fruit
are wholly suggestive of the apricot.
(Natural size.)

THE PLUMCOT 187

later were to produce the plumcot. It was like
entering an unexplored country.

Apricot flowers were dusted with plum pollen
and plum flowers with apricot pollen. But for
a long time the experiment failed.

Finally, however, when about to despair of
success, several crossbred seedlings were found
among a lot grown from the seeds of a Japanese
plum that had been pollenized with various apri-
cot blossoms.

The young seedlings could be early distin-
guished readily from the uncrossed seedlings by
the foliage, bark, buds, and general appearances ;
differences being noticeable while the seedlings
were still less than a foot high. The combined
characters of the plum and the apricot were tc
be noticed in the bark, the leaves, the buds, and
especially the roots. The apricot root is bright
red while the plum root is yellow, pale yellow
or almost white. The hybrid seedlings had red
roots, of various shades.

Battling Heredities

With the recognition of characteristics began
the great work of selecting and discarding.

Moreover, fresh hybridizing tests were made
and in due course other hybrids were produced,
some having the plum and others the apricot for

188 LUTHER BURBANK

the seed parent. Where cross-fertilization could
be effected, it made no difference which way the
species were crossed.

But the conflict of hereditary tendencies was
at once apparent. Hybrids appeared that de-
parted widely from the traditions of either
parent. Moreover, there was the tendency to
sterility that threatens the offspring of every
wide cross. One of the first plum-apricot hy-
brids produced did not have a stamen on the
whole tree. It was very evidently a cross of the
plum and apricot, but in the combination the
means for perfect reproduction was lacking.
Experiments were made by applying pollen to
the malformed blossoms. But few ripened — the
majority remaining dormant.

The cross brings out this striking malforma-
tion, but there are doubtless almost numberless
tendencies striving for mastery that remain sub-
merged, apparently neutralizing one another —
perhaps destined ultimately to come to the
surface under the influence of a changed
environment.

At every stage of the development and im-
provement of a plant short cuts must be intro-
duced, where time and expense can be saved.

Instead of waiting years for a seedling to bear,
it is possible to save much of that time by the

THE PLUMCOT 189

application of methods of grafting, elsewhere
described. Some of the most vigorous and best
growers of the hybrid seedlings were grafted
onto older plum trees. After two or three
years several of them began to bear fruit
abundantly.

The grafts showed that fruit would actually
be produced — fruit of fine quality; this much
was assured.

And it was a fruit of a new order — neither

apricot nor plum. In view of its origin, it

seemed appropriate to christen the new fruit the

Plumcot.

Parental Resemblances

The new fruits are often similar to the plum
in firmness and color. In form also the cross
quite as often follows the plum parentage, for
every shape that is seen among the many thou-
sands of varieties of plums is also seen among the
plumcot seedlings. But there are numerous
varieties also that closely resemble the apricot
in form.

The stones vary widely, some of them almost
duplicating the apricot stone, and others being
similar to the plum stone. A few varieties have
stones which resemble the peach stone in many
respects, especially in the corrugated and honey-
combed appearance and in thickness of the shell.

SWEET PLUMCOT

Among the hundreds of plumcots
which have originated on my experi-
ment farms there is every variation of
the combination of plum and apricot
qualities. The variety here shown is
called the sweet plumcot; it closely
resembles the apricot in the quality of
its flesh, though growing on a typical
plum tree. {Life size.)

p ,Jg ^

m

w M 1

THE PLUMCOT 191

There is no uniformity in the color of the stones
Some of them are almost white, others yellow; £
few are wine colored; and there are browns of
various shades.

The sharp, knifelike projection from one edge
of the stone — a characteristic of the apricot — is
found in the seeds of many of the plumcots.

Notwithstanding these extreme variations,
however, it is usually not difficult to distinguish
between the plumcot seeds and those of the plum
or apricot. They are usually plumper than those
of the plum, and have an individual appearance
that would be noticed by anyone who examines
them.

Some stones are attached to the flesh, while
others are free, some are smaller than the stones
of either the plum or apricot, while some are
much larger, almost comparable to the peach
stones.

The flesh of the new fruit is — the flesh of a
plumcot.

As great production as could be desired, com-
bined with large size and other good qualities,
had not up to that time been produced. This
lack, while discouraging for the time, was by no
means an insurmountable obstacle to the pro-
duction of a fruit comparable in its relative
perfection to our other standard fruits.

192 LUTHER BURBANK

When it is possible to add to the most stub-
born plant, practically any desired element —
color, hardiness, earliness, or any other it may
lack — the plant improver may be assured that
productiveness can also be added.

In order to give an idea how a number
of seedling plumeots proved up, the following
test records of some of the plumeots pro-
duced are listed. It is to be remembered
that these are some of the results of earlier
experiments.

On consulting my record books, I find that the
earlier plumeots were usually listed as poor to
medium growers, and almost without exception
as poor bearers. Such records as these are
typical: "No. 10 — Poor grower; fruit small.
No. 14 — Strong grower and poor bearer.
No. 16 — Poor grower and poor bearer. No. 18
— Medium grower and poor bearer."

This is not as discouraging as it might seem
on the face of it. All of the trees represented
by the above numbers bore regularly; they pro-
duced a fair crop every year. Moreover, there
were others that were listed as "medium" bear-
ers, and even as "heavy" bearers.

One of these now fruiting produces such an
enormous quantity of fruit that it would seem
impossible for the tree to hold it; the branches

THE PLUMCOT 193

are literally crowded with plumcots from base
to tip.

The quality also is good. So this variety gives
a good basis for more seedlings and for crosses
that will produce regular and abundant bearers
of fruit of superior quality.

The plumcot was at first slow of improvement
owing to the comparatively few seeds available,
and the time it took those to come again to bear-
ing, yet a number of varieties which combine the
pleasing quality of the apricot with the hardiness
and productivity of the plum are already in
existence.

The larger proportion of the successful crosses
between the apricot and the plum have been
made with the Japanese plums. Few seedlings
have been raised from the apricot trees pollen-
ized with the Japanese pollen, the seeds generally
being produced from the plum tree.

The seedlings of the second generation show
an astonishing number of variations. Although
both trees and fruits of these variations usually
resemble both parents in various respects, yet
we are so unaccustomed to seeing such com-
binations of characters that they appear to
be new.

In fact, the combinations are new, though the
characters exist in the heredity of one parent or

7— Vol. 4 Bur.

ONE OF THE NEW
PLUMCOTS

The typical plumcot differs so widely
from either of its parents that it is
entitled to be called a distinct species.
Some varieties, however, show a pecu-
liar segregation of the parental char-
acteristics. The specimen here shown
reveals the plum ancestry in the mottled
character of its skin, while the seed,
blossom end of the fruit, lopsidedness ,
firmness of flesh, and round, smooth
stone, indicate its apricot parentage.

THE PLUMCOT 195

the other; but these are often greatly intensified
in certain individuals.

Further Characteristics of Tree and
Fruit

The foliage, growth and general appearance
of the plumcot trees most often combine the
characters of the two species in such a way that
it is impossible to classify them either as plums
or apricots. There are, of course, many
gradations, so that some trees much resemble
the plum, while others closely resemble the
apricot.

Several varieties of the new plumcots were
exhibited at the Pan-American Exposition at
Buffalo in 1901. The exhibit aroused interest —
both for its novelty and beauty and because of
its promise of a new fruit for the orchardist.

As announced in "The California Fruit
Grower" of May 24, 1903, a special gold medal
was struck as an award — though no award had
been scheduled, or could have been for any such
exhibit. Such fruit had probably never been
thought of by the board of awards or anyone
else.

Such recognition was pleasing. Yet the plum-
cot in 1901 was far from being a perfect fruit.
It was rather in the experimental stage. Further

196 LUTHER BURBANK

work in crossbreeding and selection was requi-
site for its perfecting.

The first one of these plumcots introduced
was sold to John M. Rutland of Australia.

Mr. Rutland came from Kiewa, Australia,
and lived near my Sebastopol proving grounds
for several years in order to study these new
fruits, as well as the cactus and other of my pro-
ductions. When he saw this plumcot, he thought
it good enough for introduction. Accordingly,
in July, 1905, he purchased the right of distribu-
tion in the Southern Hemisphere, including all
of Africa. He named this variety the Rutland.

The following year the new fruit was intro-
duced in the Northern Hemisphere by George
C. Roeding of Fresno, California.

The Rutland has long, slender branches, and
long, slender leaves. It is a completely bal-
anced combination of the Satsuma plum and the
apricot. The exact pedigree of the Rutland is
inferred rather than known. The crosses were
so numerous and so complicated at that time
that no attempt was made to keep an exact rec-
ord of all of them. There can be no doubt, how-
ever, that Satsuma is one of the parents, because
the flesh of the Rutland is red, and the Satsuma
was the only plum which had red flesh that I
was using for crossing at that time.

THE PLUMCOT 197

The fruit of the Rutland is large, globular,
clingstone; both the flesh and the skin are of a
deep crimson color. The flesh has an acid flavor
until mature, and when fully ripe resembles the
Satsuma in its acid qualities. Its principal value
is for jams and jellies. There are a dozen or
more bearing trees of this variety on the Sebas-
topol place, and they have never failed to produce
a crop each season. The amount of fruit, how-
ever, is too small to make trees valuable com-
mercially in this climate.

The Rutland was a fruit of unusual scientific
interest, and was introduced partly under that
consideration — not merely as a commercial fruit.
It was sent out as a curiosity, the type specimen
of a new kind of fruit and the forerunner of
numerous good varieties that will follow.

Fixity of the New Species

It might be thought that seedlings from plum-
cots would revert to the type of plum or of
apricot, but they do not. The combination is
complete and permanent. Among the many
thousands of seedlings which have been grown,
not one has produced either true plum or
true apricot. All are plumcots. It is there-
fore plain that the new fruit is fixed as a
species.

CLUSTER OF APEX
PLUMCOTS

This variety of plum cots shows a
pretty even balance of the character-
istics of the plum and apricot ancestors.
The fruit is very large for an early
bearer, being from 5Y2 inches to 6 inches
in circumference. The flesh is honey-
yellow, firm, rich, aromatic, resembling
that of the apricot; sweet and delicious.
The Apeoc is the only plumcot yet intro-
duced which has promise of becoming
a standard market and shipping variety,
though there are others equal or supe*
rior to it in the proving orchard. The
Apex is already shipped East in large
quantities. (Nearly life size.)

THE PLUMCOT 199

Of course it is not expected to fix any of the
varieties so that they will come true to seed, any
more than any variety of plum or apple or pear
will come true to seed.

Nevertheless, the mixed heritage of the new
fruit is not altogether obscured. The tendency
to segregation of plum factors and apricot fac-
tors in the second and succeeding generation is
variously manifested. It would probably be
feasible to select specimens that by inbreeding
and selection could be made to develop races
fairly duplicating each of the parental stocks.
Such an experiment would have scientific inter-
est rather than practical value.

The plumcots are still new; they have not
been introduced to the general trade long enough
to be fully tested in many parts of the world. It
was hoped from the outset that among the new
varieties some would be found bearing fruits
equal to or better than the apricot in flavor, on
trees at least as hardy as the standard varieties
of plums.

This expectation has been realized in a
variety of plumcot that has been named the
Apex.

This makes it possible to raise delicious
apricotlike fruits in many localities where the
apricot cannot be grown.

200 LUTHER BURBANK

The Best of the Plumcots — Up to Date

The best of the plumcots so far produced is
that just mentioned, the Apex, a final selection
in 1911. It ripens with the very earliest of the
early plums, about June 10. This means that
its season is about three weeks earlier inland. It
is now extensively grown and is meeting with
special favor as a shipping fruit.

The tree is a strong, upright grower and has
never failed to bear a full crop, even where apri-
cots are failures. In some cases the Apex has
borne a full crop of fruit even when the plums
were a short crop on account of unusual weather
conditions. This fruiting capacity is unusual in
plumcots of such superior quality, and marks
the beginning of a new race of plumcots as
productive as the plum and as valuable as the
apricot.

The fruit of the Apex is extremefy handsome,
and very large for an early fruit, being 5 Ms to 6
inches in circumference. It is globular, and
pink or light crimson in color. The flesh is
honey yellow, firm, rich, aromatic, resembling
that of the apricot, and sweet and delicious to the
taste.

The Apex tree is a much stronger grower
than the Rutland, and produces perhaps ten

THE PLUMCOT 201!

times as much fruit. The fruit is larger and
much earlier. It has yellow flesh instead of crim-
son, making it one of the most valuable market
varieties.

The Apex resembles the apricot very decided-
ly in form, size, and quality of fruit, while it is
more like the plum in foliage, upright growth,
productiveness, and smooth-skinned fruit. It
thus illustrates the tendency to segregation of
unit characters along those lines to which refer-
ence has been made.

The Apex is the only plumcot yet introduced
which has promise of becoming a standard
market variety, though there are others equal
or superior to it to follow. Its ability
to withstand the requirements of long ship-
ping have been thoroughly tested, its firm
flesh and tendency to ripen slowly are sure
indications of its value for transcontinental
shipment.

The exact parentage of the Apex is not
known. The crosses have been so extensive and
complicated that a complete record was thought
of less value than the production of a fruit that
would feed the millions. It is certain, however,
that the Apex, like the Rutland, carries blood of
the Japanese type of plum combined with that
of the apricot.

ANOTHER PLUMCOT

It is not unlikely that still better
plumcots will appear in the course of
successive seasons. This beautiful and
delicious fruit has Satsuma flesh, and
apricot stone and flesh texture, with
stem and other fruit characters well
balanced between the plum and the
apricot. It is an appetizing and
palatable fruit.

THE PLUMCOT 203

The Triumph plumcot was introduced by
myself in 1911, having been, like the Apex, pre-
viously tested for several years. It is fairly pro-
ductive here, the fruit ripening about August 1.
It is of apricot form, is six inches around, with
velvety purple skin, thickly dotted and mottled
with scarlet. The flesh is firm and apricotlike in
texture. It is not so promising as a shipping
fruit as the Apex because of its deep crimson
flesh and lateness of ripening.

The Triumph is primarily a home fruit, and
is valuable because of unique combinations of the
apricot and plum qualities.

During the several years this variety has borne
fruit the trees have never failed to bear at least
a medium crop.

Another plumcot introduced at the same time
as the Triumph is known as the Corona. It is a
strong, upright-growing tree, bearing beautiful,
large, golden-yellow fruit with a velvety skin.
The fruit usually develops a red cheek when per-
fectly ripe. It is firm, sweet or subacid, and de-
licious. The Corona is a clingstone. It ripens
July 25. It is an unusually rapid-growing tree,
but it is not so productive as the Apex. It will
probably be grown only for home use. It is pos-
sibly hardy enough to be grown in many locali-
ties where the apricot does not fruit, and may be

204 LUTHER BTJRBANK

appreciated there because of its resemblance to
the apricot. Besides the varieties that have been
introduced, I have some thirty other selected
varieties that have been given temporary names,
for further testing. Some of these will doubtless
be introduced if, as expected, they prove of value.
Hundreds of other seedlings are being tested
but have not developed sufficiently to give a very
definite idea of their qualities.

Hybridizing the Plumcot

Now that the plumcot race has been thor-
oughly established, it is necessary to make further
crosses.

The obvious way to obtain improved varieties
is to cross the best seedlings of those already
produced. This is being done every year. Seeds
of all of the plumcots grown on my place in 1912
were saved and planted; possibly two thousand
of these seedlings being grown.

One of my named varieties that has not been
introduced is perhaps one of the most prolific
fruit trees ever produced. The seeds from this
are being saved separately. It is very probable
that the seedlings grown from this variety will be
remarkable producers.

By crossing some of the plumcots with the
Prunus Pissardi plum, some purple-leaved plum-

THE PLUMCOT 205

cots have been secured. This characteristic of
dark foliage is as readily transmitted in the plum-
cot cross as it is in the plum crosses. It is ex-
pected that by this cross one or more varieties
of plumcots will be secured that are valuable both
for fruit and foliage.

The purple-leaved plum trees have proved of
great value for decorating lawns, and the plum-
cot trees are considered of even more value by
some, because of the unique combination, and the
brilliant color of the foliage.

From a study of the plumcots already pro-
duced, it is safe to say that this new fruit will
become known and grown in all climates where
deciduous fruits are found. Numerous improve-
ments must be made before the plumcot will be-
come as popular as either of its parents. But
only time and patient selection are required to
effect these improvements.

It is quite possible that in many regions the
plumcot may in time replace the apricot as well
as many of the plums.

But more important even than the quality of
the plumcot as an orchard fruit is the lesson it has
taught as to the possibility of producing new
fruits by hybridization.

The plumcot stands as the first addition to the
list of orchard fruits that has been developed

THE "BURBANK" PLUMCOT

This is one of the most delicious of
the plumcots. It will be seen from the
direct-color photograph print that this
Variety resembles the common cultivated
crab apple in appearance. This is prob-
ably accounted for by the fact that one
of the ancestors in the original cross had
the shape of the crab apple; though this
plumcot is otherwise very different.

THE PLUMCOT 207

within historical times. Apples, pears, plums,
peaches, cherries, apricots, quinces— all were
known to the Romans and Greeks and to their
forbears of Oriental antiquity. The plumcot is a
new species that originated just at the close of
the 19th century.

Its production forecasts a new era in fruit
development.

Plant improvement of any hind
tests purse and patience; at every
stage of the work short cuts must
be introduced in order that time
and expense may be saved.

THE THORNLESS BLACK-
BERRY AND OTHERS

Some Transformations in the Bramble

THE nursery rhyme about the wise man and
the bramble bush will probably have little
meaning for our grandchildren. For the
brambles of their day will have no thorns with
which to scratch out eyes — let alone scratch them
in again.

The thornless blackberry is an accomplished
fact, as thousands who have grown them will
testify ; and the value of thornlessness in a berry-
producing vine is so obvious that the new product
cannot fail to supplant the old type.

Whoever has visited a blackberry or raspberry
patch ,of the old type and attempted to gather
the fruit, will recall, doubtless, bringing away
souvenirs in the form of scratches that were far
more lasting than the fruit itself.

When those who have the recollection of such
souvenirs see the transformed plants and mam-
moth clusters of large, beautiful, sweet black-

209

210 LUTHER BURBANK

berries growing on vines as smooth as pussy wil-
lows, the impression gained is both vivid and
lasting that this is a plant improvement of a very-
notable order.

In fact, there is perhaps no other single plant
development in connection with small fruits that
constitutes so radical a change and so conspic-
uous an improvement as the removal of thorns
from the blackberry. The bush itself no longer
needs the thorns to protect it against marauding
deer or sheep as it did in the days when it grew
in the woodland or nestled in fence corners. On
the contrary, as we have elsewhere suggested,
the thorns are now detrimental to the plant
in that they take a certain amount of energy
and building material that might be put to
better use.

And from the standpoint of the horticulturist,
the thorn is not merely a detriment; it is a nui-
sance of such significance as materially to inter-
fere with the cultivation of the blackberry and
very greatly to reduce its popularity.

It may confidently be predicted that, once the
thornless blackberries are generally introduced,
the really delicious fruit that the blackberry pro-
duces will be seen far more commonly in the
market than it has been in the past, and will soon
achieve the popularity that it deserves.

THORISTLESS BLACKBERRY 211

How the Blackberry Lost Its Thorns

As long ago as 1880, while I was still follow-
ing the pursuit of a practical nurseryman and
giving a divided attention to plant development,
many experiments were made in the attempt to
produce thornless berries. But these experi-
ments were nearly total failures.

The plant with which I first worked was a
blackberry bush known as the Wachusett Thorn-
less, which was introduced and alleged to be
thornless about 1880. I raised seedlings from
this plant, and also crossed it with other black-
berries. But being much preoccupied with other
experiments and greatly handicapped for means,
I therefore neglected to carry the experiments to
a practical conclusion.

The Wachusett, which had been found partially
thornless in the state of nature, had a goodly
supply of thorns distributed here and there over
the plant. It had fewer briers than most other
blackberries, to be sure, but it was by no means
the sort of bush to handle with impunity or rub
against your face without the slightest danger,
as may be done with the thornless blackberries of
to-day.

The Wachusett was not of a really smooth
stem, and it had almost nothing else to commend

THORNLESS BLACKBERRY

AND THE RECREANT

SEEDLING

At the left a typical stem of the new
blackberry ; at the right a thorny seed-
ling. The thornless blackberry invari-
ably breeds true to thornlessness; so
it is to be surmised that this seedling is
the result of a chance fertilization with
the pollen of a thorny variety.

THORNLESS BLACKBERRY 213

it. Its berries were quite small and lacking in
flavor, and it had moreover the pestiferous habit
of suckering from the roots. So it naturally did
not achieve popularity. Nor was anything heard
of any other blackberry that laid claim to thorn-
lessness until about ten years later.

Then it chanced — in the year 1902— that Mr.
David G. Fairchild, of the United States Depart-
ment of Agriculture, foimd in North Carolina a
few plants of a wild dewberry, apparently Rubus
canadensis,, that were nearly thornless. Mr.
Fairchild and myself had frequently exchanged
specimens of one kind or another that were
thought to be useful in this work. He now very
kindly sent me a few ripe berries picked from the
partially thornless dewberry.

The seeds were carefully planted in boxes in
my greenhouse. Of the several hundred seed-
lings that these produced, probably about one or
two in the hundred were nearly or quite destitute
of thorns.

These few almost thornless plants were care-
fully selected, all the remainder being destroyed.

From the fruits borne by these selected plants,
a second generation was raised, from among
which it was possible to select a number that were
absolutely free from thorns — showing no sign of
any spicules on either stems or leaves.

214 LUTHER BURBANK

More than fifteen thousand seedlings were
raised from the fruit of the best of these thorn-
less plants, and out of that large number not a
single specimen showed any tendency to develop
thorns, every one being as smooth as the branch
of an apple tree.

