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HOW THE CACTUS GOT ITS SPINES
-AND HOW IT LOST THEM
A SIDELIGHT ON
THE IMPORTANCE OF ENVIRONMENT
T IS the acre-and-a-quarter patch of spineless
cactus on Luther Burbank's experiment farm
which first strikes the visitor's eye. In the
same yard there are 2500 other experiments under
way-new flowers, fruits, vegetables, trees and
plants of all descriptions such as man has never
before seen, but the velvet slabbed cactus-freed
from its thorns-seems more than a plant trans-
formation, it seems a miracle. Since the spineless
cactus represents the typical Burbank boldness
of conception, and reflects the typical Burbank
skillful execution, we may as well begin with it.
It occurred to Luther Burbank one day that
every plant growing on the desert was either
bitter, or poisonous, or spiny. It was this simple
observation which gave him the idea of this new
plant-a plant which already has shown its
ability to outdo alfalfa five to one, and which
promises to support our cattle on what have been
the waste places of the world; so that our
ranges may be turned into gardens to produce the
vegetable sustenance for a multiplying population.
Let us' look at the life story of the cactus as
it unfolded itself to Luther Burbank when he
realized the importance of the simple fact that
desert plants are usually bitter, poisonous, or
spiny.
"Here are plants," thought he, "which have the
hardiness to live, and to thrive, and to perpetuate
themselves, under conditions in which other
plants would die in a day or a month.
"Here are plants which, although there may
be tot a drop of rain for a year, two years, or even
ten, still contrive to get enough moisture out of
the deep soil and out of the air, to build up a
structure which, by weight, is ninety-two per cent.
water-plants which contrive to absorb from the
scorching desert, and to protect from the withering
sun, enough moisture to make them nearly as
juicy as watermelons.
"Here are plants which are veritable wells of
water, growing in a. land where' there are no
springs, or brooks-nor even clouds to encourage
the hope of a cooling rain; here are plants which
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are rich in nutriment for man and for beast, here
in the desert where the demand for food is the
most acute-and the supply of it the most scanty.
"And here they are, ruined for every useful
purpose, by the bitterness which makes them
inedible, or the poison which sickens or kills, or
the spiny armor which places their store of nutri-
ment and moisture beyond reach.
"There must be some reason for that bitterness,
that poison, those spines.
"What other reason could there be than that
these are Nature's provisions for self defense?
"Here are the sagebrush, with a bitterness as
irritant, almost, as the sting of a bee, the euphorbia
as poisonous as a snake, the cactus as well
armored as a porcupine-and for the same reason
that bees have stings, that snakes have fangs,
that porcupines have arrow-like spines-for self
protection from some stronger enemy which seeks
to destroy."
* * * * *
Self preservation comes before self sacrifice,
apparently, in plant life just as it does in human
life.
The plum trees in our orchards outdo each
other in bearing fruit to please us; the geraniums
in our doorvards compete to see which may give
us the greatest delight.
But may it not be because, for generations, we
have fostered them, and nurtured them, and cared
for them?
May it not be because we have made it easy for
them to live and to thrive?
May it not be because we have relieved them
of the responsibility of defense and reproduction,
that they have rewarded our kindly care by
fruiting and blooming, not for their own selfish
ends, but for us?
No man was ever kind to a cactus; no man ever
cultivated the sagebrush; no man ever cherished
the poisonous euphorbia.
Is it, then, to be wondered at that the primal
instinct of self preservation has prevailed-that
what might have been a food plant equal to the
plum transformed itself into a wild porcupine
among plants?
That what might have been as useful to the
horse as hay changed its nature and became bitter,
woody, inedible?
That what might have been a welcome friend
to the weary desert traveler grew up, instead, into
a poisonous enemy?
* * * * *
"If the bitterness, the poison and the spines
are means of self defense," thought Mr. Burbank,
"then they must be means which have been
acquired. The plants were here before there were
animals to feed on or destroy them, so there must
have been a time in their history when they had
no need for such defense.
"It must be true, then, that away back in their
ancestry there were desert sagebrushes which
were not bitter, desert euphorbias which were not
poisonous, and desert cactus plants which had
not even the suspicion of a spine. It could only
be the long continued danger of destruction
which could have produced so radical a means of
defense.
"We have, then, but to take these plants back
to a period in their history before defense had
become a problem-in order to produce an edible
sagebrush, a non-poisonous euphorbia, a spineless
cactus."
