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The Variation of Animals and Plants

Chapter IX: Cultivated Plants: Cereal And Culinary
Plants
PRELIMINARY REMARKS ON THE NUMBER AND PARENTAGE OF CULTIVATED
PLANTS — FIRST STEPS IN CULTIVATION — GEOGRAPHICAL DISTRIBUTION OF
CULTIVATED PLANTS.
CEREALIA. DOUBTS ON THE NUMBER OF SPECIES — WHEAT: VARIETIES OF —
INDIVIDUAL VARIABILITY — CHANGED HABITS — SELECTION — ANCIENT HISTORY OF
THE VARIETIES — MAIZE: GREAT VARIATION OF — DIRECT ACTION OF CLIMATE ON.
CULINARY PLANTS.CABBAGES: VARIETIES OF, IN FOLIAGE AND STEMS, BUT NOT
IN OTHER PARTS — PARENTAGE OF — OTHER SPECIES OF BRASSICA — PEAS: AMOUNT OF
DIFFERENCE IN THE SEVERAL KINDS, CHIEFLY IN THE PODS AND SEED — SOME
VARIETIES CONSTANT, SOME HIGHLY VARIABLE — DO NOT INTERCROSS — BEANS
POTATOES: NUMEROUS VARIETIES OF — DIFFERING LITTLE EXCEPT IN THE TUBERS —
CHARACTERS INHERITED.
I shall not enter into so much detail on the variability of cultivated plants, as in the case
of domesticated animals. The subject is involved in much difficulty. Botanists have
generally neglected cultivated varieties, as beneath their notice. In several cases the wild
prototype is unknown or doubtfully known; and in other cases it is hardly possible to
distinguish between escaped seedlings and truly wild plants, so that there is no safe
standard of comparison by which to judge of any supposed amount of change. Not a few
botanists believe that several of our anciently cultivated plants have become so
profoundly modified that it is not possible now to recognise their aboriginal parent-forms.
Equally perplexing are the doubts whether some of them are descended from one species,
or from several inextricably commingled by crossing and variation. Variations often pass
into, and cannot be distinguished from, monstrosities; and monstrosities are of little
significance for our purpose. Many varieties are propagated solely by grafts, buds, layers,
bulbs, etc., and frequently it is not known how far their peculiarities can be transmitted by
seminal generation. Nevertheless, some facts of value can be gleaned: and other facts will
hereafter be incidentally given. One chief object in the two following chapters is to show
how many characters in our cultivated plants have become variable.
Before entering on details a few general remarks on the origin of cultivated plants may be
introduced. M. Alph. De Candolle in an admirable discussion on this subject, in which he
displays a wonderful amount of knowledge, gives a list of 157 of the most useful
cultivated plants. Of these he believes that 85 are almost certainly known in their wild
state; but on this head other competent judges entertain great doubts. Of 40 of them, the
origin is admitted by M. De Candolle to be doubtful, either from a certain amount of
dissimilarity which they present when compared with their nearest allies in a wild state,
or from the probability of the latter not being truly wild plants, but seedlings escaped
from culture. Of the entire 157, 32 alone are ranked by M. De Candolle as quite unknown
in their aboriginal condition. But it should be observed that he does not include in his list
several plants which present ill-defined characters, namely, the various forms of
 
 
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