Thus by inbreeding and selection from fruit
produced by a partially thornless wild dewberry,
a race was quickly developed of thornless berries
and could be depended on to breed absolutely
true as to thornlessness.

If we interpret the facts of this development
in the light of later experience, we may infer that
the condition of bearing thorns is prepotent or
dominant over the condition of thornlessness in
the blackberry. Thornlessness is, then, a reces-
sive trait which will be submerged in a cross be-
tween a thorny bush and a thornless one, but
which will reappear after the manner of recessive
traits, in a succeeding generation, provided two
individuals of mixed heritage are interbred.

The fact that only a very small percentage of
my first seedlings grown from the seeds Mr.
Fairchild sent were almost thornless, suggests
that the flowers of the bush on which they grew
had been chiefly fertilized with pollen from
thorn-bearing bushes. The fruit from such a
pollenization would produce thorny bushes ex-

THORNLESS BLACKBERRY 215

clusively, owing to the dominance of the factor
for thorns. But if a few berries or individual
drupelets of a berry had been fertilized with
pollen from a flower of the thornless plant itself,
these would (according to a formula with which
we are already familiar) stand one chance in four
of combining recessive factors and thus of pro-
ducing thornless progeny.

And of course from then onward the case pre-
sented no difficulty as far as this character was
concerned. We must now be at hand to make
sure that the thornless flowers were fertilized
solely with pollen of their own sort. This, of
course, could bring together only recessive fac-
tors, that is to say, factors for thornlessness, and
the result could not be in doubt. The thorn-
producing factor would be left entirely out of
the composition of bushes sprung from such a
union, and they would inevitably be thornless.

Thornless, but Lacking Quality

But while the production of a thornless race
of dewberries was thus accomplished with com-
parative ease, it must be understood that this was
really only the beginning of the task.

The original berries from which the thornless
vines were grown were of no commercial value.
They were small and of very indifferent flavor.

216 LUTHER BURBANK

To have produced a thornless race from them
was an interesting scientific achievement, but
one that at this stage had no very practical
significance.

In order that the experiment should lead to
the practical results at which I aimed it was
necessary now to improve the fruit of these
thornless proteges. And, while something could
be done in this regard by mere selection — in
Avhich case, of course, there would be no danger
of having the plants backslide from a thornless
condition — I soon found by experiment and ob-
servation that selection alone would be much too
slow and doubtful a method for the development
of such fruit as would be necessary to compete
with the highly developed blackberries already
in the market.

For of course it could not be overlooked that
the ultimate purchaser is much more vitally in-
terested in the quality of fruit supplied him than
in a question of whether this fruit grew on a
thornless vine or on a brier brush.

By the time I had reached the conviction that
it would be necessary to adopt a more energetic
procedure than mere selection in the education
of the thornless berries, I had acquired through
experience a very clear comprehension of the
methods that must be depended on to inculcate

THORNLESS BLACKBERRY 217

the desired lessons. I knew that crossbreeding
afforded the only feasible means of introducing
good qualities into the fruit of the thornless
dewberries.

Now the work of developing took on aspects
closely comparable to those that we have already
reviewed at length in the development of orchard
fruits. It was necessary to bear in mind such
items as increased size of fruit, good flavor, firm
flesh, and time of ripening — all of these being
matters regarding which the thornless berries
were defective.

Improvement Through Hybridizing

Of course there was no dearth of material with
which to effect hybridization.

The dewberry is merely a trailing variety of
blackberry, and it crosses readily with all other
species of blackberry.

I had at hand any number of blackberries
bearing fruit of the finest quality. There would
probably be no difficulty whatever in producing
hybrids between the little thornless berry and
the Lawton blackberry, for example, or my new
Himalaya berry, or any one of a dozen others.
And some of these would give, among varying
seedlings, a certain member that would bear ex-
cellent fruit

218 LUTHER BURBANK

But, unfortunately, when such crosses were
made, it was at once apparent that the thorny
condition had shown prepotency, and all the seed-
lings that grew from thornless berries thus cross-
fertilized were seen to be bearers of thorns.

This was precisely the experience that had dis-
heartened me when, back in 1880, I had made
the experiments with the Wachusett partially
thornless blackberry, to which reference was
made above. But in the intervening time I had
made many thousands of hybridizing experi-
ments, and I now clearly understood — what at
the earlier period I had known vaguety if at all
— that in such a case as this we must look to the
second filial generation for the kind of results we
are seeking.

The case is precisely comparable to that of
the white blackberry, for example, or to that of
the stoneless plum. When the white black-
berry is crossed with a black blackberry all the
offspring of the first generation are black. And
when the stoneless plum is crossed with the stone-
bearing plum all the offspring of the first gen-
eration are stone-bearers. But in each of these
cases the succeeding generation will show indi-
viduals in which the submerged character reap-
pears— we shall have white blackberries and
stoneless plums again.

THORNLESS BLACKBERRY 219

So I have every reason to believe that a com-
parable result would be achieved if the thorny
hybrid seedlings born of my thornless race were
given opportunity to redeem themselves in their
progeny.

The expectation was justified. In the second
filial generation the thorny seedlings produced a
certain proportion of thornless progeny. And
some of these thornless bushes now bore fruit far
superior to that of their thornless grandparent.
They had inherited some of the good fruiting
qualities of their thorny grandparent, even
though they had repudiated his thorns.

This was obviously encouraging. So the ex-
periment was continued along the same lines
through successive generations. Selection was
made of course of the one specimen in each
generation that inherited the best combination
of desired qualities and hybridized, in successive
generations, the Lawton blackberry, the giant
Himalaya, and various others, to gain size of
berry, earliness of bearing, new flavors, more
acid, and, in a word to supply whatever defects
could be discovered.

The original thornless berry was a late bearer
and its fruit lacked size, spiciness, and refreshing
acidity. But these qualities were supplied in
abundant measure through successive crosses.

ONE OF THE NEW THORN-
LESS BLACKBERRY
CLUSTERS

Should any doubt remain that this
curious plant with its absolutely smooth
stem is really a blackberry, a test of the
fruit will at once convince the most
skeptical. Not only is this a thornless
blackberry, but it is a fruit of very
superior quality. It has the peculiarity
of maturing very late in the fall.

THORNLESS BLACKBERRY 221

One seedling in particular, grown in 1906, had
exceptional qualities, and the subsequent stock
was largely grown from the fruit of this single
bush. Like its fellows, it bore strains of half a
dozen races of high-grade market berries,
blended with the thornless strain.

Of course each successive crossing with a
bearer of good fruit meant the introduction of
thorns in the seedlings of the next generation.
This was inevitable, since of course all the bear-
ers of commercial blackberries were bearers also
of thorns. The Himalaya in particular is an
exceedingly thorny bush, and the otherwise com-
mendable Lawton is an almost equal offender.
But whereas these thorny shrubs were pre-
potent in their influence over their direct
offspring as was expected, some of their
grandchildren always reverted to the thornless
state.

And so here, as in various other experiments
already described, advance was made by indi-
rection. We are forced to seesaw back and forth
in successive generations between thorny bushes
and thornlessness ; yet on the whole there was
progress, inasmuch as each successive generation
gave better qualities of fruit, and each alter-
nate generation the recurrence of the thornless
condition.

222 LUTHER BURBANK

Inasmuch as the thornless bushes, of whatever
generation, will breed true to thornlessness if fer-
tilized among themselves, it is obvious that each
thornless generation constitutes a fixed race, pro-
vided the plant experimenter does not elect to
disturb its fixity by a new hybridization.

The result, up to date, is that after twenty-
four years of selective breeding along these lines,
tlie descendants of the little North Carolina dew-
berry (who are descendants also, of course, of
various and sundry berries of more aristocratic
bearing) constitute a race of blackberries grow-
ing on large, well-shaped, spreading bushes that
are always absolutely thornless. The fruit itself
is a large, handsome, glossy blackberry, of ex-
cellent flavor, profusely clustered — a fruit that
makes inviting appeal to all and which will exact
no penalty in the way of scratches from those who
gather it.

The story of the thornless blackberry is thus
told at length because the development of this
fruit quite eclipses all my earlier work with the
blackberries, and makes the record of the de-
velopment of the thorny varieties, however
excellent their fruit, seem an almost archaic
performance.

It must be recalled, however, that the present
thornless blackberries of superior quality could

THORNLESS BLACKBERRY 223

not have been secured so expeditiously had not
material been at hand for the hybridizing experi-
ments through which size and flavor were bred
into the fruit until, as just related, the perfected
thornless varieties were developed.

And this material was largely the product of
some earlier experiments through which black-
berries of the old type had been improved as to
their fruiting qualities.

It is necessary, therefore, in the interests of
completeness, to retrace our steps and briefly tc
review the earlier experiments — some of which
indeed, were carried forward coincidentally with
the development of the thornless — through which
new races of blackberries of exceptional quality,
though still handicapped by thorns, were de-
veloped.

In this connection it is interesting to recall that
the cultivated blackberry is essentially an Ameri-
can product. No other country until quite re-
cently has appreciated the quality of this fruit
sufficiently to cultivate and develop it. Wild
species, to be sure, are abundant in Europe,
growing everywhere in England and in Ireland,
along hedges and in waste places; but the horti-
culturist has all along seemingly been prejudiced
against the fruit, mostly perhaps because of its
offensive briers.

224 LUTHER BURBANK

The prejudice against the wild bramble was
retained by the Colonial settlers of America —
retained so persistently that fully two centuries
were needed for this excellent berry to make its
way into the fruit gardens.

Not a single horticultural variety of black-
berry was introduced until almost the middle of
the nineteenth century. Then the Dorchester
was brought to notice, and about a decade later
a better berry, the Lawton, which is still a stand-
ard, and two other varieties, the Holcomb and
Wilson's Early, were brought to the attention of
fruit growers.

As a significant industry, blackberry cultiva-
tion is even more recent. It has almost wholly
developed since 1870. It began with planting,
on a commercial scale, the Lawton, which was
later supplanted by the Kittatiny in some sec-
tions. This in turn gave way to the Snyder, and
still more recently better varieties were devel-
oped. The evolution of the fruit had been
gradual, but it has at last established a place in
the horticultural ranks. I repeat my prediction
that it will gain a new impetus now that the one
great drawback of the blackberry, its thorny
stem, has been completely eliminated.

It will take some time, however, to spread the
thornless berry universally, and in the meantime

THORNLESS BLACKBERRY 225

the blackberries of the older type retain a meas-
ure of interest.

Materials for Development

The chief American wild species, which fur-
nished material for the development of the races
just named, are the common Eastern black-
berry (Rubas nigrobaccus) , familiar everywhere
throughout northeastern America, and a closely
related form, considered by some botanists a
mere variety, known as Rabus sativus.

The common wild plant is an upright grower,
stout, has little recurving canes that are usually
deeply furrowed lengthwise, and clothed with
stout more or less hooked prickles.

The other species or variety is slightly more
erect, with fuller and firmer canes, differing
somewhat also as to shape of leaves. It bears
berries that are usually rounded, generally soft
and juicy, and of superior flavor. At my old
home in New England this variety grew abun-
dantly on sandy soil, being one of the best wild
blackberries in that vicinity. Very early I had
noticed that this plant was inclined to vary
widely. For example, the vines, although usu-
ally stiff upright growers, sometimes more re-
sembled the common blackberry, or even tended
to take on the trailing habits of the dewberry.

8— Vol. 4 Bur.

226 LUTHER BURBANK

When I came to know more about plant de-
velopment this tendency to variation was re-
called, and here, as always, a fruit of this
tendency should furnish material for the develop-
ment of improved varieties.

In due course I worked with the various culti-
vated varieties of blackberry, and soon developed
some improvements, particularly with reference
to the size of fruit, its flavor, and lengthening the
season of fruit bearing.

One of the improved varieties with which I
worked had been lately introduced under the
name of the Early Harvest; another was named
Wilson Junior. But the most notable results
attended the use of the native species, and in par-
ticular the introduction of foreign species from
remote parts of the earth.

As early as 1879 I was earnestly working on
varieties of blackberries, and of raspberries as
well, that were obtained from my collector in
Japan, combining these with other wild and cul-
tivated varieties from various sources.

The first really notable success, however, came
about through selection, without the aid of hy-
bridizing, from a berry that I had introduced
from India. This berry, in recognition of its
origin, was named the Himalaya, sometimes
shortened to Himalya.

THORNLESS BLACKBERRY 227

The Prolific Himalaya

The seed from which this improved black-
berry grew was obtained from India through
exchange.

It would appear that transplantation to an
altogether new soil and climate had the same
stimulating effect upon this blackberry that we
have seen manifested in the case, for example, of
the Japanese plum, the New Zealand winter
rhubarb, and sundry other plants. For there ap-
peared among seedlings of the second generation
an individual that was a very marked improve-
ment over its parents.

This exceptional seedling was cultivated and
propagated, and its qualities proved so unique
that it was introduced in 1885 by a special circu-
lar, being christened, as just stated, the
Himalaya.

After the usual decade or so of probation, dur-
ing which every new fruit of whatever quality
must wait for recognition, the Himalaya took its
place, first on the Pacific Coast, and later in some
of the Central States and in foreign countries, as
a standard blackberry. After it came to its own,
so to speak, its popularity was so great that for
several years the plants could not be multiplied
fast enough to meet the demand.

228 LUTHER BURBANK

It is a plant of extraordinary vigor. A single
cane may grow more than twenty-five feet —
sometimes even fifty feet — in a season, and attain
near the base a diameter of an inch to an inch
and a half.

The aggregate growth of cane of a single plant
in a season may exceed a thousand feet — one
fifth of a mile.

And in point of fruit production, the Hima-
laya far surpasses any other berry plant ever
grown. Reports tell of a single bush bearing
two hundred pounds of berries in a season.

"My daughter and I picked fifty pounds of
berries from one Himalaya bush the latter part
of August, 1906," writes one enthusiast, "and we
scarcely missed them from the bush. This was
after many others had picked from the same
bush. I picked three pounds standing in one
position. I could have picked double that
amount if I could have reached into the bushes
farther, but the entangled branches with their
sharp thorns prevented me."

The narrator adds this comment: "It is my
opinion that if this single bush were properly
pruned, fertilized, and irrigated, as well as
shaded from the extreme heat of the sun in July
and August, it would bear between three and
four hundred pounds in a season."

THORNLESS BLACKBERRY 229

Such a report is typical. The prolific bearing
of the Himalaya is the subject of astonished com-
ment from everyone on seeing this extraordinary
vine for the first time.

The fruit itself is of medium to large size, un-
usually sweet, and spicy, with small seeds, and
extra fine in quality. The berries grow in clus-
ters sometimes a foot or more across, and they
continue to ripen after most other blackberries
are gone.

If not pruned, the vines of the Himalaya
will grow to a length of one hundred feet
or more, like grapevines. They appear to
be absolutely resistant to disease, and have
recently shown the ability to resist the extreme
cold of Michigan and the far Northern
States. It should be known that the Himalaya
takes a year or so more to come to its best
bearing condition than ordinary blackberries,
but when in full bearing a single plant
will produce as much as a dozen ordinary
blackberry vines.

The elimination of the thorns is a matter to
which sufficient reference has already been made.
As to abundant bearing, nothing more is to be
desired. The improved Himalaya at present
produces all the berries that a vine can possibly
support.

230 LUTHER BURBANK

Development Through Hybridization

As the experiments in the development of the
blackberries continued, I quickly passed from the
stage of selection to that of crossbreeding and
hybridization.

The plants utilized in these experiments in-
cluded not only all types of native blackberries
proper, and numerous foreign species, but plants
of the allied race of dewberries.

The dewberry, to be sure, is closely related to
the blackberry; it is, indeed, a blackberry that
has assumed a trailing habit. Or possibly the
case would be stated more truly if we say that the
bush of the blackberry is a dewberry that has
risen from the ground and assumed the habit of
upright growing.

There is, nevertheless, a sufficient divergence
to make the dewberry seem to casual inspection
a plant of distinct type. And, at the time when
my experiments were begun, there were prob-
ably few plant developers who would have sup-
posed it possible to hybridize even the dewberry
with the ordinary blackberry.

Successive crosses were effected, nevertheless,
at an early stage of the work, and in the course
of my experiments the interblendings were so
numerous and intricate that seedlings were

THORNLESS BLACKBERRY 231

produced showing all gradations of habit be-
tween the trailing vine and the upright one; as
well as all gradations of leaf and fruit form
and quality.

Sometimes when crossing a blackberry with a
dewberry the trailing habit is greatly intensified,
the hybrid being a long, vinelike, straggling
plant. Again, the result may be just the oppo-
site, a tall, upright, almost treelike plant being
produced. Some hybrids would run a distance
of at least fifty feet. Others, perhaps of the
same fraternity, would take on so treelike a
habit that their fruit could be reached only with
the aid of a stepladder.

But perhaps the most singular and interesting
anomaly was that some of these hybrids bore
flowers and fruit in every month of the year,
though sparingly. At the time when I had a
large colony of blackberry-dewberry hybrids,
ripe berries could be picked from one bush or
another almost every day throughout the year.

The possibility of producing, with the aid of
such hybrids, commercial varieties of blackberries
that will fruit at all seasons is inviting. Experi-
ments already far advanced have greatly ex-
tended the blackberry season, and there is reason
to expect that the blackberry lover in the future
will be able to secure this fruit, in one variety or

232 LUTHER BURBAXK

another, from early spring until almost the on-
set of winter.

As to other possibilities of blackberry develop-
ment, something was said in the earlier chapter
that described the development of the white
blackberry. But much remains to be told.
The chief development, however, through which
not merely new varieties but new species of ber-
ries have sprung from the amalgamated stock of
the forty-odd species of bramble fruit with which
I have experimented, have had their origin in
hybridizations that linked the blackberry with its
relative the raspbeny.

The account of the altogether notable results
that have arisen from this alliance is an integral
part of the story of the blackberry. But it may
be told to best advantage in connection with the
story of the raspberry in the succeeding chapter.

The thornless blackberry is an ac-
complished fact, and the value of
thornlessness in a berry-producing
vine is so obvious that the new
product will not fail to supplant
the old type of brier bush quite
rapidly and effectually.

THE RASPBERRY AND SOME
ODD CROSSES

Much Betterment — and a Few
Baffling Problems

1ET us take up the story of small-fruit de-
i velopment where the preceding chapter
left it. We are still concerned with the
blackberry, but we now have to do also with the
companion fruit, which is obviously a not very
distant relative, yet which has certain typical
peculiarities that mark it as belonging to an
altogether different branch of the race of bram-
bles. Most conspicuous of these is the fact that
the ripe raspberry separates from the receptacle
when picked, whereas the blackberry is per-
manently attached to the receptacle.

The raspberry, unlike the blackberry, has
been cultivated in Europe from an early period.
The red raspberry, in particular, grows wild all
over Europe, from Greece to Spain and north-
ward to Norway and Sweden. It was originally
christened Rubus Idceus, after Mount Ida in

233

234 LUTHER BURBANK

Greece. Like other cultivated plants, it tends
to vary, and it is said that more than twenty
varieties were under cultivation in England a
century ago.

The American colonists introduced this favor-
ite European berry at an early date, but it did
not find a congenial environment in the new
country. The long, cold winters of the Northern
States, and the dry heat of the Southern summers
were alike hostile to it; and its lack of hardiness
denied it general recognition except as an occa-
sional garden plant.

But the new continent possessed many wild
raspberries that were of course adapted to the
environment, and in time these came under cul-
tivation. Their introduction, however, was so
gradual that it was quite unnoticed. The only
raspberry cultivated extensively for the New
York market early in the nineteenth century was
known as the English Red. It is believed to have
been an offspring of a native berry, known as
Rubus neglectus (itself believed to be an acci-
dental hybrid of our wild red and black rasp-
berries), but this was not generally known, and
the name given the fruit suggests that it was
supposed to be of European origin.

During the latter half of the nineteenth cen-
tury many improved red and yellow raspberries

THE RASPBERRY 285

were introduced, and various of these have been
utilized in my hybridizing experiments.

But perhaps the chief favorite among Amer-
ican raspberries is the one introduced in the
early forties by Nicholas Longworth of Ohio,
and known as the Wild Black or Blackcap
Raspberry, Rubus occidentalis.

This berry was a great addition to the list of
cultivated fruits. It soon became a favorite
everywhere it could be successfully grown. Mr.
Longworth himself introduced it into England,
but it did not thrive in the English climate and it
never competed with the native European species.

Interbreeding the Raspberries

The familiar cultivated raspberries of the
present time owe their origin to the species just
named, and to two other allied species, one our
wild red raspberry, Rubus strigosus, a close
relative of the common European species, the
other known as Rubus leucodermis, a western
relative of the familiar blackcap.

All the red raspberries now under cultivation
have sprung from either the European or Amer-
ican red species. The Purple-cane type appar-
ently sprang from the Rubus neglectus (very
probably a hybrid between R. strigosus and R.
occidentalis) ; such varieties as the Reliance,

THE FAMILIAR BLACKCAP
RASPBERRY

This is the familiar wild black rasp-
berry or Blackcap. The specimens here
shown are better than the average run,
having been improved in size and
quality and the plants in productive-
ness by means of careful selection.
They represent the species unmodified
by crossing, however.

THE RASPBERRY 237

Shaffer, Philadelphia, and Gladstone are, at
least in part, probably of this origin, as was the
historical English Red. The Purple-cane was a
native of the northeastern part of the United
States, being common in New York and vicinity.

The original American red raspberry, Rubus
strigosuSj first became known to the horticul-
tural world in 1860, through the introduction of
Allen's Antwerp and Allen's Red Prolific.

