Chap. II. 
DOMINANT SPECIES VABY MOST. 
53 
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 subse¬ 
quently Dr. Hooker, even in stronger terms. I shall 
reserve for my future work the discussion of these diffi¬ 
culties, and the tables themselves of the proportional 
numbers of the varying species. Dr. Hooker permits 
me to add, that after having carefully read my manu¬ 
script, and examined the tables, he thinks that the fol¬ 
lowing 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 dis¬ 
cussed. 
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 ex¬ 
posed to diverse physical conditions, and as they come 
into competition (which, as we shall hereafter see, is a 
far more important circumstance) with diff*erent 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,— 
