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http://www. archive.org/details/cu31924008976866

Artichoke Blossoms

Doubtless many people who eat the artichoke fail to
realize that they are consuming a flower bud. But such is
really the case. If the head with its many succulent bracts had been
allowed to come to maturity, it would have been a composite
flower, like the one here shown. But for use on the
table, the bud must be plucked before it opens.

LUTHER BURBANK

HIS METHODS AND DISCOVERIES AND
THEIR PRACTICAL APPLICATION

PREPARED FROM
HIS ORIGINAL FIELD NOTES
COVERING MORE THAN 100,000 EXPERIMENTS
MADE DURING FORTY YEARS DEVOTED
TO PLANT IMPROVEMENT

WITH THE ASSISTANCE OF

The Luther Burbank Society

AND ITS
ENTIRE MEMBERSHIP

UNDER THE EDITORIAL DIRECTION OF

John Whitson and Robert John

AND

Henry Smith Williams, M. D. LL. D.

VOLUME VII

ILLUSTRATED WITH
105 DIRECT COLOR PHOTOGRAPH PRINTS PRODUCED BY A
NEW PROCESS DEVISED AND PERFECTED FOR
USE IN THESE VOLUMES

NEW YORK AND LONDON

LUTHER BURBANK PRESS
MCMXIV

be

A009 H

Copyright, 1914, by
The Luther Burbank Society

Entered at Stationers’ Hall, London
All rights reserved

VII

Volume VII—By Chapters

Ore WGI 2 soccaleunancece causa eal bhee Page 3
How to Get the Most
Out of the Garden
—A: Preli
Outline 7

ee ee eee ee ee eer ee eer eee ey

Some Common Garden Plants
and Their Improvement
—Half-Hour Experiments
With Many Plante, ..........cccccccessccessceesseees 39
Peas and Beans as
Money Crops

—Improvements Which
Premise Much 73

The Tomato—and an Interesting
Experiment

—A Plant Which Bore Potatoes Below
and Tomatoes Above... ,.........cccsecsscecsssessces 109

Pink Chives—and Other

Foods for Flavor

—Some Successful Work With 5
the Onion Family, ..........cscscsscceescesesscesseees 14

Artichokes—and Some

Garden Specialties

—Finding New Food Plants
Wild in the Woode...0--.c.scsesscssesesesseeseesees 179

Winter Rhubarb—and Other
Interesting Exotics

—The Possibilities When Plants are 2 09
Brought From the Tropica, ............sccceascesseees

The Camassia— Will It
Supplant the Potato?

—And Other Tubers of
Value for F00d . 355 sities ai ss vieiaraasisiaicreris Seasons 239

The Potato Itself—Who Will

Improve It Further?

No Plant Is Ever a Finished Product— 2 67
Potato Suggestions, .,........ceeccescescecnasneeestees

List of Direct Color Photograph Prints.......... 305

FOREWORD TO VOLUME VII

This may be called the Vegetable Volume. In
it, Mr. Burbank gives the details of his experiments
in gardening, and an outline of his viewpoint, not
alone for the benefit of the man who takes a lively
springtime interest in his kitchen garden, but for
the man, as well, who grows vegetables for the
market.

Nor is attention directed solely to the com-
moner forms of garden vegetables, a wide range
of hitherto unthought-of food plants being dis-
cussed as well.

In this volume will also be found a complete
history of Mr. Burbank’s work with the potato
and a sketch of the improvements, which, for
more than forty years, he has been striving to
make, together with his suggestions to those who
would like to take up the work of bettering this
important crop.

THE EDITORS.

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.qupjiodun Ayyfiy Dp ajnjiys
-u02 flay} ‘amp flay} sp AuLl
‘ajpnaa1a API pvad suoj}
-njos jualajnu ayy yorya
y6noiy} sjjom uTye ym

+ wmspjdojoid jo sjuaumly

fiuyy yng ‘asuas sadosd ay}
ui saipy jou asinoa jo aD
‘pajypa-os ‘sary Jooy *}1DS
jualzmu yum uapD] aan}
-slour dn ayD} 0} syjnour
sp aadas ‘flos ay} Buljp4}
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yyim papjaoid arp ‘abp}s
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sjoo1 Jno umory} spy JoYR
paas OSwujoulusiad pv
smoys ainjajd sty

SJIDH JOoYy
juvjiodul] ay]

How To GET THE Most
OUT OF THE GARDEN

A PRELIMINARY OUTLINE

F course you have heard of the feat of
O growing a mango tree, as performed by
the Hindu jugglers.

The trick consists, according to those who claim
to have witnessed it, in causing a mango tree to
grow to fair proportions before the eyes of the
audience from a pot which at first contained no
visible plant.

The plant appears first as a small sprout and
then grows to tree-like proportions under the ma-
nipulation of the conjurer before the very eyes of
the astonished witnesses.

I believe modern skepticism, aided by the
camera, has demonstrated that what the juggler
really does is to throw a hypnotic spell over his
audience and to cause them to confuse the magic
picture of his word-conjuring with actual vision.
But even if we were to take the feat of mango

[VoLume VII—Cnapter I]

LUTHER BURBANK

growing at its face value, it would still be no more
miraculous, properly interpreted, than things we
may observe everywhere about us— say in any
vegetable garden—or that you may yourself per-
form at any time in your own room.

Suppose, for example, that you were to take a
tiny seed no larger than a grain of sand, and place
it in a bowl on the window-sill.

You may leave it there indefinitely and it will
give no sign that it differs in any wise from the
grain of sand.

Yet if you wish to perform a miracle along the
lines of that alleged to be performed by the grower
of the mango tree, you have only to pour a tum-
blerful of water over the seed. Then in due course
a transformation will be effected. The little seed
will germinate and put forth a sprout and a sys-
tem of rootlets and lift its head into the air and
presently develop a bud that will swell and open
into a beautiful flower.

This, surely, is a feat of conjuring that more
than duplicates the alleged miracle of the Hindu
fakir even though we were to take that perform-
ance at its face value.

To be sure, we have required more time for
our miracle than he required for his; but what,
after all are a few days more or less in the per-
formance of such a feat? And, indeed, are we not

[8]

ON GARDENING

entitled to a little latitude of time considering that
our miracle, which includes the creation of a beau-
tiful flower, is so much more wonderful than his?

Perhaps you are inclined to demur, and to say
that your miracle of flower-growing is no miracle
at all because you had nothing to do with the mat-
ter. The growing of the plant, with its ultimate
production of the flower, you will perhaps allege,
was altogether the work of nature; a work in
which you had no share.

Not so; for had not you supplied the cupful of
water, nature would have been as powerless to
transform the seed into a flower as you would be
to transform the water into a flower without the
aid of Nature.

Your feat of jugglery, like that of any other
conjurer, required appropriate paraphernalia and
the aid of an accomplice.

You chose as paraphernalia a tiny seed and a
cup of water; and for accomplice you chose Na-
ture herself.

You invoked the aid of natural laws, just as
every other conjurer must do; and the results you
finally achieved were surely more wonderful, more
mysterious, more inexplicable than the results of
any other kind of trick that human ingenuity could
devise.

In effect, you held a cup of water before your

[9]

LUTHER BURBANK

audience, waved your hand over it with magic in-
cantations, and transformed the water into an ex-
quisitely petalled and perfumed blossom.

Who could ask to witness a more marvelous
feat of jugglery than that?

Yet such miracles as this are matters of every-
day observation with the gardener. Is it strange
that he finds peculiar fascination in his work and
sees in his plants something more than the mere
combinations of root and stem and tuber and seed-
pod that they present to the casual observer?
Rather to the gardener who goes about his task
with the right spirit must every plant appear as
the most wonderful of laboratories in which mir-
acles of transformation, outmatching the utmost
feats of the most skillful conjurer, are being per-
formed every hour.

Tue ALL-IMPORTANCE OF WATER

I have chosen the imagined incident of the
flower seed grown in the bowl on your window-
sill because I wished to emphasize the important
principle that the one essential element without
which no plant can maintain life or take on growth
is water.

The plant grower has always given much heed
to soil. He talks of sandy loams and clayey earth,
and of humus and fertilizers. And all these, as
we shall have occasion to see presently, have vast

[10]

Baby Plants

The leaf-like appendages put forth from a germinating
plant when it first comes from the ground are called cotyle-
dons. The entire coteries of higher plants are divided into two great
classes, accordingly as their germinating stalks put forth one or two
cotyledons. All the plants with which one deals in the garden are
di-cotyledons, like those here shown. The cotyledons are uniformly
smooth in contour (Mr. Burbank has seen but a single ex-
ception to this in his entire experience), and they
serve as a reserve supply of food while the
young leaves are getting under way.

LUTHER BURBANK

importance. Yet in the last analysis the constitu-
tion of the soil—the very existence of the soil it-
self —is of incidental or subsidiary significance
only in the plant economy. The richest soil that
was ever prepared would not grow a single blade
of grass or the tiniest weed if that soil were abso-
lutely dry.

Nor could the hardiest weed maintain exist-
ence for a single day if transplanted into a soil,
be it never so rich, that is absolutely devoid of
moisture.

There must be water in the soil, to dissolve out
and transfer its elements, in order that the rootlets
of the plant shall be able to make the slightest use
of these elements. Every essential constituent of
plant food may be present in just the right pro-
portions in soil that is packed about the roots of
the plant with just the right degree of firmness,
and yet the plant would perish as inevitably as if
it were uprooted and suspended in the air, if there
were not water present to bring the food materials
into a state of solution.

But on the other hand, as we have seen, a plant
may grow and thrive for a time quite without the
presence of soil of any kind or quality if its roots
are placed in water.

If we look a little farther into the intimate
structure of the plant, utilizing the knowledge

[12]

Illustrating Leaf

Structure

The leaf at the
left presents the up-
per surface, and that at
the right the lower sur-
face, It will be seen that
the upper surface is more
smooth and glossy, in con-
trast with the more clearly
ribbed and reticulated
lower surface. The ali-
important stomata, or
breathing pores, are
largely located on the
lower side of the leaf.

LUTHER BURBANK

gained with the aid of the microscope and the stud-
ies of the chemist, we shall quickly come to under-
stand why it is that water plays this all-important
part in the functions of plant life. For it appears
that the essential basis of life itself, namely, pro-
toplasm, is a substance composed largely of water
and having the physical constitution of a viscid
liquid.

We find, moreover, that no particle of solid
matter can, under normal conditions, penetrate the
walls of the cells that make up the minute com-
partments in which the individual masses or pro-
toplasm lie.

Ramifying everywhere among these are spaces
and tubules that convey water and air. And por-
tions of this water and air are absorbed by the bits
of protoplasm through their cell walls.

With the water they gain the mineral constit-
uents that are essential for their nourishment. But
these include no minerals that are insoluble.

It is true that the plant rootlets may on occa-
sion secrete certain fluids that aid the water in
bringing into solution some intractable chemicals.
But these secretions themselves are watery fluids
and they would be ineffective if there were not
water present to complete the work that they begin.

In a word, then, the all-essential element for
which provision must be made by the gardener or

[14]

ON GARDENING

other plant developer is water. Where water is
present, anywhere in the world, we find plant life
luxuriating. Where it is absent, we find the des-
erts. There is no acre of soil anywhere that might
not produce its crop of vegetation if properly wa-
tered. And, on the other hand, some of the rich-
est soils in the world are those that are absolutely
barren and fully merit the designation of desert
lands because water is lacking.

Of course the gardener in many regions is sup-
plied with water in adequate quantity for his
plants by the natural rainfall and may disregard
the question of artificial irrigation. But even in
regions where the rainfall is usually adequate,
there are almost certain to come periods of
drought and the wise gardener who wishes to
make sure of his crop will make provision for the
meeting of this emergency.

Even where the soil is fairly moist, it is often
possible to force the growth of a plant by addi-
tional watering.

You may readily test this for yourself by the
free watering of alternate plants in a row in a time
when the rainfall is only moderate. You may thus
produce giants and dwarfs, say in a row of toma-
toes, from the same lot of seed, under conditions
which are absolutely identical except as to the
matter of water supply.

[15]

Leaves by the Acre

Probably no one ever had time and patience, or thought

it worth while, to measure the leaf surface erposed by the total
foliage of a large tree. But one may readily enough measure a few
leaves, and make an estimate; and it then appears that the leaf sur-
face of a good sized tree must be measured in acres. When we re-
flect that the breathing pores are scattered thickly over the under
surfaces, and sometimes over the upper surfaces also, of the leaves,
and reflect that under normal circumstances each pore is taking in
air and giving out moisture, it no longer seems surprising that a tree
must send its roots far into the earth in search of water, or that the
carbon taken from the air can build up as rapidly as it is observed -
to do the bulk of the tree trunk, A few leaves spread out together,
as in the picture, give one a realizing sense of the way in which the

surfaces take up space, Remember, too, that each leaf

has a lower surface, doubling the_area here exposed.

ON GARDENING

Of course it is possible to overdo the matter,
super-saturating the soil and so shutting off air
from the plant roots. But that aspect of the sub-
ject will claim our attention in another connection.

How THE PLant Uses WATER AND AIR

If we would have a clear comprehension of the
function of water in a plant, we must go a little
more fully into the physiology of plant growth, fol-
lowing the water, with its salts in solution, from
the rootlet by which it is absorbed up through the
stem of the plant to the leaf.

In an earlier chapter something has been said
as to the forces that operate to make the water rise
in seeming defiance of gravitation from the root
to the leaf system of a plant of whatever size. The
rise of the watery juices in a garden plant does
not seem, perhaps, quite as mysterious as the rise
of the sap in a tall tree. But there is no difference
in principle. The laws that govern the movement
of the sap are quite the same in each case.

We saw that there is reason to suppose that the
principle of osmosis, acting between the cells, has
an important share in transferring water from one
cell to another, and ultimately, step by step, from
the root to the topmost leaf.

It should be added, however, that the entire
subject of the rise of sap in the tree has been mat-
ter for debate, and that there is not entire una-

[17]

LUTHER BURBANK

nimity among plant physiologists as to the forces
that are involved. That osmosis has a share, no
one doubts. But it is alleged that the principle of
capillarity through which liquids are drawn into
minute tubes also has a share in elevating the
water in the plant.

And it is further suggested that the constant
transpiration of water from the leaves of the
plants acts as a sort of suction force drawing the
water upward. It should be understood, however,
that this alleged suction power, when analyzed, is
nothing more than a drying out of the cells of the
leaf which makes them more absorbent and thus
brings into play the principles of osmosis and cap-
illarity through which they take up a new supply
of water from neighboring cells.

Thus, properly understood, the effect of trans-
fusion of water from the leaves is to be interpreted
in terms of osmosis, and capillarity.

So also must be interpreted the so-called root
pressure through which water is forced upward
into the stem of the plant at a time when the plant
has no leaves—as in case of a tree in the early
spring time. Such root pressure undoubtedly ex-
ists, but this also is explicable as due to the ab-
sorption of salts in solution by the rootlets from
the water in the soil about them, leading to osmotic
action between these superficial cells and the ad-

[18]

Where the Tree Is Alive

This section of the trunk of a small tree is pictured in

such a way as to expose the Cambium layer, just beneath the
outer bark. In this layer are located all the protoplasmic cells, aside
from those in the leaves, that are really alive, <A portion of the
woody tissue just beneath the Cambium conveys the watery solution
upward from the roots; but the return flow of sugary sap takes place
solely in the Cambium layer, where also the protoplasmic or life

activities go on, through which the tree grows; growth itself

being due to the deposit of what is virtually waste
material from the cell. The central wood
fibers of the trunk are totally dead.

LUTHER BURBANK

joining cells, which in turn pass the water, with
its modicum of nutrient salts, to yet deeper layers
of cells, and ultimately up along the stem of the
plant or tree—constituting the familiar phenom-
enon of the “rise of sap.”

Regardless of the precise explanation, however,
the fact is obvious and long familiar that water
bearing a certain quantity of minerals in dilute
solution is absorbed by the roots of the plant and
is carried up in due course to the ultimate buds
and growing tips and leaves.

It has been known for a good while also that
the leaves of the plant have on their under surface
vast numbers of little mouths or stomata, through
which a certain amount of the water that has come
to them from the roots is transpired or exhaled,
and through which also air is inhaled.

But it has only somewhat recently been learned
that the air which thus enters the structure of the
leaves is transmitted everywhere throughout the
tissues of the plant, through little crevices or ca-
nals that may be likened to the bronchial tubes of
an animal or of man, except that they are infini-
tesimal in size,

Through these channels, air is brought in con-
tact with all the cells of the plant, and, during pe-
riods of growth, there is a constant, even though
slow, interchange between the air in the inter-

[20]

Mr. Burbank’s
Ideal Soil

Such piles of soil
as that here shown are

always at hand in and
about Mr. Burbank’s green-
house. The soil consists
of about fifty per cent. of
clean, rather coarse, sharp
sand; forty per cent. of
good pasture or forest soil,
containing leaf mold; and
about ten per cent. of finely
ground moss. This makes
an ideal soil for the seed
boxes, and seeds of any
and every kind may be

germinated in it.

LUTHER BURBANK

cellular spaces and the structure of the protoplasm
within the cells.

This interchange includes the absorption of
oxygen and the giving out of carbonic acid on the
part of the plant cell, which is precisely the same
thing that occurs in the functioning of the cells
in the tissues of an animal. In point of fact the
essential properties of protoplasm are the same,
whether that protoplasm is found in the tissues
of a plant or in the tissues of a man.

Plants, like animals, in breathing take in oxy-
gen and exhale carbonic acid gas.

PLanT CELLS AND ANIMAL CELLS

This fact, as was said, has not been clearly
understood until somewhat recently.

The phenomenon of the absorption of oxygen
and the exhalation of carbonic acid has been ob-
scured in the case of the plant by the further fact
that the plant leaf absorbs constantly from the air
during the daytime, under the influence of light,
a relatively large quantity of carbonic acid gas
from the minute quantity in the air, so that the
net result is that it takes up from the air more
carbonic acid than it exhales.

It was only by studying the plant in the dark,
when the elaborate processes through which it
utilizes the excess of carbonic acid are in abey-
ance, that the fact of the close analogy between

[22]

ON GARDENING

vegetable protoplasm and animal protoplasm as
to the ingestion of oxygen and the giving out of
carbonic acid as a waste product was demon-
strated.

Now it is known, however, that the protoplasm
of a plant cell, as it exists in the root and trunk of
a tree, for example, and indeed in any part of a
plant where there is no green matter, not only
functionates in the same way as the protoplasm of
animal cells, in regard to absorbing oxygen and
giving out carbonic acid, but that the two have
precisely the same food habits in general.

The average plant cell, as it exists in the root
or stem of the plant, is in precisely the same
position as the cells of an animal, in that it can
secure nourishment only from food that has been
prepared in a particular way.

It can no more take a crude solution of mineral
salts and extract nourishment from them than can
the animal cell.

All the necessary constituents that go to make
up the best food may be present, but neither the
plant protoplasm nor animal protoplasm can
make use of these constituents unless they have
been compounded in a unique and extraordinary
way.

But when we consider the matter one stage
farther we come upon this vital difference: the

[23]

Transplanting Selected Seedlings

Here some seedlings grown in the ideal soil in Mr. Bur-
bank’s regulation type of ‘‘flat’ are being transplanted at a
very tender age. The process is very simple, being effected with the
aid of a knife blade, as the picture clearly shows. There
is no particular rule about it, except to be sure that
you get all the roots of the tiny plant.

ON GARDENING

plant, unlike the animal, has provided a special
mechanism—a unique laboratory—through which
it is able to manufacture from the crude salts in
watery solution, with the aid of another element
taken from the air, a new compound which will
serve the protoplasmic cell with food.

That is to say, the plant organism as a whole,
comprises a laboratory for compounding the crude
elements, which by themselves cannot be used as
nourishment, into a substance that can be used as
nourishment.

Stated in slightly different terms, every well-
organized plant has a food factory as part of its
regular equipment.

Here indeed is a difference and a very vital
one between the plant and the animal. For no
animal is equipped with such a food factory as
this.

And when we add that the food factory of the
plant is the only place in the world where food
stuffs are manufactured, and that no animal of
any kind could live an hour without nourishment
that was originally manufactured by some plant,
the vital importance of the matter will be manifest.

THE Puiant’s Foop Factory

Now of course the plant in operating its won-
derful food factory is functioning to supply its own
needs.

[25]

LUTHER BURBANK

It must supply nourishment to the multitudin-
ous cells that make up its root and stem and
branches, which, as we have seen, are quite in-
capable of extracting nourishment from the crude
salts in solution that they are constantly trans-
porting.

But incidentally, in manufacturing food for its
own cells, the plant is producing a supply of food
that will be available for the sustenance of animal
cells also. Thus the entire animal world may be
said to be a vast parasitic colony as absolutely
dependent upon the vegetable colony for its essen-
tial food supplies as any other parasite is
dependent upon its host.

When we consider the matter in thic light,
it is pretty obvious that about the most interesting
thing in the world, from the standpoint of animal
economy—which of course includes human
economy—is the wonderful laboratory or factory
of the plant where alone is effected the transfor-
mation of the crude inorganic elements into such
combinations as are available for the sustenance
of life.

When we reflect that the plant laboratories in
which this wonderful and vitally essential trans-
formation is effected are chiefly located in the leaf
of the plant, it appears that the thoughtful person
must regard this structure—the most ordinary

[26]

Selected Seedlings

The little ‘plants
in this “flat” have
been transplanted with a
knife blade, as shown in
the preceding picture, te
give them an opportunity
to show their possibilities.
They are set out carefully
in rows—for Mr. Burbank’s
work is always neat and
artistic; but the new soil
does not. differ from that
in which they were germi-
nated. The only difference
is that here the planis are
no longer crowded, and
each can be given individ-
ual attention. The com-
paratively few individuals
here shown may be ail
that are left from the
scores of “flats’”’ that orig-
inally germinated thou-
sands of seedlings.

LUTHER BURBANK

green leaf of tree or shrub or vine or the tiniest
blade of grass—as in some respects the most
wonderful thing in the world.

When the wise plant developer goes into his
garden or orchard, therefore, his eyes turn always
first and foremost to the leaves of the plants with
which he works.

The reader will perhaps recollect that over and
over I have called attention to the predictions that
may be made as to the future fruiting powers of a
given plant—apple seedling or pear seedling or
grape seedling or what not—from observation of
the leaves. The reason for this will now perhaps
be more apparent. It will be still more clearly
evident if we inquire a little more in detail as to
the exact processes that take place within the
structure of the leaf-laboratory in which is brought
about the all-essential manufacture of food on
which the future growth of the plant itself and
its fruiting possibilities must absolutely depend.

No one needs to be told that all normal leaves
are green in color. But perhaps it may not have
occurred to you what a really remarkable fact this
is. The trunks and branches and roots of plants
may vary widely in color; and flowers and fruits
may show all diversities of the rainbow. But from
one Arctic circle to the other and around the
circumference of the globe, plants of every tribe

[28]

ON GARDENING

(with the rare exception of parasites which take
food predigested by the green plants), from the
minutest creeper to the most gigantic sequoia or
palm or eucalyptus, have leaves of the same
primary color.

And the reason for this is that the leaf derives
its color from the massed effect of little structures
called chlorophyll granules that nestle in its indi-
vidual cells, constituting the really essential part
of its food-forming laboratory. These have
adopted a green uniform as the insignia of their
office, and they hold as rigidly to this color as if
their very lives depended upon it. And for aught
we know to the contrary, their lives may depend
on it; for no one has yet been wise enough to say
just what relation the color bears to the wizard-
like powers of the so-called chlorophyll granules
that wear it, and that, seemingly with its aid,
effect the marvelous transformation of inorganic
elements into food-stuffs of which they alone of
all created things are capable.

As I say, no one knows just what relation the
green color of the chlorophyll granules bears to
their work because no one knows just how their
work is performed.

That is to say no one at all understands why it
is possible for the plant cell that bears within its
substance one of these green chlorophyll bodies to

[29]

Inspecting a Root System

Should a question arise in Mr. Burbank’s mind as to why
a particular plant is not thriving just as it ought, he may “go
to the root of the matter” in a literal sense, to see if he can find out
what is wrong. Of course such an examination must be made very
carefully, and it is not to be recommended as regular treatment for
many plants, but on occasion it may be of service to dig into the
ground beside the plant, and find out how its roots are getting
on, A young plant with defective roots is in precisely
the position of a child with very bad _ teeth,—it
cannot possibly get proper nourishment.

ON GARDENING

combine certain inorganic elements into nutritious
foods, a feat that no human chemist can perform.

But on the other hand, we do know, thanks to
the analysis of the chemist—who can sometimes
tear things to pieces and find out what they are
made of even when he cannot put them together
again—what the chlorophyll granule accomplishes,
even though we cannot understand just how or
why it is able to perform its work.

CHLOROPHYLL AT WorRK

What takes place within the structure of the
leaf, then, with the aid of the wonderful green
workmen, is this: A certain number of molecules
of water, brought to the leaf from root and stem,
are taken in hand and compounded with a certain
number of molecules of carbon extracted from the
air that has been brought into the leaf laboratory
through its mouths or stomata from the outside
atmosphere.

When the compound has been effected, we still
have the atoms of hydrogen and oxygen that com-
posed the water molecules and the atoms of
carbon, but they are so marvelously put together
that they no longer constitute the liquid water or
the gas in which the carbon was imported. They
now constitute an altogether new substance which
is termed sugar.

Thus only three elements are dealt with and

[31]

LUTHER BURBANK

these very familiar ones. It would seem as if
almost any chemist should be able to manage a
simple combination like that. But in point of fact
no human chemist knows how to manage it. There
are forces to be invoked in effecting that combina-
tion of which no chemist has any knowledge.

Only the chlorophyll grains in the plant leaf
have learned the secret, and up to the present they
have kept their secret well.

There are other feats of atom-juggling per-
formed with the new compound that are wonderful
enough. For example, the sugary compound is
ordinarily transformed, in part at least, into
granules of starch to be stored away for safe
keeping. And this transformation implies a bit of
juggling that is by no means easy. But after all it
is only the changing of one organic compound into
another, and the human chemist can do some
extraordinary feats in that line. The really won-
derful work done in the leaf laboratory is the
original transformation of inorganic materials into
an organic compound.

Of course there are other important stages of
the work through which final assimilation is
accomplished. To make starch or sugar into
protoplasm it is necessary to bring another element
into the combination. This element is nitrogen.
There must also be incorporated small quantities

[32]

Artificial Rain in Mr. Burbank’s Garden

The kind of sprinkling apparatus that Mr. Burbank uses
and recommends is that here shown, It consists of long pipes,
attached to a hose, the pipe having little nozzles at intervals of a few
inches, and thus sending forth a series of tiny streams which, rising
high in the air, descend on the plants in a shower that closely simu-
lates rain from the clouds. The pipes can be turned to
throw the spray in either direction, and to regulate the
distance at which the shower descends, Remem-
ber always that water is food for the
plants,—absolutely indispensable food.

LUTHER BURBANK

of a number of minerals; notably compounds of
phosphorus and potash and lime, but including
six or eight others that must be present in in-
finitesimal amounts.

And the building of these substances into
combination with the sugar in such a way as to
produce the substance called protoplasm, the basis
of all life, constitutes the culminating stage of the
miracle. But the way in which this is effected is
even less clearly understood.

We do know, however, that all these substances
are brought to the plant in watery solution.

Nitrogen constitutes about four-fifths of the
atmosphere, as everyone knows, and hence it
seems rather strange that the plant does not draw
what nitrogen it needs from this source, in par-
ticular since it gets its carbon from the air.

But in point of fact the plant, no less than the
animal, might starve to death from lack of nitrogen
even while its tissues are everywhere bathed in
nitrogen gas. To make the nitrogen available for
the purpose of nutrition it must be made into
soluble compounds called nitrates, and must be
supplied in dilute watery solution.

Such nitrates, therefore, are among the most
important of the soluble compounds that must be
contained in the medium surrounding the roots of
the plant. Sucked up by the rootlets in dilute

[34]

A Beautiful Thief

The mistletoe has green leaves, and so is able to take car-
bon from the air, and to manufacture sugars and starches. But
it sends its roots into the bark of a tree, and draws its moisture and
part of its nourishment from the cambium layer and sap-wood of its
host. The seed of the mistletoe is covered with a very sticky
pulp (used sometimes for making bird-lime), which ad-
heres to anything it touches, and so is likely to find
appropriate lodgment on the trunk of a tree.
Should it fall to the ground instead,
its days are numbered.

LUTHER BURBANK

solution, along with much smaller quantities of
phosphorus and potash and the other essential
minerals, it is carried to the plant cells and ulti-
mately compounded with sugars made in the leaf
laboratory to make living protoplasm and thus to
promote the growth and development of the plant.
THE FINISHED PropuctT

This protoplasm is, of course, in the last analy-
sis the vitally important substance. Without it
there is no life. Even the chlorophyll body is
itself a protoplasmic substance and establishes its
workshop in a protoplasmic cell. All the life
processes — growing, flowering, fruiting — are
linked with the protoplasmic activities, just as are
all the life processes of animals of every kind.

But from the standpoint of the gardener, which
furnishes our present outlook, interest may be
said to center on the production of the non-
nitrogenous carbon compounds, starch and various
sugars, the creation of which in the leaf of the
plant we have just witnessed. For the chief
products of the vegetable garden (with the notable
exception of peas and beans) contain only a small
proportion of the nitrogenous matter which the
food specialist names protein. We depend for our
nitrogenous foods largely upon the animal world.

The products of the vegetable garden are stores
chiefly of carbohydrates, that is to say of starches

[36]

ON GARDENING

and sugars. These make up the chief bulk of such
tubers and roots as potatoes and carrots and
parsnips, and the main nutritious matter of the
principal garden vegetables, except, as just inti-
mated, that peas and beans have a relatively high
proteid or nitrogenous content.

After what has been said, it will be understood
that the starch and sugar content of the potato, for
example, is not developed in the tuber itself, but
is manufactured in the leaf of the plant and is then
carried down in the elaborated sap that runs as a
sort of return current to the roots and is there
deposited for the uses of the new plant next season.

In the case of the carrot and parsnip, the same
thing, of course, is true. Here a large root, with
its deposit of starch and sugar, is designed to live
through the winter and next season to supply such
nourishment for the plant as will enable it to take
on rapid growth and to develop a large quantity
of seeds. These plants are biennials and do not
fruit in their first season. It is this fact that has
been taken advantage of by man in developing
their roots and diverting them to his own uses.

PRINCIPLES VERSUS METHODS

In all this, it will appear, we have said nothing
as to practical methods of gardening. But I have
thought that a clear outline of the principles in-
volved in the all-important matter of the nutrition

[37]

LUTHER BURBANK

of the plant, and in particular a full presentation
of the reason why the leaf structure of the plant is
of paramount importance, might serve better to
prepare the would-be gardener for his task than a
mere categorical citation of methods, unexplained
as to their final purpose.

Whoever has carefully followed the outline just
given will have a clear notion of the needs of the
plant and might depend, were it necessary to do
so, on his own ingenuity to devise means for
meeting these needs.

But, as a matter of course, we shall have occa-
sion to deal more at length with specific methods
of procedure with reference to the different types
of garden vegetable when we take up in successive
chapters the story of my work in the development
of plants of the vegetable garden. And the general
methods of soil preparation, drainage, irrigation,
and fertilization are elsewhere treated in detail.