How, in a dozen years, Mr. Burbank carried the
cactus back ages in its ancestry, how he proved
beyond question by planting a thousand cactus
seeds that the spiny cactus descended from a
smooth slabbed line of forefathers-how he
brought forth a new race without the suspicion
of a spine, and with a velvet skin, and how he so
re-established these old characteristics that the
result was fixed and permanent - all of these
things will be explained in due course where the
discoveries involved and the working methods
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employed may be made applicable, as well, to the
improvement of other plants.
It suffices, here, to say that, beginning with his
simple observation and reading the history of the
cactus from its present-day appearance, he was
able to see outlined before him the method by
which a plant yielding rich food and forage has
been produced, which, more than any other plant,
promises to solve the present-day problem of
higher living costs.
* * * * *
"But, Mr. Burbank," asked a visitor at the Santa
Rosa Experiment Farm, "do you mean that the
cactus foresaw the coming of an enemy which was
to destroy it? Is it believable that a plant, like
a nation expecting war, could armor itself in
advance of the necessity? And if the cactus did
not know that an enemy was later to destroy it,
would it not have been destroyed by the enemy
before it had the opportunity of preparing a means
of defense?"
Let us look into the history of the plant as it
revealed itself to Mr. Burbank and see the answer
to these questions.
* * * * *
The likelihood is that parts of Nevada, Arizona,
Utah and Northern Mexico were once a great
inland sea-that the deserts now there were the
bed of that sea before it began its long process of
leakage or evaporation.
In these regions, so far as is known, the North
American cactus seems to have originated.
Back in the ages before the evaporation of the
inland sea was complete, the heat and the moisture
and the chemical constituents of the sandy soil
combined to give many plants an opportunity to
thrive. Among these was the cactus, which was
an entirely different plant in appearance from
the cactus of today, no doubt, with well defined
stalks and a multitude of leaves, each as broad as
a man's head.
As the heat, which had lifted away the inland
sea, began to parch its bottom, the cactus, with the
same tendency that is shown by every other plant
and every other living thing, began to adapt itself
to the changing conditions.
It gradually dropped its leaves in order to
prevent too rapid transpiration of the precious
life-supporting moisture. It sent its roots deeper
and deeper into the damp sub-stratum which the
sun had not yet reached. It thickened its stalks
into broad slabs. It lowered its main source of
life and sustenance far beneath the surface of the
ground and found it possible, thus, to persist and
to prosper.
Perhaps there were, in the making of the
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desert, other plants not so adaptable as the cactus,
plants which perished and of which man has no
knowledge or record.
And so, we may assume, the cactus and those
other plants which adapted themselves to the new
conditions crowded out those which were unable
to fit themselves to survive, and covered the drying
plains with their verdure.
But there came animals to the bed of this
one-time sea, attracted, perhaps, by the cactus and
its contemporaries, which offered them food of
satisfying flavor and easy access.
Of the plants which had survived the evapora-
tion of the sea and the heat of the broiling sun,
there were many, quite likely, which failed to
survive the new danger-the onslaught of the
animals.
Species by species the vegetation of the desert
was thinned out by the elements and by the
animals; and the animals, with plant life to
feed on, multiplied themselves in ever increasing
hordes, till perhaps the cactus was but one of a
dozen plants to survive.
Then came the fight of the cactus to outdo the
beasts which sought to devour it-the fight as a
family, and the fight within the family to see which
of its individuals should be found fit to persist.
Of a million cactus plants eaten to the ground
by ravenously hungry antelopes, we will say-
antelopes which had increased in numbers year
by year while their food supply year by year was
relentlessly dwindling - of these million plants
gnawed down to the roots, perhaps but a thousand
or two had the stamina to throw out new leaves-
and to try over again.
But just as in its previous experience, the
cactus had changed the character of its stalk, so
now it undertook another change-the acquisition
of an armor.
This armor at first consisted of nothing but a
soft protuberance, a modified fruit bud or leaf,
perhaps, ineffectual in warding off the onslaughts
of the hungry animals.
So, of the thousand or two left out of the
million, there may have been but a hundred which
were able to ward off destruction.
The hundred, stronger than the rest, though
eaten to the ground, were able still to send up new
leaves, and with each new crop the hairs became
stiffer and longer, the protuberances harder and
more pointed, until finally, if there were even only
one surviving representative of the race, there was
developed a cactus which was effectually armored
against its every animal enemy.
One such surviving cactus, as transformed
throughout ages and ages of time, meeting new
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conditions with changes so slight as to be almost
imperceptible, but gradually accommodating itself
to the conditions under which it lived and grew-
one such survivor out of all the billions of
cactus plants that have ever grown, would have
been sufficient to have covered the deserts of the
world with its progeny-to have produced all of
the thorny cactus which we have in the world
today.