For several years preceding 1880 I had been
raising seedlings of blackberries, raspberries,
gooseberries, Juneberries, strawberries, currants,
and various other berries on my experiment
farm, and many variations were developed in
that way which aroused my enthusiasm.

These experiments were largely instrumental
in teaching me the then not known or not gen-
erally accepted value of cross-pollenizing as the
means of introducing the tendency to vary among
existing species or varieties. And my experi-
ments with the different raspberries had a prom-
inent share in the demonstration of this very
important and hitherto unappreciated principle.

In the course of these experiments it was first
found that the blackcap would cross with the
red raspberry, although with difficulty.

Seedlings from this cross sometimes bore per-
fect berries abundantly, but much oftener they

238 LUTHER BURBANK

bore imperfect berries having perhaps only two
or three seeds. Again, after blooming, there
would be no development of fruit, only a core
or stem remaining.

Among some of these crosses I met with a dif-
ficulty not encountered in crossing any other of
the members of the great Rubus tribe. The
plants at first seemed sickly, having little or no
vitality. When transplanted from greenhouse
to open field they made little growth the first
season and the second season at about the time
for fruit bearing they all seemed to fail utterly.

Every seedling among a lot of these hybrids
would sometimes thus be suddenly destroyed.

In continuing the experiment, I found that
there was strong individuality among the differ-
ent plants, so that some of the red or yellow rasp-
berries crossed readily with the blackcaps, while
others failed to do so ; there being all gradations.
In some cases the resulting seedlings would show
the prepotency of one parent or the other. But,
generally, in the first generation there would be
a blending of the characteristics of the two.

Underlying Principles

At that time no plant developer fully realized
that all the best variations and recombinations in
a hybrid stock appear in the second and a few

THE RASPBERRY 239

succeeding generations. A recognition of this
principle constituted my first very important
step toward the development of new forms of
plant life.

I discovered, in connection with the raspberry
hybrids, that in the second and a few succeeding
generations different combinations were brought
out in the most wonderful variety ; and that from
these certain individuals could be selected hav-
ing almost any qualities of either parent com-
bined in almost all possible proportions, and
often greatly intensified.

This was, as we now know, substantially the
discovery that Mendel had made almost twenty
years before. But no one heard of his discovery
till long afterward (about 1900), and at about
the time when I was independently learning the
same lesson Mendel himself died, quite unknown
to fame, without having been able to bring
his discovery to the attention of the scientific
world.

Meantime, without formulating the principle
in precise terms as Mendel had done, and with-
out following up results with numerical exact-
ness, I came to full recognition of the principle
of blending of characters in the first filial gener-
ation and their reassortment and segregation in
the second and succeeding generations.

240 LUTHER BURBANK

All my experimental work was carried for-
ward with a clear recognition of that principle.

As to the work with the raspberries, my first
aim was to accumulate as much available mate-
rial as possible.

This has been my custom throughout. The
chances of obtaining results from a large num-
ber of experiments are proportionately greater
as the number increases, and I find, within limits
of time, that it is just as simple to conduct a
thousand or ten thousand experiments, or even
a hundred thousand experiments, as to conduct
a few.

So I worked on a comprehensive scale with
the raspberries from the outset; and it was not
long before several varieties of value were devel-
oped; varieties, in fact, superior in size, quality,
and productiveness to any raspberries hitherto
known.

First Fruits or the Experiments

The first of my new raspberries offered to the
public was named the Eureka.

This raspberry, introduced in 1893, was de-
scribed as "larger than any raspberry in cultiva-
tion; bright red, firm, very productive, and sim-
ilar to Shaffer's Colossal in its piquant acid flavor.
It is nearly twice as large as Shaffer's Colossal,

THE RASPBERRY 241

its great-grandparent, and a better color and
quality, firmer, handsomer, and in all respects an
improvement on that well-known variety. The
bushes are more compact in growth, almost free
from prickles, and of a sturdy appearance."

Particular attention should be called to the
fact, just stated, that the new raspberry was al-
most thornless. This was true of a number of
my raspberries, as by selective breeding I was
able to give these vines smooth stems at a
time when my similar attempts to remove
the thorns from the blackberry had not been
successful.

The difference was due, perhaps, to the fact
that the raspberry, having been long under culti-
vation, had partly lost its thorns through more
or less unconscious selection on the part of many
generations of fruit growers. The thorns had
been reduced in many varieties to prickles, and
occasionally individual specimens appeared that
lacked even these. By selective breeding from
such specimens I was able to produce varieties
that had practically smooth vines.

A selected seedling of the Eureka was remark-
able for its habit of bearing in October as well
as for the enormous size of the berries, which
were frequently almost four inches in circum-
ference. The berries were of a beautiful bright

THE PRIMUS BERRY

This highly interesting plant is one
of the first that could properly be
termed a new species developed under
the direct guidance of the hand of the
experimenter. It is the progeny of the
California dewberry and a hardy little
berry indigenous to Siberia and Rus-
sia, called the Siberian raspberry. The
remarkable Primus berry appeared as
a first generation hybrid, and it always
breeds true, having the characteristics
of a new and permanent species.

THE RASPBERRY 243

red, but were rather too soft except for
home use.

Another of my crossbred raspberries, orig-
inated at the same time with the Eureka, was
called the Dictator. This also is a mammoth
bright red berry. It combines the flavors of the
Gregg and Shaffer's Colossal from which it orig-
inated. The combination is one of the happiest,
as the acidity of one is modified by the sweetness
and aroma of the other. The berries were more
than three times as large as those of the Gregg,
and almost twice as large as those of Shaffer's
Colossal, which until the production of these new
hybrids bore the largest raspberries known.

Another cross of the Gregg, this time with the
Souhegan, produced a seedling that had astonish-
ing crops of fine, medium-sized, red berries that
ripened during October. The Souhegan was also
crossed with the Shaffer, and this union pro-
duced in the second generation a new variety
that was known as the Sugar.

From the seeds of other members of this same
generation two or three other promising berries
were produced. One of these bore large, firm
berries, conical-shaped, and a dark, rich purple
color; some of these proved too tender for the
colder States; some were renamed and others
now supersede.

244 LUTHER BURBANK

A New Species — The Pkimus Berry

All the raspberries commonly known to the
cultivator, and many new ones that I imported
from Asia and the Southern Hemisphere, were
growing on my grounds from 1890 to 1900, and
were intercrossed very extensively. Numbers of
highly interesting hybrids were thus produced,
and at least one of these was of so distinctive a
character as to merit the title of a new species.

This was the fruit that was introduced as the
Primus berry.

This highly interesting fruit, probably the first
plant of any kind that could properly be termed
a new species to be developed under the direct
guidance of the hand of the experimenter, was
the progeny of a hardy little berry indigenous
to Siberia and Russia, called the Siberian rasp-
berry (Rubus cratcegifolius) , and the California
dewberry.

The little hardy Northern raspberry bore fruit
about the size of a pea, of a dark mulberry color,
with rather large seeds, and a flavor not such as
particularly to commend it. It is, however, re-
markable for its large palmate leaves, and the
sturdy growth of its stems.

The California dewberry, Rubus vitifolius, is
a trailing vine which is extremely variable in f o-

THE RASPBERRY 245

liage, habit of growth, size, and quality of fruit.
It is found wild everywhere in the foothills and
lower elevations throughout the Pacific slope of
the United States, but seems to be at its best in
northern California and Oregon. The berries of
this wild species are often produced abundantly.
They are black, usually of good size, though
rather soft, and of superior quality. They are
often gathered in large quantities for market
and home use.

The fact that this species bears dioecious flowers
— that is, flowers of opposite sexes on separate
plants — has discouraged a very general culti-
vation of the plant. It is necessary to grow both
male and female plants to insure fertilization,
and fruit growers do not relish the idea of hav-
ing half their vines unfruitful.

Nevertheless, there was one variety of the Cal-
ifornia dewberry, called the Aughinbaugh, which
had been under cultivation for several years.
This was the one selected for most of my ex-
periments in hybridizing the dewberry; and this
plant had a share in the production not only of
the Primus berry, but of the even more remark-
able Phenomenal berry to which reference will
be made in a moment.

The cross between the Siberian raspberry and
the California dewberry, from which the Primus

246 LUTHER BURBANK

sprang, was made without particular difficulty.
I had learned by this time that blackberries and
raspberries and dewberries could be hybridized
almost indiscriminately ; and the fact that one of
the parents in the present combination had grown
originally in Siberia and the other in California
offered no barrier to the union.

With the first lot of seedlings, five hundred or
more, from this union of the California dewberry
and the Siberian raspberry, some strange speci-
mens were revealed.

Nearly all were worthless plants, some of
which seemed hardly to have vitality enough to
live, much less to produce fruit. Others bore
small, unattractive berries, insignificant in every
respect. Three or four individuals, however,
grew with unusual vigor. They differed so
widely from the others that I was at first in-
clined to suspect that they were dewberries un-
hybridized. As to this, however, the result
proved that I was in error.

One of these exceptional vines was partic-
ularly notable. It neither trailed nor stood up-
right, but took an intermediate position. The
leaves were not palmate like those of the rasp-
berry, nor were they like the foliage of the
dewberry. They were a compromise between
the two.

THE RASPBERRY 247

The fruit, which was larger than that of either
parent, resembled the blackberry most in form,
but was of a dark mulberry color.

When the fruit was just ripe it parted from
the stem like the blackberry; but when fully ma-
ture the core came out as it does in the raspberry.

Thus the combination of all these important
characteristics was almost absolutely complete.
The hybrid was a perfect blend.

It was this plant that was christened the
Primus berry.

Seedlings by the thousand (5,000 one season)
were raised from this selected hybrid and all of
them came as true as the seeds of any wild spe-
cies of the family. The offspring closely resem-
bled the Primus, but none of them quite equaled
it in fruiting qualities.

If found growing wild, the original Primus
plant and its progeny would be pronounced by
any botanist a distinct species.

The explanation of the summary production
of a hybrid differing in this remarkable manner
from either parent and being so fixed in type as
to breed true to the new form thus suddenly de-
veloped would seem to be that the two parent
species were separated almost to the limits of
affinity. The fact that most of the hybrids of the
same generation with the Primus were feeble and

248 LUTHER BURBANK

degenerate creatures is corroborative. It ap-
peared, however, that there were elements in the
two types of germ plasm that if combined in just
the right way would produce a virile offspring.

By chance the right combination was effected,
and the Primus berry was the result.

The berry itself has not proved a great com-
mercial success, but that is a matter of small
importance. The real importance of the experi-
ment was in what it proved as to the possibility
of the production of new species through hybrid-
ization. This was, in short, one of the first in-
stances to come under my observation of the
production of a hybrid that blends the character-
istics of the parents, producing a new type and
breeding true to that type.

To my mind — and I think the facts are con-
vincing to any unprejudiced mind — this and
many similar experiments that have been suc-
cessfully accomplished demonstrates beyond dis-
pute that hybridization is one of nature's
methods of creating new species.

As this subject has been dwelt upon at length
in earlier chapters, I revert to it here because of
the importance of the subject itself, and also
because the Primus berry furnishes us a new
and striking illustration of the truth of the
principle.

THE RASPBERRY 249

Of course, the Primus berry was produced by
artificial pollenizing of the plants that were so
located geographically that they would have had
no chance to hybridize unless brought together
by man. But my observations show that natural
hybrids are not at all unusual among wild mem-
bers of this family. I have met with them often
where two or three closely related species were
growing side by side.

Near Lake Sycamore, for example, in Al-
berta, Canada, I have observed two common
raspberries, Rubus strigosus, a red raspberry,
and Rubus leucodermis, a blackcap, growing in
close proximity around the hillsides and along
the streams.

In every case where I found these two species
growing together there were numerous natural
hybrids in evidence. None of these hybrids
were as productive as the parents, but the vines
were usually stronger growers than either, and
appeared to be hard pressing both parent spe-
cies, with the prospect that they would in time
supplant them in this region. I gathered large
quantities of seeds from the best of these hybrids
and brought them home for planting. Many
seedlings were thus raised which obviously car-
ried the combined characters of both their wild
parents.

THE PHENOMENAL BERRY

The color print shows this remark-
able berry much reduced in size. Many
of the berries are an inch and a half
long and an inch in diameter. In flavor
the Phenomenal berry combines the
qualities of raspberry and blackberry,
both flavors seeming to be intensified.
Its individual qualities are so marked
and distinctive that it is entitled to be
designated a new species.

THE RASPBERRY 251

These representatives of a new species devel-
oped by hybridization under natural conditions
have obvious scientific interest even though they
failed to develop sufficient productivity to be of
commercial value.

Let me repeat that natural hybrids are much
more numerous than is generally supposed.

I have found them among other wild plants.
Especially are they to be observed among straw-
berries, blueberries, huckleberries, and California
lilacs (Ceanothus). I have elsewhere cited in-
stances of the hybridization of the tarweeds
and the mints. There can be no doubt that
some of our well-known species of to-day were
produced by nature in this way within recent
times.

I have elsewhere observed, and I emphatically
repeat, that any theory of the origin of species
that does not recognize this among the methods
employed by nature for the production of new
species is altogether inadequate.

Another New Species — The
Phenomenal Berry

The result of thus mating the dewberry with
the little raspberry from an almost arctic
climate having proved so remarkable, almost
numberless tests were made in which the dew-

252 LUTHER BURBANK

berry was crossed with a great variety of other
raspberries and blackberries.

And among the hybrids thus produced there
was at least one that might be considered more
remarkable even than the Primus beriy.

This was the fruit which afterward became
famous as the Phenomenal berry.

This extraordinary berry was the outcome of
a series of experiments in which the red and
yellow raspberries were variously combined with
the dewberry.

In the first generation of these hybrids, nu-
merous red berries and black berries were pro-
duced, but no yellow ones. A large proportion
of the red varieties followed the raspberry in
general characteristics except in form, but some
of them acquired the high flavor of the dewberry
combined with the aroma of the raspberry.

Most of the seedlings of this first generation
resembled the wild dewberry in habit of trailing
along the ground. Yet there were some that
favored the raspberry, standing upright. In
flavor many were a good combination of the two
parents, but the variation was not pronounced in
this respect. Some were highly flavored while
others were quite insipid, and between the two
were all gradations. Variations in size and
shape were equally marked.

THE RASPBERRY 253

Most of these seedlings were quite productive,
but no one plant was sufficiently valuable to
warrant its introduction as a new variety worthy
of cultivation.

Berries were gathered, however, from the most
promising of the dewberry-raspberry hybrids.
Among the second-generation seedlings thus pro-
duced was one that was of different caliber from
all the rest as shown by the character of its fruit.

No such berries were perhaps ever seen before
as those that grew on this second-generation off-
spring of the Cuthbert raspberry and the Cali-
fornia dewberry.

Some of the berries were an inch and a half
long and an inch in diameter. They were a dark
rich crimson color, slightly downy, and glossy.
In flavor they combined the qualities of rasp-
berry and blackberry, both flavors seeming to be
intensified. In a word, the fruit was a blend be-
tween the fruits of the parent races. It was a
new variety so markedly distinct from either
parent as to justify the designation of a new
species.

The new berry was originally called the Hum-
boldt, but was subsequently rechristened the
Phenomenal by the purchaser.

The new fruit was not altogether unlike the
loganberry, which was an accidental hybrid dis-

254 LUTHER BURBANK

covered by Judge J. H. Logan on his place near
Santa Cruz, which was believed to be a hybrid
between the red raspberry and the California
dewberry. But the Phenomenal is far superior
in size, quality, color, and productivity, and it is
gradually displacing the loganberry.

Unfortunately the two are sometimes con-
founded, and unscrupulous dealers have been
known to sell the loganberry under the name
Phenomenal.

The new fruit, like most other plant develop-
ments— the Burbank plum, the Wickson plum,
and the Pineapple quince, for example — was not
fully appreciated for about ten years. But it is
now a standard berry on the Pacific Coast, and
as far as possible it is being introduced in other
regions wherever it will thrive. As already noted,
it is probably the largest of all known berries.
As a fruit for market or home use for diying
and canning it is of the first importance.

From the standpoint of the plant developer
the Phenomenal is of additional interest because
of its almost exact combination or blend of the
qualities of its parents.

I have raised numerous seedlings from the
Phenomenal, but up to the present have found
none that quite equals it in all its excellent quali-
ties, though, like the Primus, it is a fixed new

THE RASPBERRY 255

species, the seedlings not reverting to either
parent form. The new berry has also been used
as seed parent in a number of crosses with other
blackberries and raspberries, and some thousands
of seedlings thus produced are now under ob-
servation.

Among these hybrids great variations will, of
course, occur, and while nearly all will undoubt-
edly be of inferior quality, I have confidently ex-
pected to find at least one that surpasses even
the Phenomenal; and now this expectation has
been fully realized in a new very sweet variety
which will later be introduced.

Other Perfectly Balanced Hybrids

Hybridizing experiments of almost equal in-
terest, even if not quite so striking in results,
have been made between the various raspberries
and the Lawton blackberry.

The Lawton is a very prepotent parent in
these crosses, and its characteristics will almost
invariably be found to predominate. Even the
pollen of the Lawton when applied to the rasp-
berry more often produces the Lawton type of
berry than any other type. But in exceptional
instances I have produced Lawton hybrids in
which the prepotency was not so strongly
manifested.

AN INTERESTING HYBRID

The fruit here shown is a cross
between the yellow Golden Queen rasp-
berry and the Lawton blackberry. It
possesses qualities of both blackberry
and raspberry. When blackberry-rasp-
berry hybrids are picked, it is not
unusual for them to bring away the
receptacle with the fruit, like a black-
berry, if they are not quite ripe; and to
leave the receptacle, like a raspberry,
if entirely ripe. Few experiments have
greater scientific interest than those in
which the raspberry and blackberry
have been hybridized.

THE RASPBERRY 257

Such was the case, for example, with a cross
between a yellow raspberry known as the Golden
Queen and the Lawton. This produced a
hybrid so well balanced that no one who saw it
could tell whether it was a raspberry or a
blackberry.

Numerous seedlings of this hybrid strain were
raised, and in the second generation the qualities
of the hybrid were reproduced, as in the case of
the Primus berry and the Phenomenal. No
variation occurred such as is usual in the second
generation of most hybrid blackberries and
raspberries.

The bushes had prickles that were short and
stout instead of long and slender as in the rasp-
berry. The leaves also had the rough, ribbed
appearance of the blackberry.

The berries would cling to the receptacle (a
blackberry trait), or part from it (a raspberry
trait), according to ripeness. As to color, there
were both red and yellow varieties among the
hybrid plants. The flavor of the berries was not
exceptional, but in some other similar crosses
made at a later period the fruit was in some cases
greatly superior in quality to that of either of
the parents.

Still greater interest attaches, perhaps, to a
hybridizing experiment in which the parents were

9 — Vol. 4 Bur.

258 LUTHER BURBANK

Shaffer's Colossal raspberry and the Crystal
White blackberry.

Some of the plants from this cross were of the
most treelike proportions. Most of them, how-
ever, were barren, though they bloomed freely.
But there were exceptional ones that fruited, and
selected seedlings were grown from these through
a series of generations. In the fourth generation
a plant appeared which was of such extraordi-
nary characteristics that it was given the name
of Paradox.

This plant was in all respects a most perfect
combination of the two ancestral forms from
which it sprang. The wood, bark, leaves, blos-
soms, prickles, roots, and seeds could not by any
test be proved to be like one or the other. The
fruit, produced in abundance, was an oval, light
red berry of good size, larger than that of either
progenitor, and of fair quality.

Many of the first generation descendants of
the Paradox were partially barren, though
blooming freely. Sterility as to fruit was often
associated with gigantic growth.

But some of the seedlings were fertile, and
they manifested almost every possible combina-
tion* of qualities of the raspberry and blackberry.
Some were similar to the Paradox, except that
they had white berries instead of red.

THE RASPBERRY 259

By saving seeds from the white and the
red varieties separately, I found that they
bred true, each constituting practically a fixed
species.

As to the vines themselves, there is very little
variation, the canes and foliage presenting an
exact balance between the raspberry and the
blackberry.

The berries are not of great commercial value,
as the fruit, though large, is soft. I hope, how-
ever, to harden the berry by selective breeding,
and introduce a better flavor.

Although this hybrid progeny of raspberry
and white blackberry may ultimately have com-
mercial importance, it is chiefly prized for the
scientific significance of its revelations.

Descended as it is from a cross between the
raspberry and the blackberry, it constitutes a
fixed species differing radically from every other
Rubus known.

So in this regard the Paradox takes its place
besides the Primus and the Phenomenal berries
as offering an impressive object lesson in the pro-
duction of new species by hybridization. Let it
be recalled, however, that the Primus was a first
generation hybrid, whereas the Phenomenal ap-
peared in the second generation, and the Para-
dox in the fourth.

260 LUTHER BURBANK

There has been occasion in an earlier chapter
to tell of hybridizing experiments in some re-
spects even more curious, in which the raspberry
was fertilized with pollen of the strawberry.
These experiments will be further examined in a
later chapter, with reference to the interpretation
of the observed phenomena of hybridization of
the various brambles.

But perhaps no comment could greatly add to
the impressiveness of the simple recital of facts
as to the production of new forms that, according
to all botanical standards, rank as distinct fixed
species, through the purposeful blending, under
the hand of the plant developer, of the germinal
strains of the various blackberries and rasp-
berries.

The chances of obtaining results
in plant improvement are directly
proportionate to the number of ex-
periments tried; and a hundred
thousand experiments may be con-
ducted as simply as a few.

DESIGNING A STRAWBERRY

TO BEAR THE YEAR

AROUND

And Other Work with Strawberries

A PLANT enthusiast was explaining the
functions of plant life one day to that
most appreciative and stimulative of all
audiences, a company of school children.