—I wish to emphasize the im-
portant principle that the one
essential element without which
no plant can maintain life
or take on growth, is water.

SOME COMMON GARDEN PLANTS
AND

THEIR IMPROVEMENT

Hair Hour Experiments With Many PLANTS

garden vegetables, all the common forms
fall into a few groups.

Thus there is the great family of melons and
squashes, technically known as the gourd family,
which gives us such familiar vegetables as the
gourds and squashes, the pumpkin, the water-
melon, and muskmelon, and the cucumber.

Then there are the cabbages of various types,
with which is botanically associated the turnip,
and with which the gardener will also associate
the familiar lettuce plant.

Another group includes the familiar root vege-
tables, the carrot, parsnip, and radish. These have
a characteristic manner of growth, demand some-
what the same texture of loose, sandy soil, and
respond to the same treatment.

In a quite different class are the peas and

N OTWITHSTANDING the large number of

[Votume VII—Cuapter IT]

LUTHER BURBANK

beans, which, in all their varieties, are obviously
related to one another and quite as obviously dis-
tinct from all the other members of the garden
coterie.

The onion and its allies may be recognized as
constituting a class of vegetables that supply savor
rather than nutritious principles. From the
standpoint of the gardener there may be listed a
number of less familiar plants to make up the
category of vegetables that are grown merely
because of their appeal to the palate and for the
flavor that they impart to other foods rather than
for their genuine food value.

Two other prominent plants which complete
the list of the ordinary garden vegetables of
greatest popularity are classed together by the
botanist, and indeed are to casual observation
closely similar in foliage, yet so distinct as to the
character of their product that the gardener would
never think of associating them. These are the
potato and the tomato—own cousins—notwith-
standing the widely different character of the food
products they supply.

Some of the plants just named will be given
individual treatment in successive chapters of the
present volume. But two or three companies, in-
cluding a wide range of species and varieties, may
be grouped together here as illustrating, jointly

[40]

An Attractive
Melon

That these improved
canteloupes are of good
quality, might have been
predicated from inspection
of their surfaces. A musk-
melon with a closely netted
or reticulated surface like
this is usually a good one.
There appears to be some
coordination between the
fineness of the network on
the surface and the sweet-
ness and juiciness of the
flesh. There is no very
obvious reason why this
should be so, unless, as is
probable, horticulturists.
have found the reticulation
attractive, and have se-
lected for this quality.

LUTHER BURBANK

and severally, the methods of the plant developer
when applied to garden vegetables, and as offering
interesting possibilities of development for the
amateur gardener.

THE MELON FAMILY

At the outset we may consider the melons,
partly because the product that they offer the
gardener may be said to occupy an intermediate
place between the fruits proper, as grown in the
orchard, and what are commonly spoken of as
garden vegetables. The melons are, indeed, fruits
of a distinctive order. They seem of unique type
to us merely because our point of fact is that of
residents of a temperate zone. In tropical regions, ©
fruits like the melons abound, the family to which
the melon belongs being a very extensive one,
represented in the aggregate by several hundred
species.

The most generally cultivated member of the
melon family in the ordinary kitchen garden is
doubtless the form known as the cucumber. The
ordinary cucumber has long been under cultivation
and has been greatly improved, especially in
Europe. It has been made to take on various
forms of fruit, and the best varieties have been
practically relieved from the spines with which
the plant was originally endowed, and partially
also of the seed.

[42]

The Familiar

Cucumber

Perhaps no other
member of the melon
family is so familiarly
known and so universally
appreciated as the cucum-
ber. This is rather sur-
prising, considering that
the vegetable has a bad
reputation as regards di-
gestability, when eaten in
the green state. The vast
Majority of cucumbers,
however, are used as
pickles; and when prop-
erly prepared they are at
once savoury and whole-
some. The cucumber un-
der cultivation is a very
thrifty plant, far less fin-
ical than its cousins, the
watermelon and the '

jmauskmelon.

LUTHER BURBANK

The common cucumber may be crossed with
the variety known as the Russian cucumber, but
in general this plant proves its individuality by
refusing to hybridize with its not very distant
relatives, such as the melons. But the other
members of the family hybridize readily. Indeed
there is so little difficulty in crossing them, that it
is necessary to plant the different species in widely
separated rows to prevent accidental hybridization
through the agency of the bees.

With the cucumber there is no such difficulty.
In our experience it refuses to hybridize with other
melons. Doubtless because of its lack of affinity
for other species, the cucumber is relatively easy
to fix as to new varieties, differing very markedly
in that respect from the squashes and gourds.

The so-called snake cucumber is in reality a
muskmelon. It will cross readily with the other
varieties of muskmelon. The product, however, is
inferior, considered either as a cucumber or as a
melon. The banana melon is probably a cross
between the snake cucumber and some other
muskmelon; or it may have originated from the
same source as the snake cucumber itself.

The banana melon has been improved by
selection until in some varieties it is a fairly good
melon, although generally lacking the high flavor
of the cantaloupe and other specialized musk-

[44]

ON SOME COMMON GARDEN PLANTS

melons Some varieties of these so-called snake
cucumbers attain a length of three or four feet,
and coil up in such a way as to resemble a serpent,
justifying their name.

A form of melon introduced, I believe, from
Syria, and known as the Santa Claus melon has
interest because it keeps well until mid-winter. It
is a longish oval muskmelon, with red and green
stripes. Its chief demerit is that it is variable in
quality, some specimens being of delicious flavor
and others distinctly inferior. It has the further
fault of cracking seriously.

In working with this variety during the past
few years, I have succeeded in largely eliminating
its faults, and in so doing have produced a type
that might be considered a new variety. My work
with the species has been entirely along the line of
selection, for I knew the danger of producing too
great variation by hybridizing the members of this
family and the almost impossibility of fixing any
variation. Most forms have originated by hybridi-
zation at no remote time in the past, and it is
far better to work with them by selecting indi-
viduals that are observed to vary rather than by
attempting to produce wider variation. By this
method alone I was enabled in a few years to
develop a form of the Santa Claus melon that was
considered worthy of introduction. The company

[45]

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ON SOME COMMON GARDEN PLANTS

that purchased it have renamed it the Florida, and
are planning to grow it along with other products
on a large tract in Florida.

Not only is it necessary to keep the muskmelons
in different parts of the garden to prevent crossing
through the agency of insects, but it is also neces-
sary to be exceedingly careful in selecting the seed
year after year, saving only that from vines that
come true to type. Otherwise the stock soon runs
out and comes to lack individuality of form and
flavor of fruit. This is because the muskmelons
have been cultivated for a very long period and
have developed many varieties that have con-
stantly been more or less crossed.

This mixed heredity is likely to make itself
manifest in the progeny of any generation, and
constant attention is necessary if a type is to be
kept pure.

The muskmelon grows best on sandy land,
and of course a warm climate is necessary to the
perfection of the fruit. It acquires a particularly
sweet, spicy flavor where the nights are warm as
well as the days. In recent years the small, green-
fleshed muskmelon, generally called cantaloup,
has become exceedingly popular. The variety of
melon known as the Casaba, which matures later
in the fall and has peculiar lusciousness, is also
much grown. This has been introduced from the

[47]

LUTHER BURBANK

Syrian region in various forms, and it thrives par-
ticularly in dry climates like that in which it has
grown for ages. It does not thrive in the moist
eastern climates, but is better adapted to semi-arid
conditions.

There are certain distinctive features of the
different cantaloups and muskmelons to which the
gardener should give attention. The light-fleshed
ones should have light skins, and the dark-fleshed
ones dark skins. The network on the skin is an
important guide in seed selection, as a fine, com-
pletely netted melon usually is of better quality
than one that is incompletely netted. These two
conditions seem generally correlated, though not
necessarily so. The flesh of the melon should be
thick, and tender throughout, except that for ship-
ping purposes it is sometimes desirable to have the
flesh a little harder toward the skin.

The seed cavity should be small, and the seeds
should be in a compact mass, occupying a mini-
mum amount of space.

Now and again one hears of attempts made to
grow seedless melons. A moment’s reflection will
show that this suggestion must be intended as a
joke. The melons are annuals, and must be grown
year by year from the seed. To eliminate the seed
would be to exterminate the melon in a single
season. The case is obviously very different from

[48]

Two Squashes

in One

Here are two speci-
mens of Mr. Burbank’s
perfected Patagonia
Squash. The one at the
left presents the face that
shows the very strange
conformation of this vege-
table. It looks as if two
squashes had been grown
together, through some
freak of nature; but in
reality this is the habitual
form of this curious vege-
table. This peculiar con-
formation gives the squash
a certain resemblance to a
monster seedless
navel orange.

LUTHER BURBANK

that of fruit trees, which may be propagated by
grafting, or of such plants as the horseradish and
potato, the roots or tubers of which carry the
species over from one season to another.

In raising melons, especially in colder climates
where the seasons are short, it is desirable to use
ammoniacal fertilizers to force the plants along
rapidly. A liberal use of one of the nitric fertiliz-
ers will often double the crop or, indeed, insure a
crop where otherwise the melons would not ripen.

The gardener who wishes to grow melons
extensively will not overlook the pomegranates
and so-called orange and pocket melons. These
have interest because of their unusual appearance,
even though they are somewhat lacking in quality.
There are also large Persian and Syrian melons
that are favorites not only for their delicious
quality but also because they keep until late in the
winter, even until the first of January with com-
mon storage. Probably in cold storage these
melons would keep throughout the winter.

Unfortunately these Persian and Syrian melons
are exceedingly variable as to quality. Some are
fully equal to the best cantaloup, while others will |
be hardly edible.

The amateur gardener might find it a useful
and interesting task to improve these melons in
this regard by careful selection.

[50]

Some
Experimental
Gourds

The gourds, like
their cousins the mel-
ons and squashes, are of
tropical origin; but they
thrive in any more tem-
perate region where the
summers are reasonably
long and hot. Mr. Bur-
bank has experimented ex-
tensively with many spe-
cies, and a few typical
specimens of gourds un-
dergoing education are
here shown.

LUTHER BURBANK

The squashes, gourds, and pumpkins constitute
a tribe of melons that differ from the watermelon
and muskmelon in that their flesh is not edible
until it is cooked.

There are great numbers of species of this tribe,
a large variety of which are under cultivation.
Among these are the forms colloquially known as
crookneck, turbine squash, giant Chile Hubbard,
bush scallop, and gourds of various types both
ornamental and useful.

The pumpkins, grown often in the cornfield of
the farmer but seldom in the garden, constitute a
form of squash rather distinct from the others, as
evidenced not only by their appearance but by the
fact that they do not cross readily with the other
squashes.

There is, however, a good deal of confusion in
the use of the names pumpkin and squash in
different regions. This is brought out prominently
in California where a squash if grown for stock
food is called a pumpkin, whatever its variety.

The earliest form of squash with which I
worked was the winter or Canada crookneck,
which in my boyhood was one of the most popular
of squashes. It had run into several forms, one
being of immense size with a short and heavier
neck. The summer crookneck squash, also com-
mon at that time, was a long, bright yellow, warty

[52]

ON SOME COMMON GARDEN PLANTS

squash, grown for summer use. Another form,
somewhat less familiar here but very popular in
England, is the vegetable marrow. The scallop or
Pattypan type of bush squash has also attained
popularity in some regions, being an especially
early variety.

There was a squash introduced some years ago
under the name of cocoanut which was a splendid
keeper, lasting from harvest time to harvest time,
although not improving in quality after the first
six months.

THE Husparp SquasH

The Hubbard squash was introduced by J. J.
H. Gregory, of Marblehead, Mass., and it is prob-
ably on the whole the best squash now under
cultivation. It is of a very rich, sweet quality and
is a splendid keeper. Mr. Gregory obtained the
first seed of this squash from the garden of a
sailor’s widow, and no one has ever found the
Hubbard squash in any other country except as
introduced from this stock. It was never known
where the sailor obtained the seeds that produced
it.

Reference has been made to the ease with
which the various squashes may be hybridized.

In point of fact it is necessary to grow squashes
of different species at a distance of nearly a quar-
ter of a mile or there is danger that they will be

[53]

LUTHER BURBANK

cross-fertilized and the strains rendered impure.
So of course the plant developer has no difficulty
in effecting almost any cross he may wish. It is
only necessary to take pollen from one flower and
deposit on the pistil of another to have reasonable
assurance that the cross will be effected.

But the results of such hybridizing are usually
altogether disconcerting. The hybrid progeny
seem to branch in every conceivable direction. A
gardener of mine declares that hybridized
squashes “go crazy”, so widely varying are their
forms and so little subject to prediction. More-
over, it is exceedingly difficult to fix any new type
thus developed or to restore an old type thus
disturbed by crossing.

Even if the hybrids do not vary greatly in the
first generation they may become entirely chaotic
in the second.

A classical illustration of this is furnished by
some experiments of Prof. L. H. Bailey, who de-
veloped a variety by crossing that seemed to come
reasonably true to type one year. Thinking the
variety fixed he sold the seed to a prominent seeds- _
man, and it was said that the following year no
two specimens of the entire lot bore any close
resemblance to each other.

This happened a good many years ago, and was
so disconcerting as to lead Prof. Bailey for a time

[54]

Too Much Seed

This picture shows
why the gourds prev-
iously shown are in need
of education. They look
very well on the outside,
but within they are mostly
seeds. The seeds of the
melon tribe are not the
part one seeks to cultivate,
and this one must min-
imize its seeds and de-
velop its pulp before it
will have any value.

LUTHER BURBANK

to question whether the laws of heredity apply to
plants as they do to animals.

Needless to say all doubt on that subject was
dissipated by wider observation. But the hybrid -
squash remains to this day one of the most difficult
plants to fix as to any particular form.

Some very interesting and useful experiments
might be made in the endeavor to sort out the
unit characters that are mosaiced together to make
up the squash. If it could be determined that
there are pairs of unit characters governing im,
portant matters of size and quality, such as are
found in so many other plants, an understanding:
of these as to their respective properties of domi-
nance and recessiveness might enable the plant
developer to hybridize the squashes and forecast.
the results of certain unions with a greater meas-
ure of assurance. But as yet little or nothing has
been done in this direction.

My own work with the squashes has included
hybridizing experiments on a somewhat extensive
scale, more for the general interest of the subject
than for the development of new commercial
varieties.

I have produced, however, one somewhat im-
portant variety from seed sent by my collector’
in Chile. This is a variety the original of which
somewhat resembled the acorn squash—having the

[56]

Some Gourds from

Australia

As the reader is
aware, Mr. Burbank
sends all over the world
for specimens to carry out
any line of experiment in
which it is desirable to in-
troduce new hereditary
tendencies, or stimulate
variation, or test out unex-
plored possibilities. These
Australian gourds are of
interest because no one
can say what may result
when they are crossed
with gourds from other
continents. The results
are likely to be notable,
and they are sure to be of
interest. Such tests are
now being made in Mr.
Burbank’s gardens.

LUTHER BURBANK

form of a rather irregular acorn in its cup, giving
it a unique appearance. This is of very large size
and it will grow on dry land where other squashes
do not thrive, attaining a great weight.

The vines first grown from the seed showed
evidence of mixed ancestry. But some of them
gave such promise that it seemed worth while to
sort out the best strains.

To effect this, I used hand pollenation and
the most rigid selection. Only the specimens
showing the desired qualities were used in the
crosses, and only the best individuals preserved
for seed.

In the course of a few generations a fairly fixed
plant was thus produced. The most marked
peculiarity of this squash was its exceptional
specific gravity. For its size it was incomparably
the heaviest squash I have ever seen. The meat is
thick, solid, and of dark color. Its seed cavity is
of medium size, thickly studded with large, heavy
seeds. Exteriorly the squash is white, striped with
green, generally but not always smooth. :

This new variety found favor in many localities:
for planting in dry places or as a dependence in
dry seasons. It was named the Chiloe by the
company who introduced it, in recognition of the
home of the ancestral stock from which it was
developed.

[58]

The Freakish
Martynia

The Martynia is a
food plant that is not
very familiar in our gar-
den, but one with which
Mr. Burbank has experi-
mented rather extensively.
The curious scheme
adopted for the distribu-
tion of its seed by this
plant is described at some
length in Volume I, to
which the reader is re-
ferred. In the tropical re-
gions to which this plant
is native, the struggle for
existence is so sharp that
it is necessary to take ad-
vantage of every possible
opportunity, and each
plant has its own way of
endeavoring to get ahead
of its neighbor.

LUTHER BURBANK

Notwithstanding its cannon-ball like solidity, it
is of exceedingly sweet flesh. Its firmness gives
it remarkable keeping qualities; it often lasts until
May or even June of the following season.

My work with this squash shows that it is by
no means impossible to fix a new type. But there
is abundant work to be done in this direction with
large numbers of varieties now under cultivation.
Much may be done also toward developing thick-
ness of flesh and sweetness of quality. Moreover,
attention should be given to the seed cavity, which
may be made much smaller. The seeds cannot
be altogether eliminated but their number might
be advantageously reduced.

Again, varieties may be developed having
shorter or more compact vines. There should be
no great difficulty in attaining these ends, and the
field is obviously one in which any amateur
gardener may work with ease. The facility with
which squashes may be hybridized gives them
added attractiveness from the standpoint of the
novice.

Tue CrucireR FAMILY

The tribe of Crucifers is represented by a large
number of annual and perennial herbs of wide
distribution, the most conspicuous members of
which are the cabbage and its allies.

It is supposed that all of the near relatives of

[60]

ON SOME COMMON GARDEN PLANTS

the cabbage are modified descendants of a single
species that grows wild along the Mediterranean
and Atlantic Coasts of Europe. Turnips are
descended from another closely related species
having the same habitat. The radish, horseradish,
water-cress, and mustard are other members of
the family that are not quite so closely related.

The members of this group occupy a position
of considerable importance in the vegetable
garden; chiefly, however, because of their various
flavors rather than because of their nutritious
value. There is comparatively little nourishment
in the substance of any of them, except the
cabbage.

From the standpoint of the plant developer,
the members of the cabbage tribe have exceptional
interest, not so much because of possibilities of
future development as because of what they
reveal of past development.

If, as is believed, they have all sprung from a
single species and within comparatively recent
times, they afford highly interesting illustrations
of the varied lines of development that the off-
spring of a single plant may be induced to
follow.

Thus the edible head of the cauliflower and
broccoli consist in reality of thickened and con-
solidated flower peduncles. The edible part of the

[61]

The Familiar Beet

These exceptionally fine specimens present an improved
variety of a plant that grows in every garden. Nowadays, how-
ever, the beet is not merely a garden vegetable, but a field plant of the
very highest importance; inasmuch as it is the chief source
of the world’s sugar supply. Through selective breeding,
the sugar content of the beet has been enormously
increased within recent years, and this hum-
ble vegetable now outrivals the sugar-
cane as a producer of sweets.

ON SOME COMMON GARDEN PLANTS

kale consists of expanded but tender leaves.
Brussels sprouts are thickened buds developed in
the axis of the leaves. The cabbage is merely a
single monstrous bud, with its leaves unexpanded.
And in the kohl-rabi—perhaps the most recently
developed of all the garden vegetables—it is the
short and few-leaved stems that become thick,
bulbous, and edible.

Here, then, is a plant in the different races of
which, the stem, the leaves, and the flowers
respectively have been modified until they are
edible monstrosities. Few other plants show such
versatility; so the familiar colloquialism that dubs
a dunce a “cabbage head” is obviously lacking in
fitness of application.

If the cabbage tribe were to develop a member
having an edible root, its versatility would be
universal; and, indeed, a very near relative belong-
ing to the same genus makes up the deficiency in
this regard: for the turnip has about as much root
in proportion to its size as a plant can possibly
produce.

As might be expected, considering their origin,
the different crucifiers vary greatly. The various
cabbages and cauliflowers and Brussels sprouts
may be hybridized with one another or with the
strap-leaved turnips without difficulty.

But the result is usually a rather curious lot of

[63]

LUTHER BURBANK

mongrels that have no utility, all apparently tend-
ing to turn back toward the wild parent form.
Each member of the family has been developed
to its present specialized form through many
generations of selection alone; and the specializa-
tion is so great that there is small prospect of
securing a useful form by bringing them together. .

Such a development is not impossible, however,
but it would certainly be difficult to fix the new
type after it had been produced.

My own experience with the cabbage tribe was
chiefly gained in the early day of my experimental
work, nearly half a century ago. I discovered that
it was easy to cross the cabbage with the cauli-
flower and with other members of the tribe; that,
in fact, it is necessary to grow them quite a dis-
tance apart in order to keep the seeds pure. But
the hybrids produced were all what we were
accustomed to describe as mongrels. Some of
them had small cauliflower heads of inferior
quality.

At the time when these experiments were made
I did not fully understand the importance of the
second generation, and I have never found time
to take this line of experiment up again.

I have had good success, however, in crossing
the purple-leaved cabbage with other varieties of
cabbage, developing thus a purple cabbage with

[64]

Another Old
Friend

The radish can
claim no such _ eco-
nomic importance as the
beet has now attained; but
it is perhaps even more
universally distributed in
the gardens of the world.
The specimens here shown
illustrate very tangibly the
wide variation. of. form
among the different varie-
ties that have been de-
veloped through se-
lective breeding.

LUTHER BURBANK

a very large head. They were somewhat less dark
in color than the parent stock.

My work with the turnip has not extended
beyond the stage of experimental crossing with the
cabbages, which led to no prospect of useful
results. With the radish, which might be described
as a dwarf turnip, my work has been carried
along the line of selection, without hybridizing.

There are enough variations among the seed-
lings of any given root to afford ample opportunity
for selection as to form, color, and qualities in
general.

In the course of the experiments a dozen or
more of the most popular kinds of radish were
used, the principal aim being to get the roots very
uniform and smooth, all developing at the same
time, instead of at different times as most radishes
now do; and all of uniform color.

Another object was to develop varieties with
the smallest amount of foliage that would be
adequate to build up the roots quickly under good
conditions.

I also gave attention at one time to the flavor
of the radish, developing the sweet pungency for
which the vegetable is relished.

As just noted, all the radish seed used in these
experiments proved exceedingly variable; and
even those that were selected and re-selected per-

[66]

A Universal Favorite

The carrot is a close competitor for position of first favor-
ite among the root vegetables of the garden. Notwithstanding
its popularity, however, it has not been given very great attention by
the plant developer, and it does not vary greatly from the typ-
ical form here shown. It is worth experimenting with.

LUTHER BURBANK

sistently for several years showed a tendency to
reversion. But this variability, while it is annoying
to the practical gardener, should give the radish
added interest from the standpoint of the plant
developer. The amateur who wishes to experi-
ment with this species can begin with plants grown
from any root or seed that he may secure. He
might then hybridize these plants with seed of a
Japanese or Chinese variety.

The radish is supposed to have originated in
China and the vegetable is still very popular in the
Orient, where besides being eaten raw it is pickled,
dried, and preserved in various ways somewhat
as we preserve fruits.

THE ORIENTAL RapDIsH

The oriental radish is of large size and may be
grown readily in a soil adapted to radishes in
general; that is to say, a white, clean, sharp sand,
which should be fertilized with chemical fertilizers
only. The plants should have plenty of moisture
and sunshine, thus being urged to rapid growth.
They are much more subject to disease and liable
to become pithy or hard when grown in rich soil
than when grown in the sand, and are also of less
satisfactory flavor.

There is little doubt that by crossing the
oriental varieties with our common ones some
interesting variations would be produced that

[68]

ON SOME COMMON GARDEN PLANTS

might lead to the development of new varieties
not without importance.
SomE OssTINATE Root BEARERS

‘In marked contrast with the members of the
crucifer family, with their extraordinary tendency
to variation, are the two familiar members of the
garden family that are most prized for their roots,
the carrot and the parsnip. For these have
assumed a characteristic shape from which they
show very little tendency to vary, and even under
persistent cultivation have held very true to their
type.

The plants are closely related, and both are
descended from wild forms that are poisonous.
Moreover the cultivated species themselves, if
allowed to hold over until the second season, may
develop a poisonous quality. But as ordinarily
grown from the seed and pulled in their first
season, they constitute wholesome vegetables of
deserved popularity.

My work with the parsnip has been confined to
the attempt to develop a race having roots that
are smoother and of a broader or more compact
form. But I found this a thankless task, as the
roots tend to reach downward in spite of all the
education that could be given them. It is a per-
sistent quality that the plant seems very unwilling
to give up. In this the parsnip shows its retention

[69]

A Bunch of Parsnips

Not even a tyro at gardening or botany needs be told that

the parsnip is own cousin to the carrot. It is equally obvious,
however, that the two belong to quite different species. Like its cousin,

the parsnip has been rather neglected by the plant developer.

Mr. Burbank has experimented with it to a certain extent,

but the demand for the vegetable is not sufficient to
justify his giving a great amount of time to
it. Some one who cares to make the
effort can no doubt improve it in
a good many directions.

ON SOME COMMON GARDEN PLANTS

of the habit of its wild ancestor. The carrot also
is not altogether free from its wild instincts, and
will pretty readily revert to the wild state.

I have experimented with the wild carrot,
which has a long, hard, slender root, and found
that this could be brought back to the production
of what might be called a civilized root.

I have also found that color can be added to
the carrot root or taken away from it by selection
through successive generations.

This is quite what we might expect when we
consider the difference in color between the roots
of the carrot and the parsnip, which in their wild
forms are very closely related.

There is opportunity for some one to undertake
the improvement of both parsnip and carrot as to
the quality and shape of their roots, and such ex-
periments might very likely prove successful if
carried out persistently, notwithstanding my fail-
ure to produce marked modifications in this
regard. The flavor of the carrot could also be
improved, probably without great difficulty.

SALSIFY OR OYSTER PLANT

There is another root that offers a challenge to
the plant developer somewhat as do the parsnip
and carrot, by the very fact of its obstinate resist-
ance to any change. This is the plant called the
Salsify, usually known to gardeners as the oyster-

[71]

LUTHER BURBANK

plant or vegetable oyster. It is a biennial plant
having long, slender, light-gray roots.

There is only one greatly improved horticul-
tural variety. This is known as the Sandwich Is-
land Mammoth. It is fully twice as large as the
ordinary salsify, which it otherwise closely
resembles.

I have worked with the Sandwich Island Mam- .
moth with particular reference to improving the
smoothness and plumpness of its root. But it was
found to be one of the most stubbornly fixed of
plants. This is quite what might be expected of a
plant that has only one species under cultivation.
We have elsewhere seen that the plants that have
many species are the ones that tend to vary.

There are, however, two or three wild mem-
bers of the tribe, one known as the Spanish salsify
and another as the black salsify, a native of Eu-
rope. It is possible that these might be used to
hybridize with the ordinary and the Sandwich Is-
land species, and that the element of variability
might thus be introduced.

Possibly through selective breeding, based on
such hybridizations, new varieties of salsify might
be developed and the plant might thus conceivably
be made to occupy a much more important
position than it does at present among garden
vegetables.

[72]

PEAS AND BEANS AS
MONEY CROPS

IMPROVEMENTS WHICH PROMISE MucH

breeding is furnished by the case of the
Empson peas.

This was a case in which I received an order
for the development of a new variety of pea that
would fulfill certain definite specifications, some-
what as a manufacturer of cloth or of electric
dynamos or of machinery of any sort might receive
an order for a new product to meet a special
condition.

It is gratifying to record that I was able to
meet the specifications, and “deliver the goods,”
as a manufacturer might say, about as accurately
and satisfactorily as if the product had been one
to be turned out by factory machinery instead of
by selective breeding of a living plant.

The specifications were these: A variety that
shall mature all its pods at the same time; bearing

A VERY good illustration of directive plant

[Votume VIJ—Cuapter IIT]

LUTHER BURBANK

individual peas of reduced but uniform size, sweet,
and of superior flavor.

Here, it will be observed, there are several quite
distinct characteristics to be borne in mind. Per-
haps the most important, or at least the ones most
difficult to attain and fix, were the uniform time
of ripening and uniform size of the peas them-
selves. How these difficulties were met will be
detailed presently.

First, however, let me tell just how it came
about that the order for peas having just these
specifications was received.

MANUFACTURER AND PUBLIC

The order was given by a large canning fac-
tory, located originally in Colorado, but now hav-
ing branch factories in other regions, with capacity
to handle in the aggregate forty-six thousand cans
of peas per hour.

The head of this company, Mr. J. H. Empson,
is a man who has made a study of his public, and
who aims to give the public what it wants. He
discovered that there was a demand for canned
peas of very small size. This had come about,
probably, through the example set by the French,
who can the peas when they are half grown, at
which stage they appear to be sweeter than when
more fully ripened.

The American public developed a liking for

[74]

Three Kinds of Burbank Peas

The story of these peas, and of some others, is told in
detail in the text. It illustrates very vividly the possibility of
making a particular type of vegetable-product to order. The “Little
Ones” in the upper can represent one of Mr. Burbank’s triumphs
in this direction. The canners knew just what they
wanted, and Mr, Burbank knew just how to
get it for them by selective breeding.

LUTHER BURBANK

these small peas, and a willingness to pay more
for them than for the larger ones, but no American
canner could duplicate them in size and quality.

The American canners are themselves con-
vinced that peas of medium size are really better;
but they were desirous that the public should have
what it wanted.

So it came about that I received a letter from
the management of the canning company asking
me to undertake the work of developing a pea that
would meet the specifications as to size, and yet
would mature in such quantities and with such
uniformity that there would not be great loss in
handling, as there would be if the pods matured
at different times.

The reason that this specification is imperative
is that peas for canning, according to modern
methods, are not gathered by hand. Indeed they
are not touched with the hand at any stage of their
existence, even in planting. The crop must be
ready all at once, because the vines themselves
are harvested. A machine is drawn along the rows
cutting off the roots about an inch underground,
and raking four rows together in a windrow.

Cutting below the ground keeps the peas fresh
and also ensures getting the entire crop.

A wagon immediately follows, gathering up
the pod-laden vines like a load of hay, and hauling

[76]

Giant and Dwarf

These pods illustrate variation in peas of the same race.

By selecting among the different plants grown from the same
handful of seed, Mr. Burbank was able to make a dwarf variety, and
at the same time to develop also several other varieties, includ-
ing one or two very large ones, of quite different type. And
progress was so rapid that the experiment was car-
ried to a practical conclusion in three seasons.

LUTHER BURBANK

them to the factory, where they are fed by ma-
chinery into a sheller, which consists of two big
cylinders with vulcanized rubber cups on their
surfaces, so arranged that the air pressure splits
the pods open without crushing them.

The peas roll down an inclined plane with per-
forations of different sizes, and are thus automat-
ically sorted into five grades, just as oranges of
different sizes are sorted in California. The peas
all fall into clean running water and are imme-
diately canned without being touched. It may be
interesting to add that a factory of this type has a
record of putting canned peas on the shelves of
the grocer within two hours of the time when they
were growing on the vine in the field.

Peas in cans under these circumstances may be
fresher than those purchased in the pod usually
are.

These details as to canning obviously have no
direct bearing on the methods of the plant devel-
oper. But they explain the specifications that were
given along with the order for the new variety.

In attempting to meet the specifications, I
followed the methods of rigid and systematic selec-
tion. There was no occasion for cross-fertiliza-
tion, as the peas were of superior quality, and
showed enough variation as to all of the desired
characteristics to offer material for selection.

