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.
Alphonse de Candolle and others have shown that plants which have very wide
ranges generally present varieties; and this might have been expected, as
they are 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 the 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), oftenest 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, 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.
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