* * * * *
"You see," said Mr. Burbank, "the cactus did
not prepare in advance to meet an enemy-it
simply adapted itself to changing conditions as
those conditions arose. First, surviving the desert
drought and the broiling sun, it threw its roots
deep so that its main. source of life was below
ground. Then, attacked by an enemy which ate
off the leaves above the surface, it still had life
and resistance to try again. Ineffectually, at first, it
began to build its armor, but each discouragement
proved but the incentive to another attempt. It
is a vivid picture: the whole cactus family in
a death struggle for supremacy over an enemy
which threatens its very life - millions and
millions of the family perishing in the struggle,
and perhaps but one victorious survivor left to
start a new and armored race.
"It is wonderful, too; but, whenever we plant a
cactus slab today we see evidences of adaptability
more wonderful than this.
"The slab of cactus is a brilliant green as we
put it in the ground. It is flat, of an oval shape,
an inch or less in thickness. Its internal structure
is of soft, mushy fiber, mostly water.
"As that slab sends down roots, it begins to
prepare itself to bear the burden of the other slabs
which are to grow above it.
"The thin, flat shape thickens out until it is
almost spherical; thus presenting a curved surface
in four directions instead of in two, it braces itself
against the winds which will play with the new
slabs far above it.
"Its mushy wood fibers grow tough and
resistant; it loses much of its watery character.
"It changes in color, from green to brown; it
loses its velvety skin and develops a bark like
that of a tree.
"Within a year after planting, this cactus
slab will have changed in appearance and in
characteristics to fit itself to the new conditions
which surround it.
"It will have changed its structure to bear
weight and stand strains. It will have modified its
internal mechanism to transmit moisture instead
of to store it. It will have remodeled its outer
skin to protect itself from the ground animals from
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which, when it was a slab high up on another
cactus plant, it knew and feared no danger!"
- ~* * * * *
Is it more wonderful that, unseen by us, a
plant should have adapted itself to the desert
and, through the ages, have armored itself against
an enemy, than that, before our eyes, in a single
year, it should meet changed conditions in an
equally effective way? F
Is it more wonderful that it should grow spines
than that it should grow slabs which in turn have
the power to grow other slabs?
Is not the really wonderful thing the fact that
it grows at all?
* * * * *
The cactus is one of the most plastic of plants-
educated up to this, perhaps, by the hardships
and battles through which its ancestry has fought
its way.
- A slip cut from a rose bush, for example,
must be planted in carefully prepared ground of
a suitable kind, at a certain time of the year, with
regard to moisture and temperature-it must be
watched and cared for until it takes root and
begins for itself. Under continued cultivation, the
rose bush has lost some of its ability to make its
own way.
But the cactus, having come up from a line
of warriors with every hand against it, needs no
such care. Evezry one of the fifty or more wart-like
eyes on its every slab is competent to throw out
a root, a fruit, or another slab-whichever the
occasion seems to warrant.
Lay a cactus slab on hard ground, unscratched
by a hoe, and the eyes of its under side will throw
long yellow roots downward, while the eyes on
the upp.er side await their opportunity, once the
slab is rooted, to throw their other slabs and their
blossoms upward.
As the tiny buds grow from the eyes, it is
impossible by sight or microscopic examination to
determine which will be roots, which will be
fruits, or which will be other slabs. It is as though
the cactus, inured by hardship and prepared for
any emergency, waits until the very last possible
moment to settle upon the best-suited means of
reproduction-as though the bud, having started,
becomes a root if it finds encouragement for roots,
or a fruit if seed seems desirable, or an upward
slab if this can be supported.
Nor does its attempt at reproduction require
much encouragement. Fifty young cactus slabs
laid on a burlap-covered wooden shelf four feet
above ground were found to have thrown long
roots down through the burlap and through the
cracks of the boards within a few days.
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A cactus plant pulled from the ground and
tied by a string to the branch of a tree remained
hanging in the air for six years and eight months.
During this time it had no source of nourishment,
and its slabs withered and turned brown. But,
planted again by sticking one of its slabs six
inches in the ground, it immediately took root,
and within a few weeks began to throw out new
blossoms and slabs.
Another detached cactus slab, long forgotten
in a closet, and after having been in the dark
for more than a year, was found to have thrown
out a sickly looking baby slab when the closet
door was left open for a few days.
The more the adaptability of the present-
day cactus and its tenacious hold on life are
observed, the easier it becomes to understand
its fight against a devouring enemy which lived
during the desert-forming age, and to see the
origin of the thorny cactus of today.
* * * * *
Nor is the cactus the only desert plant which
shows evidences of such a struggle.
The goldenrods of the desert are more bitter
than the goldenrods of the plains.