[78]

Peas in the Pod

Some such variation as this you may discover if you will
search among the pods on different vines of the peas in your
garden. If you will use the Burbank method of selection, as fully de-
scribed in the text, and have sufficient patience, you may develop fixed
races of peas along any of the lines suggested by these varying pods.
Mr, Burbank has never developed peas that were “square
so they will not roll off the knife,” as a popular joke
narrates; but he has developed lenticular peas,
as well as round ones in great variety, and
with widely varying characteristics.

LUTHER BURBANK

My plan was to pick out in successive genera-
tions the vine that came nearest to meeting specifi-
cations as to number of pods, uniformity of ripen-
ing, and small size as well as uniform size of the
peas themselves.

It was necessary, as in some other experiments
of a similar kind, to watch the individual plants,
selecting the very best individual plants, and har-
vesting them by themselves, counting the pods and
counting the peas, and making careful record of
results.

Fortunately it is possible with the pea to raise
two crops in a season. Thus I was enabled to
progress very much more rapidly than otherwise
could have hoped to do. We could do two years’
work in one.

So we were able to deal with six generations
of peas in three years. And yet by that time the
undesirable qualities had been so systematically
excluded and desirable ones so persistently sought
for that the educated pea vines fulfilled the speci-
fications exactly.

I find in my files a letter bearing date of
February 29, 1908, that may be quoted here as
summarizing the results of the experiments:

“By express to-day,” I wrote, “I send you all
the peas raised from the one best of all my selec-
tions. This one is the one which produced the

[80]

ON PEAS AND BEANS

most peas to the pod, the most pods to the vines,
had the most uniformly filled pods, and in all re-
spects was the most productive and best; on the
whole, the best pea, taking quality, quantity, and
everything into consideration, which I have ever
seen. They are fifteen per cent smaller on the
average. One other thing which I have added to
them is that they are sweeter than the pea which
you first sent me. They all came from one single
vine which was the best in all respects and the
seed has been reselected through six generations.”
MULTIPLYING THE NEW VARIETY

Of course, the selected pea, as thus produced,
existed only in small quantities. But it had been
fixed as to type and could be depended on to breed
absolutely true. It was necessary, however, for
the company to multiply the seed for a number
of years before there was enough of it in existence
to use for the purposes of the canner. By growing
the crops in California, however, where from two
to four crops could be raised each year, and by
using the entire product for the seed in successive
years, the progeny of the single vine from which
I developed the new variety had been multiplied
by 1912 so that material enough was at last in
hand to plant hundreds of acres and supply the
cannery with the small, sweet, uniform-sized and
uniform-ripening pea that was desired.

[81]

Showing Variation in Beans

The bean is even more variable than its cousin the pea;
and there are a good many species under cultivation, so there is
almost endless opportunity for developing new varieties. Here are
some samples that suggest the possibility of easy
and interesting experiments.

ON PEAS AND BEANS

I have cited this case in detail, not because it
is of exceptional importance in comparison with
other of my plant developing experiments, but
simply. because it illustrates the possibility of
developing quite rapidly a particular plant to meet
a specific commercial need.

But to understand fully the conditions met even
in this single experiment, it is necessary to add
that I did not confine attention to the production
of the single variety just described, even in the
line of experiments that were undertaken specific-
ally for the purpose of producing that variety.
On the contrary, while scrutinizing the vines for
small peas of uniform size, I kept vigilant watch
also for other vines that varied in the opposite
direction.

Peas Mopiriep IN OTHER DIRECTIONS

By carrying forward several series of selections
at the same time, a number of varieties were simul-
taneously developed that differed widely both
from one another and from the original stock.

I found, for example, in the observation of the
early generations grown from the seed, that some
plants would produce four or even five times as
much as others. This habit of productiveness was
carried to the next generation with a good deal of
certainty. So it proved possible, by careful selec-
tion, in three years, to develop new forms of peas

[83]

LUTHER BURBANK

which produced regularly four and five times as
much as the average production of the parent
form.

Of course, this quality of productivity was
combined with the various other qualities and was
manifested in the perfected pea that was delivered
along with the letter just quoted.

But there were other qualities which obviously
could not enter into the combination, because of
variation in exactly the opposite direction from
the one in which we were developing the little
canning pea. Thus, for example, one variety
instead of having small peas had exceptionally
large ones. Another variety produced lozenge-
shaped peas. These seemed to be unusually sweet,
and as they were also among the most productive,
I made two strains of this selection alone. One of
these is a very large lozenge-shaped pea, circular,
and indented on the flattened sides.

Both are practically fixed, coming true to type
from seed.

In point of fact, by having different ideals and
bearing them in mind all along, I developed four
strains of new varieties that the canners were glad
to purchase, in addition to the one that they had
specifically ordered. And all this was done, as
just noted, by selection, without the aid of hybrid-
izing experiments.

[84]

A Burbank

Perennial Bean

Mr. Burbank began
experimenting with
beans when he was a mere
boy. At that time, back in
Massachuseits, he hybrid-
ized different species, and
produced some quite ex-
traordinary results. In re-
cent years he has taken up
the work again, attacking
it with. undiminished zeal.
The picture represents one
of his present-day
successes.

LUTHER BURBANK

It should be explained that the pea is normally
self-fertilized, so that there is the closest inbreed-
ing, and it is therefore relatively easy to fix a type.
Moreover the pea is a very pliable plant, produc-
ing new varieties with little care and labor as
compared with many other plants. Although I
have devoted much less time to it than to many
other plants, I have developed numerous varieties
that are specially modified for color, for produc-
tiveness, for size, for quality, or for resistance to
mildew and other affections. And other experi-
ments are under way that will probably lead to
still further developments.

MENDEL’s Famous EXPERIMENTS

Although much may thus be accomplished with
the pea by mere selection, it should be remem-
bered that this plant offers exceptional opportuni-
ties also for development by hybridization. In ~
particular it should be recalled that the extraor-
dinary experiments through which the Austrian
monk, Mendel, made the discoveries that have cre-
ated such commotion in the biological world, were
made with the common garden pea.

Reference to these experiments has been made
more than once, but it will be worth while to
examine them a little more in detail in the present
connection.

The discovery that Mendel first made, to which

[86]

Burbank Lima Beans

Mr. Burbank says that the bean, notwithstanding its pop-
ularity, has been somewhat neglected. Perhaps it would have
been more coddled and developed if it had been less hardy. But
beans grow anywhere, and under any conditions, and so do
not seem to demand attention. Nevertheless they
reward the experimenter by their responsive-
ness, as these giant limas, developed
under Mr, Burbank’s tute-
lage, clearly testify.

LUTHER BURBANK

we have already referred, was that certain quali-
ties of the pea are grouped into very conspicuous
pairs.

His investigation led him to believe that there
are at least seven differentiating characters that
could be relied upon to reproduce themselves with
certainty in the offspring of the pea. These char-
acters, which he came to speak of as “unit” char-
acters, are the following:

(1) The form of the ripe seed, which may be
roundish, either with or without shallow wrinkles,
or angular and deeply wrinkled.

(2) The color of the reserve material in the
cotyledons or little leaves that first appear when
the seedling comes out of the ground; the colors
being pale yellow, bright yellow, orange, or green.

(3) The color of the seed coats; white, as is
usual in peas with white flowers, or gray, gray-
brown, leather-brown, with or without violet
spots, ete.

(4) The form of the ripe pods, whether inflated
or constricted or wrinkled.

(5) The color of the unripe pods, whether light
or dark green or vividly yellow, these colors being
correlated with colors of stalk, leaf, vines, and
blossoms.

(6) The position of the flowers, whether axil-
lary or terminal.

[88]

ON PEAS AND BEANS

(7) The length of the stem of the plant itself,
whether tall or dwarfish.

It is obvious that in each case the different
qualities named are antagonistic or mutually ex-
clusive. The seed cannot be at the same time
round and angular; it cannot be at the same time
smooth and wrinkled; cotyledons cannot be at
once yellow and green; the pods cannot be at once
inflated and constricted. And as each race of peas,
when inbred, holds true to its type, there was
opportunity to observe the effects of crossing the
different races in relation to these different fixed
characters, ,

The results Mendel obtained have already been
outlined, and more than once referred to in this
and in previous volumes.

It will be recalled that, as regards the various
pairs of antagonistic characters, he found that one
or the other proved prepotent or dominant in the
first generation; but that in the second generation
(when the first generation hybrids were inbred)
the submerged or recessive character would reap-
pear in one case in four on the average. Thus he
found that in the pea tallness of stalk is dominant
to shortness of stalk; that yellowness of seed is
dominant to greenness of seed, etc.

This was demonstrated by the fact when a tall
pea was crossed with a short one all the offspring

[89]

A Stripling from the Tropics

In the foreground, the South American bean whose stalk
suggests the one that Jack grew, according to the nursery legend.
To appreciate the size of this tropical bean, growing now in Mr. Bur-
bank’s garden, it should be explained that the corn in the experi-
mental bed beside it is more than eighteen feet tall.

ON PEAS AND BEANS

were tall, but one-fourth of the offspring of the
second generation were short.

Similarly when a pea with yellow pods was
crossed with one having green pods, all the plants
of the first generation had yellow pods; but one-
fourth of their offspring of the next generation
had green pods.

THE SEGREGATION OF CHARACTERS

A second very important feature discovered by
Mendel was that the different antagonistic pairs
of qualities are transmitted quite independently
of one another.

For example, the relations of tall and short
peas, blended in heredity, are quite independent
of the question of yellowness versus greenness of
pod. So observation may be made as to two or
more qualities in the course of the same
experiment.

Thus if a tall variety of pea that bears green
pods is crossed with a short variety bearing yellow
pods, all the offspring will be tall peas with yellow
pods—therefore unlike either parent. But the off-
spring of the next generation will show a recur-
rence of each of the recessive factors in one case
in four, so that one-fourth of them will be short
and one-fourth will have green pods. But it
appeared, so far as Mendel could determine, to be
a mere matter of chance—like the throwing of

[91]

LUTHER BURBANK

dice—as to the exact number of cases in which
shortness of stalk would be combined with the
bearing of yellow pods.

PaIRING THE FACTORS

If we assume—as Mendel finally came to do—
that each of the different qualities about which we
are speaking is represented in the germ plasm by
a definite mechanical factor which must be paired
with another factor, either like or unlike itself, in
order to stimulate the development of the char-
acter it represents, then at least a provisional
explanation of the observed facts might be found
in supposing that a dominant factor when mated
with a recessive one hides or obscures the recessive
one in that particular combination; but does not
eliminate it.

And when the factors are again mixed to pro-
duce a new generation, they are still equal in
number, and if we think of the factors as tangible
things—let us say like black or white checker men
—it will appear that if equal numbers of each are
mixed together and taken from a bag in pairs at
random or blindfold, it will come about, accord-
ing to the mere theory of chances, that one time
in four two of the white checkers will be paired.

This accounts in a crude and mechanical but
on the whole a rather satisfactory way for the
appearance of the recessive character—say short-

[92]

Giant Horse

Beans

This is a variety
of horse beans im-

proved by Mr. Burbank
through selection, and now
growing en masse in his
experiment gardens in
Santa Rosa. The _ horse
bean is frequently used as
a cover crop, and the value
of this perfected variety
for such a purpose is well

illustrated in the

photograph.

LUTHER BURBANK

ness of vine or greenness of pod—in one individual
out of four of the second-generation progeny.

And when we apply the same reasoning to the
case where two pairs of factors are under consid-
eration—tallness versus shortness, and yellowness
versus greenness in the present case—it appears
that each pair of factors will follow precisely the
same law, so that one in four of the second gen-
eration descendants will be short and one in four
will be green; but that the same law of chances,
applied to this more complex case, gives us only
one case in sixteen in which two factors for short-
ness are combined with two factors for greenness
in the same group.

In other words, one pea in sixteen descended
in the second generation from the tall pea with
green pods and the short pea with yellow pods
will have a short vine and at the same time will
bear green pods.

This will be a new variety. It has no new qual-
ity, but it has the old qualities in a new com-
bination.

Extending the experiment one stage further,
Mendel found that the second-generation peas that
show the recurrence of the recessive factor will
breed true to that factor. And this, again, is quite
what might be expected on the theory just out-
lined. For the pea that contains two factors for

[94]

Roots of the Mammoth Soy Bean

This picture shows the nodules due to the nitrifying
bacilli, through which the leguminous plants are enabled to
perform a feat that other plants find impossible,—namely the direct
extraction of nitrogen from the air. Other plants might starve for
want of nitrogen, although bathed in the atmospheric ocean which is
so largely composed of nitrogen. But.the legumes, thanks to the par-
ticular types of bacilli that colonize the roots, can get a supply, or a
partial supply, of nitrogen, without waiting for it to be com-
bined and made into soluble compounds. Nowadays cul-
tures of the nitrifying bacilli are sometimes
thrown on a field, as one sows grain or
the innoculated seed, put out under the
trade name “Nitragin’, is sown.

LUTHER BURBANK

shortness will obviously have no propensity to
grow tall, and the pea that contains two factors
for greenness of pod will obviously have no capac-
ity for the production of pods other than green.

So our short pea vine with its green pods,
although it represents a new variety, which, for
the sake of argument we assume never to have
existed before; and although it appeared sud-
denly as what might be considered a mutation, yet
is fixed from the outset, and will breed true, and
constitute an established variety.

All this we have referred to in earlier chapters,
and we have seen many illustrations of this so-
called Mendelian inheritance in the case of a good
many of our plant developments—the white black-
berry, for example, the stoneless plum, and the
thornless blackberry among others. But it seemed
worth while to make specific reference to Mendel’s
work with the peas, in the present connection, in
particular because this work doubtless represents
the most important thing that has been done with
the pea at any recent stage of its development.

Peas VERSUS BEANS

It was perhaps fortunate that the Austrian
monk chose the pea for his investigation rather
than the bean, for, notwithstanding the fairly close
relationship between these two, there is a rather
marked difference between them as to their prac-

[96]

ON PEAS AND BEANS

tical response to the efforts of the plant developer.
Perhaps because the pea has been cultivated
under varied conditions, and selected for a wide
variety of qualities, this plant shows a marked
tendency to vary, suggesting in this regard the
evening primrose and the godetia, and the new
varieties are often practically fixed from the outset.

With beans it is less easy to trace and classify
the opposing “unit” characters, and in practice it
is often necessary to select rigidly and continuously
for five or six successive generations in order to
fix a new variety.

An illustration of the complexities that may
result when beans of different kinds are crossed
was given me at the outset of my work as a plant
developer.

CROSSING THE PoLE BEANS

Almost my first experiment in hybridizing was
made by crossing the horticultural pole-bean or
wren’s egg with another variety of pole-bean
known as the red cranberry bean.

The hybridization was effected with some diffi-
culty, inasmuch as only one blossom in perhaps
fifty responded to cross-pollenization and a part
of the offspring seemed to lack vitality, as I suc-
ceeded in bringing but one plant to maturity. But
this was in some respects the most astonishing
bean plant that I have ever seen. It bore long

[97]

Cow Peas Under Cultivation

This picture shows another form of leguminous plant
that has become popular in comparatively recent years. It is
of solid and compact growth, and makes a remarkable cover or for-
age crop. Like the other legumes, its product is rich in nitro-
gen, a fact long recognized but the explanation of which
has been given only in comparatively recent years.

ON PEAS AND BEANS

black pods and the beans within them were as
black as ink.

Yet one of the parent beans had produced a
crimson pod with a red seed, and the other a crim-
son and white striped pod, with red and white
striped seed.

Here, it will be seen, there was no such sharp
differentiation of the color-factors for pod or seed
into opposing pairs, with dominance in one and
recessiveness in the other, as was shown by the
peas in Mendel’s experiments. On the contrary,
the union of red beans with red and white striped
ones produced something totally unlike either—
namely, a jet black bean.

But in the succeeding generation the offspring
of the black bean showed a breaking up into new
groups of characters suggestive of Mendelian
heredity. Some of them were black, some red,
some speckled, and some white. There were cor-
responding variations also as to size and shape of
the beans, some being large and some small, some
round and some flat. And there was marked
diversity in time of ripening.

As to the vines themselves, the original hybrid
showed the enhanced vitality that commonly char-
acterizes the offspring of rather widely separated
parents. The original first-generation vine (which
bore the black beans) grew enormous, outstripping

[99]

LUTHER BURBANK

either parent by eight or ten feet, and rivaling the
growth of a hop vine. The vines of the second
generation were as diversified as the seed.

Some of them were long and vigorous, while
others were extraordinarily dwarfed, some being
so stocky as to grow pods that almost immediately
touched the ground and were obliged to bend back
like hairpins to find room for growth. There were
corresponding variations in size, shape, and color
of the leaves.

All this suggests that the beans originally
hybridized were themselves of very mixed ances-
try, and that a large number of hereditary traits
that had been blended in them were permitted to
make themselves manifest through the recombina-
tion and segregation of hereditary factors.

The reader cannot fail to note a similarity here’
between the results obtained and those that were
obtained when the Persian walnut and the Cali-
fornia black walnut were hybridized. There, as
in the case of the beans, the immediate offspring
were of gigantic growth, but their progeny in turn
showed both giants and dwarfs.

The interest of both cases (and of a number of
other allied ones that will be recalled) in illustrat-
ing the Mendelian principle of the segregation of.
recessive factors for size, leading to the produc-
tion of a race of dwarfs, will be obvious.

[100]

Soy Beans

Yet another legume
that is extraordinarily
vigorous and prolific. Like
the others, it develops nod-
ules on its roots, under
influence of a particular
type of nitrifying bacillus,
and so takes up nitrogen
from the air, whereas oth-
er plants are obliged to de-
pend upon soluble nitro-
gen compounds which are
relatively rare. The value
of such a crop as this in
restoring nitrogen to the
soil is inestimable.

LUTHER BURBANK

Another hybridizing experiment with the beans,
also undertaken in the early day of my investiga-
tions, brought together two varieties that are even
more distantly related.

Crossinc Pote BEANS AND Limas

In this experiment I hybridized the horticul-
tural pole-bean, or “wren’s egg,” with the lima
bean. It proved exceedingly difficult to make this
cross, but after many fruitless efforts I at last suc-
ceeded in securing a single pod containing four
sound beans by using the pollen of the lima on the
pistil of the horticultural bean.

When these beans were planted, in the summer
of 1872, a very strange result was observed—the
beans themselves had in all respects the form, size,
and appearance of the horticultural bean, but
when their sprouts broke ground it was at once
observed that the upper part of their cotyledons
(varying from one-quarter to three-quarters of
their length in different specimens) were indubi-
tably those of the lima bean; while the lower part
of each cotyledon was precisely that of the horti-
cultural pole-bean.

These parts were connected with serrated
edges, which at last separated, allowing the lima
bean part to drop away. Such separation, how-
ever, did not occur until the vines had made a
foot or more of growth.

[102]

ON PEAS AND BEANS

The cotyledons on each side were divided
uniformly in every case.

Thus the influence of the pollenizing parent
was very markedly shown in the young vines from
the moment of their appearance. But after the
cotyledons had fallen, all evidence of the paternal
parentage of the plants disappeared. The vines
did, indeed, show unusual vigor throughout the
season, this, of course, suggesting their hybridity.
But as to appearance and characteristics in gen-
eral, with this exception, they were essentially
horticultural pole-beans like their maternal parent.

The experiment was carried on for several
succeeding generations, but the progeny showed
no reversion to the traits of the lima bean. The
characteristics of the pole-bean had seemingly
been prepotent or dominant to an overwhelming
degree.

This, then, would appear to be another case
in which a new race was formed in a single gen-
eration by the mingling of two widely divergent
racial strains. These hybrids of the lima and the
pole-bean may be compared, in that regard, to the
Plumcot and the Primus berry, to name only two
of the various allied instances that have come to
our attention. This is what I call a seed-graft-
hvbrid. This and one other instance elsewhere
described are the only two similar ones that ever

[103]

LUTHER BURBANK

came under my observation, and they never, so
far as I know, have been duplicated before or
since.

But the fact that the lima bean, the conspicuous
traits of which were submerged and subordinated
in the mature hybrid, should have made its influ-
ence strongly felt in the seedling at the beginning
of its growth is peculiarly interesting.

One recalls the similar case of the raspberry
plant hybridized with pollen from the strawberry.
In that case, the young hybrids at first bore close
resemblance to the strawberry plant, yet subse-
quently shot up into the air and took on the aspects
of the raspberry vine. In both cases, then, the
influence of the seed plant was at first submerged
but ultimately preponderant.

We cannot be sure, however, that this was more
than a coincidence. To determine that point it
would be necessary to make a reciprocal cross.

It has been pointed out that as a rule it appears
to make no difference in the ultimate character
of the hybrid as to which of its parents is the
staminate and which the pistillate one. Yet the
cases of animal heredity in which there is a
marked tendency to cross-inheritance — from
father to daughter and from mother to son—sug-
gests that there may be analogous cases in plant
life. In any event, the analogy between the hybrid

[104]

A Hairy Vetch

Here a leguminous plant, cousin to the peas and beans, is

. shown with both top and root, to illustrate the luxuriant growth
of the foliage, and the nodules on the roots that enable the plant,

thanks to the nitrifying bacilli that inhabit them, to take up a

supply of nitrogen from the air. These plants may have

the most luxuriant foliage, even when growing on
leached and barren soil, that will scarcely
support other types of vegetation.

LUTHER BURBANK

beans and the hybrid strawberry-raspberry, each
following first the staminate and then the pistillate
parent, is not without interest.

OPPORTUNITIES FOR FURTHER EXPERIMENT

After an interval of many years, during which
I did not experiment further with the bean, I have
somewhat recently found time to turn attention
again to this very interesting plant, and have
developed a large number of new varieties of
unusual quelities.

The recent ‘experiments have had to do with
the bush bean, and I have paid attention to a large
number of attributes, including form of the plant,
color of bean, and the quality and flavor. The
new experiments have involved the crossing of
many varieties and have brought to light many
interesting developments, although none perhaps
as striking as those just outlined.

I have found that it is feasible to segregate and
recombine the traits of different varieties of beans
in almost any desired combination. Thus, for
example, it is perfectly feasible to put the pod of
one bean on the vine of another, quite as Mendel
did with his peas. Observation will show what
qualities or characteristics are prepotent or dom-
inant even without directive effort on the part of
the plant experimenter.

It will be observed that in the second, third, and

[106]

ON PEAS AND BEANS

fourth generation plants will appear that show
the pods and beans of one of the original parents
combined with the leaves and vine of the other, in
all possible combinations.

As I have operated with about forty varieties
of beans in the course of these experiments, it will
readily be surmised that the number of new com-
binations that have been presented is almost infi-
nite. Among the hybrid stock can be found beans
of almost every color and combination of colors,
black, brown, blue, slate, yellow, green, and white;
mottled, striped, and otherwise variously marked
and shaded. Moreover, if beans of one color are
selected and planted, as a rule all the other colors
appear in the progeny.

One finds the offspring bearing beans that are
speckled, spotted, striped, and shaded in every
conceivable way.

Yet beans that show this diversity of color may
be quite uniform as to size of the beans and time
of ripening, as well as in regard to the size and
general appearance of the plants on which they
grow.

In other words, a certain number of characters
may have become fixed while other characters are
still variable. And here the obvious explanation
is supplied, at least provisionally, by the supposi-
tion that the plants in question are unmixed as to

[107]

LUTHER BURBANK

their Mendelian factors for size and character of
vine, but retain mixed factors for color of seed.

No one as yet, however, has worked out in
detail the combinations of hereditary factors for
the bean as Mendel worked it out in the case of
the pea. Such an investigation would constitute
one of the most interesting experiments in plant
breeding that any one who has time for it could
undertake. It is true that the hybridizing of the
plant of this genus is rather difficult, inasmuch as
the flowers must be opened and the stamens
removed with a pair of small forceps to avoid
self-fertilization.

But, on the other hand, once cross-fertilization
has been effected there are obvious advantages in
later generations in working with a plant that is
normally self-fertilized, the pollen of which is
inaccessible to insects.

All in all, I think the bean offers as many
inducements for improvement as any other plant
under cultivation.

—Although much has been and
may be accomplished with peas
and beans by mere selection,
these plants offer exceptional
opportunities also for improve-
ment through hybridization.

THE ToMATO—
AND AN

INTERESTING EXPERIMENT

A PLant Wuictt Bore Potators BELOW AND
Tomatoes ABOVE

VISITING scientist who had seen my little
A preserving tomato and had learned its

origin was curious to know just how I
came to make the hybridizing experiment that
resulted in its production.

I found it difficult to answer the inquiry to his
entire satisfaction. One does not recall all the
details as to methods, let alone motives, after an
interval of twenty-five years. But so far as can be
recalled, I had no very definite object in combin-
ing the common tomato and the currant tomato
except the one of general interest in the processes
of nature, and a sort of all-inclusive desire to see
what would happen when plants of such diverse
character were united.

My visitor felt that I must have had some defi-
nite idea in mind—some ideal tomato at the pro-
duction of which I was aiming, and he seemed to

[VotumE VII—Cuapter IV]

LUTHER BURBANK

feel distinctly dissatisfied when assured that in
this particular case a result had been achieved that
had not been forecast. The plant developer had
been like a chemist putting together newly discov-
ered elements. He knew that he would probably
get something interesting, but just what that some-
thing was to be could not be predetermined.
Two Types oF INVENTIONS

I recall this incident by way of illustrating
another phase of the plant developer’s art than
that illustrated by the development of the canning
pea as detailed in the preceding chapter. In that
case, it will be recalled, the plant developer was
in the position of an inventor called upon to meet
a precise set of specifications. He knew from thé
outset what was to be aimed at and, having
acquired a certain craftsmanship, he knew how to
set about securing it.

A large number of inventions in the mechanical
world have such an origin as this.

When Edison started out to find a filament that
would show just the right resistance to the elec-
tric current, and yet would not be consumed with
its own heat, he knew just what he was seeking,
and his problem of the development of an incan-
descent light bulb was comparable, in a general
way, to the problem of producing a canning pea
of just the right size and quality.

[110]

ON THE TOMATO

But, on the other hand, a long list might be
cited of inventions and discoveries of vast impor-
tance that were matters of accident. Perkins’ dis-
covery of the aniline dye; Nobel’s discovery of
nitro-glycerine; Roéntgen’s discovery of the X-ray;
Becquerel’s discovery of radio activity—these are
instances where a man found something for which
he was not specifically looking. Of course he had
to be in line of discovery. It was essential that he
should be handling the right materials, and work-
ing in a laboratory having the right accessories, or
the discovery could not have been made. Never-
theless, in each case, the discoverer found some-
thing for which he was not seeking; his experi-
ment had results that he could not have prede-
termined.

And here again, the analogy with that other
type of experimentation through which, for exam-
ple, the preserving tomato was developed will be
obvious.

LooxkING FoR SURPRISES

The point to be emphasized is that the plant
developer is an inventor who works sometimes
according to one method and sometimes according
to another. He is dealing always with complex
and intricate matters. Sometimes he has studied
them so well that he knows what to expect of them
in certain combinations. In other cases he is feel-

[111]

LUTHER BURBANK

ing his way, and has no very clear notion of what
to expect.

It might be said that he is looking for surprises
rather than for anything definite; and in that event
he is pretty sure to find what he is looking for.

Such at least was my experience in the early
experiments with the tomato that led ultimately
to the production of the particular hybrid at the
moment under discussion. These experiments had
their origin at the very beginning of the period of
my investigations in the field of plant develop-
ment, a good while before I came to California.

But in those days, notwithstanding one or two
successes, I was only laying the foundation for my
future work—learning how to handle the tools of
my trade. So although there may have been inter-
esting discoveries within reach, I did not always
know how to grasp them.

I had not learned, for example, the all-impor-
tant lesson that the second-generation hybrid,
rather than that of the first generation, is the one
that must be looked to, in a large number of cases,
for important development.

THE Story oF 4 Fruit-Like Tomato

But when I came to California and found
opportunity for expanding the work, I from time
to time took up the old New England experiments
where they had been left.

[112]

The Burbank

Tomato

Mr, Burbank has
done some very re-
markable work with the
tomato, as we have learned
in an earlier volume, and
as will be illustrated in
other pictures. This pic-
ture shows one of his fin-
est tomato products, which
has been thought worthy
of introduction under. his
name, As to symmetry of
form, smoothness of skin,
and attractiveness of color,
it speaks for itself. Its
qualities of flesh cor-
respond.

LUTHER BURBANK

In some cases I had brought seeds with me,
and was able to complete under the new conditions
experiments that had been begun in New England.
In other cases it was necessary to start anew, but
I had experience as a guide, and that constituted
an asset that often proved a wonderful time saver.

In the case of the tomato, experimentation was
reopened on a comprehensive scale about the year
1887. It was at this time that I hybridized the
common potato and the currant tomato and pro-
duced the interesting new form about which we
have just spoken. The common tomato needs no
description, but the currant tomato is much less
familiarly known. It is a plant with long, slender,
trailing vines and slender leaves and it bears
racemos of small currant-like fruit. It occurred
to me that it would be highly interesting to hybrid-
ize this trailing plant with a particularly tall,
upright, compact variety of the common tomato.

The cross was made reciprocally, pollen from
each plant being used to fertilize the stigma of the
other.

The fertilization was effected without difficulty,
and an abundant supply of seed was produced.
The hybrids that grew in the next generation were
many of them pretty clearly intermediate in form
and appearance between the parents. But some
of them were almost ludicrous in appearance,

[114]

ON THE TOMATO

They took on twisted and contorted forms, and in
particular their leaves were curled and twisted
into fantastic shapes.

As to fruit, some of the plants produced long
clusters with tomatoes much larger than cherries;
others furnished small fruit like that of one of the
parents. And in some cases a plant that had re-
tained the short stocky tree form of the common
tomato bore clusters of small tomatoes in bunches
similar to those of the other parent.

The foliage varied astonishingly between the
two types. In some there was an exact compro-
mise that was very curious. The dark, blistered
leaves of the ordinary tomato, combined with the
long, slender leaves of the currant tomato, pro-
duced a most interesting effect. Other specimens
showed every possible gradation between the
parent forms.

Here, then, was a case in which there was no
conspicuous dominance of one parent or the other
as regards any individual character that could be
segregated and classified.

Neither as to size and form of plant-stalk, nor
as to leaf, nor as to the fruit itself, was there clear
prepotency or dominance of one parent over the
other.

If there was an exception to this it was perhaps
that the fruit tended to be borne in clusters, as in

[115]

Vigor Through Crossbreeding

At the left a hybrid tomato which has altogether out-
stripped a representative of one of its parental forms, shown
at the right. Similar illustrations of the extraordinary vigor that
hybrid plants sometimes take on has been shown in earlier vol-
umes. The contrast here, however, is peculiarly striking.

Here the giant seedling is probably only mimicking
some equally gigantic ancestor, as we should
learn could we trace its full pedigree.

NGS

ON THE TOMATO

the case of the currant tomato, rather than singly
or in small groups as with the ordinary tomato.

Attention is called to these diversities because
it is well to emphasize anew that the phenomena
of the clear segregation of “unit” characters, with
the exhibition of dominance and recessiveness—
which the pea with which Mendel experimented
manifests so beautifully, and which we have seen
manifested in the characteristics of numerous
other plants—is not a universal phenomenon that
the plant experimenter may confidently expect
always to discover and use as an easy and simple
guide along the path of plant development. Dif-
ferent species of plants, different varieties, even
different individuals show diversity as to the
extent to which the so-called unit characters are
segregated and mutually combined or antagonized,
as the reader who has followed the story of various
plant developments already outlined is clearly
aware.