He had told of the supreme importance of the
seed — how nature must first and foremost think
of that, because it is the link between successive
generations of plants ; the only means of assuring
a continuance of the race. To bring the illustra-
tion home, he had said that the seed is the very
heart of the plant.

A little miss who had absorbed every word
with the eager receptivity of the child mind
looked up quickly as he finished and said:

"Then the strawberry is a plant that wears its
heart on its sleeve, isn't it?"

It is only the imagination of children — or of
the chance individual here and there who remains

261

262 LUTHER BURBANK

a child all his life and whom therefore we term a
poet — that can sound the depths of a great sub-
ject with a single phrase like that.

"The plant with its heart on its sleeve."

That is the strawberry. Cowering, timid,
nestling among the grasses, seeking obscure cor-
ners, retiring as far as it may from observation —
and wearing its heart on its sleeve !

The strawberry, it must be recalled, is own
cousin to the peach and plum, the apple and
pear, the rose, the blackberry, and the raspberry.
But where these raise their heads into the air and
hold out their flowers and fruit to the inspection
of all the world, the strawberry has taken to earth
and become a creeper.

Yet whereas the other fruits shield their seed
always with pulp of the fruit, and some of them
even inclose it also in armor plate shells, the
strawberry puts its seed on the very outside of
the fruit, where they will inevitably be eaten by
any bird that so much as pecks at the fruit itself,

Hence the pertinency of the little girl's
characterization.

The Odd Custom Explained

But, of course, there must be an adequate
reason for the curious conduct of the strawberry.
A plant does not depart from the traditions of

THE STRAWBERRY 263

its ancestors and take on new and strange cus-
toms unless it finds advantage in so doing. The
case of the strawberry is no exception. That this
plant is admirably adapted to its environment,
and for that matter to environment of great
diversity, is shown by the fact that strawberries
of one species or another grow in regions as
widely separated as Patagonia and Norway and
Alaska.

And that the anomalous character of its fruit
has very distinct advantages is evidenced by
the fact that in all the diversified regions in
which it grows the strawberry holds to precisely
the same architectural scheme in the building
of its fruit.

The leaves and stems and manner of growth of
the different species may vary considerably, al-
though even here there is no very wide diversity.
But as to fruit, every strawberry of whatever
species may be instantly recognized as a straw-
berry by the most casual observer. You may
never have seen the species before, but you could
not possibly mistake the fruit for the fruit of any
other tribe of plants.

A pulpy berry with tiny seeds sprinkled over
it and only half imbedded in the pulp, like seed
on the frosting of a cake, is a strawberry and
nothing else.

A SAMPLE SEEDLING
STRAWBERRY

I have experimented very extensively
with strawberries, and this specimen is a
fair example of the results which may
be expected from seed of the best
varieties.

THE STRAWBERRY 265

Almost every other fruit has counterparts that
suggest close relationship. Peaches and necta-
rines, apricots and plums, apples and quinces,
oranges and grapefruit, lemons and limes, black-
berries and raspberries, watermelons and musk-
melons — these and sundry other fruits seem to go
in pairs, as it were. They show the result of
nature's constant tendency to experiment and to
find new ways of doing the same thing, each
method reasonably well adapted to its purpose.

But when the scheme of the strawberry had
been perfected, it would seem that it must have
proved so very admirable that there was little
chance to improve upon it and no occasion to
vary from it. Hence strawberries are quite in a
class by themselves from the botanical stand-
point, just as they are from the gastronomic
standpoint.

In admitting this, it does not follow that we
must agree with the enthusiast who declared, not
long ago, that the strawberry is the one fruit that
is past all improvement.

We shall urge in a moment that there is still
very much to do before the strawberry can be
considered a really perfect fruit from the stand-
point of the consumer. It can be made, and
should be made, to give up its seeds altogether,
for example.

266 LUTHER BURBANK

Now that it has come under man's protection,
it does not need the seeds, any more than the
pineapple and the banana need them.

Aforetime it placed the seeds on the very out-
side, where they would necessarily be eaten by
any bird or animal that tasted the fruit, because
it was imperative that the seeds should find means
of transportation in order that the race of straw-
berries might spread and inhabit the earth.

The plant that cowers close to the ground can-
not depend in the least degree on the wind or any
other inanimate agency to transport its seeds. It
must look to birds and animals to aid in this
direction.

So the strawberry sprinkled its seeds on the
outside of the fruit, having first taken the precau-
tion to cover the inconspicuous seeds themselves
with an altogether indigestible shell of cellulose.

The subterfuge served the little plant ex-
tremely well, as its wide range of wanderings and
secure foothold in diverse soils and varied
climates sufficiently attests.

The Seeds No Longer Needed

But now, as was said, this expedient is no
longer necessary. Men will take good pains to
see that the strawberry is abundantly propa-
gated. And as such propagation may most

THE STRAWBERRY 267

advantageously be made through the agency of
roots and runners rather than with the seed, there
is no longer any necessity whatever that the seed
should be retained. There are a good many
scores of them on a single fruit; and the draft on
the energies of the plant required to produce this
large quantity of concentrated germinated mat-
ter must be very marked.

So when the strawberry has been induced to
give up the seed-producing habit altogether, de-
voting its fruit energy to the production of the
juicy pulp of its unique product, the plant itself
will advantage by the change, while at the same
time gaining added favor with the fruit lover.

Nothing has hitherto been done toward reliev-
ing the strawberry of its seeds, because hitherto
the plant developer has been more concerned to
increase the fruit itself and has given small
thought to the seeds or has ignored them alto-
gether.

But the briefest inspection of different straw-
berries will show that they differ a good deal as
to relative abundance of seed; and there is no
reason to doubt that the plant developer who
undertakes this selective breeding with an eye to
the preservation of plants that show a tendency
to minimize the seed product, will gradually
develop a race of seedless strawberries.

268 LUTHER BURBANK

It appears to be quite the rule that plants
habitually propagated by root division or by root-
ing stalks or runners tend to lose their power of
seed production when long thus cultivated. The
pineapple, the banana, the sugar cane, the horse-
radish, and the potato, have been previously re-
ferred to in this connection.

All of these, as is well known, are propagated
by the cultivator without the use of seed, and it
is only under the most unusual conditions that
any one of them nowadays produces seed at all.

I took occasion to emphasize this fact once in
a lecture by saying that I would very willingly
pay a thousand dollars an ounce for horseradish
seed. The joke went the rounds of the papers
and hundreds of people all over the country
watched their horseradish plants the ensuing sea-
son with an idea to gaining the prize.

Needless to say no one has yet produced the
ounce of seeds, or any fraction thereof.

Of course there are certain disadvantages that
will attend the entire giving up of the habit of
seed production.

It is not that the plant propagated exclusively
from the roots, buds, grafts, or cuttings degen-
erates, as was once thought to be the case. In
reality there seems to be no limit to the number
of generations through which a plant thus propa-

THE STRAWBERRY 269

gated by division may maintain its original stand-
ards of quality. The familiar cases of the orchard
fruits sufficiently support this belief. It may
even be possible to improve a plant slightly by
selection when propagated solely in this way.

But, on the other hand, it is obvious that the
plant that gives up the habit of seed production
renounces the possibility of benefiting by the in-
troduction of new strains through hybridizing —
a process, as we have all along seen, that is the
principal means through which plant evolution is
brought about.

So, as regards the strawberry, it will be desir-
able to make sure that we have developed fruits
to approximate perfection before we induce it to
give up the habit of seed production altogether.

It can hardly be claimed that the strawberry
has reached this stage of development, notwith-
standing the verdict of the enthusiast already
quoted. But, on the other hand, it must be ad-
mitted that the best varieties of fruit approach an
ideal standard rather closely. And when we re-
call that the development of these almost perfect
varieties has taken place rapidly and within com-
paratively recent times, it seems a fair conclu-
sion that it will be possible to complete the
perfection of the fruit in other directions in less
time than it will take to remove the seeds.

AN ALL-SUMMER BEARER

One of the new strawberries which
blossoms and bears all summer. This
tendency to bear continuously possibly
results from the blending of the heredi-
ties of species from the Northern and
Southern Hemispheres. (About one-
third life size.)

THE STRAWBERRY 271

So the plant experimenter who would under-
take the task of eliminating the seeds from the
strawberry need not hesitate for fear of succeed-
ing too soon. Unless nature should produce a
chance sport that is without seeds, or nearly so,
somewhat like the nearly stoneless plum, the task
of removing the seeds of the strawberry by mere
selection would prove an arduous one.

Yet it can doubtless be accomplished; and the
game is thoroughly worth the candle.

Origin of the Cultivated Strawberry

Partly because all strawberries are so much
alike, it has been unusually difficult to trace the
origin of this fruit. But it is known that the
modern varieties have been developed in a period
of not more than two centuries.

The strawberry has indeed been under cultiva-
tion for an indefinite period. But the ancients
were doubtless content, as we know that the
moderns were until a few generations ago, with a
small berry scarcely superior to the ones that
grow wild in many regions of America. The sys-
tematic cultivation of the fruit began in England
after new species of strawberry were introduced
from North and South America.

But the really notable progress did not take
place until the South American species known

272 LUTHER BURBANK

as Fragaria Chiloensis was introduced early in
the eighteenth century from Chile.

Nor indeed was there any immediate improve-
ment from the introduction of this fruit. But
about the year 1760 a new variety suddenly
appeared that was called the Pine strawberry
because its fragrance suggested that of the pine-
apple. There was no record as to its origin, but
the best authorities argue with good reason that
it was a hybrid between the Chilean strawberry
and the American species introduced much earlier
from Virginia.

As usually happens when different species are
hybridized, a tendency to variation was produced,
and before the close of the eighteenth century
there were two important types of new straw-
berry of the Pine variety, one of which was
named by the botanist Fragaria ananassa and
the other Fragaria grandiflora.

It is argued with plausibility that these are
modified forms of the South American straw-
berry introduced from Chile, the precise share of
other species in the combination not being per-
haps clearly established.

The most popular modern varieties of straw-
berries are the descendants of this so-called Pine
stock, the most notable impulse to the develop-
ment of new varieties having been given through

THE STRAWBERRY 273

the introduction of Keen's seedling in England
in 1821 and Hovey's seedling in America in
1837.

Subsequent development has come about
through the usual method of crossing and selec-
tion. Of course, many varieties, differing in such
minor details as the production of runners, re-
sistance to fungus attacks, and precise qualities
of the fruit have been devolepd. Different races
also show a diversity as to manner of flowering,
certain varieties bearing pistillate flowers, just
as the California dewberry does, whereas others
bear perfect or bisexual flowers, as is custom-
ary with the members of the rose family in
general.

But these are minor differences; and, as we
have seen, the strawberry type in all its essentials
has been marvelously maintained from first to
last. Now as always this fruit is unique and
curiously isolated.

Hybridizing Experiments

My own experiments with the strawberry have
been carried out on rather expansive scale,
although I have given by no means as much
attention to this fruit as to many others.

I have crossed all the familiar cultivated varie-
ties, and in addition have made hybridizing ex-

EVERBEARING STRAWBERRIES

The strawberry has been under culti-
vation for an indefinite period, but it is
only in comparatively modern times
that any such berries as those here
shown have been grown. The ancients
were doubtless content, and the mod-
erns were also, until a few generations
ago, with a small berry not greatly
superior to the ones that grow wild
in many regions of America, The
ever-bearing strawberries are a new
production. (One-half life size.)

THE STRAWBERRY 275

periments in which numerous wild species, some
of them imported from distant regions, have had
a share. I have, for example, commingled the
strains of the best varieties of the cultivated
strawberry with those of strawberries from Nor-
way and from Alaska, and the native Chilean
species, as well as with various wild species of
our own.

I have also attempted to hybridize a species
from India, the Fragaria indica, with other
strawberries, but have been unsuccessful. It does
not by any means follow that this cross cannot be
effected. But it is perhaps not worth while to
devote an undue amount of time to the experi-
ment, as the qualities of the Indian species are
not such as make it certain a hybrid thus pro-
duced would have any value, except possibly as
introducing a tendency to variation.

The Indian plant bears a small, insipid
berry, and is cultivated for ornamental pur-
poses only.

There are various wild strawberries growing
along the Pacific Coast that offer interesting pos-
sibilities of hybridization. It is rather interest-
ing to know that some of these are of the same
type with the Chilean species that has already
been named as the chief progenitor of the culti-
vated strawberry.

276 LUTHER BURBANK

One of these, known as the sand strawberry, is
quite common along the coast, especially in the
northern part of California.

This is a plant with large, woolly leaves. It is
greatly inclined to produce runners. It fruits
sparingly, but the berries themselves are sweet
and of fine flavor. There is great variation as to
foliage and flowers, as well as in capacity for
fruit production.

The variation is best explained by assuming
that this strawberry is itself a natural hybrid.

Another California strawberry that has in-
terest is the wood strawberry, Fragaria cali-
jornica, a plant that usually has small leaves,
rather upright in growth, and producing fruit
abundantly, though the fruit itself is insipid and
hardly worth gathering.

This plant also varies widely in different
localities. In the Yosemite Valley I found a
most astonishing variation in these as well as in
other strawberries. Some of the wild varieties
growing there were fully equal to the cultivated
strawberry, while others were insignificant to
the last degree.

Some of the plants grew strictly upright;
others had leaves that hugged the ground and
spread in all directions. There was a wide range
of variation as to form, size, foliage, and fruit.

THE STRAWBERRY 277

This was quite the most interesting group of
wild strawberries that I have come across any-
where. But these plants do not seem to thrive
in the valleys as they do in their mountain home.

As to the latter point, there is a striking pro-
pensity on the part of certain strawberries to
degenerate when placed under changed condi-
tions of soil and climate.

We have seen that plums and many other
plants are stimulated to exceptional growth by
precisely such a change. But when the most
promising wildlings from the Yosemite were
transplanted to my gardens they ran to vines
and produced very little fruit, although in their
native habitat they had borne abundantly.

The experience was precisely the same with
certain strawberries that were sent from Alaska
and from Norway, and in many of those from
Chile. When the Alaskan vines came to me,
through the kindness of the captain of an
Alaskan steamer, they were in full bloom and
later supported an abundance of splendid
berries. But under cultivation in my grounds
they failed to produce fruit, but persisted in
making runners only. The new soil and climate
which had proved such a stimulus to Japanese
plums and New Zealand rhubarb and European
daisies, and almost countless others, proved a

ANOTHER PERPETUAL
VARIETY

In form and color these berries re-
semble pretty closely those shown in the
preceding plate. They differ markedly,
however, in flavor. Like the others,
they are of mixed ancestry, blending
the strains of berries from two hemi-
spheres. This variety bears luscious
fruits all summer, and all winter, too, in
a greenhouse. (One-half life size.)

THE STRAWBERRY 279

handicap to the Alaskan strawberries. The
new environment was not adapted to their
constitution.

I have often had the same experience with
other plants, including certain varieties of cur-
rants, blueberries, huckleberries, and raspber-
ries, as well as maples, beeches, hickories, and
other trees and plants from the eastern United
States, Canada, Alaska, and other northern

climates.

New Hybrid Varieties

But, of course, there are many other species
and varieties that have shown no such antipathy
to the conditions we had to offer, and I have pro-
duced large numbers of crossbred strawberries
from various importations that have prospered.

In the course of the past forty years I have
probably grown and fruited strawberry seed-
lings to the number of more than half a million ;
and among these have appeared some varieties
that have had qualities of a high order, yet
among them all I have not until somewhat
recently secured one that was thought in all
respects superior to some existing variety.
Therefore, none of these were introduced. Ten
or twelve years ago I had one that was nearly
perfect but which proved to be a poor keeper
and therefore not suitable for the market.

280 LUTHER BURBANK

But more recently, as the strawberry strains
became blended, varieties have been produced
which not only excel in quality but also have
the highly desirable characteristic of persistent
bearing.

The new strawberry has been developed
through hybridizing stock that had among its
ancestors such well known varieties as Long-
worth's Prolific, Brandywine, Monarch, and the
Arizona Everbearing, and one or two varieties
from Texas.

The later hybridizations, through which the
perfected strawberries were finally secured, have
involved crossing the Chilean strawberry with
the small wild white strawberry from Virginia
and with the wild Pacific Coast strawberries.

From these two lines of hybrids I have ob-
tained the only seedlings that have been thought
worthy of introduction.

The paragon of these is a plant of vigorous
growth which makes just the right number of
runners, and which has a healthy, thick, dark
green foliage. The fruit is borne in clusters
well up from the ground, and is delicious in
quality, I confidently believe, beyond any straw-
berry before known.

This has been the universal verdict of those
who have tasted the fruit of this complex hybrid

THE STRAWBERRY 281

When John Burroughs visited my farms, for
example, he unhesitatingly pronounced this
strawberry the finest in the world. So great
was his enthusiasm that he wrote to eastern
seedsmen, advising them to secure this straw-
berry, as everyone would soon be wanting it.

The fruit of this hybrid is not extraordinarily
large, but it is firm in texture, of a fine crimson,
and unlike most other strawberries it has a
yellow flesh. Its lusciousness and deliciousness
of flavor will give it a place apart even among
the most select varieties of the fruit.

But quality of the fruit is not the only merit
of the new hybrid. The plant has also, as just
intimated, the singular and important quality
of bearing fruit throughout the whole summer.

The main crop comes at the usual time for
strawberry ripening, but berries continue to
ripen, even if less profusely, month after month,
until the frosts of winter arrive.

Doubtless this habit of perpetual bearing is a
trait brought out by the mingling of so many
racial strains ; in particular by the union of races
from the two hemispheres. The summer of Chile
is of course our winter. I have several times
adverted to the confusion that seems to overtake
many plants when brought to our northern lati-
tudes from the Southern Hemisphere.

YET ANOTHER HYBRID
VARIETY

Were it not for the marked difference
in the leaves, one might think this bunch
of berries of the same variety as the
ones shown on the preceding plate.
They are, however, very different,
although of the same ancestral strain.
They represent the segregation of char-
acters in later generations, of which
we have seen so many illustrations.
Btit with the strawberry, the characters
referred to concern the texture and
flavor rather than form and exterior
color. (One-half life size.)

THE STRAWBERRY 283

The case of some of the New Zealand apples,
which were confused as to time of bearing for
two or three years after being imported, will be
recalled.

Also in the case of the winter rhubarb,
which came to be a perpetual bearer partly
perhaps through the influence of such trans-
plantation.

The new hybrid strawberry, which combines
ancestral strains from the two hemispheres, fur-
nishes another illustration of the tendency to
retain ancestral habits as to time of fruiting,
and thus, where parents from both hemi-
spheres are involved, to develop among some
of their seedlings a new habit of perpetual
bearing.

It will probably be possible, by further selec-
tion from the new race of all-the-summer-
bearing strawberries, to extend their time of
fruiting, as was done with the winter rhubarb,
until they bear throughout the year in any
climate where the winters are sufficiently mild

New Varieties in the Making

Other novelties that have developed among
the progeny of the company of widely hybrid-
ized strawberries include constant producers
and enormous producers that as yet lack

284 LUTHER BURBANK

some other quality which will presently be
supplied.

I have also a white strawberry, grown from
a variety that I grew in my childhood back in
Massachusetts, and which was said to have come
from Virginia.

By hybridizing this species a few promising
white strawberries have been produced with new
and delicious flavors. Second generation seed-
lings in great numbers are being raised, and
interesting results are sure to be attained in the
near future.

This strawberry stock, like my stock of plums
and some other fruits, now consists of complex
hybrids from which almost anything may be
expected. At least it is certain that new com-
binations of qualities, within the extreme range
of strawberry variation, will appear among the
seedlings of these conglomerate yet carefully
nurtured and selected stocks.

Summarizing my work on this fruit, I would
say that selections have been made primarily for
flavor rather than for size and color. I thought
that a good home strawberry that is tender,
sweet, and of fair size rather than of exaggerated
proportions, combining these qualities with the
exquisite flavor of some of the wild berries,
would be a distinct acquisition.

THE STRAWBERRY 285

The varieties already in the market were many
of them of enormous size, but for the most part
they lack flavor.

Anyone who has known the small wild straw-
berry at its best must always experience a cer-
tain disappointment in eating the cultivated
varieties.

Moreover, most of our market strawberries
are hard, being judged by the growers and the
dealers by their shipping quality rather than by
their flavor.

It seemed desirable, particularly for home
use, to develop the strawberry for its appeal
to the palate as well as to the eye; in other
words, to restore to the fruit something of its
pristine flavor, while retaining the good quali-
ties introduced in recent times by selective
breeding.

Such an endeavor to improve the flavor of
the fruit, combined with the idea of all-the-year
bearing and ultimately of seedlessness, may be
said to suggest the lines of improvement along
which the plant developer of the immediate
future should work in perfecting the strawberry.
But the production of the seedless strawberry,
as already pointed out, must be the final stage
of the process of development. When the seeds
are gone, there will obviously be no further

286 LUTHER BURBANK

opportunity for improvement by selective breed-
ing, with or without hybridization. But long
before the seeds are bred out, we shall doubt-
less have many varieties of strawberries that
approach perfection as to all other desirable
qualities.

Nature has done much for the
luscious strawberry, but there is
still as much or more for us to do.

THE SUNBERRY-A PRODUC-
TION FROM THE WILD

A New Food Plant from the
Potato Family

SUPPOSE that you had been trying for
twenty-five years to effect a certain pur-
pose— say the cross-pollenizing of a par-
ticular pair of species of plant.

Suppose that year by year your efforts had
met with total failure; but that finally, just as
you were on the point of giving the matter up
as hopeless, you were to attain success.

Doubtless under these circumstances you
would be somewhat elated over your achieve-
ment, the result of so much effort.

Suppose, then, further, that the plant that
grew from this hybridization, achieved with sucl;
infinite difficulty, proved a producer of a valu-
able new fruit. Suppose that the fruit met with
almost immediate recognition, and that the plant
was widely introduced and attained exceptional

popularity.

