VARIATION UNDER NATURE 89 



other, and tliat it does not essentially 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 arbitr. .ily, 

 for convenience' sake. 



Wide-rangiJig^ much diffused, and common Species vary most 



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 til ere were many diificulties, as did subsequently Dr, 

 Hooker, even in stronger terms. I shall reserve for a 

 future work the discussion of these difficulties, and the 

 tables 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," "diver- 

 gence 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 an 

 equally or more important circumstance) with different 