We shall have occasion to revert to this subject
more than once, and to point out various possible
interpretations of the phenomena, various under-
lying harmonies that do not appear on the surface.
But for the moment we are concerned with the
story of the new tomato, and may be content to
put forward the facts regarding it without great
insistance on their theoretical interpretation.

[117]

LUTHER BURBANK

Suffice it that the progeny of the tree-like
tomato and the trailing one were a varied com-
pany, giving the plant developer almost endless
opportunities for selection.

I chose, naturally, from among them those that
bore the handsomest and largest fruit, and in
planting these, was enabled, in the course of sev-
eral generations, to secure a very handsome plant
with attractive fruit of new type which came true
from seed. It required about six years to produce
and make sure of the new variety, which was
announced in my first catalog of new plants, issued
in 1893. The description there given of the new
fruit was as follows:

AN INTERESTING Hysrip

“This distinct novelty and ornamental fruiting
plant grows about twelve inches high by fifteen
inches across.

“The curious plated, twisted, and blistered, but
handsome leaves, sturdy, compact growth, and odd
clusters of fruit will make it a favorite ornamental
plant.”

Another account supplemented this by describ-
ing the fruit as “a small, round, scarlet tomato,
borne in clusters, the individual fruits measuring
only three quarters of an inch in diameter; of
splendid scarlet coloring and unusually rich, sweet
flavor.”

[118]

Fruits of a
Tomato Hybrid

These interesting
cherry-Like tomatoes
were the producis of an
early experiment by Mr.
Burbank, in which the so-
called currant-tomato was
crossed with an ordinary
upright variety. The re-
sult is a fruit that is not
- only very novel from the
standpoint of ordinary to-
mato traditions, but dis-
tinctly attractive from a
gastronomic stand-
point.

LUTHER BURBANK

The comparatively rapid development of this
curious form of plant, so widely divergent from
the ordinary tomato, illustrates the possibilities
and suggests the compelling interest of such ex-
periments in hybridizing and selecting even our
commonest garden plants.

The work is of course no different in principle
from that followed by the plant developer in the
orchard, whose work has been detailed in earlier
volumes. But there is this important practical dif-
ference: In experimenting with such a plant as the
tomato, we get results quickly because the plant
grows and fruits in a single season. The results
of any given experiment may be known within a
few months of the time when the seed is planted.
This is quite different from the case of the orchard
trees, which require, as we have seen, long periods
of patient waiting, few of them bearing, even
under forced methods of grafting, in less than two
or three years, and some of them, such as the pear
and fig, requiring a much longer period.

On the other hand, there is one regard in which
the orchardist has an advantage. It is not neces-
sary for him to fix his new varieties so that they
will come true from the seed, inasmuch as his
plants will propagate by division. But in dealing
with plants of annual growth, like the tomato, it
is obvious that a new variety can have little value

[120]

ON THE TOMATO

unless it will come true from the seed. (The
tomato is really a perennial, that is treated as an
annual.)

So the task is not completed when a new vari-
ety is produced; additional experiments must be
conducted to fix the variety. Even this may be
accomplished, however, by careful attention to
selection, in the course of a few years, as we have
just seen illustrated in the case of the hybrid
tomato.

NINETEEN-YEAR-OLD SEED

Among my later experiments with the tomato
were some that had exceptional interest because
of the material used.

It chanced that when I left home in the east,
many years before, I brought with me seed of sev-
eral of the standard varieties of plants and of
some crossbreed varieties; and, as has been
pointed out, I was hybridizing tomatoes as well as
beans and other plants even at that time.

The lot of seed thus brought to California
included some seeds of the tomato. As was cus-
tomary in those days, this seed had simply been
pressed out of the fruit, and dried on a piece of
paper with the surrounding pulp still clinging to it.

Nineteen years afterward I planted some of
these seeds, being interested to see whether they
retained their power of germination. Somewhat

[121]

Another Interesting Hybrid

This picture shows foliage as well as fruit of another type

of tomato hybrid. The tomato is a comparatively recent acqui-
sition in the vegetable garden, and its possibilities of variation through

hybridization and selection have by no means been exhausted,

It is a hardy, thrifty plant, vigorous of growth and pro-

lifle, with which any amateur may experiment to
his heart’s content; and it is almost sure-to
repay the effort expended upon it.

ON THE TOMATO

to my surprise, almost every seed germinated. But
the majority of the seeds did nothing more than
form cotyledons, lacking the central bud for fur-
ther development. There were a few exceptional
plants, however, among the large company—per-
haps altogether two dozen—that continued their
growth and in due course fruited.

The fruit of some of these plants grown from
nineteen-year-old seed was sent to an eastern hor-
ticultural journal, whose editor commented on the
fact that seed kept for this long period still pro-
duced fruit quite equal to anything that had been
developed in the intervening nineteen years.

In planting the nineteen-year-old seed, I re-
tained a certain quantity from the same lot for a
further test. The following year it was planted in
the same careful manner. But although a few of
the seeds germinated and sent up cotyledons of a
weaker type, not one had the power of developing
beyond that stage.

All of these seeds in the tewntieth year seemed
to have lost the capacity to produce a central bud
from which the plant stem could develop.

Of course it may have been only an accident
that a few seeds were able to take on mature
growth after nineteen years, whereas not one could
do so after twenty years. But I am inclined to
think that the seeds had reached just about their

[123]

LUTHER BURBANK

limit of suspended vitality. The fact that ger-
mination began, but that it did not continue
because of lack of a central bud, suggests that
degeneration of part of the substance of the seed
had taken place. Seemingly it was only the most
resistent seeds that were able to stand this degen-
erative process, and retain unimpaired vitality to
the end of the nineteenth year. The heredity of
those that grew was preserved intact: the seeds
producing exactly such plants and fruit as if they
had been planted nineteen years before.
THE VITALITY OF SEEDS

The interesting question arises as to whether
the degeneration of germinal matter was confined
entirely to the store of nutrient substance in which
the germinating nuclei of the future plant are
imbedded, or whether it included any portion of
the germinating structure itself.

The fact that failure to continue growth—in
the case of the seeds that put forth cotyledons and
then died—was due to a lack of the central bud
that usually puts forth between the cotyledons,
suggests that the germinal substance itself was
impaired. Of course this germinal matter is of
tangible, even if very minute, size and there is no
apparent reason why it might not be impaired as
to a portion of its substance.

Conceivably, the substance of the complex

[124]

Tomato Leaf

Variation

These leaves from
hybrids of a blending
of different tomatoes are
peculiarly interesting, both
because of their wide range
of variation, and because
of the similarity of some
of them to the leaves of
the potato, a cousin of the
tomato, with which it has
many points of
ffinity.

LUTHER BURBANK

molecules making up the germinal protoplasm
may undergo a gradual process of decay or disin-
tegration through the throwing out of some of
their atoms, somewhat as radium and its allied
substances are disintegrated. This of course is a
pure assumption, yet it is not altogether without
plausibility.

But whatever the precise manner in which the
degeneration of the germinal plasm is brought
about, the suggestion that one portion of its struc-
ture may be affected more than another raises a
question as to whether, conceivably, such a deteri-
oration of the germ plasm within a seed, in an
exceptional instance where a seed is stored for a
number of years before being placed under condi-
tions proper for its germination, might not result
in the production of a deformed or modified plant.

Whatever differences of opinion may be held
among biologists as to the possible transmission
of modifications of the body plasm, all are agreed
that modifications of the germ plasm become a
permanent heritage and are passed on to the off-
spring. So it seems at least a possibility that we
have presented, in the deterioration of the germ
plasm within the seed, an explanation of the
appearance of mutants or sports that may become
the progenitors of new races.

Attempts to produce mutants by treating the

[126]

ON THE TOMATO

ovules of plants with chemicals, including radium,
have been made by several experimental botanists,
notably by Dr. D. T. MacDougal, of the Desert
Laboratory at Tucson, Arizona, and by Prof. C. S.
Gager. Prof. MacDougal’s evening primroses,
grown from seeds that were treated with chem-
icals while in embryo, sometimes differ markedly
from other plants of the species.

Prof. T. H. Morgan has made similar experi-
ments with the eggs of a fly, treating them with
radium, and thus ‘producing individuals strikingly
different from their parents.

These experiments, then, although they mark
merely the beginning of a new line of research,
are interesting in their suggestiveness. And it
occurs to me that the case of the nineteen-year-old
tomato seeds may have a bearing on the same
subject.

It would be well worth while to conduct a
systematic line of experiments in which seed of a
fixed species is stored in large quantity, and a
certain proportion planted each year, careful
record being made of the characteristics of the
successive groups of plants, with an eye to any
modifications that may occur when the seed
approaches the limit of the term through which it
can maintain vitality under the conditions given it.

It is said that there are records of wheat

[127]

*Bunjjnsuod
ywiom si ‘sjjasnya
-“psspyy uroif asofaq samafi
uny ym jybnoiq poy
ay JDY} Spaas ojDUIOZ ym
sjuaulliadxa syupvqing
“dW {0 }xXa] ay} ul U0IJ]d1419$
-ap ay “sijmsazr juajjao
-Xa9 pasiuoid yo1ym pup
‘uaai6 uaaq poy u01jUa}}D
{fO jvap joa18 Dv YyoIymM oO}
auo spm Juauiliadxa ay} sD
‘sso] }su1D6p pavnG 0} ‘paua
-dit jamal ay} a1ofaq paas
dof pajjazj09 asam ‘imaf
padojaaapun Jjay)y ym
‘saula OJDUIO] asauL

p29s
Jo} paj2aj}0)

ON THE TOMATO

germinating after it had been preserved for cen-
turies in the tombs of Egypt, although there is no
proof of this; but most seeds have far more
restricted capacities for maintaining vitality. My
experiment suggests about twenty years as the
limit for the tomato seed under fairly good condi-
tions. So the seeds of some fixed type of tomato
might very well be among those selected for such
an experiment as that just suggested.

My own observations in the matter are chiefly
confined to what has just been related to my nine-
teen and twenty-year-old tomato seeds; and I
must leave further investigation along this line to
younger experimenters.

GRAFTING ToMATO AND Potato

Doubtless among my most interesting experi-
ments (to the general public) with the tomato
have been those in which this plant was grafted
on the stalk of the potato; together with the com-
plementary experiments in which the potato was
grafted on the stalk of the tomato.

The grafting of herbaceous plants such as
these presents no complications as a mechanical
procedure. The fact that the stem is succulent
throughout makes such grafting a less delicate
process than the grafting of twigs of trees, for
example, in which, as we know, it is necessary to
bring the cambium layers of the bark in accurate

LUTHER BURBANK

contact. With herbaceous plants like the potato
and tomato, the stem may unite at any portion
where the cut surfaces come in contact. To make
a neat and thoroughly satisfactory graft, however,
it is of course desirable to select stems of exactly
the same size.

The splice graft, elsewhere described, is the
best one to use, and if the incisions are made with
care, so that the incised surfaces fit accurately
together, it is only necessary to tie a piece of cloth
about the united stems for a few days until union
has taken place. It is not necessary to use grafting
wax, if protected from winds and too hot sun.
The operation is preferably performed in the
greenhouse.

With this method, I grafted the vops of young
tomato plants on the main stalks of potato plants,
at a time when the stems were about one-quarter
of an inch in diameter. The reverse operation,
grafting amputated potato tops on tomato roots,
was performed at the same time.

Of course the tomato and potato belong to the
same genus, and it seemed reasonable to suppose
that such grafting might be successful. But, on the
other hand, numerous attempts have been made
to hybridize the two plants by cross pollenation,
and these have always resulted in failure. I have
tried it many times, and have never been able to

[130]

ON THE TOMATO

fertilize one plant with pollen of the other. We
know that, as a rule, plants that cannot be cross-
pollenized cannot be mutually grafted. The same
barriers usually exist in one case as in the other.

The potato and tomato grafts, however, proved
very notable exceptions to this rule. In both
combinations, the union between the foreign stems
took place quickly, and resulted in a stem as
strong as the ordinary stem of either plant. Growth
continued, and the plants came to maturity at
about the expected season.

But the results of the strange alliance were
interesting to the last degree.

They must be considered in detail because they
have a bearing on one of the most interesting
open problems of plant development—the question
of sap hybridism.

PotaTors GROWN ON ToMATO VINES

The tomatoes that grew on the root-stalks of
the potato developed much as other tomato vines
do, although in some cases it seemed that the
vines bore closer resemblance to potato vines than
is usual. But the fruit that appeared in due
season was a tomato differing in no very obvious
respect from other tomatoes of the same variety.
They, however, were not of as good quality.

Meantime the potato roots, which supplied
water and mineral salts to the tomato vine above

[131]

*38ataqUy

qoai6 aapy pinoys jms
-al ay, ‘OJDUuIO} ay}? YIM
Wt azzpriqhy 0} Buyduiaz
-jD sajojdwajuod yupqing
“IY pup ‘jinaf ay1]-0j]DuI0]
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sioziuaboid s]1 yoy, sauids
Buifiouun ay} fo japd Jofpua
ay} dn 2a16 0} appul uaaq
spy pup ‘uoljajas ybnory}
paaoidun fi2}7Da16 uaaq
spy umoys aiay fijalima aye
‘pip $410}]Sa9uD $]}1 JsDa] JD
‘pizoig woif uapsp6 s,yupq
-Ing ‘djy 0} aura jt puD

‘ojDjod pup o}nulO} ay}

{0 u1sno0d D Si SINT

umup}0s
pooidory V¥

ON THE TOMATO

them, and which in turn must receive material for
the growing of their tubers from that vine, showed
quite unmistakably the influence of the foreign
system of leaves with which they were associated.

Instead of being smooth and symmetrical like
ordinary potatoes the tubers were small and ill-
shaped, and some of them had rough and corru-
gated scale-like surfaces, suggesting the skin of a
lizard rather than that of a potato. Moreover,
they were bitter in flavor and utterly unlike the
ordinary potato in taste. They further showed
their departure from the traditions of their kind
by manifesting a tendency to sprout even while
the tomato top was still growing vigorously.

Perhaps these results, as regards both the rela-
tive normality of the tomatoes borne by the grafted
vine, and the abnormality of the potatoes grown
by the roots, might have been expected. At least
they seemed quite explicable.

It will be recalled that the conditions of plant
growth were detailed somewhat at length in the
first chapter of the present volume, and that it was
there pointed out that the plant roots absorb from
the soil about them mineral salts in solution that
are carried up to the leaves of the plant before
they are transformed into organic matter by
combination with carbon drawn from the air. It
was noted that the organic compounds thus

[133]

LUTHER BURBANK

manufactured in the leaves of the plant must be
sent back down the stem of the plant to be depos-
ited, in case of a tuber-forming plant like the
potato, in connection with the roots in the ground.

It follows, then, that the tomato plant, even
though its source of supply was the root system
of a potato, merely gained from these roots part
of the raw inorganic materials with which its
leaves were to manufacture the special compounds
that go to make up a tomato. Inasmuch as the
tomato leaves were themselves unmodified, there
was no reason why their product, the tomato,
should be greatly modified.

In receiving its supply of raw material from a
foreign root, the tomato top was in no different
condition from the ordinary cions in a fruit
orchard, which, as we have seen, are habitually
grafted on roots or branches of a foreign species.

But the case of the potato tubers is obviously
quite different. Their substance is made up of
material that came originally, to be sure, in part
from material gathered by potato roots; but this
material had traveled up to the leaves of the
tomato plant and had there been transformed; so
when it returned to be deposited and form tubers
it was a tomato compound and not a potato
compound.

It was not absolutely different in material from

[134]

|
|
|
|
|

Potatoes With a
Strange History

These are potatoes
grown on a vine on
whose stalk a tomaio top
had been engrafted. The
tomato leaves were unable,
apparently, to supply just
the right kind of material
in abundanee for the
making of the best varie-
ties of potatoes; but they
made a creditable effort
nevertheless, Considering
that no tomato vine had
ever grown a pofato at all
before, the result might
be said to be notable.

LUTHER BURBANK

the material of the ordinary potato, because the
tomato and potato are cousins.

But the modification had been great enough to
transform the tuber, and make it a deformed and
perverted thing, more or less comparable, doubt-
less, to the tubers of some ancestral race from
which both the tomato and potato have developed.

The extraordinary thing, perhaps, was that the
tomato should have manufactured starch in such
quantity as to have supplied material for even
these dwarf tubers, inasmuch as the normal tomato
plant produces no tubers of its own. But seem-
ingly the buds designed to produce tubers on the
potato roots made an incessant appeal that the
vine above could not resist, even though it was
able to fulfil but imperfectly the specifications for
a potato tuber.

AERIAL POTATOES

Meantime, what of the potato tops that were
grafted on the stem of the tomato? How did these
prosper?

Here, it is obvious, were complications of a
different order. The tomato vine obviously could
bear no tomatoes because it had no tops. Mean-
time the potato vine was equally handicapped as
to the production of subterranean tubers since it
had no roots of its own kind.

But the tomato roots of course sent up their

[136]

ON THE TOMATO

supply of water and salts in solution, and the
potato leaves set to work as usual developing
material for the manufacture of tubers. When,
however, the effort was made to send this material
for tuber formation back to the roots, there was
an embargo put on such transportation because
the tomato roots have no knowledge of the art of
tuber making.

In this dilemma the potato crop, under spell of
the compelling instinct of tuber formation, made
the only compromise possible by growing aerial
tubers at the joints where the leaves appear from
buds springing from the point of union with the
leaves of the stem.

What would ordinarily have been leaf-bearing
branches were terminated with small potatoes,
which, because of exposure to the sunlight, gener-
ally took on a greenish tint, those in full sunlight
sometimes being thoroughly green, while those
that were shaded by leaves were of a lighter color.

The potato vine growing on a tomato stem and
bedecked with aerial potatoes, like some strange
form of exotic fruit, was certainly one of the most
curious forms of plants ever seen. It is perhaps
needless to add that the potato vine produced no
fruit that gave any suggestion of the influence of
the tomato. The tubers it grew were potatoes and
nothing else; their modifications in form and color

[137]

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Bury} ay} joy} s}sabéns
sjupjd om} ay} 6t13{016
ul ssaaans s,yuvqing
“I pup ffamurpsopijxa aq
pinom sjjnsaa ayy ‘pajaaf
-{2 9q pjmoo uo0ljn71p141q
-fiy ji aof ‘fizjuajsisiad jno
pajiivd aq pjnoys ojynuro}
ay} pup OJDJod ay} 2z1p}11q
-fly 0} }duraj]D ayy *ojD}
-od pup ojpuroy fo saijai4
“va padojaaap usapour ay}
uaamjaq ajpipaursajur yoym
-aulos yunjd jo adfij pv fo
‘Ajqvuqoid $= ‘saaijpjuasaidas
ffijalmpa_=yv21d04} = abupays
D fo saojpjod aim sjon
-poid snolima asayz

O}DUIOT, ay],
fo sujsno ppo

ON THE TOMATO

were obviously due to the lack of their natural
protective soil covering.

But the fact that the vine, handicapped by lack
of roots of its own kind, should have been able to
transform leaf buds into tuber-growing aerial
rootlets furnishes an interesting lesson in the meta-
morphosis of parts. How the great poet Goethe,
who first expounded the theory of metamorphosis
of parts, and clearly recognized the fundamental
unity of stem and leaf and flower, would have
enjoyed the viewing of a spectacle like that!

Questions oF Sap HysripisM

And for the modern plant developer, the
strange compound vines have no less interest, for
they suggest a number of questions that are much
easier to ask than to answer.

How, for example, was the leaf system of the
potato that grew the aerial tubers to know that
tubers were not being formed about its roots in
the ordinary way? It did know this, obviously,
else it would not have adopted the unprecedented
expedient of growing tubers in the air.

It is easy to speculate, and to suggest, for
example, that the potato plant producing an excess
of sugar and starch in the usual way, must find
some place to deposit it, and that as no demand
came from the roots, the only available buds were
made to do vicarious service. But the explanation

[139]

LUTHER BURBANK

obviously lacks a good deal of complete satisfac-
toriness. For the moment, we perhaps must be
content to recognize in this another illustration of
the fact of communication between the different
parts of a plant, and of the harmony of purpose
through which the plant as a whole is made to
respond to the conditions of the environment in
the way that best meets its needs.

But we are forced to recognize, through such
an illustration, a greater capacity for adaptation,
seemingly almost of a reasoned character, than we
are commonly wont to ascribe to the plant.

The case of the tomato plant growing on the
potato roots, which so perverted the character of
the tubers that it supplied, has practical interest
for the plant breeder, and in particular for the
orchardist, because it demonstrates the effect of a
cion on the stalk on which it is grafted. Of course
the ordinary fruit tree does not develop a system
of tubers, and so it does not call for such a supply
of starch, for example, as that which the tomato
vine was induced to produce for the tomato roots.
But the root system of any tree requires nourish-
ment if it is to develop, and this nourishment, as
we have seen, must be supplied by the leaves of
the tree above it, even though the roots themselves
first collect part of the materials.

It follows that the root system of any tree, while

[140]

ON THE TOMATO

it is absolutely essential to the leaf system above
it, is also very largely dependent on that system.

In other words, there is the closest reciprocal
relation between root system and leaf system.

This relationship, which many orchardists over-
look, I have long recognized and have repeatedly
referred to. But the case of the tomato on the
potato root emphasizes the lesson in such terms
that no one can ignore it. With this illustration
before us, we can scarcely doubt that the root
system of any stock on which a foreign top is
grafted (as is the custom in most orchards) is
modified in some measure by the cions it bears.
The foreign leaves cannot supply precisely the
same quality of nourishment to the root that leaves
of its own kind would have supplied.

In the main, no doubt, the protoplasm of the
root assimilates the nourishment that comes to it,
and makes it over into its own kind of protoplasm.
But we know that the flesh of animals varies in
quality with the food given the animal, and we
cannot well doubt that the protoplasm of the root
of a plant must similarly be modified by the
character of its food.

And this line of thought suggests the further
possibility that when more cions than one are
grafted on the same branch or on the same trunk,
there must be a certain intermingling of the sap

[141]

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aarjdajas fiq sadfij
oMsI4ajIDIDYI dojaaap
9} 71N91{f1p 11D 7D jou $2 31
pup ‘{sauia Bulsoqybiau uo
aloul 111]8 Pup ‘aula OyDUI
~Oo} aums ay} wosf jinif
ayj Buownp uolpiapa fo
yoap pooh vd si alay, “uol
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-as fo sj]nsa1 ay} moys
saojpulog asau

Sa0JDUIOL,
paj2ajag aul0g

ON THE TOMATO

from the different leaf systems in the course of
the journey to the roots of the tree; and that it
might very conceivably happen that a sufficient
blending would take place so that the modified sap
might find its way to the fruit buds of a given cion,
and effect the character of the fruit in a way not
altogether unlike the effect of hybridizing.

This would account for the case narrated at
length in an earlier chapter, in which a cion of
the purple-leaved plum grafted on the stem of a
green-leaved Kelsey plum tree, appeared to influ-
ence the fruit of a neighboring stem so that the
seedlings that grew from that fruit bore purple
leaves.

As before stated, such a striking instance of
evident “sap hybridism” is exceedingly rare; but
can we be sure that influences of a less tangible
character are not constantly exerted by engrafted
limbs?

May it not be possible, even, that the influence
of cions from many sources on one another, when
they are placed together in large numbers on a
single tree, as in the case of my colonies of plums
and cherries and apples, may be very notable
indeed, even though of such character as not to be
demonstrable? Is it not at least possible that the
improved quality of the new and splendid varieties
that appear on the various cions of these multiple

[143]

LUTHER BURBANK

trees, is in some minor part to be ascribed to the
mutual influence of cions of many different strains
of past generations, one on another?

If this thought be permitted, we must recognize
in such fruit colonies as those in question an
influence exercised by the community for the
benefit of the individual that is comparable to the
intangible influences through which a community
of human beings affects the moral character of
its individual citizens.

All this carries us somewhat afield from the
case of our grafted tomato-potatoes, but only to
the extent of a natural application of principles
clearly suggested by the phenomena exhibited by
these extraordinary plants.

A GLaNcE AHEAD

Let us repeat that the grafting of these two
plants is not a difficult procedure.

It is well worth the effort of any amateur to
repeat these experiments (so far as I know, this
has not been done until recently, and its signifi-
cance has never been fully appreciated), and to
observe for himself the curious phenomena that
will result.

Possibly the results of my own early experi-
ments might not be exactly duplicated. But there
is little doubt that interesting and encouraging
developments would result.

[144]

PINK CHIVES AND OTHER
FOODS FOR FLAVOR

SoME SUCCESSFUL Work WITH THE ONION FAMILY

HAT there is such a thing as being too
popular, many plants have learned to
their sorrow. For popularity, with the
plant, implies a kind of attractiveness that results
in the plant being eaten by some herbivorous
animal. The animals can secure food in no other
way, so they are not to be blamed for their
marauding. But in the meantime the appeasing
of their appetites spells destruction for the succu-
lent herbs.

The only resource of the plants is either to
develop extraordinary capacity to thrive under
adversity, as the familiar lawn grasses do; or to
develop weapons of defense.

These defensive measures may take the form
of a tough and indigestible fiber as in the case of
. woody shrubs; the studding of the plant surface
with spines as with the blackberry; the production

[Votume VII—CuaprtTer V]

LUTHER BURBANK

of a crop of stinging hairs as with the nettle; or
the secretion of oils or other chemicals that have
offensive odors, or bitter, acrid, or peppery taste.

In the present chapter we are concerned with a
conglomerate group of plants that have resorted
to the last-named expedient in the attempt to
protect themselves against the unwelcome atten-
tions of herbivorous beasts. The onion and its
allies, the mints, mustard, peppers, and the others
of this company, are for the most part lowly herbs
or succulent bushes that have qualities of flesh that
make them attractive. In self-defense they have
developed added qualities, chiefly through the
manufacture of essential oils, of odors or flavors
that are the opposite of appealing.

But as in a good many other instances, these
plants by their very zeal to some extent defeat
their own purposes. The unique quality of the
flavors they develop, even though at first repellent
to the palate, serve as a stimulus to the receptive
mind of man, and urge him to develop a taste for
the very things which at first seemed repellent.

So it has happened that plants that seem by
the very nature of their product to be denied
presence on the table have come to be regarded
everywhere as admirable accessories to the dietary,
supplying flavors that pique the appetite and
facilitate digestion. These stimulators of jaded.

[146]

Chilean Garlic
On the Stalk

This is the im-
proved garlic shown in
the preceding picture. It
will be seen to have grown
to seemingly ungarlic-like
proportions under stimu-
lus of changed climate and
skillful tutelage. The gar-
lic experiments are stilt
under way at Santa
Rosa.

LUTHER BURBANK

appetites are perhaps of somewhat doubtful bene-
fit, if we are to accept the findings of the physiolo-
gist, but they have a recognized place in the mod-
ern kitchen, and various and sundry of them are
among the most important of garden vegetables.

At the head of the list, doubtless, if we consider
universality of vogue, are the members of the
onion family, including onions proper of many
varieties, and such allied species as the garlic, the
leek, and the chive.

Work WitH THE CHIvVE

I have worked a good deal with most of these,
but have found perhaps greatest interest in devel-
oping the one of them that is least generally known
—the chive. The particular work of recent years
with this plant has had to do with a variety which
bore a flower that was originally dull crimson in
color, and which, notwithstanding its disagreeable
odor, appeared to combine the qualities of a bor-
der plant with those of a food plant.

I secured seed of this variety of chive in Europe
and raised seedlings for five years, carefully select-
ing in each generation the ones that most appealed.
There was a considerable tendency to vary within
rather narrow limits, some plants being deeper in
color than others, but the divergence was not at
first very marked.

In the third year, however, there suddenly

[148]

ON THE ONION FAMILY

appeared a mutant having a blossom of bright red
color instead of the usual rather dull crimson.

As the chive can be multiplied indefinitely by
division, this single plant might have become the
progenitor of a race of red flowering chives. But
I wished to see what the hereditary tendency
would be, and so raised about ten thousand
seedlings from the red flowering stock. Nearly
all of these seedlings reverted to a pink color.
There had been a faint tinge of rosy pink in the
original flower, obscured by the crimson, but the
new seedlings bore blossoms of a pleasing pink
color, and constitute a new and highly attractive
variety.

While thus developing a pleasing flower and
thereby adding to the attractiveness of the chive
as a border plant, I paid attention also to the bulb
and stalk of the plant itself as well as to the flavor.

In the course of five or six generations I
developed the bulb so that the average size is
about twenty times that of the bulbs of the stock
with which we began.

Thus the new race of chives not only supplies
a pink flower which has a very handsome effect
when massed in contrast with the characterless
flowers of its ancestor, but it is also relatively
gigantic in bulb as compared with them. Thus
its value as an ornamental plant and its utility as

[149]

An Improved
Garlic

i-
ment gardens for a num-
at

im-

is

It
‘he climate of

the northern hemisphere—
at all events the climate of

ducation
At the right
with
this particular garlic.

is seen a head of the orig-
as imported

This is a garlic
California—agrees

rom Chile that has
Mr. Burbank’s exper

roved descendant.
obvious that t.

f
been undergoing e

from South America
the left its developed and
greatly enlarged and

ber of years.
inal form,

in
Pp.

ON THE ONION FAMILY

a food plant were enhanced simultaneously, and
somewhat in the same proportion.

These results have been attained by selective
breeding, without hybridizing, in the course of a
comparatively small number of generations.

Development has progressed along yet another
line. The one chief objectionable feature of plants
of this tribe, as every one knows, is their odor.
But it is well-known also that different members
of the onion tribe differ greatly in this regard. In
recent years the Italian and Bermuda onions,
which are very mild and relatively odorless, have
been introduced, and the possibility of removing
from the members of the tribe their objectionable
odor has come to be more generally recognized.
It appears that the Italian varieties have been
rendered odorless by selection from ordinary
onions. Some of the improved Italian varieties
are so mild in taste that they can be eaten like an
apple.

In experimenting with the chive I . have
naturally not overlooked this quality, and some
of these improved varieties show a marked
advance upon its ancestors in regard to odorifer-
ousness as in regard to size and quality of bulb
and beauty of flower.

IMPROVING OTHER ONIONS

‘My work with the other members of the family

[151]

LUTHER BURBANK

has been fairly extensive, inasmuch as I have
experimented first and last with about fifty species
of wild and cultivated Alliums (that being the
technical name of the genus) from Europe, Asia,
and America, and with various forms from Chile
and from China.

The onion is a very interesting plant with which
to work, from the fact that it shows a good meas-
ure of responsiveness. The wild onions are
exceedingly variable and the cultivated species no
less so. Indeed, this might be taken almost for
granted considering the long period during which
the onion has been under cultivation and the large
number of varieties that are in existence.

In addition to the ordinary species with its
well-known qualities, there are numerous hand-
some-flowering varieties of onion. And in the
Sierras there is also a variety growing along the
mountain streams which has a delicious, sweet
flavor much superior to the cultivated onion. I
have cultivated also an onion from China which
is peculiarly sweet flavored.