287

288 LUTHER BURBANK

And then, finally, suppose that some one
should come along and decry the fruit, not be-
cause of its lack of merit, but because the parent
plants from which the hybrids grew belonged to
a family of poisonous plants.

Suppose the hue and cry thus raised should be
given an element of plausibility by the fact that
some unscrupulous person had sold to gardeners
a plant of a different species from either of the
parents of your hybrid, yet of an allied race,
and had claimed that this plant, which bears a
fruit of doubtful edibility, is identical with the
one you had introduced.

Suppose all this, I say, and then try to
imagine just what would be your attitude of
mind toward the work you had accomplished on
one hand, and the persons who — not always for
the best motives or without prejudice — were its
traducers.

The Sunberry and Its Critics

In suggesting this I am only asking you to
put yourself in my place and imagine what must
be my natural attitude of mind toward one of
the most celebrated, and without doubt the most
berated, of all my plant productions — the fruit
which I named the Sunberry, and which the
dealer to whom I sold it rechristened — without

THE SUNBERRY 289

my consent and much against my wishes — the
"Wonderberry."

For the supposititious case that I have just
outlined really summarizes the facts as to the pro-
duction and introduction and traduction of that
fruit.

The Sunberry, far from being merely a
familiar form of Solanum introduced under a
new name, as some ignorant and misguided
critics have alleged, is in reality the product of
one of the longest and most persistent series of
experimental hybridizations, culminating in the
blending of two specific plant strains that had
seemed to be antagonistic beyond the possibility
of amalgamation.

The parent plants themselves, though they
no doubt belonged to a poison-bearing family,
like the egg plant, tomato, pepper, were not
in themselves poisonous. And the fruit of
their hybrid progeny is not only palatable
in high degree, but altogether wholesome, as
thousands who have eaten it habitually could
testify.

Let me quote a paragraph from a letter re-
cently received, by way of substantiation, and
then let me turn from this controversial aspect
of the subject to consider the story of the Sun-
berry itself:

10— Vol. 4 Bur.

SUNBERRIES

This is in some respects one of the
most remarkable, and unquestionably
the most maligned, of fruits. It resulted
from a hybridization of two Solanums
effected after years of unsuccessful
efforts. It was named "Sunberry,"
but was subsequently rechristened the
"W onderberry " quite against my will,
by the dealer who purchased and intro-
duced it. It has been fiercely assailed,
largely because it was foolishly con-
founded with a quite different species
of Solanum; notwithstanding which it
has made its way in the fruit garden,
and is destined to be far more popular
than ever, and is now grown every-
where. (One-half life size.)

THE SUNBERRY 291

"I have grown the Sunberry for the past three
years," says a college professor who is an
amateur gardener. "We have used the berries
for sauce, cobbler, and pies — principally for pies.
Some were eaten raw from the vines. For me
the pie is the one great way to use the berry.
Without exception I place a Sunberry pie at
the head of the pie list, and I do this with a full
appreciation of the excellence of cherry pie,
apple pie, pumpkin pie, mince pie, blueberry
pie, etc.

"I think it hardly does the Sunberry pie jus-
tice to compare it to blueberry pie. They have
much in common, but the Sunberry is richer.

"I have never kept account of the yield, nor
tried for a large yield. I have a small strip of
ground, eight by sixty-five feet, which gave us
a pie each day from early August until frost
usually about November 1st, and left us a
surplus of forty to fifty quarts to can for
winter use."

So much for the fruit itself. Then touching
on the other aspect of the subject, the writer
continues :

"There has been much criticism here, some of
it the most senseless stuff I ever heard outside
of an asylum, and most of the extreme criticism
by those who never grew the plant. One man

292 LUTHER BURBANK

an attorney, planted some Sunberries and pulled
them up because they looked like nightshade. I
completely converted him by sending him a pie."

In conclusion, the writer goes to the heart of
the matter when he saj^s: "I think much of this
criticism was originally due to some very unfair
articles that got copied and were thus spread
somewhat generally. As far as I can judge,
the original article was written out of pure
malice. I can account for it in no other
way."

These quotations will perhaps serve suffi-
ciently to suggest the quality of the Sunberry,
and to suggest also the animus of the criticism
that has been directed against it. It seemed
necessary to advert to this aspect of the matter
because a fair proportion of the people who have
heard of the "Wonderberry" at all have heard
only words of condemnation.

Moreover a large proportion of the people
who think they have seen or grown this fruit
have in reality never seen it.

Whoever supposes that the true "Wonder-
berry," or Sunberry as I shall always call it, is
identical with the ordinary nightshade is labor-
ing under an illusion that might readily be dis-
pelled by inspection of the respective plants
themselves.

THE SUNBERRY 293

And whoever doubts that the true Sunberry
is an appetizing fruit and a valuable addition
to the list of table berries might readily be con-
vinced, had he some neighbor to make the
demonstration suggested by our correspondent,
through sending him a Sunberry pie.

But let us forget all controversial aspects of
the subject and make inquiry as to the origin
of the new fruit.

The Nightshade Family

I have elsewhere referred to my interest in
the members of the nightshade family, or, as
the botanist calls them, the Solanacece.

The fact that the potato, with which my first
experiments in plant development were made,
belongs to this family would naturally give me
an interest in the tribe. But I was particularly
attracted also because of the diversity of charac-
teristics among the almost innumerable and very
variable members of the family.

Here, on one hand, are the potato, the tomato,
and the egg plant, ranking among our most
highly important garden vegetables, and the
strawberry-tomato or ground cherry among the
minor vegetables that have a good share of popu-
larity; and, on the other hand, closely related
species are bearers of the most powerful nar-

294 LUTHER BURBANK

cotic poisons, including belladonna and hyoscy-
amus, drugs that have an accepted place in the
pharmacopoeia.

Add that the tobacco plant is another member
of the family, and it is clear that this is one of
the most curiously versatile, and, from a human
standpoint, one of the most important of all the
plant tribes.

My interest in the family extended beyond the
familiar plants just named, and included several
species of nightshade that are chiefly known as
roadside weeds and bearers of berries some of
which are eaten on occasion by country folk, but
which in the main have a bad reputation, some
of them being accounted highly poisonous.

The name "deadly nightshade," applied to one
of the most familiar species, suggests the repute
in which these weeds are commonly held.

Yet it is known to the residents of some
country districts, particularly in the Mississippi
Valley, that the little black berries of the night-
shade, if thoroughly ripe, may be made into pies
and eaten with at least relative impunity. It is
only in lieu of any fruit of more acceptable char-
acter that anyone would be likely to make the
experiment, however, as the distant relationship
of the plant to the deadly nightshade, Atropa
belladonna, and the henbane, Hyoscyamus

THE SUNBERRY 295

niger, from which well-known poisonous drugs
are obtained, is at least vaguely recognized,
and the plants as very generally held under
suspicion.

Nevertheless, the potato, the tomato, the
egg plant and numerous other well-known semi-
tropical fruits may be cited as affording a con-
vincing demonstration that there is great merit in
the family, even though one were to dispute that
the tobacco could legitimately be put in evidence
in the same connection. And, for me at any rate,
there was interest in the knowledge that at least
two species of Solarium were available for ex
perimental purposes that were not under sus-
picion as to the production of poisonous fruit,
however lacking in attractive qualities their prod-
ucts might be.

Progenitors of the Sunberry

One of the solanums in question is a rather
large plant known botanically as Solarium
guinense, which found its original home in
Africa, but which has been known for a genera-
tion or so in this country, and is sometimes
referred to as the "garden huckleberry."

The other is a smaller species, known as Sola-
rium villosum, which was indigenous to Europe,
but which is said to have been accidentally intro-

296 LUTHER BURBANK

duced to California many years ago from seed
mixed in the ballast of a ship. This chanced to
be thrown out where it had opportunity to estab-
lish itself.

The African plant is a strong and heavily
fruiting shrub, growing about two feet high on
good soil, and spreading to be about three feet
in diameter.

It produces large black berries in clusters that
stand upright, and that, in the case of some
varieties, are nearly as large as cherries. The
fruit is not unattractive in appearance and, as
already noted, attempts have been made to intro-
duce it as the "garden huckleberry." But such
attempts have met with small measure of suc-
cess for the very excellent reason that the berry
is practically inedible.

I have tested it often, and have always found
that one berry is more than any person is willing
to eat, and I have never known a person who
could be induced the second time to attempt to
eat this so-called "garden huckleberry," the taste
being most villainous.

The plant is indeed somewhat closely related
to the black nightshade, Solatium nigrum, the
American species that is common everywhere,
one form of which, known as the stubbleberry,
is said to be poisonous, especially if eaten by

THE SUNBERRY 297

children in large quantities when not fully ripe,
although fairly palatable when cooked.

The stubbleberry in one or another of its
varieties has been used for cooking, in all coun-
tries where it grows, when fruit is scarce, chiefly
to make pies, as well as for canning. But it is
necessary to have the fruit fully ripen; which is
often accomplished in cold climates by spreading
the berries thinly on shelves and allowing them
to mature slowly.

In some regions, as in the Dakotas, the bushes
are pulled and hung in the cellar, the fruit being
used from time to time as it ripens.

In France the young shoots of this plant are
used as a green vegetable, and the plant is even
advertised in French catalogues.

The "garden huckleberry," however, differs
considerably from the ordinary French stubble-
berry, the fruit being much larger in size but far
inferior in flavor. It is, however, more nearly
free from poisonous qualities, notwithstanding
its vile taste.

The differences between the plants themselves
are marked, the Solarium guinense being, as
already noted, a rather heavy shrub, while
Solarium nigrum, though varying considerably,
is usually a slender plant. It may be said, how-
ever, that both of these species, like most other

298 LUTHER BURBANK

members of the family, show a strong propen-
sity to vary. The black nightshade in particular
takes a great variety of forms according to soil
and other conditions; each locality having its
own variety differing in minor respects from
plants of other regions.

I have gone somewhat into detail in this mat-
ter, because I wished to establish clearly the
standing of the Solarium guinense that was used
in my hybridizing experiments, and which thus
became one of the parents of the Sunberry ; and
in particular I wished to make clear that this is
a species differing considerably from the better
known black nightshade, Solarium nigrum, with
which it has by ignorant or viciously inclined per-
sons been confounded.

The other parent of the Sunberry, already
named as Solarium villosum, is a plant differing
conspicuously from either of those just de-
scribed. It is low, and tends to a spreading
growth a few inches above the ground, never
growing upright. The foliage of the plant is
pubescent or downy, accounting for its scientific
name. In this regard also it is quite different from
both Solanum nigrum and Solarium guinense.

The fruit grows in clusters of five berries that
droop characteristically and always remain
greenish in color even when ripe, whereas the

THE SUNBERRY 299

fruit of most other Solanums turns black on
maturing.

The berries are borne abundantly, and like
the tissues of the plant itself they are wholly
free from any poisonous qualities. The whole-
some nature of the plant is attested by the fact
that it is eaten freely by herbivorous animals
wherever it grows. Rabbits, cattle, pigs, and
poultry eat it with avidity.

Producing the Sunberry

Reference has already been made to the
long series of fertilizing experiments through
which I endeavored to cross the various
Solanums.

I may add that Professor Hansen, of North
Dakota, has also been interested in crossing the
two fruiting Solanums of which we are speaking,
and from which the Sunberry was ultimately
produced. But his efforts at hybridizing these
species were unsuccessful.

These details are mentioned to emphasize the
fact that the production of the Sunberry —
although, as will appear in a moment, it came
about ultimately as the result of a single success-
ful experiment — was by no means a task to be
accomplished offhand by the first person who
chose to place pollen of one flower on the pistil

300 LUTHER BURBANK

of the other. This was done season after sea-
son, seemingly with no effect whatever.

At last, however, in the season of 1905, after
I had more than once half decided to relinquish
the effort to cross these plants, my perseverance
was rewarded.

I had cross-pollenized the great African
stubbleberry, Solatium guinense, and the little
downy nightshade, Solatium villosum, as I had
done many times before, with no change or
added detail of method and for the moment I had
no reason to suppose that the efforts had been
more successful than before.

But when the seeds were sprouted in the
greenhouse, a certain dozen or more plants were
discovered that differed from any I had seen
before.

These plants were of a new type, and as they
developed it became increasingly clear that they
represented almost an exact compromise be-
tween the two parent species.

There could be no question that they were the
hybrids which were so long sought.

But the appearance of these hybrids was such
as to corroborate the belief, founded on my long
series of unsuccessful hybridizing experiments,
that the two Solanums I had finally mated were
so widely different in constitution as to stand at

THE SUNBERRY 301

the very limits of affinity within which cross-
breeding is possible.

We have discussed a number of instances in
which similar crosses have been made between
species widely separated. Such, for example, was
the cross between the California dewberry and
the Siberian raspberry, which j>roduced the
Primus berry; also that between the dewberry
and the Cuthbert raspberry, which produced the
Phenomenal berry; and that between the plum
and the apricot, which produced the Plumcot.

In each of these cases, it will be recalled, the
hybrid showed intermediate characteristics be-
tween its parents, constituting virtually a new
species, and proving its individuality by breed-
ing true to tjrpe from the seed.

It was rather to be expected, then, that the
hybrid Solarium would similarly prove its
individuality, and the expectation was fully
realized.

As the plants came to maturity, one bloomed
but failed to produce fruit. The others, how-
ever, fruited quite abundantly, some of them
profusely.

The fruit was intermediate in size between the
fruits of the parent plants. Its quality was en-
tirely different from that of either parent. It
had the flavor of the blueberry or huckleberry

302 LUTHER BURBANK

of the East, and was especially delicious when
cooked.

It differed as widely as possible from the vile-
tasting fruit of one parent and from the insipid,
tasteless fruit of the other.

It should be explained that there were only
about twenty of these hybrid plants in a large
colony of seedlings. The remaining members of.
the company were precisely similar to the mother
plant on which they grew — this being the small,
downy species, Solarium villosum — thus showing
that they were not hybrids. It is probable that
there was only a single fruit that had been
hybridized, although the foreign pollen had been
applied to many pistils.

The entire company of new hybrid Solanums
were probably produced from the seeds of a
single berry, the other berries having been quite
unaffected by the attempt at cross-pollenizing.

But it sufficed to have produced a score or so
of hybrids; I should have been delighted with a
single one, after all these years of waiting.

New Species

Naturally two or three individuals were selec-
ted from among the twenty hybrids — the ones
excelling as to profusion, size, and flavor of
berries.

THE SUNBERRY 303

The seeds of these plants were carefully saved,
and next season there grew from them a crop of
plants precisely like the parents. The progeny
of the hybrids followed their parents more
closely than the unhybridized offspring of
either of the Solanums used in the original
cross usually do.

As already noted, all species of wild Solanums
tend to vary, but the new species reproduced
itself exactly , except that a very slight differ-
ence in the flavor of the berries was barely
perceptible.

As two crops of these plants could be raised
in a season, they were multiplied rapidly, and
there was astonishingly little variation in the
size, quality, or growth of the bushes. Without
exception the plants resembled the original hy-
brid, and differed radically from either parent of
that hybrid.

It was obvious, therefore, that a new and
fixed species of Solanum had been evolved
through the hybridizing experiment. As the
reader already knows, the new plant was
christened the Sunberry.

The unwarranted change of the name from
Sunberry, the only name I ever authorized or
approved for the plant, to "Wonderberry," and
the misstatements that have gained currency re-

304 LUTHER BURBANK

garding the origin of the plant and the charac-
teristics of its fruit have been sufficiently re-
ferred to.

The true qualities of the fruit itself have
also been revealed through the quotation from
one of the many amateur gardeners who have
grown it in successive seasons and found
it a valuable addition to the list of garden
fruits.

It may be added, however, that the Sunberry
makes particular appeal because it ripens late in
the season, after most other berries have ceased
to bear. It is well to note, also, that the plant
shows the hardiness and thrift and vitality usual
with hybrids, and will often grow to better ad-
vantage on a poor soil and without much cultiva-
tion than when especial attention is given it. In
most regions, to water it is a mistake, and to fer-
tilize the soil for it an even greater one — making
the blossoms drop.

In a word, it is a plant that resents too much
petting. It retains something of the character of
its wild ancestors.

As to inherent constitution, the Sunberry is a
perennial, but it may best be grown annually
from seed, quite as its relative the tomato is
grown, although that plant also can live from
year to year in the proper climate.

THE SUNBERRY 305

As already stated, it grows true from seed
year after year, proving thus its specific individ-
uality, and differing not alone from hybrids in
general but from the greater number of our cul-
tivated fruits.

The Sunberry has unexpectedly been found
adapted to cold northern climates. In the
Alberta country, in the latitude of southern
Alaska, the Sunberry is highly appreciated,
especially as it is about the only berry that can
be raised where the thermometer often goes to
40 or even to 60 degrees below zero.

Varying Traits of Hybrids

From the standpoint of the gardener, the Sun-
berry has importance as a notable addition to the
list of small fruits.

From the standpoint of the plant developer it
may be said to have perhaps greater importance
as illustrating the possibilities of the develop-
ment of new species by hybridization — species
markedly different from, and superior to, those
from which they spring.

It is true that other experiments have been
detailed that illustrate the production of new
forms of plant life through hybridizing already
existing ones. A few paragraphs back several of
these were named — the Primus berry, the Phe-

LEAF VARIATIONS IN
A HYBRID

This very striking picture illustrates
the range of variation that may be
shown in a crossbred plant. The solid
leaf at the left resembles the California
dewberry; the leaf at the right shows
the characteristics of the Oregon ever-
green blackberry — these two being the
parental forms. The segregation of
ancestral hereditary factors is strikingly
shown in these hybrid blackberries.

THE SUNBERRY 307

nomenal berry, and the Plumcot. But in the
case of these fruits, it will be recalled, the par-
ent forms were one or both bearers of valuable
fruits. The hybrid plants improved upon their
parents, but did not show entire departure from
the traditions of their ancestral races.

But the Sunberry, as we have seen, sprang
from parent forms neither of which produced
edible fruit.

This was a union of two racial forms that were
separated almost to the point of permanent seg-
regation. The combination of hereditary fac-
tors of two distinct species from two hemispheres
developed a hybrid that differed very widely
from either parent. As it chanced, this hybrid
had qualities of fruit that gave it a new appeal
and a standing, from the viewpoint of man,
quite different from that accorded either of its
parents.

The case, then, of the Sunberry emphasizes
anew the principle that new species may be pro-
duced through hybridization, and that, provided
the parents are genetically separated just widely
enough, their offspring may show such a
blending of characters as to constitute a new
form, and to be able to transmit these characters
to its progeny in such a way as to meet the test
by which species are everywhere recognized.

308 LUTHER BURBANK

We have seen that there is possibility of hy-
bridization between forms that are a shade more
widely separated, in which case the hybrid off-
spring have the appearance of new species, but
lack fertility. Such instances were presented in
the hybrid colony of offspring of the dewberry
fertilized by pollen from the apple and pear and
mountain ash and rose; also by the hybrid be-
tween strawberry and raspberry.

These strange hybrids would clearly enough
have been entitled to recognition as new species
had they been able to reproduce themselves. But
their sterility reduced them to the rank of mules
— to make comparison with the most familiar in-
stance of an infertile hybrid in the animal world.

From these sterile hybrids the Sunberry dif-
fers fundamentally in that it is if anything more
prolific than either of its parents.

Meantime the Sunberry differs from the hy-
brids of another and more familiar type that arise
from the union of parents that are so closely
related that cross-pollenizing is easily effected
between them. Such hybrids, of which we have
seen many examples — crosses between the differ-
ent daisies, between black and white blackber-
ries, thorny and thornless briers, stone-seed and
stoneless plums, and sundry others — follow, as
we know, a characteristic line of development.

THE SUNBERRY 309

The hybrids of the first generation often resem-
ble one parent more than the other. The hybrids
of the second generation show wide variation,
some of them reverting to one ancestral strain
and some to the other, the characteristics of each
being variously segregated and recombined.

Nothing like the direct and complete repro-
duction of the characteristics of the hybrid in its
offspring, as shown by the Sunberry, is mani-
fested in the case of these familiar hybrid forms
that spring from the union of closely related
species or varieties.

What the Sunberry Teaches

All this should be borne in mind by anyone
who is prone to reduce the principles of heredity
to formulae of undue simplicity.

The new formulae of the Mendelians, for ex
ample, which have such admirable application to
many cases of the crossing of related forms —
where particular unit characters are segregated
and recombined — have no application, or to be
applied must be greatly distorted from their
original implications, in dealing with such a case
as that of the Sunberry.

Here there is no clear balancing of dominant
and recessive factors, with the overwhelming
presentation of the dominant factor in the first

310 LUTHER BURBANK

generation and the reappearance of the recessive
factor, beautifully segregated, in the second.

Instances of inheritance of that order we have
had presented again and again. We shall hear
of more of them before we are through.

But, in the meantime, let us not forget the
lesson taught by the Sunberry — let us recognize
that there are conditions of hybridization under
which characters appear to be permanently
blended when first brought together; not mo-
mentarily linked in an unequal union to be segre-
gated in the next generation, but fixed in a new
and lasting combination that strikes a balance be-
tween the combinations presented by the parent
forms.

It is possible, to be sure, to interpret this aspect
of heredity in Mendelian terms. Nor should we
deny altogether the validity of such application,
for we may well believe that there are gradations
all along the line, could we search them out, be-
tween the case of the sterile hybrid, born of
widely diverged parents, and the case of off-
spring of members of the same species that differ
only as to some varietal character.

The same laws, could we fathom them in their
broader aspect, apply to each and every case.

But, on the other hand, it is at least open to
question whether it would not be better to re-

THE SUNBERRY 311

serve the application of the Mendelian terms to
such types of inheritance as Mendel himself
studied, in which there was interplay of dominant
and recessive factors, and the varied segregation
of the different factors in new combination in the
second filial generation.

