ruly 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, &c., 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 {306}
incidentally given. One chief object in the two following chapters is to
show how generally almost every character in our cultivated plants has
become variable.

Before entering on details a few general remarks on the origin of
cultivated plants may be introduced. M. Alph. de Candolle[519] 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[520] 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 pumpkins, millet,
sorghum, kidney-bean, dolichos, capsicum, and indigo. Nor does he include
flowers; and several of the more anciently cultivated flowers, such as
certain roses, the common Imperial lily, the tuberose, and even the lilac,
are said[521] not to be known in the wild state.

From the relative numbers above given, and from other arguments of much
weight, M. De Candolle concludes that plants have rarely been so much
modified by culture that they canno