Some of the Chilean and Canadian leeks that I
have had under cultivation differ widely in form
from their Northern relatives. Some of the Chilean
wild garlics have been classified as leeks by the
botanists and gardeners in this vicinity; whereas
the same observers classify certain of the true

[152]

Burbank Onions

Grown for Seed

Mr. Burbank has
worked extensively
with the onion, as with
numerous other members
of the tribe of alliums.
Here we see a fleld of per-
fected Burbank onions that
have been allowed to go to
seed. The excellent char-
acter of the bulbs may be
inferred from the size and
vigorous development
of the tops,

LUTHER BURBANK

leeks as garlics; which suggests the divergence of
form of these South American species.

I am now cultivating a wild garlic from the
mountains of Chile which is a wholly distinct
species from the common cultivated garlic, having
much larger bulbs and a taller stalk similar to that
of the leek.

I have in contemplation the hybridizing of this
Chilean garlic plant with the familiar form of
cultivated garlic. My attempts to cross the species
with the onions have not met with success,
although I still think it possible that this cross may
be effected.

My large collection of flowering Alliums from
California and other countries has of course been
made with the expectation of hybridizing these
plants among themselves or with commoner
varieties of the onion. There are interesting
possibilities of development all along the line.

There is a Spanish onion named the Prize-
Taker because of the extraordinary size of the
bulb, which sometimes attains a weight of five or
six pounds. That new developments, perhaps of
unexpected character, will result when the varied
races from Europe, Asia, China, and Chile are
blended with American stock, is quite to be
expected.

The onion is not very easy to hybridize because

[154]

ON THE ONION FAMILY

of its small flowers. But it is only necessary to
use reasonable care to effect hybridization, and
the results are likely to repay the effort.

Indeed, whether by hybridizing or by mere
selection, the onion is susceptible of great
improvement along almost any line one may
choose. The odor, for example, may very readily
be intensified or decreased, and the size and
flavor modified. On the whole I regard this as one
of the most interesting vegetables with which to
work. But there are many other plants prized for
their flavor that also merit attention.

THE ParSLEY FaMILy

Prominent among these are the members of the
parsley family.

The common parsley and its close relative the
caraway vary a good deal in flavor in individual
plants grown from the same lot of seed. Only
persons with a developed or specialized sense of
taste are likely to notice this, however.

To the person who tastes them carefully, it will
be obvious that some specimens are much sweeter
and better flavored than others.

But as the general public is not very discrimi-
nating, it is perhaps doubtful whether it would be
profitable to develop these into fixed varieties.
The market for these plants is of course restricted
at best.

[155]

A South American Allium

Here is a plant with a nightcap; or, if you prefer, a
dunce-cap. The protective covering of the flower-bud has burst
open, but has not been discarded; hence the curious effect. This is
not, as might be supposed, a mere accidental individual pecu-
liarity, but is characteristic of the species. It might be
difficult to guess, however, what protective
function the nightcap subserves.

ON THE ONION FAMILY

A more tangible property, and one that is likely
to appeal to the user of the plant, is the shape and
quality of the leaves. I have worked on the curled
parsley to some extent and have found that by
careful selection it can be improved greatly in a
few years. The different tendencies of the leaves
can be fixed quite readily in three or four genera-
tions.

At one time I also developed a golden-leaved
parsley, something like the golden-leaved celery.
This was a plant of great promise and I expected
to introduce it. But greatly to my regret, it was
destroyed by millipeds just before it was ready to
produce seed.

I have never seen another specimen, but of
course similar mutants might appear at any time,
for what has happened once to a plant may
happen again.

Another genus of the parsley family,
Ligusticum of the botanist and commonly known
as lovage, is cultivated to some extent in our
gardens for its aromatic seeds. There is a Cali-
fornia species (L. Canadense) that grows along
the ground, and seeds quite commonly in Northern
California. The root is gathered and used by the
Chinese.

I have worked with this and with several allied
species very extensively for a number of years.

[157]

LUTHER BURBANK

There are several native species or varieties of this
family that are hard to differentiate, especially as
_ they vary widely in different localities. All have

seeds or roots with a characteristic pungent odor,
but the quality of the odor varies throughout the
widest range, from the most fragrant and
attractive to the most disagreeable.

Undoubtedly some of these wild species offer
opportunities for development through cultivation
and selective breeding. My own work in this
regard has scarcely passed the experimental stage,
however, even though it has involved a large
number of species and varieties. There is oppor-
tunity for interesting and valuable work in the
development of the possibilities of these bearers
of flavors that appeal to the palate.

MINTS AND THEIR ALLIES
I think I have grown all the mints and pot herbs
that have been under cultivation, and have found
them without exception variable in quality when
grown from the seed.

Indeed, to the persons who taste them with
care, it will appear that variation is the universal
rule. Each individual plant when grown from
seed has a slight difference in fragrance, and in
the amount of essential oil that it contains; this
oil being, of course, the source of the fragrance.
It is not difficult by selection alone to obtain varie-

[158]

A Burbank
Allium

This is another of

the company of al-
liums with which Mr. Bur-
bank has experimented ex-
tensively. The relationship
with the onion is shown in
the form of leaf and, par-
ticularly, in the flower
head. Some of Mr. Bur-
bank’s alliums have really
handsome flowers; and an
ornamental onion is cer-

tainly an interesting

anomaly.

LUTHER BURBANK

ties that are of exceptionally fine fragrance and
that produce a relatively large percentage of the
essential oil for which the plants are usually
grown.

When a new variety has been obtained, it is not
necessary to fix it so that it will breed exactly true
from the seed; for the most of these plants can be
increased by division.

The mints hybridize naturally where various
species grow in the same vicinity, as we have
pointed out in another connection.

In this way natural hybrids are sometimes
produced that are so vigorous as to replace the
original parent plants in the state of nature, driv-
ing them out of existence on their own ground.
Among hybrid mints, whether natural or produced
by hand pollenation, there will be seedlings that
grow with exceptional rapidity, and that present
peculiar shapes and much variation as to rough-
ness and smoothness of leaves and form of the
spikes and blossoms. In my work with all these
plants, I found that quality was the one thing
lacking. In any lot of seedlings grown from the
pot-herbs or plants some individuals have odors
that are positively disgusting, and those of some
add nothing to the value of the plants, but detract
when mixed with the better ones.

All this is quite what might be expected when

[160]

ON THE ONION FAMILY

we reflect that the mints are a rather numerous
family—that fact by itself proving their tendency
to variation.

Among the mints that I have worked on
recently are species from South America that
resemble the peppermint yet are in some respects
distinct. An unnamed species with a tendency to
cling to the ground more closely than other mints
and growing so rapidly as soon to cover a large
surface gives considerable promise.

A species said to be hardy, sent by my collector
from the mountains of Southern Chile, has some-
what the fragrance of the native peppermint. The
yerba buena (Micromeria douglassi) is a common
little trailing plant in the red wood forests, some-
times growing also among shrubs and along the
edge of fields. It has sweet-scented, round leaves,
and small, pale, insignificant, purplish flowers.

This plant is fairly constant in any given
locality, but specimens from different regions vary
a good deal, some being rather packed growers
while others run out to great lengths, with long,
runner-like branches. A species of this plant of
exactly the same flavor, but growing as a shrub,
with brilliant fuchsia-like flowers, has been sent
me from the high mountains of Chile. These evi-
dently sprang from one original ancestor, but in
our California varieties it is an insignificant trail-

[161]

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Zof aauaynoans 9}}s14aj9D
-i1DYy2 ay} SUIDjaz }2 Jali ‘saa
-moy aaijavsjj0 sayja6o}]0
yyim ‘jupjd sapi0q yo}uaut
-puIO uD SI jy ‘*Summy][D
fo aqia} ay} Guawn suot}
-onpord 6uljsazaju1 j}sour

s,yupqing ‘tj {o auo

81 aaqya yud ayy

saaiy)
M07}9X PuD yuid

ON THE ONION FAMILY

ing plant, and its relative of the Southern hemis-
phere is a tall shrubby plant with brilliantly col-
ored flowers. The Chilean plant is also called
yerba buena.

I have attempted to cross this plant with the
species from Chile, hoping thus to stimulate varia-
tion and perhaps to produce a plant of larger size,
and through selection a variety of permanent
value. But the flowers of the plant are quite small,
making the process of cross-pollenization a rather
delicate one, and my experiment has hitherto not
proved successful. This, however, is doubtless due
to operating on too small a scale. I have no doubt
that more persistent efforts will result in
hybridizing these species, notwithstanding they
came from different hemispheres.

Other mints with which I work are the melissa
or balm, and the common garden thyme.

Of the former I have raised many thousands of
plants from seed, and have secured among these
half a dozen in which the flavor and aroma are
exceptionally pure and strong. In one of these
individuals the flavor is so much more spicy than
is usual that it may be said to constitute almost a
new type of flavor. The experiments in improving
the plant are still under way and the response
made by the plant itself is prompt, giving assur-
ance of the production of improved varieties. And

[163]

LUTHER BURBANK

scores of other plants of similar nature have given
like results, but need not be specifically mentioned
here.

The thyme also I have grown from the seed,
and have noted with this as with other members
of the family a very marked tendency to variation.
The most interesting variety that I have developed
has been produced by selection from a seedling
the leaves of which showed a beautiful white
center with very uniform edges of a dark green,
instead of the usual yellow and green markings.

This plant, in addition to its beautiful leaf, was
a more compact grower than the old variegated
thyme. By selecting through successive genera-
tions I accentuated and fixed the novel leaf until
it would come almost uniformly true from the
seed. I offered this new ornamental variety to a
dealer, but he responded that the demand for
thyme was so small as not to justify its purchase.
So the new plant was allowed to drop out of
cultivation.

Tue Mustarp FaMILy

The members of this family, quite unrelated
botanically to the ones we have considered, illus-
trate the tendencies of different races of plants to
adopt similar expedients in furthering their ends.

Being succulent herbs, like the parsleys and
mints, the mustards have devised a similar pro-

[164]

Horse Radish Plants

The horse radish belongs to the small company of plants
that have given up the habit of producing seed. It is propa-
gated solely by division, and therefore is not subject to improvement
by selective breeding. Mr. Burbank once facetiously offered to give a
thousand dollars an ounce for horseradish seed. He received many
packages of seeds in response to this offer; but none of them pro-
duced horseradish plants. Mr. Burbank says the offer is stiil
open, but there is small probability that any one will win
the prize, for the horseradish seems to have perma-
rently abandoned the habit of seed production.

LUTHER BURBANK

tective measure, namely the development of
essential oils that have a pungent and biting taste.
But here as with the others man has cultivated a
taste for what seemed a prohibitive quality, and
the mustards, including not only the plants that
give their name to the family, but such allies as
the peppergrass, the cresses, and the horseradish,
have long held a secure place in the culinary
department of every household.

My most extensive experiments in the
cultivation of the mustard were carried out some
thirty-five years ago. I worked quite largely with
the Japanese and Chinese mustards, in combina-
tion with the common European mustard.

These Japanese and Chinese mustards are quite
distinct from our species. One kind very
extensively used in China, and introduced by the
Chinese in California, has the appearance of a
large compact bunch of celery. The leaves are
perhaps two inches in width or even more, grow-
ing so compactly that the plant is even more solid
than an ordinary cabbage head, each plant
weighing from two to five pounds. The leaves are
blanched like celery. They have a spicy taste
suggestive of mustard that is very palatable and
refreshing. The plants are cooked like other
garden vegetables.

Another Chinese variety has greener leaves and

[166]

ON THE ONION FAMILY

a looser habit of growth, the plant being also
considerably larger. This also is a pleasant, spicy
vegetable when cooked.

All the Chinese mustards run to seed quickly
at the approach of warm weather, so the seed is
usually sown quite early in the winter. The young
plants are stimulated to rapid growth by good
cultivation and fertilization, and fine large plants
are ready for the market in the early spring. The
plants are usually grown on raised beds and are
planted about a foot apart each way. These are
really remarkable vegetables that should be much
more generally cultivated in the United States.

In the Northern States, unless planted very
early in cold frames, they run to seed without
forming the large, succulent head that gives them
value.

Both the black and white mustard are common
plants in California, the black mustard in particu-
lar being prized for culinary purposes when young
and tender early in the spring and winter. The
white mustard grows in enormous quantities in the
fields, especially in the region about Monterey
Bay, where the seed is collected by the ton, to be
ground into commercial mustard. The white
mustard in particular may become a pest, as it is
exceedingly difficult to eradicate it, the seeds

[167]

Improved Mustard

The mustard is a plant to which the ordinary amateur
gardener pays very little attention. ‘Mustard is mustard,”
would probably be his comment, and it would not occur to him that
the plant is one having any particular interest from the standpoint of
the would-be plant developer. In point of fact, however, there is a
good range of variation between different mustards, and Mr. Bur-
bank has seized on these variations for material to work
conspicuous improvements, notably as regards the
amount and quality of the pungent principle
for which the mustard seed is prized.

ON THE ONION FAMILY

sometimes remaining in the ground several years,
part of them germinating each season.

About the only way to eradicate it completely
from the grain and other crops, is to pull it just
as it comes into bloom in successive seasons.

My systematic work of selective breeding of
the mustards was carried out while making similar
experiments with other members of the family,
including the turnips, cabbages, and radishes. I
developed some superior varieties by selection,
and sent the seed east to various parts of the world.
But the demand was small and I presently dis-
continued work with these plants, although several
of these and similar varieties developed are still
catalogued by some American and European
seedsmen.

Other Crucifers that the gardener thinks of
collectively, though they represent various genera,
are the peppergrass and the various cresses,
including the nasturtium.

The common peppergrass is as variable as the
lettuce. There are large numbers of plants
horticulturally called cresses, with a considerable
range of variation.

One of the most interesting forms with which
I have worked is a Chilean cress (Nasturtium
Chilensi), which is as tender as the common water
cress during the rainy season, and which has an

[169]

LUTHER BURBANK

astonishing ability to resist drought. This Chilean
variety will withstand our summer, even if
exposed to the blazing sun, and after a period of
dormancy will revive and grow freely as soon as
the fall and winter rains come.

My experiments with it have been confined to
selection for the development of varieties showing
the best qualities of the plant.

With the peppergrass I have worked somewhat
more extensively. Some specimens of this plant
have very finely dissected leaves. I have worked
to develop this variety, producing leaves very
similar to those of the improved varieties of
parsley.

The plant is rather obstinate, but I have
nevertheless been successful in developing and
fixing varieties having many of the desired
characteristics.

As the peppergrass is an annual it is of course
necessary to fix the new qualities so that they will
be reproduced in the seedlings. It is this rather
than the mere production of the variety that offers
difficulties.

The familiar horseradish offers a notable
contrast to the peppergrass and to most other
members of the family in the matter of seed. For
whereas the mustard, radish, turnip, cresses, and
the rest produce seed in the greatest possible

[170]

A Basket of
Peppers

Like most other
products of the garden,
the pepper has come under
Mr. Burbank’s careful
scrutiny, and has felt the
benefit of his guiding hand.
The large and handsome
specimens here shown have
been developed in the
course of a few generations
of selective breeding, with-
out hybridization. Simi-
lar results will attend the
efforis of any one who will
go about the work of im-
proving the pepper with
enthusiasm and zeal, using
the ordinary garden va-
riety. The plant deserves
to be cultivated much
more generally
than it is.

LUTHER BURBANK

abundance, the horseradish produces no seeds at
all.

The horseradish does, indeed, bloom with the
greatest profusion. But the blossoms prove
sterile. The plant has entirely and probably
forever lost the power of producing seed.

I have elsewhere referred to the fact of my
having created a small commotion amcng amateur
gardeners by the joking offer of one thousand
dollars an ounce for horseradish seed. Of course
I knew that no horseradish seeds were to be had,
yet I would gladly have given then, and I would
gladly now pay, at the rate of $1,000 an ounce for
horseradish seed. But there is not the remotest
probability that any one will ever legitimately
claim the prize. If the seed should ever be found,
it will probably be dark colored, about the size of
a common black mustard seed.

I have received nearly or quite a thousand
letters informing me that the parties writing could
supply me with all the horseradish seed I could
wish, inasmuch as their plants were blooming
abundantly.

I may add that I subsequently received large
quantities of dried horseradish buds, as well as
great quantities of the seeds of weeds of various
sorts. I have even received what were alleged to
be horseradish seeds from market gardeners. But

[172]

ON THE ONION FAMILY

the plants that grew from these seeds bore no
resemblance to the horseradish.

The interesting features of this loss of the
power of seed production by plants that have for
long periods been propagated by the root or from
cuttings or tubers—including plants of such diverse
races as the banana, the pineapple, the sugar-cane,
and the potato, and nearly all plants generally
cultivated in greenhouses, along with the horse-
radish—have elsewhere been referred to. I may
add that the loss of power to produce seeds in the
case of the potato is not of necessity comple-
mentary to the capacity to produce tubers. For
at least once in my experience a potato plant that
by rare exception produced seed developed at the
same time some of the largest tubers that I have
ever seen.

Nevertheless there is an association between
seed production and development of the root
system, as we have seen illustrated. And it is not
unlikely that development of the root of the horse-
radish may have had an influence on its seed-
bearing capacity. It may be recalled that the
carrot and parsnip which produce roots somewhat
suggestive of that of the horseradish in shape and
relative size, are biennials, and do not take on
the functions of root and of seed-development in
the same season.

[173]

LUTHER BURBANK

The roots are formed in the first year partly at
least to supply nourishment for the development
of the stem and flowers and seeds in the ensuing
season.

Whatever the relation between the root of the
horseradish and its lack of fertility, the fact
remains that the plant is propagated solely by
division, and that hence there is very little oppor-
tunity for the development of new varieties or the
improvement of old ones. Each horseradish root
is in effect a part of an original plant now end-
lessly divided, and the variation in different roots
depends upon conditions of cultivation or nourish-
ment, not upon inherent differences between the
different plants.

It may chance some day that an exceptional
horseradish plant will produce seed, just as an
exceptional potato plant does from time to time.

In that case there will doubtless be opportunity
to improve the horseradish somewhat as I was
able to improve the potato by growing plants from
the seed.

But until such an exceptional seed-bearer is
‘found, we must accept the horseradish as it is, and
admit our powerlessness to change it markedly.

THE PEPPERS

The versatile family of Solanums, several

members of which have already claimed our

[174]

Giant Mexican
Peppers

There is good op-
portunity for the de-
velopment of new varieties
of peppers through the
blending of strains of va-
rious races, as several are
available. Peppers grow
far to the North, but they
were originally of semi-
tropical habitat. This
handsome specimen from
Mexico. is being utilized by
Mr. Burbank in some
crossbreeding ex-
periments.

LUTHER BURBANK

attention, supplies an important group of plants
that are prominent among the producers of
pungent and aromatic flavors.

These relatives of the sunberry, tomato, potato,
and eggplant, are the peppers, of which there are
large numbers of cultivated varieties in different
countries.

The different peppers vary from the size of a
barleycorn to that of a very large apple, and in
color from black through scarlet, crimson, orange,
and yellow to pure white. In form, some are
nearly flat, others oval, yet others round or heart-
shaped, or like drawn-out cylinders. Some are
annuals and others perennials. As to flavor, some
are sweet and palatable, while others are among
the most pungent and fiery of substances that are
ever purposely put into the mouth.

I have worked quite extensively with the
peppers, hybridizing them in various ways, and
raising large numbers of the seedlings.

In crossing the very small varieties with the
very large ones, and the very light-colored with the
very dark-colored, one produces the most unusual
combinations. Even in the first generation some
bushes appear having diminutive fruits and others
having unusually large ones; and there is a display
of different colors, including stripes, that is quite
beyond prediction.

[176]

ON THE ONION FAMILY

Occasionally, though not often, fruit of different
colors will appear on the same plant.

Some hundreds of varieties of pepper have
been described, but only perhaps less than a dozen
are cultivated ordinarily in the gardens of tem-
perate climates.

The large sweet peppers are becoming popular.
In some varieties, they are almost mild enough in
quality to take the place of their relative the
tomato.

My own work has included the cultivation and
crossing of a large number of species and varieties
of pepper. At least one of these will stand a very
low temperature, the plants showing no trace of
injury when left where ice forms a quarter of an
inch in thickness.

As most of the peppers are exceedingly sensitive
to frost, this hardy Chilean variety seems to offer
opportunities for hybridizing experiments through
which other varieties of the plant which at present
are of restricted habitat may be made suitable for
growth in cold climates.

I have just referred to the great diversity of
forms shown by such hybrids.

There can be no question that selection among
these and breeding through successive generations
would produce almost any desired combination of
qualities.

[177]

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JaUUINS JSD] Usas aq O}
som yjmoi8 auospupy $10
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ARTICHOKES AND SOME
GARDEN SPECIALTIES

Finpinc New Foop PLants WILD IN THE Woops

scheme ever devised by any flower to

meet its essential needs is that adopted by
the Sunflower family—the tribe popularly repre-
sented by the sunflowers, asters, thistles, and
daisies.

The botanist classifies the members of this tribe
as Compositae or Compound Flowers. The name
might be misleading if taken to imply that the
flowers of this family differ essentially from other
flowers. In point of fact, the individual flowers
of this tribe are in all essentials of pistil and
stamen like other flowers. So the modern botanist
objects to the name “Compound” as applied to
them, although he retains the Latin title that they
have borne for some centuries.

But if we properly interpret the term, the name
“compound flower” seems appropriate enough,

LD wee the greatest labor-saving

[Votume VII—CuHapter VI]

LUTHER BURBANK

inasmuch as what would commonly be called a
single blossom—say a single daisy, or aster, or
dandelion, or thistle—is in reality made up of a
very large number of individual flowers grouped
together into a floral community, which adver-
tises its location to the insects by arranging a
single circle of petaloid colored emblems that do
service for the entire community.
A MEasurE OF EcoNoMY

The economy of this arrangement, in the matter
of saving of plant energy, is obvious.

Flowers that have not adopted this system are
obliged to supply a colored advertising emblem
for each individual set of stamens and pistils.
These composite flowers make one such floral
emblem serve the purpose of scores or even
hundreds of flowers.

Of course the floral community, even though
the individual flowers are very small, occupies
considerable room. It is necessary, therefore, to
provide a largish receptacle to hold the flowers,
and in particular to hold their seeds when
developed. The outside of this receptacle is
usually covered, for protection, by overlapping
series of scaly bracts or little leaves that form a
sort of armor.

A glance at a sunflower will illustrate the plan
that has been pretty generally adopted in the

[180]

Another Burbank
Dooryard View

So strong has been

the appeal of the arti-
chokes to Mr. Burbank,
that they have been per-
mitted to invade his front
dooryard as well. Here is
a wonderful group of them,
photographed just at blos-
soming time. As the fence
in the foreground is of or-
dinary height, an idea may
be gained of the enormous
size of the artichokes

which tower above it.

LUTHER BURBANK

provision of a covering to shield the flower-village,
particularly during its early development.
EpisLeE FLOwer-HEADS

In at least one case, a plant of the tribe has
been induced to develop this receptacle until the
leaves of its scale-like covering have been
enlarged and thickened and made succulent at
their base, so that they are edible; the receptacle
on which the flowerets grow being correspond-
ingly developed.

The flower that has thus been induced to put
itself at the service of man and add to the delica-
cies of his dietary is known as the artichoke.

This plant is widely cultivated in Southern
Europe and is exceedingly popular there. In Italy,
indeed, it occupies in some regions about the posi-
tion in the dietary of the masses that the potato
does in Northern Europe and America. In this
country, however, the artichoke has only some-
what recently begun to gain popularity. As the
manner of its cultivation is better understood, it
will doubtless gain wider vogue, for its leaf scales
and pulpy receptacle are regarded as delicacies by
epicures everywhere.

I have worked somewhat extensively with the
artichoke in very recent years, beginning with the
French Globe artichoke and the Oval Brittany arti-
choke in 1908; subsequently using also the Paris

[182]

More Artichokes

This picture shows some heads of Mr. Burbank's im-
proved artichokes, taken just before the buds were ready to
burst. For table use the flowers are never allowed to open, as the
bracts would then be practically inedible. But these artichokes
in Mr. Burbank's garden are intended for breeding pur-
poses, and they will be allowed to come to matur-
ity, and the best of them used for
cross-fertilizing experiments.

LUTHER BURBANK

artichoke, a large green variety, and of the
so-called Perpetual artichoke.

The plants when grown from seed vary
markedly in size and shape of the leaf as well as
in size of the blossom buds. Some of the plants
are thorny. The flowers, if allowed to come to
maturity, differ little in color, though greatly in
size. Some of the flower receptacles when fully
matured open out to a breadth of about twelve
inches.

But the flower bud is not permitted to mature
to the point of opening when the artichoke is to be
used as food. If it reaches the stage when the blue
flowerets begin to be visible, the head is altogether
too old for eating. The object of cultivating new
varieties is not necessarily to increase the number
of the flowers themselves, but the flower bud,
increasing the size and the quality of the scale-like
bud-leaves and the receptacle.

My work has been carried out along the usual
lines of selection, and the results have been very
satisfactory. Selection has also taken into consid-
eration, as a matter of course, the succulence and
especially the flavor of the edible portion.

The improved varieties have flower buds as
large as a good sized fist, and are of excellent
quality. When in full bloom they are sometimes
a foot or more in diameter. They are reproduced

[184]

BVIL.60)

Artichoke Hybrids

This is an individual blossom of one of Mr. Burbank’s
best hybrid varieties of artichoke. The flowerhead has just
passed the period when it would have been in ideal condition for eat-
ing, but has not yet fully presented its stamens and pistils,
The improvement shown in some of these crossbred arti-
chokes in Mr. Burbank’s garden is remarkable; and
they are still undergoing development.

LUTHER BURBANK

with reasonable certainty from seeds, but the
method of propagation generally preferred is by
the use of suckers which the plant puts out freely.
Of course these suckers reproduce the qualities of
the individual plant from which they are taken,
as roots or grafting cions do in the case of other
plants.

When it is understood by gardeners in general
that the artichoke can be grown with comparative

‘ease, and that it produces an abundant and never-
failing crop of healthful, palatable, and nutritious
food, this vegetable is sure to attain far greater
popularity.

THE CARDOON

The young stems and leaves of the artichoke
plant itself are sometimes eaten in Europe. It is
necessary to blanch them by covering, somewhat
after the manner of celery. There is a modified
form of the artichoke, known as the Cardoon,
which is cultivated for the stems and leaves instead
of for the flower buds. These are blanched by
tying the tops of the leaves together and covering
the entire plant with straw, banked with earth.

I have grown the cardoon, but have not experi-
mented with it in the attempt to produce variation,
as the European cultivators have developed it to a
very satisfactory stage.

The plant is very little known in America, but

[186]

ON NEW FOOD PLANTS

is likely to be more extensively propagated when
its merits are understood.
THE WILD ARTICHOKE

Another member of the sunflower family is
popularly known as the Jerusalem artichoke, the
name having originated, it is said, in a Spanish
nickname, amplified to suggest the relationship of
the plant to the artichoke just described, which is
sometimes spoken of as the Globe artichoke.

‘The Jerusalem artichoke belongs to the genus
Helianthus, of which there are numerous species,
some of them growing wild in California. It is
entirely distinct from the true artichoke, both in
growth, appearance, and the purposes for which
it is used.

The part of this plant that is sometimes used
as food is not the flower bud but a tuber not very
remotely suggestive of a potato.

The plants of this tribe are variable, as is usual
with plants represented by many species. Some of
them bloom abundantly when only six to twelve
inches in height, while others grow to a height of
ten to fifteen feet. They have very large, broad,
heavy leaves, and some of them produce sunflow-
er-like blossoms of enormous size.

Others have small, delicate, slender foliage, and
produce small flowers.

The flowers are yellow, the tubers are usually

[187]

Round as a Ball

This hybrid Burbank artichoke may be considered al-
most ideal in form, being practically spherical, and as compact
and solid as could be desired. To casual inspection, it scarcely sug-
gests a flower; but to the epicure it suggest what it really
is, a most palatable delicacy for the table.

ON NEW FOOD PLANTS

pink, but white varieties have been produced in
the past decade.

Some members of the Helianthus tribe are
perennials, but for the most part they are annuals.
They are all easily grown on almost any soil,
requiring little or no attention. The member of
the tribe known as the Jerusalem artichoke is a
somewhat variable plant the tubers of which are
chiefly used as food for stock, although sometimes
used as a salad.

My own work with the tribe has had to do with
the development of the flowers rather than with
the tubers. There is one of the annual sunflowers
that has a flower quite often sixteen to twenty-four
inches in circumference that, if well selected,
comes perfectly double, as double as the finest
dahlia, producing a most brilliant yellow bloom
abundantly. This I have worked on several years
to make its flower uniformly double. I have
worked with a large number of species of the
tribe and have cultivated many field varieties
collected in Mexico, California, the Mississippi
Valley, and nearly as far north as Hudson Bay.

I have done a good deal of crossing among the
seedlings to increase the grace of the plants and
delicacy of bloom, and to make the silvery, grace-
ful leaves of one species replace the rough, coarse
leaves of another.

[189]

LUTHER BURBANK

There is no great difficulty in hybridizing the
various species, especially if care is taken to wash
away the pollen by the method described in the
chapter on artificial pollenation. But there is
great difficulty in fixing a variety after it is formed.
The hybrids tend to take on many forms, their
variability in the second generation suggesting
that of the gourd family.

Of course, this difficulty does not apply in the
case of the artichoke, as this may be propagated
from tubers, just as the potato is propagated. So
any improved variety developed is fixed from the
outset. There has not hitherto been enough
demand for the plant in this country to stimulate
the plant developer to work with it. But it is
probable in the near future there will be renewed
interest in certain less common garden vegetables,
comparable to that shown in recent years in the
development of the orchard fruits, and in that case
the Jerusalem artichoke is almost certain to receive
recognition as a neglected vegetable that is worthy
of being generally cultivated.

Tue Letruce TRIBE

Doubtless the best known member of the
composite family under cultivation is the familiar
lettuce.

This plant has been so long under cultivation
that it is impossible to trace it back to the original

[190]

Q

Much Modified in Form

This hybrid artichoke ie very different in form from the
one last shown, It is much less compact, and makes a somewhat
less presentable appearance on the table. Nevertheless it is not with-
out value, as its bracts contain a goodly quality
of well-flavored pulp.

LUTHER BURBANK

wild species. In token of its long cultivation, it is
one of the most variable of plants. There are
hundreds of varieties of lettuce described in the
catalogs but those all quite naturally fall under
two distinct groups—the cabbage or head lettuce
and the cos or upright growing lettuce, the latter
of which is mostly grown in cool, moist climates.

The cos lettuce requires too much care in
blanching, and in our dry American climate runs
up toe quickly to seed in warm weather.

My work with the lettuce was done about ten
or twelve years ago, when I experimented in the
endeavor to produce different forms, and attained
a measure of success. In working with the cos
lettuce I endeavored to get a more solid head
which would be a very tender compact grower,
and would not so quickly run to seed. The part
of the lettuce that is eaten is, of course, the leaf,
and the plant that runs to seed quickly develops
a toughness of leaf fiber that impairs its value.