Thus restricted, the Mendelian formula has in-
dividuality and specific meaning.

There is danger that it may lose such individ-
uality and such specific meaning, and with these
a large measure of its real value and importance,
if the propensity of some present-day enthusiasts
to make the words Mendelism and Heredity
synonymous is generally followed.

Be all that as it may, at least we hazard
nothing in saying that the case of the hybrid Sun-
berry, sprung at a bound into existence as a full-
fledged species, is of compelling interest to the
student of heredity, from whatever aspect he may
view the subject.

Whatever else may be said of the
Sunherry, for or against, the fact
remains that it was a successful
union of two racial forms that were
separated almost to the point of
permanent segregation.

A DOZEN OTHER DELIGHT-
FUL BERRIES

Offering Encouragement to Com-
bine and Construct

IN THE ensuing chapter will be brought to-
gether for brief consideration the records of
investigations having to do with a varied
company of berries, some of them among our
most familiar garden fruits, others practically
unknown to anyone but the specialist.

It must not be inferred that these berries lack
importance because they are grouped here to-
gether instead of being given individual chapters.

It is only necessary to name the currant, the

gooseberry, the huckleberry and blueberry, and

the cranberry as members of the list to give

assurance that the fruits under consideration

have considerable economic importance. But it

chances that my work with these fruits, and the

others listed with them for present consideration,

has been somewhat less extensive than with the

small fruits already described.

313

314 LUTHER BURBANK

So much remains to be told concerning the
plants with which more notable developments
have been achieved, that it seems best to conserve
space by treating the fruits that are now under
consideration somewhat summarily.

It will appear, however, that the amount of
work done in connection with these various fruits
is by no means inconsiderable; and that in more
than one instance results have been attained that
would warrant more extended consideration were
it not that they must be viewed in a relative
scale.

Let us then somewhat briefly run over the list
of a number of interesting fruits that fully
justify the title under which they are classified in
the present chapter, yet which have associated
with them no story quite so spectacular as some
others that have been reviewed in recent pages.

We may first recall a few less conspicuous
members of the great Rubus family — the bram-
bles. The more notable members of this remark-
able family have been dealt with at length. But
we cannot take leave of so notable a group with-
out at least incidental reference to a few other
members of the tribe that have shown interesting
possibilities of development.

One of the most interesting among these minor
Rubuses is the western raspberry, a wild black

DELIGHTFUL BERRIES 315

species, known to the botanist as Rubus leuco-
dermis. This plant, as its Latin name suggests,
has a white stem. As to fruit, it rather closely
resembles the eastern black raspberry which is a
parent of our cultivated blackcap. It is a strong,
vigorous grower, producing stout upright canes
and berries that are unusually sweet and of a
pleasing flavor.

Several years ago, while in the Eel River
region in Humboldt County in California, I dis-
covered many excellent plants of this western
blackcap of specially vigorous growth, and pro-
ducing berries of extra size and quality. A large
number of berries were gathered from the most
promising plants, and their seeds carefully
planted.

After several years of planting and selecting,
a promising berry was produced, fully as good, I
think, as most eastern blackcaps and much larger
than any then known. Unfortunately, the stem
and backs of the leaves of the plant are covered
with long, sharp prickles, and these are so an-
noying in cultivating or picking the fruit that it
seems not worth while to introduce a plant thus
handicapped.

There is opportunity, however, to do away
with these prickles through hybridizing and
selective breeding along the lines already fully

HAWAIIAN RASPBERRIES

This interesting berry is of fair qual-
ity and of the largest size. It does not
last long enough for market purposes,
but is being used for crossing. The
experiments which are still under way
give promise of very interesting and
perhaps important results.

DELIGHTFUL BERRIES 317

detailed in the account of the thornless black-
berry in an earlier chapter of the present volume.
When this has been done, the developed variety
of the western blackcap will be worthy of a
place in the small-fruit garden side by side
with the very best varieties of raspberry under
cultivation.

It should be added that this species, like a
number of the eastern Rubuses, occasionally
produces nearly white berries. These also
might be developed into fruits of real merit
and doubtless will be when some one finds the
time and interest to carry out the experiment
of developing them along the now familiar
lines outlined herein.

The Cape Raspberry

One of the strangest forms of Rubus with
which I have experimented is a species that came
to me from New Zealand, but which had its orig-
inal home in southern Africa.

This form is known as Rubus capensis, in rec-
ognition, presumably, of its having been found in
the Cape region of southern Africa. It is not
confined to this region, however, as it is believed
to be the same species described by Stanley as
growing in various regions in the heart of the
Dark Continent.

318 LUTHER BURBANK

The fruit borne by the Cape raspberry is of a
dark mulberry color. It is of the raspberry type
quite unniistabably, but is larger than any other
raspberry I have ever seen. The quality of the
fruit is fair, and its large size makes it attractive.

The foliage of the plant is peculiar, having a
curious resemblance to leaves of the grape. In-
deed the resemblance is so striking that people
passing it at a little distance have often asked
what kind of a grape I had that grew upright
like a bush.

The entire plant is highly ornamental, growing
about four feet in height and bearing its hand-
some, large, leathery leaves in profusion. The
prickles on the leaves grow so close together and
are of such texture that they can scarcely injure
the skin in handling them.

The plant is not very hardy, but its other qual-
ities make it a very desirable species for hybridiz-
ing experiments. Indeed, I know of no wild
species of Rubus in the world that gives more
promise of being useful. My own experiments
with the plant were not carried far enough to
produce particularly notable results. But the
plant invites attention from anyone who is inter-
ested in the further development of our small
fruits. Coming from the Southern Hemisphere,
it should introduce a tendency to variability in a

DELIGHTFUL BERRIES 819

conspicuous degree when crossed with some of
our northern species.

Among other good qualities of the hybrid
progeny, there should be a tendency to prolonged
bearing, such as we have seen in the case of the
strawberry produced by the crossing of species
from the two hemispheres.

The Salmonberry

Another very interesting Rubus that shows
great possibility of development is the native
species familiar along the Pacific Coast from cen-
tral California to Alaska known as the Salmon-
berry, Rubus spectabilis.

This is a tall, erect bush or small tree with
stout, perennial canes. The stalks are usually
sparsely clothed with weak, slender prickles, but
are sometimes nearly smooth. The flowers are
borne singly and in pairs on slender stalks ; they
are large and showy, being bright red or purple.

In Humboldt and Mendocino Counties, Cali-
fornia, I have seen this berry growing in the
pastures where it became a genuine tree from
twelve to fifteen feet in height, some of the stalks
being two or three inches thick. It is reported
sometimes to grow six inches in diameter. The
cattle in the pastures browse on the plants as high
as they can reach, and the berries are gathered

320 LUTHER BURBANK

with a stepladder or more commonly from the
back of a horse.

The berries themselves are large and soft, al-
most falling to pieces in the picking. They are
unusually juicy, and with almost no acidity.

There are two strongly marked varieties of
Salmonberry. One has pale yellow fruit, the
other reddish, varying to dark crimson. These
two varieties may be seen growing side by side,
in some instances without intermingling, each
individual bush producing berries of one distinct
quality and color.

The Salmonberry requires a damp, cool at-
mosphere and moist soil. When transplanted
into the warm valleys it does not thrive. There
chances to be a moist piece of sandy land on my
Sebastopol farm, however, where it thrives fairly
well. Here we have grown the Salmonberries
from Alaska, Washington, Oregon, northern
Minnesota, and various parts of northern and
central California for more than twenty years.

Among these I have noticed considerable vari-
ation in the size and color of both fruit and flow-
ers. My experiments, however, have not been
carried out extensively, partly because of the diffi-
culty that attends the growing of the Salmon-
berry in this locality and partly on account of
the lack of firmness and flavor in the fruit. But

DELIGHTFUL BERRIES 321

I have gone far enough to know that the fruit is
worthy of further development, although I shall
probably leave the task for some one who is more
favorably situated geographically for the culti-
vation of this particular fruit.

The Japanese Golden Mayberry

We have already learned that the Rubuses are
cosmopolites. The facility with which the seeds
of the brambleberries of various kinds are dis-
tributed by the birds doubtless accounts in part
at least for the wide migrations of the tribe, and
this in turn accounts for the great range of varia-
tion among the different species.

In the course of my experiments with the fam-
ily, I very naturally looked to Japan to supply
material, just as in the case of so many other
tribes of plants. The species that I received from
there certainly did not appear to be an encourag-
ing plant to work upon. Yet it proved suscep-
tible of development, and well repaid the efforts
bestowed upon it.

The plant in question was found growing wild
high up on the sides of Mt. Fujiyama in Japan.
It is known botanically as Rubus palmatus. The
collector who secured it for me sent the best speci-
mens of the fruit that he could find, and roots
of the plant itself. The plants from these bore

11— Vol. 4 Bur.

THE BUFFALO BERRY

This plant is indigenous to the Rocky
Mountain region and the dry plains of
the West. The fruit is edible t and
makes a good quality of jelly. Unlike
its nearest relative in Japan (the Gounii
berry — Ela?agnus longpipes) it is not
thorny, and in our cultivated varieties
every plant bears heavily, while in the
wild state the trees are dioecious, only
half of them bearing fruit.

DELIGHTFUL BERRIES 823

large, white blossoms, solitary and drooping on
long, slender stems swinging from the leaf axils.

But the berries were a great disappointment,
being small and of a dingy, yellowish, unappetiz-
ing brown color and their flavor was as unattrac-
tive as their appearance.

Knowing the possibilities that lie in the hybrid-
ization of oriental species with their American
relatives, however, I did not despair of the May-
berry, but hybridized it with the Cuthbert rasp-
berry, a plant that proved a remarkable parent,
as will be recalled, in connection with other
hybridizing experiments — notably the production
of the Phenomenal berry.

The hybridization was effected without diffi-
culty, and the progeny showed a tendency to
rapid improvement. After a few generations
the berries were greatly enlarged, and took on a
bright yellow color instead of the original dingy
brown. The improvement in quality was also
very appreciable.

But what was perhaps most notable was the
extreme earliness with which the hybrid plants
fruited. It was, indeed, the early bearing habit
of this Rubus that stimulated me to make the
cross. It proved possible to retain and accentuate
this habit while introducing the Cuthbert quality
into the berries. The result was a new type of

324. LUTHER BURBANK

berry as large as the Cuthbert raspberry, ripen-
ing in April, a month before the Hansell, a
variety then famed for its early fruiting.

Indeed the hybrid Rubus bears fruit at a time
when the earliest of the standard raspberries have
hardly awakened from their winter rest.

This habit of early bearing, combined with the
unusual qualities of the berry itself, seemed to
justify its introduction. So it was announced to
the public in 1893 as the Golden Mayberry.

The bushes on which the Mayberry grows are
distinct from all others of the tribe, attaining a
height of six or eight feet and being almost tree-
like in form. All along the branches the white,
bell-shaped blossoms are pendent, soon succeeded
by the large, sweet, golden, semitranslucent
berries.

The plants do not at first bear very heavily,
but as they advance in age they produce an
abundance of fruit.

Unfortunately the hybrid Mayberry is not
hardy, and so is not adapted to the climate in
many parts of the United States. It has become
almost the standard berry in the Philippine
Islands, and it is sure to gain popularity in any
climate to which it is adapted.

More recently I have given attention to im-
proving the variety, and the developed races bear

DELIGHTFUL BERRIES 325

luscious fruit fully an inch and a half in diameter.
The fruit is rather soft and more suitable for
home use than for the market. But it is a pro-
ductive and delicious berry, well worthy of intro-
duction in all milder climates.

Possibly a series of hybridizing experiments,
introducing some northern species of Rubus,
would result in giving the plant hardiness, in
which case it should become popular everywhere.
Such a line of experiment is well worth under-
taking.

The Cloudberry

In marked contrast to the Mayberry in point
of habitat and hardiness is the Rubus from the
far North that is commonly known as the Cloud-
berry, or, in some regions, the bake-apple berry,
and known to the botanist as the Rubus chamce-
morus, a name given to it more than a century
and a half ago by Linnaeus.

The plant inhabits the peat bogs and similar
localities far to the north, even within the Arctic
Circle. Like many other arctic species of plants
it does not confine its habitat to a single continent
but is found in northern Europe and Asia as well
as in North America. The same thing is true of
arctic species of birds and animals; the obvious
explanation being that it is easy to wander
from one longitude to another in the regions

326 LUTHER BURBANK

where all longitudes merge toward a common
center.

On this continent the Cloudberry extends
southward along the mountain ranges to Maine,
on the east coast, and on the west coast to south
British Columbia.

The plant bears berries of the characteristic
Rubus type that are more commonly flattened
raspberry shape or nearly globular, of a bright
red or yellowish color, and of a pleasing acid
flavor. They are highly prized in all northern
countries, being among the best fruiting Rubuses
of Norway, Sweden, and Alaska and Labrador in
America.

It was my good fortune while in Alberta,
along the North Fork of the Saskatchewan
River, to see this interesting northern species
growing wild. The plants with their small,
slender, trailing branches and rounded or almost
heart-shaped leaves, were very attractive. Some
of the seeds were procured for cultivation.

The seeds germinated perfectly and vigorous
plants developed. But, although they were
placed in as damp and cold a spot as could be
found on my grounds, they did not thrive in the
warm, dry atmosphere of a sunny California
summer. The change from the northern habitat
was too great, and, although the plants lived for

DELIGHTFUL BERRIES 327

a year or two, no important developmental ex-
periments were made with them.

They so obviously found the conditions un-
congenial that it was thought best, after a year
or two, to discontinue the attempt to reconcile
them to the change.

Whoever considers the production of hardy
varieties of raspberries, however, should bear the
Cloudberry in mind. It offers obvious possibili-
ties as a hybridizing agent to give hardiness of
the most "ironclad" kind to a variety that may
lack that essential quality.

Possibly the Japanese Mayberry will ulti-
mately be made adaptable to northern climates
by such an infusion of new blood.

The Evergreen Blackberry

As further illustrating the wide range of the
bramble tribe, we may refer to a species that is
indigenous to the South Sea Islands, whence it
was introduced into this country and Europe so
long ago that there is no clear record of its
coming. Indeed, the precise place of its origin
is somewhat in doubt.

The species referred to is the Evergreen
Blackberry, Rubus lacimatus. In our north-
western States, especially in western Oregon,
this blackberry is cultivated extensively. It is

328 LUTHER BURBANK

popular as a home berry, since it produces fruit
from midsummer until late autumn.

As its name implies, this is an evergreen, or
nearly evergreen plant. It is a trailing bush
with thick perennial canes armed with very stout
recurved thorns.

This blackberry was worked upon quite ex-
tensively on my place in 1890 and the following
years, at the time when my chief experiments in
the hybridizing of the Rubuses were at their
height. Among the hybrids produced were some
very curious forms, the variation in the shape of
the leaves being especially remarkable. Some
of the leaves resembled those of the grape, others
were much dissected, like the leaves of a wild
carrot.

The most promising of the hybrids were pro-
duced from a cross between the Evergreen and
the popular Lawton blackberry. Some selected
seedlings from this cross, in the second genera-
tion, were rampant growers, thorny, with curi-
ous, handsome, palmate leaves, and delicate pink
blossoms. The berries ripened late in the fall.
Some were rather large and possessed a su-
perior aromatic sweet quality not found in the
common summer varieties.

One of these promising hybrids was men-
tioned in my "New Creations" in 1893. It was

DELIGHTFUL BERRIES 329

never introduced into cultivation, however, as
its merits were not quite equal to those of some
other varieties of different parentage. But there
is no doubt that if the experiments with the
Evergreen blackberry, of this or some other
hybrid combination, were carried to a more ad-
vanced stage, really useful varieties would be

obtained.

The Common Currant

Notwithstanding the importance of the Rubus
family, its members have by no means a
monopoly among the popular small fruits of
the garden.

There is at least one other bush that may
claim to compete with the brambles in wide
range of habitat and in general popularity
among gardeners. This, of course, is the
familiar currant.

The forbears of the currant grow wild, repre-
sented by various species in both Europe and
America. The wild red species, Ribes rubrum,
from which all our common cultivated red, white,
and pink currants, large and small, sweet and
sour, are descended, is indigenous to both con-
tinents. It has maintained its specific identity
remarkably through long generations, as the
close similarity of the specimens found wild in
Europe and America testifies. The more com-

INTERESTING HYBRID
BERRIES

Some of my most recent and interest-
ing experiments have been with new
types of berries. The boxes here shown
contain some second- generation seed-
lings of berry crosses. There are also a
number of straight seedlings, of both
parents , in some slight way indicating
the range of a season's work along a
single line.

DELIGHTFUL BERRIES 331

nion American wild species, however, in most
regions is the black currant, which also has a
European congener.

The American black currant is a hardy plant,
growing far north in Canada. It varies greatly
in different regions, both in appearance and in
the quality of the fruit it bears.

There are other wild species and varieties
without number, so that there is abundant mate-
rial supplied the plant developer for work with
this valuable fruit.

I have experimented with a large number of
varieties from different regions, and have pro-
duced some interesting anomalies. One of these
was the result of crossing the varieties of a native
red-flowering species known as Ribes sangui-
neum. By selection and cultivation, varieties of
this plant have been produced on my grounds
that bore flowers of brilliant colors and the
largest fruit, perhaps, ever seen on a currant
bush.

Most of the crosses of this species were made
between a form collected on Vancouver Island,
British Columbia, and the forms native to the
regions about San Francisco. The Vancouver
forms had long racemes of light crimson flowers
and small bluish fruits. The coast form has
larger fruits with a more resinous odor, the ber-

332 LUTHER BURBANK

ries varying in color from bluish to black. My
efforts with these species were mostly directed
toward increasing the size of the fruit. As just
stated, the results are quite noteworthy.

But the experiments are still under way and
the ultimate possibilities of development are yet
to be revealed.

These experiments in hybridizing the currant
have extended to all the species and varieties
that could be obtained. At times I have had five
thousand crossbred currant seedlings under
observation.

In addition to the European and American
crossbred species, I have worked extensively on
varieties imported from Japan and China, and
from northern Asia and Russia.

I have also crossed the currant with the goose-
berry, but the hybrids in this case produced no
fruit. Notwithstanding the large number of ex-
periments and their interesting results, I have
not produced any new currant that was thought
worthy of introduction. There is now under
observation, however, a hybrid seedling from the
Californian species already referred to — Ribes
sanguineum, which is several generations re-
moved from the original, and which bears long
clusters of extremely large blue berries with few
seeds.

DELIGHTFUL BERRIES 333

This is the best of the thousands of hybrids
grown, though I have produced a few really
good currants of unique form and flavor, as well
as some flowering currants of unusual size and
beauty.

All in all, my work with the currants, while
substantiating and emphasizing the principles of
plant development that work with other plants
had made familiar, and while showing many
features of interest, has not resulted in any very
striking developments; largely, perhaps, because
attention was diverted from this line of work
to other experiments of greater immediate
promise; and because the experiments were too
radical, taking in so many species that so many
unique characters appeared that I had not time
to segregate them. If I had worked with a
single species, more immediate commercial re-
sults would have been attained. Much of the
work with currants was done for its aesthetic and
scientific interest rather than for immediate
commercial prospects.

The Gooseberry

The currant has a very close relative which
vies with it in popularity, particularly in
England — the familiar gooseberry. This plant,
indeed, is in reality a currant that has developed

334 LUTHER BURBANK

or retained the habit of bearing prickles both on
the stem and often on the fruit itself.

This is the practical distinction between the
gooseberry and other varieties of currants. All
the plants of this tribe belong to the same genus.
There are several species in California that
puzzle a botanist as to whether they should be
classified as currants or gooseberries.

In Europe, and particularly in England, the
gooseberry has been cultivated with the greatest
possible care and through selection the fruit has
been brought to a very large size, superior qual-
ity, and unusual productiveness.

But unfortunately the thorns have never been
eliminated, except in the case of one or two
inferior varieties. These were offered several
years ago by an English firm, but their quality
of fruit was so inferior that they have not be-
come popular.

It has already been mentioned that I was able
to hybridize the gooseberry and the currant.
The cross is very difficult to make, however, and
in my experience the hybrids were sterile. This
suggested that the two plants, notwithstanding
their affinities as judged from the standpoint of
the botanist, have really diverged rather widely.

But there are many species of gooseberry
as well as of currant, and it would doubtless

DELIGHTFUL BERRIES 335

be quite possible to find varieties of the
two plants that have closer affinity. The
hybridizing of these would offer interesting
possibilities.

Experiments with the gooseberry as with the
currant have been extensive and have produced
a great number of gooseberries of superior qual-
ity; none, however, until very lately have been
really notable.

Some of the most interesting experiments had
to do with the native species known as the Coast
gooseberry, Ribes divaricatum, which grows
around Tomales Bay, but have also worked with
the Canyon gooseberry, Ribes Menzieszi, a tall,
rapid-growing shrub with rather small leaves
and very prickly stems.

The berries of this variety resemble a chestnut
bur rather than a gooseberry, the spines occu-
pying the whole surface of the fruit. The fruit
itself is excellent in flavor and is prepared for
eating by being placed in hot water so as to
soften the prickles, after which the pulp is easily
crushed out.

I have developed several partially thornless
varieties of this gooseberry, and have also had
partially thornless ones sent me, showing that
the species tends to vary in this direction. But
the seedlings from these partially thornless

336 LUTHER BURBANK

plants always produced thorny varieties. It is
probable, however, that further experiments
might reveal specimens that would drop the
thorns altogether and would breed true to thorn-
less as the thornless blackberries do.

This, indeed, should be the aim of the plant
developer in connection with all varieties of
gooseberries. The plant offers a splendid oppor-
tunity for hybridizing and careful selection.

