sentially differ from the term variety, which is given to less
distinct and more fluctuating forms. The term variety, again,
in comparison with mere individual differences, is also applied
arbitrarily, and for mere convenience sake.

Guided by theoretical considerations, I thought that some interesting
results might be obtained in regard to the nature and relations of the
species which vary most, by tabulating all the varieties in several
well-worked floras. At first this seemed a simple task; but Mr. H. C.
Watson, to whom I am much indebted for valuable advice and assistance
on this subject, soon convinced me that there were many difficulties, as
did subsequently Dr. Hooker, even in stronger terms. I shall reserve
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 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 t