The wormwood of the desert is more bitter
even than the wormwood which grows where there
have been fewer enemies.
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The yuccas, the aloes, the euphorbias, all have
counterparts in their families which, needing less
protection, show less bitterness, less poison, fewer
spines.
And even rare cactus plants from protected
localities, and those of the less edible varieties,
give evidence, by the fewness of their spines, that
their family struggle has been less intense than
the struggle of the cactus which found itself
stranded in the bed of a former inland sea.
* * * * *
Plants which have shown even greater adaptive
powers than the cactus are to be found in the well
known algae family.
One branch of this family furnishes an apt
illustration of the scant nourishment to which a
plant may adapt itself.
Microscopic in size, it lives its life on the upper
crust of the Arctic snow storing up enough energy
in the summer, when the sun's rays liquefy a thin
film of water on the icy surface, to sustain life in
a dormant stage during the northern winter's six
months of night.
With nothing but the moisture yielded front
the snow, and what nutriment it can gather from
the air, this plant, called the red snow plant,
multiplies and prospers to the extent that it covers
whole hillsides of snow like a blanket-covers
them so completely that the reddish color of the
plant, imparted to the snow, first gave rise to the
tales of far northern travelers as to the color of the
snowfall and explained the apparent phenomenon
of red snow.
Another division of this family, going to the
opposite extreme, thrives in the waters of Arrow-
head Sulphur Springs in California-lives its life
and reproduces itself in water so hot that eggs may
be easily cooked in it.
Contrasted with these microscopic members,
one thriving on the Arctic snows, the other in water
at the boiling point, there is still another member
of this family which has become the largest plant
in the world. This, the gigantic seaweed of the
Sargasso Sea, is taller and larger than the greatest
giant redwood which California has produced.
And so on; some of this family of the algae
grow on and in animals, some on other plants,
some on iron, some on dry rocks, somne in fresh
water, and some in the salt seas.
* * * * *
The monkey-puzzle tree, a form of which is
illustrated by a direct color photograph print,
shows an adaptability to environment as striking
as that of the cactus-although for an entirely
different purpose.
At the top of the monkey-puzzle tree, so called,
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are borne several nuts containing the seed of the
plant.
In the case of the cactus the thorns were thrown
out to protect the plant itself from destruction, but
in the case of the monkey-puzzle tree the animals
threatened not the tree itself but its offspring-its
nuts were so highly prized by the monkeys, and
their number was so few, that it was forced to take
protective measures to keep its seed out of the
reach of enemies.
From this we begin to see that each plant has
its own family individuality, its own family
personality. Some plants, in order to insure
reproduction, produce hundreds or thousands of
seeds, relying on the fact that in an over-supply
a few will likely be saved and germinated; while
other plants producing only a few seeds protect
them with hard shells or bitter coverings, or, as in
the case of the monkey-puzzle tree, with sharp
spines which make access impossible.
* * * * *
In the deep canyons of California's mountains
there grows a member of the lily family, the
trillium.
At the bottom of these canyons there are places
where the sunshine strikes but one side. The
flowers on the shady side of the canyons are larger,
and the leaves of the plants are broader, and the
bulbs are nearer the surface than those of the
plants which grow where the sun gets at them.
On the other side of the same canyons the
bulbs grow deep in the soil, and the leaves and the
blossoms transform themselves to protect their
moisture from the sun.
Which is all that the cactus did when the sea
was turned into a desert.
* * * * *
Along the Pacific coast from Oregon well down
into California, there grows a common wild flower
of the pipewort family.
Inland a little way, say ten or fifteen miles, the
stalk of this plant is smooth and with hardly the
suspicion of a hair. But along the shore, where
the northwest winds pick up all of the finer
particles from the beach and form a sand blast,
the plant has developed a stalk so covered with
hairs that it is as woolly, almost, as a sheep-
perfectly protected against the sand-enemy.
Which is all that the cactus did when the
antelopes came to destroy it.
* * * * *
Let the cactus, battle-scarred and inured to
hardship, teach us our first great lesson in plant
improvement:
That our plants are what they are because
of environment; that simply by observing their
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structures, their tendencies, their habits, their indi-
vidual peculiarities, we can read their histories
back ages and ages before there were men and
animals-read it, almost, as an open book; that
our plants have lived their lives not by quiet
rote and rule, but in a turmoil of emergency;
and, just as they have always changed with their
surroundings, so now, day by day, they continue
to change to fit themselves to new environments;
and that we, to bring forth new characteristics in
them, to transform them to meet our ideals, have
but to surround them with new environments-not
at haphazard, but along the lines of our definite
desires.
Is not the really
wonderful t h i n g
the fact that the
plants grow at all?