If it could be induced to shed its thorns and
still bear large fine fruit, the gooseberry would
gain enormously in popularity. At present there
is a not unnatural prejudice against this fruit
because the thorns constitute an almost in-
tolerable nuisance, their sting being peculiarly
irritating.

My own experiments were carried far enough
to suggest the probability of the production of
good thornless varieties. As to fruit, several
varieties were produced that were thought su-
perior to any previously seen. But I was not
able to introduce them properly, and after keep-
ing them several years the bushes were destroyed
to make room for other plants of greater
promise. Subsequently, however, I regretted
this and now feel that these plants might have
rewarded further experimental efforts had I
been able then to find time for them.

DELIGHTFUL BERRIES 337

Certainly the gooseberry is well worthy of
greater attention, from some plant developer
who works along modern lines, than it has hither-
to received.

The Blueberry and Cranberry

Another interesting tribe of plants supplies us
with the familiar market fruits known as bilber-
ries, blueberries, and cranberries.

These berries are little grown in the garden,
but remain even to this day products of the wild,
although the bushes on which they grow may be
taken under man's protection and given a cer-
tain encouragement in woodland or swamp.

The botanist classifies the various blueberries
and cranberries in the genus Vaccinium. There
are widely scattered representatives of the tribe
in both hemispheres. Most of them are branch-
ing shrubs or creeping vines. A large proportion
of them are vigorous shrubs like the various blue-
berries ; whereas on the other hand the cranberry
is a trailing evergreen. The varieties in the dif-
ferent species are so numerous as to tax the skill
and patience of the botanist.

The berries are produced in enormous quan-
tities. A mass of blueberries in fruiting time
may seem to spread a blue carpet throughout
acres of cleared woodlands and pastures. And

338 LUTHER BURBANK

as to the cranberry, on my father's meadow
lands where these plants grew, we used to rake
the berries off the vines instead of picking them
by hand, so profusely were they clustered.

A very interesting feature of the blueberry
and cranberry pastures, observed even as a boy,
was the great variation, sometimes within the
same square rod of ground, not only in the size
of the berries, but in their shape and quality.

From the same patch, some blueberries would
be sweet and very highly flavored, others insipid
and more or less flavorless. But individual
patches of the low blueberry V. pennsylvanicum
as a rule appeared to be developed from one orig-
inal seedling which had suckered out in various
directions just at the surface of the ground, the
trailing branches rooting under the fallen leaves
wherever they touched the earth.

Individual groups of plants, sprung thus from
one seedling, would of course show the same
qualities of fruit.

On one of my last visits to New England I
selected from the old blueberry grounds some
of the best plants, and transplanted them to the
experiment farms at Sebastopol.

It has often been stated that the blueberry
cannot be cultivated to advantage, because it
ceases to produce much fruit when removed from

DELIGHTFUL BERRIES 389

the wild state. My experiments did not justify
this belief, as the bushes brought from the East
were if anything overproductive. I have never
seen plants of any kind produce a greater quan-
tity of fruit in proportion to the weight of the
plant.

During the ripening season the bushes seemed
to be a solid mass of berries. This overproduc-
tion of fruit greatly restricted the growth of the
plants themselves.

One season, by way of comparison, all the
fruit was removed from a certain number of
bushes. Relieved of the burden of fruit produc-
tion, these plants made a large growth, quite
outstripping the others; and the second year
they produced an unusual crop. Under proper
conditions, the blueberry may become profitable
under cultivation in California and no doubt
will, sooner or later, be largely grown.

The same may be said about a collection of
huckleberries, bilberries, and other blueberries of
various kinds that I had gathered from British
America, Oregon, Washington, and even Nor-
way, and of an allied plant said to be of unusual
value, that I received more recently from the
mountains of central Japan. No important re-
sults from the development of this plant have as
yet materialized, however.

340 LUTHER BURBANK

The blueberry and huckleberry are generally
thought to be extremely difficult to raise from
seed. But if kept sufficiently moist in a peaty
soil this may be readily accomplished.

Cranberry seedlings can be grown by washing
out the seeds and sowing in a protected place or
in damp sphagnum moss.

The young seedlings can be transplanted like
other fruiting plants, but the operation is rather
delicate as with all other Vacciniums. The soil
must always be virgin soil, and with hardly a
trace of lime, as all Vacciniums prefer what is
commonly called an acid soil.

The cranberry, like most other members of
the tribe, spreads by sending out runners. It
can be propagated by cutting the vines into
small pieces. The plant does not thrive in Cal-
ifornia except in some bogs of the northwestern
part of the State. In regions to which it is
adapted, however, the cranberry is a crop of con-
siderable importance, and there appears to be an
unusually good opportunity for some one to con-
duct experiments for the development of better
varieties.

Mere selection from the existing varieties
would probably accomplish much. And of course
still further progress could be expected if the
different varieties were hybridized. By such

DELIGHTFUL BERRIES 341

work the crop could without doubt sooner or
later be more than doubled in quantity, the size
of the berries greatly increased, and their qual-
ity improved.

The most desirable characters for the plant
developer to have in mind would be, first, qual-
ity of the fruit; next, size and color. The vines
themselves could be readily improved, both as to
manner of growth and abundant production.

Here as with other berries it would perhaps
be possible to eliminate the seed, and this would
obviously be of some advantage.

The cranberries differ less than plants that
have been more under cultivation, but they
nevertheless show enough of variation to give
full opportunity for selective breeding; and of
course the variation could be increased by cross-
ing as with other species. The common swamp
blueberry V. corymbosum is one probably prom-
ising the most in the way of improvement for
general cultivation.

Two Interesting Tree Fruits

To conclude this survey of common fruits that
beckon the plant developer, yet which have been
largely neglected, brief reference must be made
to the berries of two plants that differ radically
from those we have had under consideration,

A NEAR VIEW OF TWO BOXES
OF BERRY SEEDLINGS

These are second- generation hybrids.
They were raised in the season of 1914,
and had not then come to bearing.
Interesting results have been obtained
from these plants.

DELIGHTFUL BERRIES 343

inasmuch as they are trees or large shrubs rather
than bushes.

The plants referred to are the Mulberry and
the Elderberry.

The mulberry is a relative of the fig, and it
bears abundantly a fruit that is distinctly sug-
gestive of the blackberry in general appearance,
but which has a characteristic flavor of its own.

Although the fruit of the mulberry is not
altogether neglected, yet in general the tree is
raised to furnish food for the silkworm or for
ornament rather than for its fruit. It is obvious-
ly difficult to gather a crop of berries distributed
among the branches of a tree, and this fact no
doubt accounts in part at least for the failure of
the mulberry to gain general popularity as a
fruit producer.

It would be possible, however, to train the
mulberry tree to a lower and more spreading
growth, as it is generally propagated by graft-
ing after the manner of orchard fruits. Indeed,
that is the best way to propagate the fruiting va-
rieties of mulberry, as they cannot be depended
on to breed true from the seed. In fact, the fruit
of several of the best cultivated varieties is
altogether seedless.

Reference has been made in another connec-
tion to my experiments in hybridizing the mul-

344 LUTHER BURBANK

berry with its relative the fig. Notwithstanding
the lack of success of these experiments, mostly
no doubt from lack of time, it seems possible that
further experiments along the same line might
lead to interesting, and perhaps to very valuable,
results.

As to the other berry-producing tree just men-
tioned, the elder, the possibilities of fruit devel-
opment are even more inviting.

The common European elder, Sambucus ni-
gra, has developed into a number of handsome
ornamental varieties, most of which are offered
by the American nurserymen. Our native east-
ern species, the Sambucus canadensis, the com-
mon elder of the eastern United States, has also
developed several forms; and there is a Califor-
nia species, S. glauca, that shows a like tendency
to variation, both as to size of tree and size and
quality of fruit.

The berries of the elder are borne in large
clusters, sometimes in enormous profusion, so
that the bushes fairly break under their weight.
The fruit is generally bluish black, with a very
thick white bloom.

A curious anomaly is sometimes shown by an-
other European or Asiatic species, S. racemosa,
a variety of which grows in various parts of
northern California and northward along the

DELIGHTFUL BERRIES 345

Pacific coast. This sometimes makes a large,
rambling, treelike bush, and the singularity in
question consists in the fact that some of the
bushes bear berries of a brilliant yellow color and
others reddish purple or almost black berries.

The bushes intermingle almost indiscrim-
inately, yet there is no intermingling of the dif-
ferent berries on the same bush. Each plant
bears exclusively berries of one color or the
other.

I have experimented extensively in the im-
provement of the berries of the different elders
and these experiments are still under way.

These experiments began with the planting of
seeds of the Mexican elder, which bore berries of
medium or small size and of black color. Some
of the plants that grew from these seeds pro-
duced, much to my surprise, berries yellowish
white in color.

Observing this tendency to variation, it at
once occurred that improvements might be made
in almost any direction with a plant that showed
this tendency. More seedlings were raised,
and selection was made according to my usual
method.

From the best of these seedlings many plants
were produced that bore berries of a yellowish
white or sometimes grayish color. While the

346 LUTHER BURBANK

berries were bitter, like elderberries in general, I
noted that some were less bitter than others.
Moreover, there was a diversity in size, and a
great variation as to productivity. A few of the
trees bore a constant crop all summer, blooming
and bearing fruit throughout the season and well
into winter.

This was another unusual break in the tradi-
tions of the family and one that seemed to offer
pleasing possibilities.

The experiment has continued along the lines
of further crossing and selection. A few seasons
ago I had from twenty-five to thirty thousand
elder plants in bearing. From these the best, to
the number of about seventy-five, were selected.
And the trees of the generation now under obser-
vation bear really delicious berries, without a
trace of bitterness. Some are quite sweet, others
acid.

The best of them are an astonishing improve-
ment over any elderberries I had ever seen
before.

The berries are grown in abundant clusters
and they are individually of the size of small cur-
rants. When dried they turn a light golden
color, like the whitest of the white raisins. In
flavor they can hardly be distinguished from the
best raisins, though so notably different in size.

DELIGHTFUL BERRIES 347

The progress already attained makes it cer-
tain that we shall soon be able to educate these
elders to a condition that will make it highly ac-
ceptable as a productive fruit, especially for arid
regions. The elder grows from cuttings and will
thrive in moist or dry climates.

I have under way also a series of hybridizing
experiments in which the different elders, no-
tably the progeny of the Mexican elder, and the
California species already referred to, Sambucus
glauca, and the hardy Dakota elders are com-
bined. To produce still further variations and
facilitate progress, I have also crossed the new
elder with species from Arizona, one of which is
a very large tree for an elder.

From a second generation cross I got prob-
ably one individual in forty that bore black ber-
ries, but from the third generation not a single
one out of several thousands was black. One
was secured, however, that bore berries of a gray
or mulberry color and two or three having a
tendency to a mixed color. All the rest were
white or amber.

It will appear, then, that a race of elders has
thus been produced that bears fruit of an attrac-
tive white or amber color and of such quality as
to commend it highly, as a fine substitute for
other berries, in regions where the garden fruits

348 LUTHER BURBANK

in general do not thrive or perhaps even where
they do. Moreover, there is every probability
that the experiments now under way will result
ultimately in the development of varieties of elder
of such improved quality as to make a valuable
addition to the orchard even in competition with
the most popular fruits.

The elderberry has qualities of its own that
will commend it strongly. If for no other rea-
son, the fact of its development on a tree or large
shrub gives it peculiar attractiveness. The vine-
like growth of many bearers of small fruit,
notably the raspberries and blackberries, necessi-
tates methods of cultivating, with perpetual
pruning that many horticulturists find irksome.
The elder shrub can take its place in the fruit
orchard along with the trees that bear apples,
or plums, or peaches, requiring no special treat-
ment or attention, and constituting a permanent
acquisition for the fruit grower.

There are opportunities in the
bypaths of plant improvement,
opportunities untold, which call
out for patient specialized effort,
and which will well repay the
investment of that effort.

GREAT OPPORTUNITIES IN
THE GRAPE

Generations of Grape Experiments
Help Us

THE grape is the patrician among climbing
plants as the strawberry is among trailers.
The family to which it belongs is one of
the smallest, as regards number of species, among
plant tribes. But it is an oligarchy having very
great distinction. What the membership lacks
in numbers it makes up in quality. The grape
is known everywhere and has been cultivated by
man from the earliest times. Doubtless as much
attention has been given to it as to any other
tribe of plants. Indeed there may be no other
that can compete with it in this regard.

Of course the main reason for the extreme
favor shown the grape by man has been all along
the capacity of the plant to produce a fruit hav-
ing a juice of unique quality.

It is as a producer of wine rather than as a
producer of fruit for the table that the vine has

349

350 LUTHER BURBANK

in the past everywhere gained greatest popu-
larity.

Nevertheless, the quality of its fruit is alto-
gether noteworthy, and such as to give the plant
distinction in the eyes of the horticulturist, even
were it considered solely as a producer of table
fruit. Moreover, there are certain kinds of grape
that contain so high a sugar content that they dry
without fermenting, constituting a third impor-
tant commercial product — the raisin.

All in all, then, it is easy to understand why
the grape must be considered as a fruit standing
in a class by itself, and having importance second
to none.

The manner of growth of the grape and the
character of the clusters in which its fruit is borne
are no less distinctive. No other fruit under cul-
tivation in the least resembles the grape in either
regard. And as to shape and appearance of the
individual berries no less than in the matter of
fragrance and flavor the grape manifests the
same individuality. Different varieties show
diversity of form and color and flavor, to be
sure, but no grape of any variety is likely to
be mistaken for a fruit of any other kind
whatsoever.

It is clear that we cannot attempt in the space
at command to present anything like a compre-

THE GRAPE 351

hensive story of the growth and development and
world conquest of this extraordinary fruit. Nor
would it comport with the present purpose to do
so. The main facts as to grape culture are mat-
ter of common knowledge. Our concern must be
with such features of habit, and constitution, and
adaptability of the grape as particularly concern
the plant developer, and have to do with the pos-
sibilities of improvement.

In particular, of course, here as elsewhere, we
shall be concerned with a presentation of the
work done at Santa Rosa and Sebastopol in con-
nection with the development of this plant.

This, as will appear presently, has looked
chiefly to the improvement of the grape as a
table fruit. I have not been concerned with vari-
eties of the grape that are utilized by the maker
of wine. These have been specialized to the point
of approximate perfection in the wine-growing
districts, and it would be useless to experiment
with them in any region except the one in which
they are to be cultivated, because it is well known
that the grape takes directly from the particular
soil in which it grows something of the unique
qualities of flavor that determine the rank of any
grape in the estimate of the connoisseur.

But the case of the grape considered as a table
fruit is obviously different. Even though this

GRAPES OF THE CONCORD
TYPE

The familiar and always popular
Concord grape has naturally been
given attention. It has produced im-
proved varieties by direct selection,
without crossing, although it has also
been used in hybridizing experiments.

THE GRAPE 353

also is doubtless influenced by the soil, the tests
applied to it are not of quite so refined a char-
acter, and the grape developed in one region
may be expected to retain at least approxi-
mately its unique flavor when grown in another
climate.

So I have striven to develop varieties that
would have commendable qualities of fruit and
such qualities of hardiness of vine and prolific
bearing as would make them suited to cultivation
throughout wide territories.

Here as elsewhere it was had in mind the needs
of horticulturists not in one region merely, but
in many regions, and I have endeavored to pro-
duce plants having the widest possible adapta-
bility to varying soils and climates.

The measure of success that has attended this
effort in the case of the grape will be partially
revealed in the ensuing pages.

During a period covering forty years I have
probably raised no less than 75,000 to 100,000
seedling grapes from the best table varieties. I
have hybridized many varieties, both European,
American, cultivated and wild; also other wild
species from Mexico, Australia, China, and
Japan, and have likewise attained interesting re-
sults by working with bud sports, and with the
tuberous grape of Mexico.

12— Vol. 4 Bur.

354 LUTHER BURBANK

Materials and Method

To raise grape seedlings, it is only necessary
to gather the seed from the variety desired, and
keep them barely moist until planting time.
Plant as soon as the frost is out of the ground
in well-drained land, in rows about three or
four feet apart. Scatter the seed thinly in nar-
row drills. Cover with sandy or leaf-mold soil,
about one inch deep in a humid climate, a little
deeper in dry soil like that of California.

In the latter case it is well to have the upper
half of the covering of sawdust, so that the seed-
lings do not have too great a weight to lift in
pushing through the soil.

During the summer the very poor seedlings,
those which are attacked by mildew or which
have made weak, uncertain growth, may be up-
rooted at once, giving the others a better chance.
Later, while the plants are dormant, transplant
the most promising of these to rows about twelve
feet apart, the individual plants being from one
to two feet apart in the rows, according to the
variety.

Like most other cultivated fruits, grapes do
not come true from the seed. Among Ameri-
can grapes, if seeds from a vine bearing black
fruit are planted, about ninety-nine out of one

THE GRAPE 355

hundred black-fruited seedlings may be ex-
pected. With red grapes about the same pro-
portion will follow the parent color. But from
a white grape probably less than one-fourth will
come white.

With the European grape, Vitis vinifera, the
most variable and commercially the most im-
portant species in the world, the proportion
would be wholly different in most cases. Plant-
ing a red grape one may expect half red or half
black, the tendency being slightly more toward
red or black grapes than white, but the propor-
tions varying indefinitely.

Certain qualities of the inherent constitution
of the plant are markedly heritable.

Thus the seeds from a strong-growing variety
are likely to produce strong-growing seedlings.
Productive grapes will usually produce a high
proportion of productive seedlings. A grape
subject to mildew is almost certain to produce
a large proportion of seedlings subject to
mildew.

A variety having abnormally large leaves will
not often reproduce that tendency in its seed-
lings, for an abnormality is more apt not to re-
produce itself, there being a tendency to return
to the normal condition, which has existed for
perhaps a thousand years.

SEEDLING SYRIANS

Several years ago we secured cut-
tings of the best Syrian grapes brought
from Palestine and vicinity. The
Syrian grapes are characterized by a
rather slender, but strong and wiry
stem, and by bunches of pleasing form,
all of about one size, and not so crowded
on the branch as many varieties of
common grapes. The seedlings vary
greatly.

THE GRAPE 357

By planting seeds of an early grape, a great
proportion of early grapes would be expected,
and vice versa, but in almost every case both
early and late, large and small, black and white,
sweet and sour, strong-growing and weak-grow-
ing grapes will be produced among a lot of
grape seedlings from any variety which has been
long cultivated and is the result of hybridization.

In a wild species, the variation would be
mostly in the size of the plants and very little
in any other respect.

The first crop of fruit on the young vine is
not a very accurate test of its future fruiting
capacity. Almost without exception the fruit
improves each season for several years both in
the size of the bunches and in quality of the fruit.

Grapes from Many Lands

With the grape as with other plants I have
sought material for development in far places;
but have also utilized the native species. A brief
notice of the different species that have contrib-
uted to the experiments will suggest the scope of
the work.

An interesting local species is Vitis calif ornica.
This is an extremely strong vine, climbing a tree
to a height of seventy-five or one hundred feet.
It is often found along the banks of creeks and

358 LUTHER BURBANK

rivers where it may attach itself to a young alder.
As alder and grape grow, the tree supports the
vine until it reaches a height of sometimes one
hundred feet and has a trunk twelve to eighteen
inches in diameter — which may seem almost in-
credible to Eastern people unfamiliar with oui
flora.

The fruit of the California grape is produced
in small quantity and is quite variable in this
locality. It ripens late, is sour, without flavor,
and is generally insignificant in all respects. It
is sometimes used for jellies.

Of the world-wide and supremely important
commercial species commonly called the Euro-
pean grape (Vitis vinifera) I have worked
largely with the Tokay variety with the idea of
inducing this vigorous vine, which bears such an
abundance of large, handsome fruit, to combine
hardy qualities and freedom from mildew with
its characteristic excellence of fruit.

The fruit of many of the seedlings is quite
acid, but some are far sweeter than the Flame
Tokay, and much earlier, which is most impor-
tant as the Flame Tokay ripens too late for our
coast climates.

These seedlings have of course been rigidly
selected to avoid mildew, susceptibility to which
is one of the faults of the Tokay, especially in

THE GRAPE 359

the coast region. Some of the seedlings of the
Flame Tokay are white, some black, some red-
dish, some of a blue-gray color. Very few of
them resemble the Flame Tokay in form, color
or quality of fruit, most of them incline to the
round form of the ordinary V. vinifera.

It is not uncommon to find natural hybrids
of the California grape and the European grape
growing wild alongside the vineyards. The
strains of the California species are in some of
the strongest-growing forms of cultivated grapes
that are recommended as stocks for the varieties
of European grape that are subject to injury
from phylloxera.

Work with Strange Species

Mr. M. K. Seralian, who removed from Pales-
tine to America some years ago, secured cut-
tings of the best Syrian grapes. The vines from
these cuttings have habits of growth not unlike
those of the Flame Tokay seedlings planted at
the same time, and are now about the same size.

Among them is one identical with our so-
called Sweetwater grape.

Another was certainly Thompson's Seedless
— a stray variety renamed since it was imported
to California about 1880, and recently identified
as Sultanina. It is an extremely productive,

A MAMMOTH CLUSTER

One of the Syrian seedling grapes,
and still unnamed. The individual
fruits are large, but notable for the
extraordinary number in a bunch, as
the picture will show. They are of
most excellent flavor. This cluster was
about fourteen inches in length by
eight inches across.

THE GRAPE 361

light-colored, strong-growing, yellowish-white
grape which has to be pruned longer than most
others of the vinifera class in order to get big
crops which it produces under ordinary vineyard
cultivation in California.

Sultanina and another called Sultana are
grapes of medium size but absolutely seedless.
They are put up in great quantities in California
as seedless raisins, and are displacing the dried
grapes of Corinth or so-called Zante currants so
extensively imported from Greece and Turkey
■ — to which they are greatly superior.