In hybridizing the lettuce, my usual plan was
to get two varieties to bloom as nearly as possible
at the same time, and to pollenize by bringing the
head of one and rubbing it against the flowerets
of the other. The pollen may be removed with a
dash of water, as already described, but there is
always a measure of uncertainty in cross-pollen-
izing composite flowers of such small size as those

[192]

An Ideal Hybrid

This hybrid artichoke possesses the fourfold advantage
of ideal form, very large size, excellent flavor, and exceptional
tenderness. It is one of an almost endless number of variations,
among which Mr. Burbank is able to select in continuing his
experiments. The variety that produces this specimen,
however, is well worthy of a place in the market-
garden without further development.

LUTHER BURBANK.

of the lettuce, as one cannot be sure in many cases
that a certain amount of the pollen does not
remain to effect fertilization of some neighboring
pistil.

I was able to combine some desirable qualities,
but did not succeed in combining all the desired
qualities in a single variety.

There is greater variation as to flavor among
lettuces than is commonly supposed. Of course,
the different types are used for different purposes
and at different seasons. Those grown under glass
must be compact growers, while those grown in
the open may be permitted to develop larger
heads. There are varieties of so-called perpetual
lettuce which have been so educated that instead
of running to seed they form new heads that can
be cut again and again.

As to all these matters there is room for im-
provement, and there is opportunity for the plant
experimenter whose experience justifies him in
working with a somewhat difficult species to
secure better varieties of this very popular salad
plant than any at present on the market.

If it were desired to produce an exceedingly
hardy variety of lettuce, it might be possible to
hybridize the cultivated species with the wild
lettuce.

I have never attempted to do this, however, as

[194]

An Aberrant Type

A comparison of this hybrid artichoke with the one shown

in the preceding picture, will suggest how wide is the varia-
tion that may be shown in the form and arrangement of the bracts

making up the flower-head. Here the bracts bristle in all di-

rections, like bayonets, and the head lacks desirable com-

pactness. Nevertheless an artichoke of this form
might be thought of interest by a restaur-
anteur in search of novelties.

LUTHER BURBANK

the wild lettuce is a persistent and pestiferous
weed which is hard to eradicate once it gains a
foothold. It will grow and ripen seed in the
corner of a brick wall when only a few inches in
height; yet in a good location will grow seven or
eight feet in height. It produces seed in vast
numbers.

But, of course, it is not the seed of the ettuce
that the gardener is seeking, and it remains to be
seen whether a combination of the wild with the
cultivated one, even if hybridization could be
effected, would ‘result in useful variations.

DANDELION AND THISTLE

There are other wild species of the composite
family, however, that offer greater inducements to
the cultivator. One of these is the familiar dande-
lion, a plant usually regarded as a weed, but really
having possibilities of usefulness.

The dandelion is sometimes used as a green
vegetable in the early spring by country folk in
various parts of the United States, but it is perhaps
nowhere cultivated. In France, however, a suc-
cessful attempt has been made to produce a dande-
lion that has much thicker, larger, and more
abundant leaves than those of the wild plant.

This developed form is sometimes cultivated
there and attains a certain value as a market
vegetable.

[196]

A Wild
Artichoke

It will be seen that
this wild artichoke, in
full bloom, is hardly three
inches across. The flower-
head as a whole is strik-
ingly suggestive of that of
the thistle. This speci-
men gives a very good idea
of the manner of flower
from which the modern
improved artichoke has
been developed. Contrast
this little flower with the
giant in the next
picture.

LUTHER BURBANK

The great difficulty which stands in the way of
cultivation of the dandelion is its exceeding pro-
lificness. The heads of the flower will ripen even
when the plant has been pulled up by the roots.
It is even alleged that the plant will develop seed
when the flowers are not pollenized. This and the
capacity to ripen seeds from the unopened bud
makes the plant peculiarly difficult to eradicate,
and it becomes an almost intolerable pest in
lawns.

Should an attempt be made to cultivate the
dandelion, therefore, the aim should be to develop
the leaves at the expense of the flower. Doubtless
it would require long series of experimental
efforts, but in the end it would probably be possible
to develop a dandelion that would produce an
abundance of large, succulent leaves somewhat as
the lettuce does. Meantime the tendency to
excessive flower production could be restricted.

At least two other members of the Composite
family that rank as weeds, and are generally held
to be obnoxious, deserve to be named as offering
possibilities of usefulness if properly educated.
These are the thistle and the burdock.

That the thistle is a succulent herb that brows-
ing animals have found palatable, is proved by
its development of an elaborate system of pro-
tective thorns. Of course, these thorns must be

[198]

The Improved Burbank Artichoke

Contrast this mammoth blossom with the relatively insig-
nificant blossom of the wild artichoke. The front of this won-
derful flower is twenty inches across, It bears scant resemblance to
the wild prototype; except, indeed, that the essential flower or-
gans at its center have the same thistle-like appearance.

So striking a modification has been brought about
only through long cultivation; but the Bur-
bank artichokes have made giant
strides in a few generations.

LUTHER BURBANK

eliminated if the thistle is to be transformed into
a garden vegetable. The thistles are not a whit
more thoroughly cursed with thorns than the arti-
choke was when first brought under cultivation;
and not more so than some of the recessive arti-
choke seedlings are at the present day, even when
grown from the most carefully selected stock.

I have grown the thistle extensively from seed,
and although I have worked more especially for
variations in color of the flower, yet I have paid
attention also to the quality of leaf, and I am
quite convinced that it would not be difficult to
produce a spineless variety.

Indeed my experiments have advanced far
in that direction.

I am convinced also that the leaf and stock of
the plant may readily be developed so as to make
a palatable vegetable, comparable in its uses to
spinach.

It is known that some of the thistles are
palatable when cooked, tasting not unlike the
dandelion. There is a thistle raised in South
America that is quite extensively used as food,
and there is a California thistle with a variegated
leaf that is sometimes eaten. These two are
certainly as good as greens. Without a doubt
their palatability could be increased by selective
breeding, and this, with the removal of the thorns,

[200]

A Field of
Hybrids

The very marked
improvement that Mr.
Burbank has been xble to
effect in the artichokes in
his garden within recent
years has been in consid-
erable measure brought
about by crossbreeding
different races. Such
crossing has of course been
followed up by rigorous
selection, and tre result is
a great variety 2f arti-
chokes of very striking
qualities of size and form
of flower-head, and of fla-
vor. Some typical speci-
mens are here shown.

LUTHER BURBANK

would give us a new garden vegetable of a type
at present rather sparsely represented.

There is also an Old World thistle, known to
the botanist as Carduus marianus, that has found
its way to this country, growing wild by the
roadsides in California, that is sometimes used for
cooking.

The flower buds, roots, leaves, and leaf-stalks
of this plant are edible—a very unusual exhibition
of versatility scarcely duplicated by any vegetable
under cultivation. As this European thistle is not
distantly related to the French artichoke, and as
it is edible even in its wild state, it would seem to
furnish good material for the experiments of the
plant developer. I have observed that cultivation
and freedom from crowding increase the size and
succulent qualities of this plant enormously. In
other words it responds to cultivation readily. I
have thought many times of improving it, and even
yet may undertake to do so.

I have done a good deal of work with a related
naturalized weed from Europe, of the genus
Sonches, known as the sow thistle.

The genus is closely related to the lettuce, and
not distantly related to the artichoke. The two
species with which I have worked are succulent
weeds that vary greatly as to their degree of
smoothness of leaves and stem. One of them is

[202]

More Material for

Selection

There is almost
endless variety of size
and form and flavor about
the artichokes in Mr. Bur-
bank’s modern colony.
Some of those already de-
veloped are approaching
perfection, as we have
seen; others, like the pres-
ent specimen, show inter-
esting possibililies, and
wiil be utilized in farther
crossbreeding experiments;
for with the artichoke, as
with other horticultural
products, there is merit in
new varieties, even when
varieties already in hand
have attained rela-
tive perfection.

LUTHER BURBANK

commonly known as the prickly sow thistle. But
the two species are so crossed that it is hardly
possible to find one in California now that is not
hybridized. Such at least is my observation.

I have worked on the smooth-leaved hybrids,
which are highly nutritious, making excellent
greens.

The plants can be raised with the utmost ease,
and varieties were produced from these wild
hybrids, by selection and cross-breeding, which
were far superior to any specimens seen in the
wild state.

So marked was the improvement that I was
somewhat disposed to introduce ‘the developed
smooth-leaved sow thistle as a garden vegetable,
but hesitated to do so lest I should be blamed for
introducing a weed. The cultivated plant retains
its ability to produce a superabundance of seed;
which are drifted here and there by the wind. So
it might escape to the field and become a pest.
This of course is a danger that must be faced in
the case of any wild plant brought into the garden.

But it should not be forgotten that all of our
present garden plants were at one time wild, and
that the tendency to superabundant production of
seed is likely to be lost when the plant is pampered
by cultivation.

I have also worked with a very fine species of

[204]

ON NEW FOOD PLANTS

Sonches from New Zealand. I found it more diffi-
cult to raise than the ordinary Sonches. Possibly
by combining the two a plant might be developed
that would lack the objectionable qualities of
undue hardiness and prolificness. At least the
experiment is worth making.

Improvinc THE Burpock

As to the burdock, doubtless the very mention
of its name suggests a highly objectionable weed.
And, indeed, the common burdock, as it grows by
the roadside, after it comes to maturity is not an
inviting plant. And by its objectionable burrs the
plant is known and judged rather than by any
other characteristic of the plant itself.

But there are Japanese cousins of the burdock
that are cultivated and have produced large and
rather tender stalks and also long, fat roots which
are highly prized as food.

At an early stage, while these stalks retain
their tenderness, they are not unpleasant to the
European or American palate if when partially
cooked the water that has extracted the bitter prin-
ciple is removed and the cooking is continued with
fresh water. The root is most used in Japan where
it is considered one of their most valuable
vegetables.

The young, tender roots are offered for sale
when about eight to twelve inches in length and

[205]

Swiss Chard

This relative of the beet is not very well known in Amer-
ican gardens in general; but it has been given much attention
in recent years by Mr. Burbank. The specimens in his garden, as will
appear from this photograph, are of large size and luxuriant
growth; but they are still undergoing development. It
is only in recent years that Mr. Burbank has
given the chards especial attention.

ON NEW FOOD PLANTS

- an inch or more in diameter. They contain less
of the bitter principle than do the leaf stalks.

The stalks themselves, at their edible stage, are
about the size and form of an ordinary leaf stalk
of the rhubarb. Several of these Japanese bur-
docks have been grown on my grounds, where the
American burdock has also been cultivated more
or less for the last twenty years. I have noticed a
great variation in the bitterness of the stalks of the
plants. .

Under cultivation they have never become
troublesome weeds, as the common burdock has
become in the Eastern United States.

They respond readily to the effort to improve
them, and I entertain no doubt that if a systematic
attempt were made to develop them along the
right lines a most valuable vegetable might be
produced, which would be appreciated by those
who live in a more favored climate.

The lines of selection should look to the
production of a plant with large fine roots, or for
a reduction of bitterness, which is the most
objectionable quality of this plant.

To anyone who has given little thought to the
subject it may seem more or less absurd to talk of
the development of useful qualities in such weeds
as these. But whoever has a clear conception of
the extent to which the vegetables now in our

[207]

LUTHER BURBANK

gardens have improved under cultivation will see
possibilities in such plants as the thistle and the
burdock that are not revealed to casual inspection.

Poisonous plants like the tomato and the potato
have been made wholesome within comparatively
recent times.

The thistle and burdock have no poisonous
principle. Some species are wholesome and nat
unpalatable even in their wild state, and all that
is required is to accentuate the good qualities that
the plants already possess in order to make them
worthy of membership in the coterie of garden
vegetables.

—li should not be forgotten
that all of our present garden
plants were at one time wild,
and that to the wild we must
look for countless new
garden plants in the future.

WINTER RHUBARB—
AND OTHER
INTERESTING EXOTICS

THE PossIBILITIES WHEN Puants ARE BrouGHT
From THE TROPICS

Rhubarb was told in an earlier chapter.

It will be recalled that the plant came to
me from New Zealand, and that in its original
form it had a small and inconspicuous stalk and
was of slight commercial value. It will further be
recalled that by selective breeding I developed
the stalk until it was of large size and of
exceptional succulence.

Meantime, the changed conditions of another
hemisphere, with the transposition of seasons,
disturbed the habit of bearing of the plant in such
a way that it ultimately became practically a
perpetual bearer, its time of greatest productivity,
however, being the winter season. After the
Winter Rhubarb had been developed and put upon
the market, I continued my experiments in
selective breeding as well as in hybridization. The

[Votume VII—Cnapter VII]

T HE story of the development of the Winter

LUTHER BURBANK

new rhubarb, as was stated in the earlier chapter,
proved variable when grown from seed.

The tendency to winter bearing, however, was
pronounced, whatever variations the plant might
show as to other qualities.

In more recent years I have continued the
development, and have produced new varieties of
the Winter Rhubarb that differ so markedly from -
the original one as to merit introduction as
separate varieties.

The new rhubarbs have been developed by
crossing the Winter Rhubarb with various races
of ordinary rhubarb, in particular with the
improved variety known as the Burbank Giant.
The crosses were made mostly with the use of the
Winter Rhubarb as the pistillate parent, but recip-
rocal crosses were also made. The progeny, as is
often the case with hybrids, showed great vigor
of growth.

The individuals varied as to many of their
qualities, and I presently sorted out no fewer than
thirty-six different types, all of them of gigantic
size.

The best of these has been introduced under
the name of the New Giant Crimson Winter
Rhubarb.

QUALITIES OF THE NEw RHUBARB
Not only does the improved Winter Rhubarb

[210]

Burbank Rhubarb

The story of Mr.
Burbank’s develo p-
ment of the Winter rhu-
barb and ifs improved va-
riety, the Giant Winter
rhubarb, has beer told in
another volume. If will
be recalled that the pro-
genitor of the Winter rhu-
barb came from New Zea-
land, but took on new ca-
pacities for development
under the changed condi-
tions of. the, California
soil and climate.

LUTHER BURBANK

produce stalks at all seasons of the year, but these
stalks are of such quality as to give this rhubarb
a place apart among garden vegetables.

The stalks have the pleasant taste of berries,
and they altogether lack the tough stringy quality
of the ordinary rhubarb.

Meantime the stalks are as large as can be con-
veniently handled and shipped, being two or even
three feet in length, and from an inch to an inch
and a half in thickness. The beautiful crimson
color of the stalks adds to their attractiveness.

An important quality of the improved Winter
Rhubarb is that a plantation can be obtained from
a few plants in a fraction of the time required to
stock it from older varieties. It is only necessary
to dig up the plants in the fall, September being
the best month, dividing them with a sharp knife,
cutting them into the smallest possible bits which
have even a single bud and a fragment of a root.

Each fragment will make a big, hardy, and
productive plant in a twelve month; and it often
happens that the smallest fragments will produce
the largest plants.

Another way to propagate the plant, if you do
not wish to injure the old plantation, is to dig
away the earth around the plant and cut out little
V-shaped pieces of the roots, one or two inches
long, v th a sharp knife, including a bud. Each

[212]

ON WINTER RHUBARB

of these pieces will make a big plant in the course
of the year, and the old plant will produce larger
stalks, though in somewhat reduced number, as
the result of this treatment.

In this way a plantation of the Giant Winter
Rhubarb may be extended indefinitely without
injury to the old crop.

Of course, the new plants grown thus from
pieces of root or from root bulbs will reproduce
absolutely the qualities of the original plant.

If an attempt is made to extend the plantation
by sowing seed, a good deal of variation must be
expected, as this plant, like so many other culti-
vated ones, is not fixed for reproduction from seed.
In the matter of winter bearing, however, all the
seedlings will reproduce the qualities of the par-
ents. The seedlings may vary in size, quality, form
of leaves, and somewhat as to color of stalks and
various minor points; but never in the matter of
winter bearing.

They will reach their time of fullest productiv-
ity in midwinter, several weeks before the ordi-
nary rhubarb begins to be productive.

The plants fruit the first year from cuttings or
when raised from seed, and two generations a year
from seed to seed can be raised by forcing in the
California climate; but of course such forcing is
not recommended.

[213]

“PINAY

-Xa atay uaurzeds
ay? fo yjmo016 j20du109 pup
ayz]01d ayy aarasqg “jid
-nd 6uijsasaju1 fijavijnaad
D puD a}qD}9D1] BD jUDId
sy punof spy pup ‘sqinq
nyt jo fjalspa joaib vp
YM pajuauisadza spy ay
°81]0S3a1 pooB yyiMm ‘sjuaw
-Miadza Bulzipiagfy pasn
Gjjuanbasqns yuvqaing
“AW ‘uolj2aJas fig padojaaap

alam SqIDqnyd 1ajUrAA
7eayy ayy yOnoyly

squpqnyy
yupqing
Jo pag Jayjouy

ON WINTER RHUBARB

Unfortunately the Giant Winter Rhubarb is
not hardy enough to grow except in regions where
the eucalyptus, the orange, and the fig can be
grown out of doors. I am working with the plant
in the expectation of producing hardier varieties,
but for the present it must be confined to warm
climates, unless it is grown in the greenhouse. It
is reported in the East that the new Winter Rhu-
barb does not respond well to the forcing methods
of the greenhouse, so I do not recommend it for
that purpose, although I see no reason why it
should not grow under greenhouse conditions, as
a cool greenhouse may practically duplicate the
conditions of California where the plant is at its
best.

It will not stand soaking with water for any
length of time, but in our California soil there is
absolutely no loss from any cause, the Giant New
Rhubarb being a much surer producer than any
other variety of the tribe.

ForciInG THE RHUBARB

It is well-known that the ordinary rhubarb may
be forced in the greenhouse, and made to produce
out of season by first freezing the roots. Curiously
enough, after this treatment, the root develops its.
stalk, granted the right conditions of soil, almost
equally well in the dark.

Mention is made of this possibility of forcing

[215]

LUTHER BURBANK

the rhubarb by inducing abnormal conditions lest
a statement of the earlier chapter in which the
habits of the new variety are explained should be
misinterpreted.

I referred there to the impossibility of changing
the habits of the ordinary rhubarb, and perma-
nently extending its period of bearing, by merely
altering the conditions of cultivation. It is of
course possible to cause almost any plant to ger-
minate out of season by greenhouse treatment.
Such treatment, however, has no influence on
succeeding generations.

The plant caused to grow out of season merely
responds to the abnormal surroundings in which
it is placed, and will immediately revert to the
habits of its tribe when placed under normal
conditions.

But the crimson Winter Rhubarbs in all the
perfected varieties produce their main crop in the
winter, and continue productivity throughout the
entire year, because of the reappearance of a latent
tendency to perennial bearing; and this revived
tendency is thoroughly fixed. As already stated,
plants retain this tendency when grown from seed,
however they may vary in other regards. So there
is no analogy whatever between the winter-bear-
ing habit of these new rhubarbs and the abnormal
habit of winter bearing that may be forced on an

[216]

Burbank Asparagus

It is almost superfluous to say that Mr. Burbank has not
neglected so popular a garden vegetable as the asparagus. In
point of fact, this plant, like practically all the other garden favorites,
has come under Mr. Burbank’s guidance, and has shown marked
improvement through selective breeding. The picture sug-
gests the quality of this improved Burbank variety.

The stalks here shown are as succulent and
savory and tender as they look.

LUTHER BURBANK

individual plant of the old variety by growing it
under hothouse conditions.

Incidentally, the fact that the old rhubarb to be
forced successfully in the greenhouse must be
frozen furnishes another interesting illustration of
the value of a period of absolute rest or dormancy
for a plant, and will suggest analogies with other
cases of the same kind elsewhere cited. Seem-
ingly the tissues of the plant root, having been
frozen even for a brief period, have no way of
estimating the length of time during which they
have remained dormant, and thus are ready to
respond to the climatic conditions about them
when thawed out. So, finding themselves in the
atmosphere of the springtime, they begin their reg-
ular springtime growth.

In a sense, the artifice of the gardener may be
said to fool the tissues of the plant, and to cause
it to take on an altogether abnormal activity.

But, as just stated, this result applies only to
individual plants, and no one thinks of develop-
ing a race of Winter Rhubarbs in this way.

Mixep HerepitiEs
; The habit of perpetual bearing, as manifested
by my perfected varieties of Winter Rhubarb, was
explained as a development based on the compar-
atively recent residence of the ancestors of the
plant in a tropical climate. The fluctuating tem-

[218]

South American Peanuts

The peanut, notwithstanding its popular name, is not re-
garded as a nut, but is in reality borne on a leguminous plant,
and therefore rather closely related to the peas and beans. The pic-
ture shows a specimen of a variety of peanut from South
America that Mr. Burbank has taken in charge to
see if anything notable can be done with it.

LUTHER BURBANK

peratures of the globe in successive ages—a time
of tropical warmth being succeeded by an ice age
—resulted in subjecting the plant at different
periods to wide extremes of temperature.

A vast number of species were in this way
wiped out of existence.

But those that survived developed powers of
resistance which were in many cases subsequently
lost when the plants migrated to the tropics, or
when tropical conditions prevailed; but which
remained as latent influences in the germ-plasm,
susceptible of being brought out again under
proper conditions of hybridization.

Thus, in order fully to understand the anom-
alous habit of the new Winter Rhubarbs, it is
necessary to recall that their immediate ancestors
came from another hemisphere, and that traits of
their latent heritage from remote ancestors both
of tropical and sub-Arctic habit were brought to
the surface under influence of the new conditions
of environment to which they were transplanted;
and the further influence of new crosses and of
constant selection through many generations.

All in all, the new Giant Crimson Winter Rhu-
barb is a plant that presents points of interest for
the student of heredity and for the practical plant
developer, no less than for the practical horticul-
turist. And for the latter—whose interests, of

[220]

Another View of
the
South American

Peanut

The great range of
variation shown by
these South American pea-
nuts suggests indefinite
possibilities of improve-
ment through selective
breeding. Even in the
first generation or two con-
siderable improvement has
been observed, and Mr.
Burbank expects that
marked development wiil
occur in the course of @
few succeeding generations.
In his hands, the peanut
seems likely to yrove as
tractable as the peas.
and beans.

LUTHER BURBANK

course, are those of the public at large—the new
rhubarb has been declared to be “the most valu-
able vegetable production of the century.”

The merit of that characterization we need not
discuss; but no one who has seen the new Giant
Rhubarb is likely to dispute that it is a plant of
altogether exceptional interest.

SoME ESCULENTS AND AN ANOMALOUS SOLANUM

The rhubarb is one of the few plants in which
the edible portion, for which the vegetable is
prized, consists of the leaf stalks.

There are a good many other vegetables, how-
ever, in which the stalk of the leaf, along with the
leaf itself, becomes a more or less valuable food
product. Such, for example, are the cabbage and
its allies, the lettuce, and some others that we have
already considered, as well as the spinach and the
celery.

A familiar example of a plant whose stem fur-
nishes a valued food product if cut at an early
stage, before it puts out its leaf stalks, is the
asparagus.

These plants have interest from the standpoint
of the experimenter and all present certain oppor-
tunities for improvement. I have grown them all,
and have done something in the way of selective
breeding with most of them, but these experiments
have been relatively insignificant as compared with

[222]

ON WINTER RHUBARB

my work in other lines, and there is little to record
in connection with the work with either the spin-
ach, celery, or asparagus that would have novelty
or value. The methods of growing these plants
are well known, and there is opportunity for devel-
opment of new varieties either along the lines of
selection or of hybridization.

But the rules of selective breeding, as already
given and repeatedly illustrated in connection with
other vegetables, will sufficiently guide anyone
who wishes to work with these.

There is a tropical plant of a quite different
order, however, to which I shall merely refer, be-
cause I myself have not experimented with it very
extensively, but because work of considerable in-
terest has been done with it by others, that will
illustrate the possibilities of development of trop-
ical plants even when grown in relatively inhos-
pitable climates. The plant in question is the not
unfamiliar Solanum known as eggplant. Very in-
teresting work in experimental breeding has been
done with this relative of the potato and tomato
by Professor Byron D. Halsted of the Experimen-
tal Agricultural Station of New Jersey. It involves
no principles, however, that have not been fully
exposited in connection with other plants, and for
details of the work the reader may be referred to
Professor Halsted’s annual Bulletins.

[223]

‘Buisso1d yno

“yum ‘Hulpaatq aarjaa,
-as jo fiva ay} uj Gyaiys
uaaq aapy fisajaa ay? ym
apoul soy YyuDgIAg “jy Joy}
sjuguiiiadra ayy *3a] qd} ayy
tol WY 81 3} ax0faq jajaja
-UlG? }2 Y9DI]1q O} Airpssazau
$132 pup ‘afdigujid 23309
-dbou fi.pjiut vp sutpju0d u07]
-1puo9 ]pUltou sji uz junjd
fitajaa ayy ‘Buryovajq
dof JP ym fisazaa ayt
buryand fo ‘spoyjaur 3saq
ay} fo auo so ‘poyjaut jsaq

ay} {0 Dap? poo fitaa D

$aai6 aanjoid ayy

fizajap fo plaid y

ON WINTER RHUBARB

The nightshade family has other members
seemingly worthy of development, that have been
given scant attention.

One of the most interesting of these obscure
relatives of the potato and tomato and eggplant
is the not unfamiliar but seldom cultivated plant
known as the Ground Cherry, sometimes dubbed
also Husk Tomato.

THE INTERESTING GROUND CHERRY

The little plant in question belongs to the genus
Physalis, and it has numerous close relatives that
inhabit various parts of the world. One of these,
the Physalis alkekengi, or strawberry tomato, has
been under cultivation for a long time. The fruit
is small, yellow, sweetish, and insipid. Other spe-
cies have been received from Japan and Korea,
and also from India.

I have grown several varieties of the common
species of ground cherry from time to time for the
past forty years.

In general the fruit of the plant appears to be a
curious misfit, the husk not being large enough to
contain the fruit when ripe, and thus splitting open
to expose the fruit itself, which thus becomes sub-
ject to cracking and splitting.

I have attempted through cultivation and selec-
tion to remedy this fault; and I have also at-
tempted to cross the ground cherry with other

[225]

LUTHER BURBANK

species, but I have had no success in either
direction.

I have made hybridizing experiments not only
with the common species and the foreign ones
already mentioned, but also with other species
from the west coast of Mexico, and from Arizona
and Texas. But hitherto I have been unable to
secure a single hybrid.

The plants grown from the seeds received from
my collector, Mr. Walter Bryant, in Western Mex-
ico, have husks of the most delightful fragrance.
The aroma clings to the husk for months. It has
no connection with the fruit itself. This form has
proved the most difficult of all the ground cherries
to germinate from seed, or to grow after the plants
are produced. It is well worthy of attention, even
if grown solely for the fragrance of the husks. But
in addition to this, the fruit is of good quality.

It is about the size of the ordinary ground
cherry, but a little more orange in color.

Even at the present stage the fruit of the ground
cherry is sometimes used for making pies, pud-
dings, and preserves. The Peruvian species in
particular produces a great quantity of superior
fruit. There is sufficient variation between the
different species to afford abundant material for
development. If hybridization could be effected,
there is every reason to suppose that greatly

[226]

t A

Wear, 33
BL

A Cousin of the Cabbage

The kale plant is a very close relative of the cabbage,
being, in point of fact, one of several related plants that have
probably developed from the same wild stock, greatly modified through
long generations of cultivation. Of the various cabbages, kale
is perhaps the least generally known. For that very rea-
son it should have exceptional interest for the
amateur worker in the vegetable garden.

LUTHER BURBANK

improved varieties of the ground cherry could be
developed.

The lack of success of my hybridizing experi-
ments should not be considered as by any means
definitive. My final success in hybridizing two
species of this particular family after unsuccessful
experiments extending over a quarter of a century
will be recalled in connection with the story of
the development of the Sunberry. There is every
reason to suppose that experiments systematically
carried out would result in finding different mem-
bers of the ground cherry tribe that could be
hybridized.

And the prospect of producing a really notable
fruit from such a union—a fruit not unworthy of
a relative of the potato, tomato, and sunberry—
seems particularly good.

IMPROVING THE PassIoN FLowER For Its FRvIT

There is another vine, known everywhere by
name at least, and famed for its flowers, that has
fruit possibilities that have been almost totally
neglected. This is the celebrated Passion Flower,
a plant represented by a few species of tropical
and sub-tropical habitat, of which two at least
wander as far north as the southern portion of the
United States.

The name Passion Flower was given to these
plants by the early Spanish missionaries, because

[228]

ON WINTER RHUBARB

they thought they saw in the blossoms an emblem
of the crucifixion.

According to an early description of the blos-
soms, the filaments were thought to resemble a
blood-colored fringe suggesting the scourge; the
column in the center was said to represent the
cross; the filaments on which the pollen sacs were
borne, three in number, represented nails; and a
peculiar arrangement of floral organs encircling
the top of the blossom did service for the crown
of thorns.

To complete the picture five spots or stains of
the color of blood found on the petals were said
to represent five wounds.

That the symbolism might lack nothing of com-
pleteness, it was noted that the leaves of the plant
were shaped like the head of a lance or spear; and
that there are round spots on the leaves that might
be taken to represent the thirty pieces of silver,
the price of the betrayal.

The merits of this symbolic characterization
need not concern us. But doubtless the name
served to draw unusual attention to the flower,
although the intrinsic merits of the flower itself
are of a high order. As a hothouse vine, it has
been cultivated everywhere, and is often regarded
as an important acquisition. Meantime it runs
wild as a trailing vine in regions where the win-

[229]

‘urtoj 1)nd

ead fo saljaima zy
Pup ajpjos1 0} sj1of~a ayy
O} SayID}}D jsatazui fo aarB
-ap ]/DWIS OU pip ‘sauapmOB
ay? fo s}1offa ay} oO} fij1poar
spuodsas junjd 66a ayy
‘dadojaaap jyunjd ay} sof
$aijiqiqissod Guljiaul sjsa6
-6ns sfipmyp uojjn1ma yang
“saljaiima juarafip fo }upjd
66a ayy fo syims{ ay} wm
uoijD1IMa fo abups apim ayy}

Appiaja =fizaa_ jsa66ns
suaunzads asayy

qunjid 669 ayy

ON WINTER RHUBARB

ters are not too severe; and in some regions it is
so abundant as to be considered a weed, notwith-
standing the beauty of its flower.

The genus Passiflora, to which the Passion
Flowers belong, is made up largely of vines and
shrubs, but there are a few members that grow to
the size of trees.

The best flowering varieties are strictly trop-
ical, and do not thrive in the northern climates.
But, on the other hand, the species that bear the
larger and more edible fruits are relatively hardy.
Doubtless there is a casual relation between these
facts. Possibly the tropical species do not find it
difficult to propagate their kind, and have not
found it necessary to develop succulent fruits. In
any event, it is fortunate from the standpoint of
the plant developer of the temperate zones that
the fruit-bearing members of this particular tribe
are the ones that are hardy enough for introduc-
tion in our climate.

In point of fact, the common species of the
Northeastern United States, locally known as the
Maypop, is so thrifty a plant that it becomes a very
troublesome weed.

It spreads in all directions by its underground
root stalks, and it roots very deeply. It is almost
as difficult to eradicate as the perennial morning-
glory. Deep plowing of the soil is about the only

[231]

LUTHER BURBANK

method of destroying it when it is once introduced.
But this very thriftiness may become an advan-
tage, once the plant has been sufficiently trans-
formed to assume position as a valuable fruit
bearer.

This common Maypop was the plant with which
my experiments in developing the fruiting possi-
bilities of the Passion Flower began. But my
interest soon extended to other species, including
the best Australian varieties of at least three spe-
cies, and a number of new species from South
America that were not named by my collector and
have not been identified.

