rve for my
future work the discussion of these difficulties, and the tables themselves
of the proportional numbers of the varying species. Dr. Hooker permits me
to add, that after having carefully read my manuscript, and examined the
tables, he thinks that the following statements are fairly well
established. The whole subject, however, treated as it necessarily here is
with much brevity, is rather perplexing, and allusions cannot be avoided to
the "struggle for existence," "divergence of character," and other
questions, hereafter to be discussed.

Alph. de Candolle and others have shown that plants which have very wide
ranges generally present varieties; and this might have been expected, as
they become exposed to diverse physical conditions, and as they come into
competition (which, as we shall hereafter see, is a far more important
circumstance) with different sets of organic beings. But my tables further
show that, in any limited country, the species which are most common, that
is abound most in individuals, and the species which are most widely
diffused within their own country (and this is a different consideration
from wide range, and to a certain extent from commonness), often give rise
to varieties sufficiently well-marked to have been recorded in botanical
works. Hence it is the most flourishing, or, as they may be called, the
dominant species,--those {54} which range widely over the world, are the
most diffused in their own country, and are the most numerous in
individuals,--which oftenest produce well-marked varieties, or, as I
consider them, incipient species. And this, perhaps, might have been
anticipated; for, as varieties, in order to become in any degree permanent,
necessarily have to struggle with the other inhabitants of the country, the
species which are already dominant will be the most likely to yield
offspring, which, though in some slight degree modified, still inherit
those advantages that enabled their parents to become dominant over their
compatriots.

If the plants inhabiting a country and described in any Flora be divided
into two equal masses, all those in the larger genera being placed on one
side, and all those in the smaller genera on the other side, a somewhat
larger number of the very common and much diffused or dominant species will
be found on the side of the larger genera. This, again, might have been
anticipated; for the mere fact of many species of the same genus inhabiting
any c