Among these seedlings of Syrian grapes there
is one early and productive class, absolutely new
to California growers. Most of the Syrian
grapes are noticeably different in several partic-
ulars from the other grapes of Europe and
northern Africa.

The stems are more slender, the peduncles
quite small, yet strong and wiry, the clusters are
very pleasing in form, the grapes usually being
set full and all of one size, and the clusters are
not usually so crowded as those of many varie-
ties of the common grape. The seeds also are
very small — almost absent. Yet all of the varie-
ties among this lot of twelve or more produce
some seeds, with the exception of the Thomp-
son's Seedless. The seeds, however, are quite

362 LUTHER BURBANK

tender, being hardly noticeable. The skins of
most of them are thin and transparent.

Having raised a great number of seedlings
from these Syrian grapes, I find them to be re-
markably precocious, coming into fruitage early,
remarkably heavy croppers, and while more uni-
form in character than most of the vinifera seed-
lings, yet they nearly all contain an astringent
principle which is seldom found in the ordinary
grapes. With this exception, they are the most
promising lot of seedlings which I have hitherto
raised.

About 1890 the United States Government
imported a lot of grapes from the Mediter-
ranean region, but none of them compared with
these Syrian grapes, which seem to be distinct,
and some of which will probably prove of great
value to California.

Most of these grapes are oval in form, not
round as is usual with other grapes.

The Vitis antarctica, which has several other
botanical names, is a curious climber from Aus-
tralia which I have grown many times from
imported seed. It is a little tender and especially
sensitive to wet weather, and though it is inter-
esting I have not experimented much with it.

The Vitis Coignetice from China is an exceed-
ingly strong-growing vine with immense leaves.

THE GRAPE 363

The foliage is beautifully colored in the fall — ■
scarlet, crimson, yellow, or brown. But there is
a great diversity in the seedling vines in the
color of the foliage. Those with brilliant scarlet
autumn colors are generally considered the best.
There are also crimson ones. There was a vine
growing on my Sebastopol bungalow for years
which bore small clusters of insignificant fruit,
but handsome foliage.

The Vitis hypoglossa is another uncommon
grape which I have grown for my own amuse-
ment and interest.

The Vitis rotundifolia, which has also half a
dozen more botanical names, is a tremendous
grower. It must be thinned out quite extensively
in order to get any fruit; the seedlings of these
make a mass of foliage and small branches, so
there is no opportunity for the vines to produce
much fruit.

The various Scuppernongs are derived from
this Southern species. I have grown them from
seed on numerous occasions. In a few cases
these have produced scanty fruits, but they were
finally destroyed as they make too much growth
and too little fruit.

I have also grown the mustang or everbearing
grape, V. candicans; the sugar grape, V. rupes-
tris; the V, monticola, Teocana or Foecceana, the

362 LUTHER BURBANK

tender, being hardly noticeable. The skins of
most of them are thin and transparent.

Having raised a great number of seedlings
from these Syrian grapes, I find them to be re-
markably precocious, coming into fruitage early,
remarkably heavy croppers, and while more uni-
form in character than most of the vinifera seed-
lings, yet they nearly all contain an astringent
principle which is seldom found in the ordinary
grapes. With this exception, they are the most
promising lot of seedlings which I have hitherto
raised.

About 1890 the United States Government
imported a lot of grapes from the Mediter-
ranean region, but none of them compared with
these Syrian grapes, which seem to be distinct,
and some of which will probably prove of great
value to California.

Most of these grapes are oval in form, not
round as is usual with other grapes.

The Vitis antarctica, which has several other
botanical names, is a curious climber from Aus-
tralia which I have grown many times from
imported seed. It is a little tender and especially
sensitive to wet weather, and though it is inter-
esting I have not experimented much with it.

The Vitis Coignetice from China is an exceed-
ingly strong-growing vine with immense leaves.

THE GRAPE 363

The foliage is beautifully colored in the fall —
scarlet, crimson, yellow, or brown. But there is
a. great diversity in the seedling vines in the
color of the foliage. Those with brilliant scarlet
autumn colors are generally considered the best.
There are also crimson ones. There was a vine
growing on my Sebastopol bungalow for years
which bore small clusters of insignificant fruit,
but handsome foliage.

The Vitis hypoglossa is another uncommon
grape which I have grown for my own amuse-
ment and interest.

The Vitis rotundifolia, which has also half a
dozen more botanical names, is a tremendous
grower. It must be thinned out quite extensively
in order to get any fruit; the seedlings of these
make a mass of foliage and small branches, so
there is no opportunity for the vines to produce
much fruit.

The various Scuppernongs are derived from
this Southern species. I have grown them from
seed on numerous occasions. In a few cases
these have produced scanty fruits, but they were
finally destroyed as they make too much growth
and too little fruit.

I have also grown the mustang or everbearing
grape, V. candicans; the sugar grape, V. rupes-
tris; the V. monticola, Teccana or Foecceana, the

UNPRODUCTIVE BUT
MERITORIOUS

Like all of the seedlings here shown,
these two are of mixed ancestry. Both
have qualities of size and superior
flavor, but the bunches are too small for
a market grape.

THE GRAPE 365

V. vulpina or cordifolia — in fact, I have worked
more or less with nearly or quite all the North
American species and many of the hybrids pro-
duced by Mr. Munson and others.

Seeds of the tuberous grape of Mexico have
been sent me several times. It seems to require
a thoroughly well-drained soil and a very warm
climate.

The first two lots of seeds received were fail-
ures on account of being placed in irrigated soil
which was not suitable to them.

Some of the third lot of seeds were placed in
sandy, well-drained soil, and made large vigor-
ous vines the first season. They somewhat re-
semble the Muscat of Alexandria in foliage and
growth and have rather large, sweet potatolike
roots. However, our winter climate did not suit
them and these also died, so I have made no fur-
ther attempt at raising them.

These Mexican tuberous grapes are said to
produce a fine fruit in large clusters, much re-
sembling the Muscat of Alexandria.

Variations in Seedlings of a Bud Sport

My constant effort to take advantage of any
disturbance in the heredity of a species or vari-
ety is justified strikingly in working with the
grape.

366 LUTHER BURBANK

The best seedlings which I have ever produced
were from the grape called Pierce or Isabella
Regia, a variety which originated as a sporting
branch from the common Isabella on Mr. J. P.
Pierce's place near San Jose, California.

This Pierce grape is the same color as its par-
ent, the Isabella, but the berries are more than
twice as large though not increased in number
on the cluster. The vine is very much stronger
and the foliage much larger, so much so that
the difference is noticeable at a considerable
distance.

Large quantities of seedlings from the Isa-
bella Regia were raised, partly for the purpose
of noticing whether bud sports would reproduce
themselves from seed and partly because it prom-
ised to be a fine variety to work upon for im-
provement.

Among the numerous seedlings which were
fruited the variations were most astonishing,
much more so than with most grapes.

Whether this is on account of the Isabella hav-
ing been moved to a new climate, thus changing
its hereditary tendencies, or whether bud sports
in general are apt to produce more variable seed-
lings, I am not yet able fully to demonstrate.
Some of these selected vines which were fruited
are unusually strong growers, some were as weak

THE GRAPE 367

in growth as the ordinary cultivated varieties of
grapes; some bore enormous bunches of grapes,
some had only a few small clusters.

One of these Isabella Regia seedlings is the
earliest grape ever recorded, ripening nearly a
month before the Early Amber, Sweetwater, and
other American and European grapes. It is,
however, small in size and not productive.

The Earliest and Latest Grapes on
Record

Another very large black grape, produced on
a large, vigorous vine, ripens nearly five weeks
before its parent. This is the earliest large grape
known. It has very delicious flavor and quality.
It was temporarily called the "Early Black,"
but was subsequently rechristened the Monte-
cito by Mr. John M. Rutland, who purchased it
for introduction in Australia.

In contrast with these early-ripening seedlings
are others that do not fully ripen their fruit un-
til December and January. These are valuable
in California if protected from the rains, as they
extend the season almost indefinitely.

Though the parent plant bore black grapes,
some of the seedlings bore white, yellow, red, or
purplish-black fruit. Some varieties were enor-
mous producers.

SMALL CLUSTER OF A
FINE SEEDLING

An unusually large seedling grape
with a fine flavor. It would almost
seem as if in this seedling the weight
of grapes which would ordinarily be
found on a large bunch had been com-
bined into a few fruits individually of
exceptional size. The clusters of this
variety are about twice the size of the
one illustrated.

THE GRAPE 369

Owing to pressure of other matters, I have
made no attempt to introduce any of these
grapes, but am satisfied that none can compete
with some of them for table use.

Among the seedlings of the second generation
raised from my own vines were three anomalous
vines of great interest. One of these was the
exact counterpart of the California wild grape.

The second was closely similar though not
quite identical; and the third might be called a
hybrid in general appearance. .

As there were no wild California vines grow-
ing within fourteen miles of the place where these
grapes were growing, I can only account for the
appearance of these degenerates, as they might
be called, on the theory that our wild California
grape and the Eastern wild grape from which
the Isabella originated were descended from
a common stock, and these three plants were
reversions.

Two of these vines grew the first season to the
height of nearly eight feet when the other seed-
lings had grown to only one or two feet in height.
The third one grew twelve feet or more, while
most of the others had grown only about as many
inches. The foliage was exactly like the Cali-
fornia wild grape, as was the wood, fruit, and
general appearance throughout.

370 LUTHER BURBANK

These seedlings have created much specula-
tion as to their heredity among experts who have
seen them. They are best explained, I think,
on the theory proposed above.

Nearly three-fourths of the Isabella Regia
seedlings bore partially seedless fruit. About
half the grapes on each bunch usually were
altogether seedless. Some entire clusters were
seedless. Yet other vines of the same fraternity
bore fruit in which the seeds were unusually
large.

By selection among these vines I have devel-
oped several races of nearly seedless grapes that
are of exceptional quality. The best of these
will be introduced, and they will also be of value
in hybridizing experiments for the production of
seedless grapes of other varieties.

Once produced, such varieties must obviously
be propagated by cuttings, but this of course
presents no difficulties.

The matter of hybridization, crossing, and
selection of fruit having been gone into quite ex-
tensively in early chapters, only a glimpse of the
special features of the work with the grape has
been here recorded. The methods of crossing
and selection having been discussed in previous
chapters, it would be mere repetition to give them
here; and for this reason the details have not

THE GRAPE 371

been elaborated as fully as in some chapters on
other fruits.

A great number of experiments with the grape
are now being carried on that are approaching
completion, and I have a large number of unique
and valuable grape varieties which are awaiting
introduction.

INEDIBLE FRUITS WHICH MAY
BE TRANSFORMED

Even the Acrid Barberry Is Changing

E have had occasion more than once
to call attention to the extraordinary
importance of the Rose family in its
relations with man, and in particular to the won-
derful value of the great genus Rubus.

The family gives us an astonishing proportion
of our cultivated fruits and berries, in addition
to a great variety of our most beautiful flowers.
The apple, peach, plum, cherry, quince, pear,
loquat, and apricot, among orchard fruits, and
the blackberry, raspberry, dewberry, salmon-
berry, cloudberry, and strawberry, among small
fruits, are all representatives of the same
tribe.

Any plant that has membership in the family
must be regarded as having good possibilities of
development.

It was perhaps largely a matter of chance that
the fruits we have mentioned came under man's

373

374 LUTHER BURBANK

attention at an early date and thus were devel-
oped to their present status.

Some other members of the family, such as the
hawthorn, the mountain ash, the wineberry, the
Juneberry, the thimbleberry, and the bridal rose,
have failed to be taken under man's protection
and hence have not had their fruiting possibilities
developed. But some at least of these are well
worthy of consideration, and from among them
there will doubtless be developed sooner or later
many new varieties of fruit that will be consid-
ered valuable acquisitions.

We shall now have our attention called to yet
another coterie of fruit bearers of which good
things may be expected. Some of these are
familiar natives or plants that have become
acclimated in this country, others are foreigners
known only to the specialist. The fact that at
least one or two of them are known as bearers of
interesting or beautiful flowers and have been
cultivated for ornamental purposes adds interest,
and makes the outlook for the development of
their neglected fruiting possibilities seem still
more enticing.

It should perhaps be added that a few of the
fruits to be referred to here are not absolutely
inedible even in their present state. But no one
of them is to be compared with our standard

INEDIBLE FRUITS 375

orchard and garden fruits. At most they show
promise of development.

Almost any one of the potential fruit bearers
about to be named offers inviting opportunities
for the fruit developer. And some of them are
so readily accessible and so responsive to efforts
made in their behalf as to make particular appeal
to the amateur.

Improving the Barberry

Those who have seen the common barberry
with its beautiful, hollylike leaves and abundance
of blossoms in the early spring, and who have
also noted the attractive crimson fruit it bears in
the fall, will readily understand why the im-
provement of this shrub was undertaken with
particular reference to making its fruit attractive
to the palate as well as to the eye.

This is a member of a rather large company of
plants that combine decorative appearance with
the capacity to bear valuable fruit. But it is well
known that the possibilities of the barberry in the
latter regard have never been developed beyond
the initial stages.

Beautiful as the fruit is, it is altogether inedible
(except when it is utilized for jelly) or was at
the time when my experiments with the plant
began.

376 LUTHER BURBANK

When I say that this work with the barberry
was taken up more than twenty-five years ago,
and that I have not as yet produced a variety
that seemed worthy of introduction as a fruit
producer, it will be understood that this plant is
not among those that are specially responsive to
the efforts of the plant developer.

It should be explained, however, that the work
with the barberries, although it has involved the
growing of thousands of seedlings of various spe-
cies, has been carried out mostly along the lines
of selection, without the aid of hybridizing. It is
almost certain that crossing the different species
would have resulted in carrying the work for-
ward far more rapidly. But the pressure of
other work has kept me from undertaking this,
and I have been content to select the best speci-
mens of the various species, generation after
generation, up to the present time, and thus to
advance somewhat slowly, although on the whole
rather surely, preparatory to getting improved
varieties of each species for crossing.

The most promising of the barberries from the
standpoint of the fruit grower is probably the
common species familiar in many regions as a
hedge plant and known botanically as Berbcris
vulgaris. The genus has many other species,
however, and the fact that these tend to vary

INEDIBLE FRUITS 377

indicates to the plant breeder that they have in-
herent possibilities of improvement. In the
course of this work I have imported other species
of barberries from South America, British
Columbia, Asia, Europe, and northern Africa.

Some of these have proved of value, but the
most important advance has been made by the
progeny of the common barberry.

During the course of the twenty-five years of
experience with this plant, I have been able by
persistent selection to facilitate the development
of a fruit much larger than that of the parent
form, far better flavored, and with a greatly re-
duced proportion of seed. The fruit has not
changed very markedly in appearance, but is
produced much more abundantly.

It has all along been noticed that when seeds
are planted there is a marked tendency on the
part of most of the progeny to revert toward the
wild state rather than to go forward, according
to man's interpretation of progress. So it is only
the exceptional plant that can be saved with any
prospect of producing unusually valuable fruit.
Nevertheless, as already noted, there has been
marked progress and it is always to be remem-
bered that such progress tends to be cumulative
and that there may come a time when the plant
may vary suddenly and give opportunity for

878 LUTHER BURBANK

much more rapid development, a critical point
having been reached by previous generations of
culture.

It is probable that the final development
through which the barberry is made to bear a
really valuable fruit will come about through
hybridizing the familiar species with somewhat
different relatives from other lands.

Material for such hybridizations are now in
hand, as I have large quantities of seedlings of
six or seven different species.

Two of these species came from the Patagonia
and Chile regions. One is a plant called Berberis
buxifolia, and known to the natives as Calafate.
Like many of the barberries the plants are quite
thorny. The berry is blue-black in color and the
natives of Chile use it to make a liquor said not to
be unlike gin.

In addition to this foreigner and a Russian
species which produces black fruit, and another
producing nearly spherical red fruit, there are
several native species that may perhaps be ad-
vantageously brought into the cross when the
hybridizing experiments are undertaken.

These include the two western barberries
(Berberis repens and Berberis nervosa) some-
times classified as a subgenus called Mahonia,
and colloquially sometimes called Oregon grapes,

INEDIBLE FRUITS 379

because of the clusters of bluish-black fruit.
These are both handsome dwarf evergreen
shrubs abundant from British America to central
California, also in Colorado. There is also a
purple-leaved variety, otherwise not unlike the
common barberry, and there are varieties with
variegated white or yellow leaves and varieties
bearing white, yellow, and black fruit, in striking
contrast to the red fruit of the common species.
Moreover there are varieties with seedless fruits.

All in all, then, there is opportunity for such
blending of racial characteristics as should give
the hybrid barberries an impetus to variation,
and afford opportunity for rapid development.

My experiments in selection may be regarded
as constituting pioneer work, and as affording
material for the hybridizing experiments through
which the plant may be perfected as a fruit
bearer. Already the fruit has been made larger
and of better flavor, and the seeds have been
minimized. With the aid of crosses of the species
named, and also, probably, with the introduction
of the racial strains of a wild species of western
Texas, Utah, and Mexico (Herberts Fremonti) ,
which I now have under culture, and which some-
times bears fruit of exceptional size and superior
quality, though not as abundantly as most other
species, it should be possible to produce a new

THE EL^EAGNUS OR GOUMI
BERRY

The original Goumi berry, as im-
ported by myself some thirty-five
years ago from Japan, was a very
astringent fruit, and with a very thorny
stem. Through selective breeding we
have had good success in eliminating
the thorns and in improving the fruit.
This is one of my thornless varieties.
(About one-third life size.)

INEDIBLE FRUITS 381

race of barberries that will be a valuable addition
to the rather meager list of small fruits.

Improving the El^agnus

During the early years of my work in Cali-
fornia I kept in close touch with all the importa-
tions made from Japan by the H. II. Berger Co.,
of San Francisco, and others. From them I
received, among other plants, a curious fruit-
bearing plant from Japan, known in its native
country as the Goumi berry, and classified by
botanists as Elceagnus longipes.

No other importation of a member of this
genus had hitherto been made, so I viewed the
plant with particular interest, and was especially
struck with the seeming possibilities of improv-
ing its fruit.

The Elceagnus longipes bears flowers of a
bright, brownish-yellow color, subject to a good
deal of variation. The fruit is a berry of varying
shades of crimson, rarely changing to yellow.
The flavor of the fruit is far from inviting. After
one has tasted five or six of the berries, one is
scarcely able to describe the flavor or to decide
whether others have any desirable quality.

The astringency of the fruit is so great as
nearly to obliterate one's sense of taste after two
or three have been tested.

382 LUTHER BURBANK

Perhaps it should be noted that the tasting of
fruit for the purpose of testing its quality be-
comes a rather unwelcome task for the fruit
developer even when the fruits under considera-
tion are plums or peaches or other orchard fruits
of the finest quality.

People have often assured me that they would
consider it a very great privilege to test different
fruits by the hour.

But such an offer only showed their inexperi-
ence. No one cares for fruit after he has tested a
certain number and the necessity of tasting one
kind after another becomes for the fruit devel-
oper who operates on a large scale a highly dis-
tasteful task. If this is true when fruits of fine
quality are in question, it must obviously be
doubly true of undeveloped fruits like the Goumi
berry, the testing of which gives nothing but dis-
comfort from the outset.

But it is equally obvious that no progress can
be made unless the fruits are constantly tested
in order to select the best for the continuance of
the experiment. And as there is no known sub-
stitute for the human palate in making such
selection, the tasting of fruits is an unavoidable
part of the plant developer's everyday work.

In the case of the Goumi berry, my efforts at
selective breeding have been rewarded by the

INEDIBLE FRUITS 383

notable progress of the plant, first in the elim-
ination of the thorns, and secondly, in the im-
provement of the fruit.

Here and there I have found a seedling, the
fruit of which is pleasant to the taste, and by
selection through successive generations a vari-
ety of Elceagnus has been produced that gives
great promise.

My experience with the genus has included
tests of five species, bearing the specific names of
Elceagnus angustifolia, E. umbellata, E. pun-
gens, and E. argentea, in addition to the original
E. longipes. There are three closely related
plants also belonging to the Oleaster natives of
North America, these being E. canadensis
(sometimes called Shepherdia canadensis),
Lepargyrea argentea, the buffalo berry (called
Shepherdia argentea), and E. argentea, the
silverberry of the far Northwest; all somewhat
similar plants in general appearance, but quite
different from the Elseagnus of the Eastern
Hemisphere. The seeds should be treated like
those of the pear — removed from the fruit when
fresh, thoroughly washed, and kept fairly moist
until planting time.

The seedlings grow rather slowly at first, but
offer no particular difficulties. I have tried to
cross the different species, but thus far without

384 LUTHER BURBANK

success, chiefly because the plants bloom at
widely different seasons.

Up to the present, therefore, the improvement
has all been due to selection and to crossing
within the species. After many years of selec-
tion my stock of E, longipes has finally been
reduced to a single plant, a large bush bearing
most abundantly each season. The fruits are
large and of very good quality. Indeed, the
improvement has been so marked that it is not
unlikely that this variety, when it has been more
fully tested, will be introduced. It has certain
attractive qualities that seem to make it worthy
of a place in the fruit garden.

The best varieties of the American Elceagnus,
especially the buffalo berry and the silverberry,
are well worthy of cultivation, and extremely
promising for work, being enormous bearers of
pleasant-flavored, currantlike fruit, which in the
wild state is often collected for making jellies,
and is far better in quality than the Goumi berry
of Japan, although very much smaller.

The best of all these species bear fruit in
astounding quantities. The crossing of the best
varieties of the American and the Asiatic Elceag-
nus gives as good promise of important results
as any fruits that I can mention.