One of the most promising Australian species
is known as Passiflora edulus. It produces a much
larger quantity of fruit than the Maypop, but is
less hardy than that plant. Several of the South
American species are too tender to be grown even
in California. One of these, known as Passiflora
ceurules, bears a fruit about the form and size of
a small watermelon, yellowish-green in color, with
an attractive edible pulp. I have cultivated this

species, but it has not entered to an important :—

extent into my experiments, because of its extreme
tenderness.

The fruit of the species with which I have
chiefly worked is usually about the size of a hen’s
egg.

[232]

Passion Flower in Bloom

The passion flower has great popular interest because of
the curious configuration of its essential parts, and the sym-
bolical meaning associated with them in the minds of the supersti-
tious. In Mr. Burbank's garden, however, the passion flower is
cultivated not so much for its blossom as for its fruit.
Varieties are being developed that give good promise
of producing a fruit of marketable quality.

LUTHER BURBANK

The usual color is orange-yellow, but some
varieties have a purplish tinge, and a purple pulp.
Some of the species of the Southern Hemisphere
are recognized as producing valuable fruit, par-
ticularly for combination with other fruits, having
a pleasing and unique flavor. But the fruit of the
Maypop has seldom been considered worth
picking.

My experiments with the passion flowers began
about 1895. I found it not difficult to grow the
plant from seeds received from different regions.
It is only essential to keep the ground warm and
moist. There is an astonishing difference in the
growth and vigor of the different seedlings. More-
over, some of the vines produce ten or even twenty
times as much fruit as others, and the flavor of
the fruit varies from exquisiteness to entire insip-
idity. Some specimens have a large amount of
edible pulp, while others are made up almost
entirely of skin and seeds.

The seedlings usually bear during the second
year, or at latest the third.

The fruit does not ripen to advantage unless
the weather is very warm.

So from the outset I selected those seedlings
that bore earliest in the season, attention being
given also, as a matter of course, to the size and
flavor of the fruit, and to the attractive qualities

[234]

Flower and Fruit

on the Same Plant

This interesting
picture shows the Pas-
sion Flower bearing blos-
soms and green fruit and
ripe fruit at the same time.
This interesting peculiarity
suggesis that when the
fruit is developed it will
have an exceptionally pro-
longed season. Many dif-
ferent species of passion
flower have been utilized
by Mr. Burbank in hybrid-
izing experiments, in his
effort—which give every
prospect of success—to de-
velop a valuable new
type of fruit.

LUTHER BURBANK

of the flowers—for I had in mind a plant that
would have not only great value as a fruit bearer,
but also a recognized place among ornamental
vines.

The passion flowers show wide range of varia-
tion, and thus furnished at the outset abundant
material for the operations of the plant developer.

But in addition to this I found it easy to hybrid-
ize the different species, thus ensuring further
variation. The pollen sacs and the pistils are very
prominent, and it is easy to effect pollenization
by removing the prominent bright colored stamens
from the flowers of one and dusting the yellow
pollen on the prominent pistils of the other.

I have given particular attention to hybridizing
the Maypop with the Australian species, Passiflora
edulus, already referred to. I thought it would
be possible to combine the good fruiting qualities
of the Australian species with the hardiness of
the American species. The fruit of the former has
a thick, hard, shell-like covering over the pulp,
and a fragrant and highly flavored interior. That
of the latter has a thin, husk-like covering, with a
minimum amount of edible matter.

Cross-fertilization was readily effected, and the
experiment gives every promise of a successful
issue.

Several hundred hybrids that have not yet

[236]

ON WINTER RHUBARB

borne fruit are now under observation. Not all
of these are hybrids of the Maypop and the Aus-
tralian Passion Flower, but the seedlings of this
cross at present appear to be most promising. The
work has not been under way long enough to give
anything like final results. But what has been
done indicates that it is at least worth while to
continue the experiments.

Indeed, there seems to be little doubt of a thor-
oughly successful and satisfactory issue.

Possibly it may be necessary to bring other
species into the combination through further
hybridization, but the material at hand is ample,
and the fact that almost every variation may be
found among the seedlings gives full assurance
that if the experiment is carried out with sufficient
zeal, it will be possible to assemble the best quali-
ties of the different species in a new variety.

The renewed vigor given by the hybridizing of
species from different parts of the world will tend
to increase the size of both the plants themselves
and their fruit, and the quality of the fruits
already secured leaves it scarcely open to doubt
that the final product will be of positive value.

—Every plant on earth is here
to serve our pur poses—if we
but train it in the service.

*sainjaid Bunpassans up
umoys Ss} paumjjp fipoat
-]D ssaaans fo aimspaul oD
‘Ajyjonb pup azis ut qing
s1y} aao1dut) of Bulr1oavap
cua sj yupqing ‘Iw puD
‘qiNq 219}p2 uD os]D spy 1]
yng *Si1amoj yoJuauiDUIO fo
daanpoid Dp sp jsazazuz lo
ainsvaur yjDuUIs ou Bbupapy
qupjd pv ‘moys 723M a1n}

-ajd siy} yD a0uD)]6 v sD

‘sp DIssoUDD ay

SDISSDUID’)
fo pag V

THE CAMASSIA — WILL IT
SUPPLANT THE
POTATO?

AND OTHER TUBERS OF VALUE FOR Foop

single quality.

If a plant produces beautiful flowers, we
do not usually demand that it shall also pro-
duce valuable fruit. We do not ask that a
plant which produces a valuable fruit like the
tomato shall also produce tubers like the potato.
It is only by accident rather than by special design
or selective breeding on the part of man that a
certain number of plants, notably members of the
rose family, produce beautiful blossoms and deli-
cious fruits as well.

The apple-tree in full bloom is indeed a beau-
tiful object, but the apple would probably be raised
quite as generally as it is if its blossoms were alto-
gether unattractive. The Japanese, to be sure,
have developed the blossoms of their fruits, but

F: the most part plants are cultivated for a

[VoLume VII—Cnapter VIII]

LUTHER BURBANK

in so doing they have usually neglected the quality
of the fruit itself.

And as to garden vegetables, about the only
member of the clan that is cultivated for its flower
as well as for its edible product is the Pink Chive
that I have recently developed.

There exists a tribe of plants, however, of
which we have hitherto made no mention, that
possesses qualities of flower-bearing of a high
order, combined with the capacity to produce
roots of such quality of edibility as to suggest com-
petition with our best tuber bearers, including the
potato itself.

These plants are certain wild members of the
lily family that have no colloquial name except
that given them by the Indians; a name that has
been variously ‘transcribed as Quamash and
Camass. From this name the botanist has devel-
oped the generic title Camassia. The not alto-
gether unappropriate name of wild hyacinth is
sometimes given the species that grows in the
Eastern United States.

But it will be most convenient in speaking of
the tribe to adopt the generic name of Camassia,
in lieu of a better.

The various species of camassia grow wild in
rich moist meadows and along small streams. All
the species are hardy. The leaves of the plant are

[240]

Individual Camassia Blossoms

It will be seen that the camassia has a really attractive
flower. This is an unusual qualification for a plant that is mak-
ing bid for a place in the vegetable garden. There are several species
of camassia available for purposes of the plant developer.

LUTHER BURBANK

usually lance-shaped, about three-quarters of an
inch in width, and of length varying according to
the fertility of the soil, usually from eight to six-
teen inches. The flower stalk in ordinary soil
varies with the different species from eighteen
inches to nearly four feet in height.

The flowers are usually purple, blue, or white.
In some of the new hybrid species the color has
changed to rose, and in others it inclines toward
crimson.

All the camassias are bulbous, of course, like
other members of the lily family. But there is a
great difference in the size of the bulbs among the
different wild species, and, as will appear pres-
ently, there is enormous variation when the differ-
ent species are hybridized.

HYBRIDIZING THE CAMASSIAS

My experiments on a large scale with the
Camassia have been carried out for more than
twenty years, and have included work with five
species.

So far as I am aware, no one had undertaken
to improve any of these until my experiments were
instituted, about 1890.

My first work was done with a species known
as Camassia Leichtlinii, which grows abundantly
on Vancouver Island. Considered as a flowering
plant this is the finest of the native varieties. It

[242]

ON THE CAMASSIA

grows almost altogether in crevasses of rocks, but
it produces very attractive large, deep purple flow-
ers, with wide petals. First the attempt was made
to improve the flower, and I introduced a good
many years ago a modified variety of the species
that was somewhat dwarfed as to leaf and stem
but in which the flowers had been much enlarged,
the petals broadened, and the color changed to a
dark blue. :

As my experiments continued, however, my
interest in the camassia increased, and I began to
give attention to the bulb of the plant as well as
to the flower.

I began working with another species, the
Camassia Cusickii, which has relatively large
bulbs; and with another of the well-known nature
species, Camassia esculenta, the bulbs of which
are much smaller but of recognized edible quality.

Most of my work in hybridizing and selective
breeding has been done with the three species just
named, but I have also raised somewhat exten-
sively two other species, known as C. Howellii and
C. Fraseri, as well as a great number of wild varie-
ties of all the different species from British Amer-
ica, Washington, Oregon, California, and Nevada.

From the outset individual plants were selected
of each species and variety that were the best I
could obtain. Here, as so often elsewhere, I was

[243]

Hybrid Camassia

The picture shows color variation in one of Mr. Burbank’s
hybrid camassias. Mr. Burbank intends to retain and accen-
tuate the good flowering qualities of the ecamassia, even while giving
especial attention to its bulb. This makes the process of se~
lection somewhat complicated, but it presents no in-
superable difficulties, as the reader who has
followed Mr. Burbank’s experiments
tn other fields is aware.

ON THE CAMASSIA

enabled to produce considerable improvement
merely by selecting individual plants that showed
the most desirable qualities of flower and bulb,
destroying the inferior ones. From the outset care:
ful attention was paid both to the flowers and to
the bulbs, as I desired to produce plants that would
be ornaments in the flower garden and at the same
time would grow enormous bulbs that would make
them valuable acquisitions to the vegetable garden.

Having secured the best representatives of each
species and variety by selection, I began an exten-
sive series of hybridizing experiments.

I found it a relatively simple matter to hybrid-
ize the different camassias. All the species seemed
to combine quite readily.

The characteristics shown by the hybrids are
those that experience with other plants led one
to expect. In the first generation, there is relative
fixity, and the greater or less dominance of one
parent or the other. In the second generation, the
hybrids break up into numerous forms, varying
widely as to color of leaves, height of stalk, and
size of flowers, as well as in form and size and
quality of bulbs.

Some of these hybrids of the second generation
produced bulbs smaller than those of their
progenitors.

But others grew bulbs of enormous size. Even

[245]

LUTHER BURBANK

to one who is accustomed to observe the striking
variations that are produced through hybridiza-
tion, it was surprising to see the extraordinary
impetus given to the bulbs of the camassia by the.
union of different species.

The bulbs of the common edible species, C.
esculenta, are relatively insignificant, usually
growing about one-half to three-quarters of an
inch in diameter. The C. Cusickii produces the
largest bulb of all, but it is large only in a relative
sense, being usually little over an inch in diameter
and two inches in length.

But among the second generation hybrids were
some that produced bulbs three and a half inches
across and four or even five inches in length.

The difference was about that between an Eng-
lish walnut and a large turnip.

In viewing these gigantic bulbs, sprung thus
from dwarf ancestors, one was reminded of the
gigantic hybrid walnut trees that came of the
union of Persian and California walnuts; of the
mammoth Phenomenal Berry; of the. Giant Ama-
ryllis; and of sundry other hybrids that were stim-
ulated to excessive growth of stem or fruit or
flower by the union of parents of just the right
degree of affinity.

FLOWER AND Bouts IMPROVED SIMULTANEOUSLY

Meantime I had taken pains to cross dark flow-

[246]

The Wild Camassia

This is one of the wild camassias that furnish material
for Mr. Burbank’s hybridizing experiments. A comparison with
earlier pictures will suggest the measure of improvement that has al-
ready been attained in connection with the flower. Succeeding pic-
tures will show the response that has been made by the bulb.

LUTHER BURBANK

ers with dark flowers, and white ones with white,
and pink with pink, wherever possible, so as to
intensify the various types.

As already noted, there is a pronounced ten-
dency to variation even among the wild species,
all the camassias sometimes producing pale green-
ish, almost white, flowers. These, if grown from
seed and carefully selected, can be changed to
snowy white. Some of the variations secured bear
flowers that are truly white, while others that are
called white are really of a pale greenish hue. The
seedlings of these greenish white ones tend ordi-
narily to produce blossoms that revert to the pale
blue color of the species from which they were
derived.

So the production of a truly white camassia
required continued selection—a process of gradual
intensification.

But of course hybridizing facilitated this pro-
cess. It also gave opportunity for selection with
regard to flowers having broad petals—narrow-
ness of petal being one of the original defects of
the camassia as a flower. Moreover, a number of
extra petals have been added in some cases, and
it is only a matter of time until double camassias
will be produced.

All along the line, then, the flowers of the ca-
massias have been improved by selecting from

[248]

ON THE CAMASSIA

among the best of the hybrids. Twenty thousand
bulbs have been under observation at the same
time, and improvement has been rapid.

In the end, the camassia will prove to be an
ornamental plant of distinct value, highly prized
for its flowers.

But it will be prized also for its bulb, which,
in the developed and selected hybrids, is assuming
satisfactory proportions, as already pointed out,
and which has undoubted food value, surpassing
the potato even, both as to nutriment and flavor.
And of course the work of development in this
direction is only at its beginning. The results
already attained justify the expectation that the
bulbs of the developed camassias will be of really
notable size, constituting a garden vegetable of
very exceptional food value.

The wild camassias generally produce but few
offsets. But some of the hybrid ones not only pro-
duce numerous offsets, but tend to divide like the
garlic, sometimes making five or six enormous
bulbs in a season. Of course this habit has been
carefully encouraged among the seedlings, as this
rapid multiplication will be of obvious importance
when the camassias are grown either for bulbs or
for flowers.

I have also successfully hybridized some of the
camassias with certain of their relatives, the squills

[249]

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ou ‘qing ayy fo say
“10nd a1qipa ay} oj Ajjunjs
-u02 «uaaiB § $1 U02}UaIzD
asinoa {Q ‘sjuarmd sj1 fo
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pajspijuo9 ‘sqing Disspumd
paaoid ui s,yupqang
“Ify JO auo 82 alayy

sqimg
ul jsp.1quo)

ON THE CAMASSIA

(genus Scilla), of which I have imported many
species from South America. The two tribes
hybridize readily. The hybrids showed conspic-
uous changes in the bulb. The outside covering
of the bulb of the squill is whitish, while that of
the camassia is usually darker. The hybrids
showed more compact bulbs of a lighter color than
those of their maternal parent, the camassia.

But there are all gradations in the bulbs as to
color and other qualities.

I have worked very extensively with the squills,
but with reference solely to the development of
the flowers, with results that will be outlined in
another connection. Here I refer to them only as
suggesting that these plants may be of value in
introducing new qualities into the strains of hybrid
camassias, stimulating further variation, and thus
giving opportunity for betterment both of bulb and
flower.

It is too soon to predict just what place these
improved camassias may take in the vegetable
garden. But the experiments have progressed far
enough to show that the species has hitherto
unrecognized possibilities.

Meantime a plant that is almost equally attrac-
tive from the standpoint of florist and market gar-
dener is an anomaly that must make wide appeal
to the horticulturist.

[251]

LUTHER BURBANK

There are twenty or more species of plants
belonging to the lily family wild along the Pacific
Coast that make up a group which the botanist
classifies under the generic name Brodiaea.

There are allied plants in South America, re-
garding the precise classification of which there is
some difference of opinion. But for the purpose
of the horticulturist the entire group may be
ranked under the name of Brodiaea. The plants
have not been extensively cultivated until recently,
and they have received no popular name.

The different species vary greatly in form, size,
and arrangement of the flower. The color of the
flower is usually either blue or rose or purple,
though sometimes white. There is also a crimson-
flowered climbing species, known as Brodiaea
volubilis, which somewhat rarely becomes white.

CROSSING THE BRODIAEAS

I have crossed this climbing species with the
species known as Brodiaea capitata, and with vari-
ous others. Some of these crosses produce most
beautiful flowers intermediate between the par-
ents. Unfortunately the best hybrids were de-
stroyed by gophers before I had opportunity to
save the seed. The interest of the brodiaeas in the
present connection hinges on the fact that the
plants have bulbs or corms that when cooked are
very acceptable as food. Several of the species,

[252]

A Wide Range of Variation

Here are camassia bulbs small, large, and medium, thick,
thin, and spindle shaped. Obviously there is plenty of ma-
terial for selective breeding. Where such variation occurs, still
greater variation will be shown in some of the crossbred descendants.
Moreover the flavor of one, the form of another, and the size of a
third may be combined in a single descendant; and all the
good qualities may then be accentuated through se-
lective line breeding. The camassia promises to
furnish a very valuable addition to the
rather small list of edible bulbs.

LUTHER BURBANK

especially the Brodiaea lactea, are relished by the
Indians, and are often dug and eaten by children.
The bulbs of some species contain a very high per-
centage of starch, probably greater than that of
the potato.

I have worked on the Brodiaea lactea to in-
crease the size of the bulbs. When growing wild
the bulbs are only about half an inch in diameter.
By selective breeding, varieties have been orig-
inated that will produce bulbs two inches or more
in diameter. The plants can be grown almost as
thickly as lawn grass, and it is probable that the
yield per acre of the bulbs could be made to equal
a good crop of potatoes.

In developing the brodiaea for this purpose, it
would be well to search carefully for bulbs that
grow to unusual size in the wild state—there is
considerable variation in this regard.

The brodiaea is well worth cultivating for its
flowers alone, and it would appear that the plant
offers possibilities of combining flower-production
with the production of a valuable food. Unfor-
tunately, however, there is a complementary rela-
tion between the seed and the bulbs, and in order
to secure bulbs of the largest size, it is necessary
to remove the seed stalk before blossoming time.

Whether cultivated for flowers or for bulbs,
the brodiaeas are very interesting plants that give

[254]

ON THE CAMASSIA

great promise of improvement under the hands of
some careful experimenter.

It is a little difficult to cross them. I have pro-
duced many hybrids, however, and it is said that
occasional hybrids are found where two wild
species are growing in the same neighborhood.
They all bear seed abundantly, though it takes
three, four, or even five years from seed before
they bloom.

They grow by thousands on each square yard
of ground, appearing almost as thick as grass on
a well-kept lawn.

In the same species there is a good deal of
variation in the form and size of the flower. On
the heights of the Sierras, the Brodiaea lactea
grows only a few inches high, whereas in the val-
leys it grows to a height of eighteen inches or two
feet.

Along the alluvial creek banks Brodiaea Laxa
grows very large and tall, with handsome clusters,
while on the mountain sides it is dwarfed.

Even plants of the same species in the same
locality vary widely as to size of flower.

Brodiaea capitata grows abundantly along the
roadsides, and especially in grain fields. It blooms
and produces seed before the grain is cut. Brodiaea
terrestris has a stem so short that the flowers
almost rest on the ground. The blossom is just the

[255]

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aulog

ON THE CAMASSIA

color of a blue violet, and the clusters may be mis-
taken for violets at a little distance.

In other localities the Brodiaea terrestris bears
flowers some of which have a white stripe. Some-
times half the blossom may be white, the other
part deep blue. Sometimes five or six blossoms
will be blue, and a single one white. In other
cases the proportions are reversed.

I have not observed any in the wild state that
could be called pure white, but by cultivation and
selection pure white varieties have been produced.

I have worked extensively on the Brodiaea
capitata, the species just mentioned as growing in
the wheat fields. On a poor dry soil this plant
grows about two feet in height, and on long,
straight, slender, wiry stems. But on good soil,
-especially in the wheat fields, it sometimes grows
to the height of three or four feet, or even more,
bearing a much larger cluster of blossoms.

In looking over a field of brodiaeas of this spe-
cies, one may expect to find one in ten thousand,
or perhaps one in twenty thousand that is almost
white. Seedlings raised from these produce a
variety of flowers, white, pale or dark blue, and
striped; with a constant tendency to revert to the
blue when first taken under cultivation.

By selection and re-selection I have produced
strains which invariably come white, and by the

[257]

LUTHER BURBANK

same process have produced varieties with flowers
twice as large as the ordinary, also making the
flower-head larger, and the plant a much more
rapid multiplier from the bulbs.

From all this it will appear that the brodiaea
is a very interesting plant. As already suggested,
it well deserves the attention of some careful
experimenter, who might develop certain strains
for flowers and others for bulbs. Plants that are
of interest both to the lover of flowers and to the
vegetable gardener have exceptional claims on
the plant developer.

OrHer NEGLECTED LILIES

There are two allied tribes of plants known as
Bloomeria and Brevoortia, respectively, that are
closely related to the brodiaea, and each of which
is of interest.

The brevoortia is usually called the Floral Fire-
cracker, from its green, crimson, and yellow flow-
ers. I have grown these plants extensively from
seed, to produce new varieties, but the experiments
were carried out only to the extent of increasing
the yellow and crimson colors.

I have grown the Bloomeria aurea extensively,
and have made minor improvements in it through
selection. The plant has a bulb like the brodiaea,
growing deep in the earth in dry, sandy places. In
the wild state the stalks vary in height, and there

[258]

Blossoms of the Brodiaea

The brodiaea is another wild plant Mr. Burbank has
brought into the garden, and which he is educating with an
eye to both its blossoms and its bulb. Some of the wild brodiaeas
are edible, and Mr. Burbank expects to improve on their qualities
through hybridization and selection. Some rather notable first
steps in this direction have already been taken. It will
be seen that the brodiaea has an_ interesting,
even if not a very spectacular flower.

LUTHER BURBANK

is also a slight variation in the color of the flower.
So there is opportunity for selective breeding.
Moreover, I judge from physiological characteris-
tics that the plant should cross readily with the
brodiaea, although I have not attempted to make
the cross.

It is almost certain that improved varieties
might be obtained by hybridization.

There is a bulbous plant called Alstroemeria,
that is botanically related to the Amaryllis rather
than to the true lilies, which offers possibilities of
tuber improvement. The plants are natives of
Western South America. I grew seedlings and
hybrids by the ten thousand for several years, and
became convinced that if the roots and tops could
be taught to grow in a more compact form this
would become a very popular flower, and perhaps
also a very valuable food plant, as the roots are
sometimes eaten and are quite palatable and nutri-
tious. I have worked on the species known as A.
Chilensis, A. pulchella, and A. Brasiliense, and
subsequently on a large number of new species
from Chile.

A great variety of colors and combinations
occur in the hybrid forms that may be fixed by
selection. I am endeavoring to obtain a more
hardy strain with improved flowers and more
compact growth.

[260]

The Chilean Alstromeria

Yet another plant that combines the qualities of beauty
of flower with those of a possibly edible root, In this case,
as will be seen, the wild flower has notable claims to beauty. Under
the hand of the plant developer, it will probably become
an exceptionally handsome flower; and the bulb also
gives good promise of proving adaptable.

LUTHER BURBANK

At one time I crossed plants of this genus with
the California lily (Lilium pardalinum) and had
several hybrids, but the root and the bulb did not
make a good combination. The plants bloomed -
one year, then died. The hybrid blossom was
smaller than that of the lily, and it resembled that
of both parents in being speckled and in its com-
bination of colors. The hybrids that blossomed
produced no seed.

The long, slender, white tubers of the Alstroe-
meria Chilensis are edible. This plant grows in
very dry soil, and is peculiarly adapted to some of
the California soils and climates. It is at present
too tender for growth in the Eastern United States, —
but it is possible that through hybridization and
selection it may be rendered hardy, and in that
event this may become a valuable garden
vegetable.

Tue Epau Potato

The lilies and their allies are not the only wild
plants with bulbs or roots that are edible and sus-
ceptible of improvement.

On the contrary there are several plants of
different families that offer noteworthy possibili-
ties in this direction.

There are, for example, tuberous varieties of
the genus Carum, relatives of the caraway, that
grow on the Pacific Coast, especially toward the

[262]

Another Type of Alstromeria

There are various races of alstromeria, and Mr. Burbank
is experimenting with as many of them as he can secure. He
will follow his usual method of hybridizing, followed by selective
line breeding. He is rather sanguine as to the outcome in
the case of the alstromeria. The experiments, how-
ever, have not yet reached a definite stage.

LUTHER BURBANK

Northwest, the roots of which are relished by the
Indians.

One species in particular, called the epau
potato, is dug in great quantities in the fall and
stored for winter use. The roots are small, almost
like those of the Ranunculus (cowslip, etc.), and
are similar in form to the roots of the dahlia,
though much smaller. They have a sweet, aro-
matic, and pleasant flavor. In different localities
they vary a good deal in size and quality. There
are places where the plant grows almost like grass,
so that hardly a shovelful of dirt can be turned
over without exposing numerous roots.

When brought under cultivation, the epau
potato appears susceptible to the influences of its
new surroundings. The roots increase greatly in
size and in succulence.

I have gathered the seeds and roots of this
plant, and have from time to time had seeds sent
me from many localities, during the past fifteen
years. The best seeds came from Idaho. Plants
grown from seed sent from Idaho developed into
herbs four feet in height, producing roots three to
four times as large as most of the California Car-
ums, and seeding quite as abundantly.

I have been able by selecting individual roots
to improve the species known as Carum gairdneri
quite rapidly. I have observed that when the

[264]

ON THE CAMASSIA

blossoms are removed, so that no plant energy is
required for the production of seeds, the roots are
much larger. This is an interesting compensatory
effect that illustrates the close correlation between
the different parts of a plant, and in particular the
reliance of the roots on the leaf system.

There are, as already stated, several species
and numerous varieties of the plant that could be
used for hybridizing purposes, and doubtless the
tendency to variation could thus be accentuated.

A very large number of plants can be grown
on a small piece of ground, and if the roots could
be developed even to one fourth the size of those
of the carrot, this would prove a very valuable
addition to the list of garden plants. The roots
are not only nutritious, but they have exquisite
flavor even when raw; and they are improved by
cooking.

I think the plant very well worthy of improve-
ment and general cultivation.

—The lilies and their allies
are not the only wild plants
with bulbs or roots that are
edible and _ susceptible of
improvement—there are
many noteworthy possi-
bilities in this direction.

‘aurpu sly si0aq
yoy} ODJOod pajpuqgajaa
mou ay} padojaaap yung
-Img “Ipf JOY] OyDjod asoy
fjipq ay? uo 130q paas
bp yons buipuy ybnory}
som jj *jsa66ns Jim aan}
-21d sly} sp ‘ojDurO, ain}
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ay} Saop j2 uaym jnq ‘paas
0} 06 fifiamulpio jou
sSaop ojnjod ayy

S110 Peeg 0}D}0d

THE POTATO ITSELF—
WuHo WILL
IMPROVE IT FURTHER?

No Puanrt Is Ever a FINISHED Propuct—PoratTo
SUGGESTIONS

told many times. But it has seldom been

told correctly. Like stories in general, it
gains or loses something almost every time it is
repeated, and it sometimes comes back to me in
a guise that is scarcely recognizable.

The real story of the production of the Bur-
bank potato is very simple. Something of the
economic value of the discovery has been sug-
gested in an earlier chapter, and will be touched
on again before we are through. The importance
of the discovery to me personally has also been
suggested. It constituted my first commercially
valuable plant development, and furnished a prac-
tical means of coming to California, where, doubt-
less, my experiments have been carried out on a
far more comprehensive scale than they ever
would have been in New England.

T HE story of the Burbank potato has been

[Votume VIJ—Cuapter IX]

LUTHER BURBANK

Yet, on the other hand, I have always been
disposed to think that if the potato had not fur-
nished a means of migrating, and pointed out the
possibilities of plant development, both these ends
would have been accomplished by some other
member of the garden or orchard family. Still
there is a wise old proverb about praising the
bridge that has carried you over, and for me, as-
suredly, the new potato served as a most important
bridge.

So I naturally look upon the development of
the Burbank potato as marking an epoch in my
life, and as standing quite apart from other plant
discoveries.

In the sense that it was my first important plant
discovery, it must always remain the most impor-
tant one.

A SrmpLe DEVELOPMENT

Considered as a problem in plant development,
the origin of the Burbank potato was a relatively
simple matter. There is no story of complex
hybridizations and elaborate series of selections
to be told in connection with it, such as we have
heard in connection with sundry other more recent
discoveries. Indeed the word discovery may be
applied with peculiar propriety to the origination
of the Burbank potato, because it all came about
through the chance finding of a seedball growing

[268]

Bodega Red

Potatoes

The Bodega Red
was the standard po-
tato in California before
the coming of the Bur-
bank; and it is still ex-
tensively grown. This pic-
ture gives a good idea of
its characteristie form
and appearance, and of
the quality that gives
it its name.

LUTHER BURBANK

on the stem of a potato vine among numerous
other vines in an ordinary garden.

Of course the observant eye was there to note
the anomaly of a potato producing a ball of seeds
in defiance of the usual Early Rose potato tradi-
tions. Also there was the receptive and inquiring
mind of youth, to challenge the product and raise
the question of what would result if these seeds
were planted. These qualities, or something akin
to them, must always be present where new phe-
nomena are under observation, else no discovery
would be made however lavishly the materials for
discovery are laid before us.

In many of my later discoveries, I myself
brought the materials together and had a share in
combining them and in directing and guiding the
processes of nature through which new plants
were developed. In the case of the potato, as
just stated, all this work was done quite without
my co-operation.

When I came upon the seedball it was far
advanced toward perfection, and my task consisted
merely of watching it and making sure that the
seeds were gathered and preserved, and in due
course planted.

A SEEDBALL Lost AND Founp

That the story should not altogether lack

picturesqueness, I must record that my incipient

[270]

ON THE POTATO

discovery came very near being rendered futile
by the accidental loss of the all-important seedball
after it had been revealed.

I had first seen the seedball, growing on an
early rose potato vine, some time before it came
to maturity. My mind was at once impressed with
the idea that this might sometime be of value,
inasmuch as this potato. had never been known to
bear seed. Moreover, I had for some time been on
the lookout for potatoes that would offer oppor-
tunities for development, as those that were grown
in the neighborhood at the time did not fully meet
my ideas as to what a potato should be in form,
size, color, production, and keeping qualities.

This was as long ago as 1872, and it should be
understood that at that time the potato, as ordi-
narily grown, was a tuber much smaller in size
and less smooth and attractive in appearance than
the ones with which the present-day grower is
everywhere familiar. Moreover, the potatoes were
wont to suffer from what was called dry rot.

Of course the average gardener accepts the
product of his vines and herbs somewhat as he
finds them, with no clear notion that they could be
made different from what they are.

But I had been imbued from the outset with
the idea that inasmuch as existing plants had
evolved from inferior types, it should be possible

[271]

Sprouting Bodegas

One of the faults of the Bodega is that it sprouts too
readily. Even if kept in a paper bag, it may sprout abun-
dantly, as shown in this picture. Of course the sprouts draw on the
food material in the potato itself, and injure
the tuber as a table vegetable.

ON THE POTATO

to develop any or all of them still further. So my
general attitude of mind toward the garden prod-
ucts was that of a workman handling plastic mate-
rials. And, as regards the potato, I had a very
clear notion that the ones we raised might be very
distinctly bettered if only the right way could be
found..

So the hint given by the seedball was instantly
taken and day by day the ripening of this precious
little receptacle was watched with the utmost in-
terest and solicitude.

Judge of my consternation, then, on visiting the
potato patch one morning—with the thought in
mind that now, probably, the seedball would be
ripe enough to pick—to find that the coveted fruit
had disappeared.

With anxious attention I parted the vines and
searched everywhere for the missing seedball. I
went over every inch of the ground for many feet
on all sides. But I could find no trace of the miss-
ing seedball.

I was obliged finally to give up the search for
the day, reluctantly admitting that I should prob-
ably never see again the little ball of seeds on
which such high hopes and expectations had been
based.

Yet I could not believe that the seedball had
been carried away, for no outsider visited the gar-

[273]

LUTHER BURBANK

den, and no one would have taken the slightest
interest in the tiny fruit in any event. So day
after day I returned and took up the search again.
I covered the ground systematically in every direc-
tion, moving each vine, and anxiously scrutinizing
the soil about its roots, and lifting every chance
leaf under which the little seed receptacle might
have lodged.

And at last this patient search was rewarded.
Several feet away from the original vine, snugly
lodged at the base of another vine, the missing
seedball was found.

Whether it had been removed by some bird
that had plucked at it inquiringly, thinking that it
might furnish food; or whether some stray dog
running through the potato patch had quite by
accident broken it off and projected it to where it
was found, I never knew. It sufficed that I had
the precious seeds again in my possession, and I
took good pains to see that they were safely stored
for the winter.

On removing the seeds from the capsule, it was
found that there were twenty-three of them. The
coming of spring was eagerly awaited to reveal
what hereditary possibilities were stored in these
seedballs.

TWENTY-THREE NEW VARIETIES
When spring came, I planted the seeds out of

[274]

Snake Potatoes

A glance shows
why these curious
Mexican potatoes are
given the popular name
of Snake potatoes. It is
more than likely that the
wild progenitor of the
cultivated potato had
some such form as this.
Mr. Burbank is experi-
menting with the potatoes
here shown, to see wheth-
er they have possibil-
ities of development.

LUTHER BURBANK

doors, as one would plant the seeds of beets or
cabbages. The ground had been prepared with
great care, and each seed was placed about a foot
from its next neighbor in the row. But no special
protection was given the seeds.

To-day I would not think of planting valuable
seeds of any kind in this way. The risk would
seem far too great.

I should now plant them in boxes, after the
manner described in the chapter on the care of
seedlings, and give them individual attention in
the greenhouse. As I look back upon the incident,
I have often wondered that I was able to sleep at
night while my precious seeds were thus exposed
to any marauders of the animal or insect world
that might chance to come upon them.

But a good many times it happens that we pass
quite safely and unwittingly through dangers that
seem very threatening indeed when we look back
upon them. And so it was with my twenty-three
potato seeds. Every one of them sent a sprout
through the soil in due course, and put out its tiny
cotyledons, and grew into a thrifty vine. And al-
though no vine of them all produced a seedball,
each one developed a fair complement of tubers.

Needless to say I watched their growth with
solicitude, tentatively digging into a hill here and
there as the season progressed, to note what such

[276]

Chilean Wild

Potatoes

Here are wild
potatoes from South
America, of forms vari-
ous and sundry. There
are numerous species of
potato still in the wild
state, and Mr. Burbank
has secured such of them
as his collector could find,,
and has tested them all in
selective and in hybridiz-
ing experiments. The re-
sults have in some cases
been very promising, but
on the whole have
been rather dis-
appointing.

LUTHER BURBANK

a novelty as a potato grown from seed would be
like.

Interesting developments were expected, but no
one could have any very clear idea as to what
these developments might be. But I certainly had
not expected so remarkable an exhibition as that
which met my eyes, when, late in the fall, the day
came for digging the potatoes, and each hill in
turn was carefully spaded and made to reveal its
treasure.

For as we went down the row, spading up one
potato hill after another, we found in each suc-
cessive hill a different type of tubers. One hill
would show smail potatoes of curious shapes;
another hill, larger potatoes with deepset eyes; yet
another, potatoes red in color, or with rough skins,
or knotted and covered with bulbous tumors.

But there were two vines that bore tubers that
were instantly seen to be quite in a class by
themselves.

These were very large, smooth, white potatoes,
excelling in all respects any vegetables of their
kind that I had ever seen.

The product of all the other vines but these
two could be at once discarded. At best they only
equaled the average potatoes of the early rose
stock from which they sprang. But the two ex-
ceptional vines bore tubers that quite outrivaled

[278]

ON THE POTATO

even the best example of the parental stock. Not
only were they superior in size, but they also
excelled in symmetry of contour, in whiteness, in
uniformity of size, and in productiveness.

Among the twenty-one discarded potatoes there
were, indeed, a few that were not without interest.
One variety was red, and not unattractive, but it
had not proved very productive, and most of the
tubers decayed soon after they were dug. So this
variety was obviously unworthy of further atten-
tion. Another vine bore potatoes that were pink-
ish in color, and having eyes so prominent that
the long slender tubers seemed to be all eyebrows,
the eyes reaching quite to the center of the potato.
Yet another was round and white, but too small
to be of any value.

As between the products of the two exceptional
vines, there was not a very marked difference.
The tubers from one averaged slightly larger than
the other, slightly more uniform in size, just a
little smoother and more attractive in appearance
—in a word, in every way just a shade better.

These best tubers were, of course, carefully pre-
served, and a considerable crop was grown from
them next year by dividing the tubers and plant-
ing them in the usual way. And their progeny,
multiplied year by year, until they are now gath-
ered by millions of bushels each season in all parts

[279]

Mexican Potatoes

These wildlings have the characteristic potato quality,
notwithstanding their peculiarity of form and their uninvit-
ing exterior. They are far from being what would be considered,
.in a comparative sense, a valuable table product, however,
It is interesting to note their resemblance to certain
potatoes grown by Mr. Burbank on vines on
which tomato tops have been grafted,

ON THE POTATO

of the world where this vegetable is grown, con-
stitute the Burbank potato.
INTRODUCTION OF THE BURBANK

The twenty-three seedlings were grown, as just
noted, in the season of 1873.

The one incomparable member of the lot
proved itself in the following season, and gave a
goodly quantity of tubers all substantially iden-
tical with the original ones and obviously quite
different from the usual potatoes then in existence.

It required no very keen eye to see that a prize
had been secured. But I did not at first know just
what to do with it. I desired, of course, that the
new potato should be introduced to the general
public, realizing the economic importance of a
potato that would produce two or three times as
many bushels to the acre as the ordinary varieties,
and at the same time give individual tubers of
superior quality.

But the first dealer to whom I offered the new
potato declined it rather curtly, and I had some
diffidence about approaching another. Finally,
however, I mustered courage to bring the new
potato to the attention of Mr. James J. H. Gregory,
then a resident of Marblehead, Massachusetts.

By way of introduction, I sent him a sample of
the new potato.

Mr. Gregory tested the potato by planting it,

[281]

LUTHER BURBANK

and was so pleased with the result that he sent
word next season that he would be glad to talk
with me. Accordingly I went to see him. I
looked forward with pleasure to the visit, as Mr.
Gregory had an interesting garden and a very
complete seed establishment. But I was a little
diffident about going, and so persuaded a friend,
the Hon. J. T. Brown, then a banker in Lunenburg,
to accompany me.

I shall always entertain the most vivid and
pleasing recollections of the day spent in Mr.
Gregory’s gardens, and of the hospitality extended
by the owner and his family.

Mr. Gregory showed a basket of beautiful
potatoes, which he declared to be quite the best he
had ever seen, and which, he assured me, were
the product of the sample I had sent him. He
asked me to sell the potato to him outright, giving
him the exclusive right of introduction of the new
vegetable. And ‘that, of course, was precisely
what I wished to do.

The matter of terms was not so easily adjusted.
I had thought that $500 would not be more than a
fair price for the new potatoes. But Mr. Gregory
said that $150 was the most that he could pay.
Other new potatoes were being developed, he
said, and this one would not have the monopoly
that it might have had a few years earlier. Had

[282]

Selecting Seedling

Potatoes

it will be ob-
servea that Mr. Bur-
bank has the potatoes dug
up and left in the hill for
inspection and identiftca-
tion. The particular spe-
cimens here shown chanced
to be second generation
seedlings of the Chilian
wild potatoes. There are
promising possibilities
in some of the lot.

LUTHER BURBANK

I developed it even two or three years sooner, he
could have paid a thousand dollars for it.

I was perhaps a little disappointed, but was
contented to accept Mr. Gregory’s verdict, and let
him have the potato without looking farther. With
the $150 that he paid, I came to California next
season, having first delivered to Mr. Gregory a
crop of the potatoes raised on my own ground and
a neighboring piece of land.

Mr. Gregory permitted me to keep ten potatoes.
These I brought to California, and thus introduced
the Burbank potato on the Pacific Coast. The
name “Burbank seedling,” I should explain, was
given the potato by the purchaser. Mr. Gregory
stated afterward, in a letter now before me, that
he chose this name because he decided, “after
pondering over the matter, that the one who
originated such a variety deserved to have it bear
his name.”

PROGRESS OF THE BURBANK

It is not necessary here to trace the story of the
spread of the Burbank potato from one region to
another until its annual crop has been estimated
to have a value of not less than seventeen million
dollars.

Suffice it that I personally introduced it in
California, and that after the prejudice against a
white potato had been overcome, the merits of

[284]

Vil 97

Salinas Burbanks

Salinas may be
said to be the home
of the California Bur-
bank. Here entire regions
are given over to the cul-
tivation of this potato, and
fine representatives of the
variety are produced in
enormous quantities. The
picture shows some
typical specimens.

LUTHER BURBANK

‘the new tuber were so quickly recognized that the
Burbank came to be the standard tuber on the
coast from Alaska to Mexico. The U. S. Depart-
ment of Agriculture aided in the distribution of the
Burbank at an early day, sending it to various
states, among others to Oregon, where it soon
became exceptionally popular.

The Burbank does its best on well drained,
sandy soil, and in a moderately cool, moist
climate. It thrives splendidly in the Sacramento
and San Joaquin Valleys.

There are single farms that raise from one
hundred to one thousand acres each of Burbank
potatoes; indeed, I received a visit recently from a
gentleman who stated that his crop of Burbanks
covers two thousand acres.

In the region of Salinas, California, the condi-
tions seem to be exactly suited to this potato, and
the crop sent from this. region brings a price so
exceptional that the Salinas Burbank has come to
be regarded as the standard for quality in
California.

Over six million bushels of the Burbank potato
were produced on the Pacific Coast alone in the
season of 1906, and the crop of that year probably
did not differ greatly from that of each year of
the past fifteen or twenty. In more recent years
it has doubtless at least held its own.

[286]

Russet Burbanks

These Burbank
potatoes, raised by
Mr. Lou D. Sweei, of Den-
ver, Colorado, have some-
what modified their coat,
in a way that does not add
to their attractiveness. It
is said, however, that this
particular variant is pe
culiarly resistant to blight,
which gives it ex-
ceptional value.

LUTHER BURBANK

Of course all the Burbanks making up the
enormous crop of the world have been produced
by multiplication of the original single hill of
tubers that grew from the one best vine among
the twenty-three seedlings of the original potato
seedball.

That the enormously multiplied product of
to-day maintains everywhere the characteristics
of the original, offers an interesting proof that
varieties do not “run out” if grown under suitable
environments.

How Expiain THE BurBANK?

But how shall we account for the original
variety itself?

I have told the story of its development without
offering any explanation of the interesting phe-
nomena observed. It remains to account not alone
for the Burbank but for the twenty-two other
varieties of potato that were its seedball sisters but
which were allowed to perish, because they did
not, on the whole, possess qualities that justified
their preservation.

Our studies of plant development through
hybridization, in connection ‘with numerous
species of flowers and trees and orchard and
garden fruits, supply clews that make the explana-
tion of the origin of the new potatoes relatively
simple.

[288]

Some Selected
Seedlings

Mr. Burbank’s ex-
periments wilh po-
tatoes have been continued
throughout the entire
period since he developed
the Burbank, more than
forty years ago. Until re-
cently he had failed to
produce any variety that
seemed, on the whole, to
excel the Burbank itself.
Some recent seedlings, of
mixed parentage, have very
admirable qualities, and
several of them are
being introduced.

LUTHER BURBANK

We have seen that a tendency to variation is
everywhere introduced when different species or
varieties of plants are hybridized. And although
no conscious experiment in hybridization was
involved in the case of these potatoes—inasmuch
as I had no knowledge of the seedball until it was
in actual existence—yet it is clear that nature had
performed the experiment, and that I was enabled
to take advantage of the results of her experi-
menting.

To be sure it is more than likely that the
seedball with which I worked was produced by
accidental fertilizing of the pistil from which it
grew by pollen from a neighboring plant; repre-
senting, therefore, the crossing of individuals of
the same variety and not a true hybridization of
different varieties; for all the potatoes in my
garden were of one kind—namely the Early
Rose.

But the Early Rose potato is itself a crossbred
variety. I am not sure that its exact history is
known, but undoubtedly it is the product of the
crossing of some other varieties of potato. The
Early Rose was a seedling of the Early Goodrich,
a white potato named after its originator, a clergy-
man who had been carrying on experiments in
crossing the potato and raising seedlings.

The crossing from which it originated occurred

[290]

The Early Rose

The Early Rose is
a well known and de-

servedly popular variety
of potato that has held its
own pretty consistently
for half a century. It has
exceptional interest from
the standpoint of _ the
plant breeder, because it
was the variety that bore
the seed ball from which

the Burbank was

raised.

LUTHER BURBANK

on the grotinds of Mr. Goodrich many years before
the time of its discovery.

But of course that does not in the least matter,
for every potato of a given variety, no matter how
far removed from the original specimen of that
variety in point of time, is of the same generation
with that original so long as all are grown from
the tuber.

All this has been clearly explained again and
again in dealing with the propagation of other
plants from tubers or cuttings or grafts or by root
division.

It follows that the twenty-three seedlings were
progeny of the second filial generation of the
original varieties that were crossed and which
produced the Early Rose. And this fully accounts
for the extraordinary range of variation that the
twenty-three seedlings manifested.

We have seen many illustrations of this
tendency to vary in the second filial generation of
hybridized species or varieties. We have observed
that the latent qualities of diverse strains of
ancestors are permitted to come to the surface and
make themselves manifest in the various individ-
uals of a second generation, once the tendency to
relative fixity has been broken up by hybridization.
So the twenty-three diversified varieties of pota-
toes that grew from the single seedball merely

[292]

ViL- 101

Selected Early Rose

The Early Rose is a crossbred potato, but it holds re-
markably true to type. There is a certain amount of variation,
however, and it is possible to isolate improved strains by careful
selection of seed potatoes. This specimen illustrates one
of Mr, Burbank’s experiments in this direction.

LUTHER BURBANK

furnish another illustration of a principle that our
studies in plant development have made familiar.

The case has interest, none the less, as present-
ing evidence from a new source of the application
of a principle of heredity that can never fail to
excite surprise however often we see it manifested.

It follows that we should not necessarily expect
the Burbank potato to breed true from the seed,
even if by rare exception a seedball should be
formed on a vine of this variety. But in point of
fact it breeds absolutely true as to color and rea-
sonably true in form, but not one of the seedlings
ever compared in its combination of good qualities
with the original Burbank. But of course this is a
matter of no practical importance. Probably not
one potato grower in a thousand ever gives a
thought as to whether the potato produces seed.
In practice the potato is grown from the “eyes” of
the tuber, and the grower gets approximately the
sort of tuber that he plants. Beyond that the
matter does not concern him.

SEARCHING For NEw VARIETIES

But of course the plant developer must view
the matter in another light.

He must consider the potato not as a finished
product but as an important vegetable that may be
susceptible of still further improvement. So for
him, doubtless, the chief interest of the story of

[294]

Wits 10%

The Burbank

and its Parent

At the left iwo
typical Burbank po-
tatoes; at the right two
typical Early Rose speci-
mens. As already noted,
the Early Rose bore the
seed bali from which the
Burbank was developed.
The difference between
parent and daughter is
explained by the fact
that the parent is itself
crossbred. The Burbank
combines the qualities
of some remoter
ancestors.

LUTHER BURBANK

the production of the Burbank variety must hinge
upon what it can teach as to the possible produc-
tion of still better varieties.or of varieties adapted
to different conditions of soil or climate from
those under which the Burbank thrives.

THE SECRET OF FurTHER IMPROVEMENT

Obviously the lesson of the Burbank is that all
further improvement must be sought through the
crossing and hybridization of the existing varie-
ties of potato, and the raising of seedlings.

My own experiments in this direction have been
extensive, and have led to some interesting results,
even though the spectacular features of the
production of the original Burbank have been
lacking.

As early as 1895, I produced a hybrid between
the Burbank potato and a variety known on the
Pacific Coast as the Bodega red. This was adver-
tised, but was never introduced. A variety that
was introduced only a few years after I came to
California was a sport that appeared in a field of
Burbank potatoes growing on my brother David’s
place at Tomales.

There were five or six hills of vines that differed
from the others in having larger tops and more
vigorous growth as well as an altered appearance.
They matured very late, and were found to have
potatoes far less regular in outline than the ordi-

[296]

ON THE POTATO

nary Burbank but much larger and coarser, and
produced in great abundance. Next year they were
introduced through a San Francisco firm.

But the potato did not differ sufficiently from
the Burbank to maintain its individuality, and it is
not now known as a separate variety.

My most interesting hybridizing experiments
have been with the wild or half wild species of
potato that are indigenous to various parts of sub-
tropical and tropical America. An account of
some of these experiments was given in Chapter 9
of Volume II, to which the reader is referred.
There, to be sure, the experiments in hybridizing
the potato were classified as failures, inasmuch as
they led to no commercially valuable result. But
it will be seen that they did not lack interest from
a scientific standpoint. In particular some of the
results in crossing the Darwin potato (Solanum
maglia) with the common potato through which a
vine was produced that bore a remarkable fruit,
were cited at some length.

INTERESTING Hysrips

Here I may refer a little more in detail to
results of this hybridizing experiment that were
not mentioned in the earlier chapter.

The Darwin potato is a slender, erect-growing
plant, bearing a tuber the flesh of which is usually
bright yellow in color, and much subject to decay.

[297]

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ON THE POTATO

In its stem and blossom, also, the plant is quite
different from the ordinary potato, and it com-
monly bears a seedball that is larger than the
seedball that the cultivated potato bears on rare
occasions; the seeds themselves, however, being
much smaller.

I grew seedlings of the Darwin potato and
improved them by selection until they produced
tubers of enormous size, some of them weighing
two to two and a half pounds. Then hybridizing
experiments were carried out between the Darwin
and the common potato.

More than half a million seedlings of hybrids
between these two species were raised.

The Darwin potato is much more fixed in its
characters than the cultivated potato, and these
characteristics proved largely dominant in the
progeny of the first generation, this dominance
extending to the tubers themselves, which resemble
their wild ancestor in size, color, irregularity of
form, deep eyes, and tendency to decay.

Eicut-Foot VINEs

There were, however, some _ astonishing
anomalies manifested by the hybrid progeny.
Some of the vines grew so prodigiously that they
reached eight feet in every direction from a single
root; and the potatoes they bore grew on long
stems or runners which spread nearly as far.

[299]

A Typical Hill of Burbank Potatoes

Here the tubers are exposed just in the position in which
they grew. Some potatoes have the defect of developing sprangly
roots, so that the tubers are widely scattered. The tubers of the Bur-
bank are as compactly placed, almost, as eggs in a nest;
greatly facilitating the gathering of the crop.

ON THE POTATO

In other cases the vines were compact, in strik-
ing contrast with their straggling sisters.

As to the potatoes themselves, some were quite
small, and the larger ones revealed the most
curious colors—bright crimson, scarlet, bright
yellow, white, black, and purple; the various colors
being sometimes intermingled in the same tuber
in the most curious way. Some were black from
skin to skin, others had a red center with an outer
layer of purple about a quarter of an inch thick.
Others were white or yellow, with purple veins
radiating from the center of the potato to the eyes.

In yet other cases the flesh of the potato was
variegated with crimson and yellow, purple and
white, blended into every imaginable form and
figure; so that when the potatoes were sliced the
effect was grotesque and sometimes fascinating, as
the cut surface revealed landscapes, faces, geo-
metrical figures, cloud effects, varying kaleido-
scopically with each new slice.

Notwithstanding the great interest of these
hybrids, I did not think them worthy of introduc-
tion, as they were curiosities rather than a prac-
tical commercial production. Yet it seems not
unlikely that a more extended series of experi-
ments in hybridizing and selection in which strains
of the Darwin potato are introduced might result
in a product of real value.

[301]

LUTHER BURBANK

Some of the improved Darwin seedlings
produced tubers of exceptional size, though as
before stated, much subject to decay. If the
breeding experiments were conducted along right
lines it would probably be possible to produce in
later generations a hybrid that combined the large
size of tuber of the Darwin with the keeping
qualities of the cultivated potato. It is really of
great importance that the experiments should be
repeated and carried forward to a successful issue.

What has just been said as to the curious results
of hybridizing experiments with this species will
sufficiently indicate that experiments of this kind.
will not be lacking in interest.

Experiments already far advanced at Santa
Rosa, using the Solanum Commersoni, a species
growing wild in the region of the Mercedes River,
in South America, for a time gave great promise.
The hybrids between this plant and the cultivated
potato showed great improvement in some direc-
tions, but all the seedlings lacked one desirable
character or another. The chief trouble was the
bitter principle which was transmitted by the
commersoni to almost all its hybrid seedlings.

I have, however, a very complex hybrid that is
about to be introduced—the fruit is of a reddish
color, almost apple shape. The plant is very
productive, and the tuber is of fine quality.

[302]

The Perfect Burbank

A glance at this picture suggests why it is that Mr. Bur-
bank has found it so difficult to improve upon the first potato
that he developed. In size, form, contour, smoothness of surface, and
reduction of eyes to the minimum, this potato approximates
the ideal. The quality and flavor of its content
ts admirably in keeping with its exterior. All
in all, it is a remarkable product.

LUTHER BURBANK

There are various other wild Solanums
growing, as did these original potatoes, in South
America, that might advantageously be tested as
to their hybridizing possibilities in connection with
the cultivated varieties. It need scarcely be added
that such experiments will ultimately be made in
which all allied species of potato will be tested;
and it is highly probable that this will lead to the
development of new varieties of tubers that will
surpass the potatoes of to-day as markedly as
these surpass the wild ancestors from which they
have been developed in comparatively recent
times.

[ENp oF VoLuME VII]

—I had been imbued from
the very outset with the idea
that inasmuch as existing
plants had all evolved from
inferior types, it should be
possible to develop any or
all of them still further.

LIST OF
DIRECT COLOR PHOTOGRAPH PRINTS
IN VOLUME VII

Alstromeria
The Chilian Alstromeria...

Artichokes
Artichoke Blossoms .........seeeeeeee eeeeceeeess Frontispiece
Artichokes in Mr. Burbank’s Back Vardi sc ciscioss oveeae 178
Another Burbank Dooryard View............ avareVs(hra- Bieieres a: 181
More Artichokes..... aOnewseeeweeany ee vasinndemneccesmeree 183
Artichoke Hybrids...............0005 P - 185
Round as a Ball Artichoke.. 188
Much Modified in Form.... eooee 191
An Ideal Hybrid Artichoke... (2k vieauseKnel etree 193
An Aberrant Type Artichoke............... EWES SH wera; 195
A Wild Artichoke...........seeeeeee sos Sasa sag ae enews 197
The Improved Burbank Artichoke. iuolsbard-evaeieve ata ayn eie/ete ts acre. 199
A Field of Hybrid............. Mono ey seccevcvecces 201
More Material for Selection..........scsccccsccccesevecsee 203

Asparagus
Burbank ASparagus......ssscccerscccccevccssscesccasevss B19

Beans
Baby Plants........cc.e00. Dia lesiseiais eeaiaie deste cececasines. AL
Showing Variations in Beans........ 82
A Burbank Perennial Bean.. 85
Burbank Lima Beans........ 87
A Stripling from the ireples: wistaie b ereteietesdisty ee eawaceeess: OO
Giant Horse Bean.........2.eeeeeee ia fore aati aiieSele Gore eesvevaie a «. 93

Roots of the Mammoth | Soy Bean.......scccscccecceeenece 95
Soy Beans.scccsncisscecssseevevereveesencseneveomeereeces 101

LIST OF ILLUSTRATIONS (Continued)
Beets

The Familiar Beet.....cscccscccccsrcscncccccsscccvscenes . 62

Brodiaea
Blossoms of the Brodiaea........... OCT OCT ER ori) eae 259

Bulbs

Some Almost-Edible Watsonias......... eee e eee hers toe: BSG

Camassias

A Bed: of. Gamassias osc sieceviesi ieee hee w wetinn's caiees ele an ave
Individual Camassia Blossoms. oe
Hybrid. Gamassi ais: cies os ccigeseiste fh javiveirrscels s asia ieee cies 8%
The: Wild Camasstaiiies 6 5.5 we irwscieeies ot cade sioeinen seamed ee
iA ‘Contrast:in’ Bulbs)... 2 vewrasigi sss cede dees sv eases 88S

Cambium
Where the Tree is Alive...... 0. ccc c cece cece sere ccnncoee 19

Carrots
A Universal Favorite. .........ccccceecnceecrceccenecseres 67

Celery

A. Field. of \Geleryeiccaisscit eiiseinsicier ene 6 de esse era ayaa 0 Saas eae ace 224

Chard

Swiss: (Gh ars aise aren oceis a a sipve ave epers sss este euersiajere 0'a: siete nwisists 0: 0/e%s 206

Chives
Pink and Yellow Chives..........cccesssccecceeseeeeceees 162

Cucumbers
The Familiar Cucumber............... BINS oy Sys pibet eres 43

Egg Plant

Variations in Fruit........ 0. cc cece cc ence ener secevencuee 230

Garlic

Chilean Garlic on the Stalk... ....... eee ee eee cence nne 147
An Improved Garlic...es es soanerercnrses er ienen aieraieiereverauans 150

LIST OF ILLUSTRATIONS (Continued)

Gourds
Page

Some Experimental Gourds............... cess ceeeeeeeeee . 51

Too: Much: Seed). so ssviiisieossis oie stone aaniislad a 8 vias waters oo ose 65

Some Gourds from Australia. ...........0.eceeeeeeeee wave OF
Irrigation

Artificial Rain in Mr. Burbank’s Garden..... thie sos Se seals) alas! »» 33
Kale

A Cousin of the Cabbage.............. reer CTT Ce err et.
Leaves

Illustrating Leaf Structure................00- PEt aoe rae 13

Leaves by the AGre, «sss e<sieasss1oeeeenan orees eeseveres 18
Melon

An Attractive Melon.............. be LIBRE RSL oe dances AL
Mistletoe

A Beautiful Thief........... cece cee cree eee eneeee jteeekee 3S
Mustard

Improved Mustard..........csesevsecceeces eedisteias steise anv 168
Onions

Burbank Onions from the Seed........... Mies Wrenntreie eee ares 153

A South American Allium..............6+ Tavs wren eiaye SN eG 156

A Burbank AMMM.iccscsccaccvscwesnvans ¥ Bigiew aie so Ges ee oe 159
Parsnips

A Bunch of ParsnipsS..........cceecceeseere iste ieteisnes see ~» 70
Passion Flower

Passion Flower in BIOOM...........cceceereecee teen eeceees 233

Flower and Fruit on the Same Plant........secseesseveses 235
Peanuts

South American Peanuts.........ceececeseceencreeneenees . 219

Another View of the South American Peanut............. +. 221
Peas

Three Kinds of Burbank Peas..........seeeeeeecstecerenee 75

Giants and Dwarfs....... cece eee e cece nent ee eeeecenecnens 77

Peas in the Pod.........ccecee errr cer rce ence reneeesaseees 79

Cow Peas under Cultivation.......... Sonraod sabe waxeeunees 98

LIST OF ILLUSTRATIONS (Continued)

Peppers ping

A, Basket. Of PenperSisseentiss icivesewssasinaseeviiacss W1
Giant Mexican Peppers.......sesccsccccsccvccssecevsscese 175

Potatoes
Potatoes with a Strange History........ccccceccsccccscee » 135
Potato Seed Ball iiss cesecwscvcasen veane iS in AT ae 208
Bodega Ved PoOmiees. vicaveckie cs sccacsveeniwxiawse enna es 269
Sprouting Bodegas.........ssceceecevsecs rE oo « 272
Snake Potatoes............ idk siete eG v Svaye lars gtotace oa: bTadeeeeehehere’S 275
Chilian Wild Potatoes.........:.0sccsceeoneee Fwlleleitanaaerayel's 277
Mexican “Potatoes iiss 0: swans 3405 vee oases 6.658 Sr asides 280
Selecting Seedling Potatoes..............s000+ av Shao reamraney sieve 283
Salinas Potatoes. cscccissanassecanaeseeuwnens , «2 285
Russet Burbanks........ 287
Some Selected Seedlings... . 289
The -Barly: ROSC jacscjs 2 eae heat Hew aie SeoPere eis este woensr 291
Seiected Early Rose............+ sss os Dodove vou vetanels ia she ote a locserel s) 293
The Burbank and Its Parent.............. sarees ee sewaiets oo. 295
The Burbank Potato as It Grows............e.0. aeceveeee 298
A Typical Hill of Burbank Potatoes...... aieintedis oeeieeesae BOO

The Perfect Burbank. < sc cavcavvesiasvesscensesivcseveccen BOS

Radish

Another Old Friemd....cccccccecsersecccscssvcccece caves 65

The Horse Radish....... vee neem ene nece ones raenanceovenens 165
Rhubarb

Burbank Rhubarb.............0eeeeeee ibe foie stbtaiete'n esa avaweuse 211

Another Bed of Burbank Rhubarb... aia ss tere seats Su osaeouanid 214
Roots

The Important Root Hairs......... 6

Inspecting a Root System 30
Seedlings

Selected Seedlings..........-.eeeeene arintnvbrwie swisvesdnua sieriee oe 27

Transplanting Selected Seedlings........ccceeseccscesccees 24
Soil

Burbank Ideal Soil. ......... cece cece cence eee een eter erence 21
Squash

A Visitor from Patagonia.............. Sidliststeln's sikiace wee sersiarers 46

Two Squashes in One... sscrecvervevccccscrevesesesseces 49

LIST OF ILLUSTRATIONS (Continued)

Tomatoes

The Burbank Tomato...........ccccccsavccccsceecs - 113
Vigor Through Crossbreeding........cseccescceseeee
Fruits of a Tomato Hybrid..........cccccccccceservcsccve 119
Another Interesting Hybrid.........cccscccscccccccccccees 122
Tomato Leaf Variation.....
Collected for Seed...... ieee
A Tropical Solanum,........csecsessccescccccccccsrccess 132
Odd Cousins of the Tomato.........ccescceseeear eovceesee 138
Some Selected Tomatoes......csccceccqsccercecsccccecnces 142

6 6 hws ea aAI ee Haweeensies eee eree's: 125

Unicorn Plant
The Freakish Martynia......cccsccrsccscccccsseccccessces 59

Vetch

Hairy Vetch.......c.ccccccescccencvccecesscccescsccevcns 108

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