70 ORIGIN OF SPECIES 



which have very v^^ide ranges generally present varieties ; 

 and this might have been expected, as they are exposed to 

 diverse physical conditions, and as they come into competi- 

 tion (which, as we shall hereafter see, is an equally or 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 considera- 

 tion from wide range, and to a certain extent from com- 

 monness), 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 varie- 

 ties, or, as I consider them, incipient species. And this, per- 

 haps, 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 spe- 

 cies which are already dominant will be the most likely to 

 yield offspring, which, though in some slight degree modi- 

 fied, still inherit those advantages that enabled their parents 

 to become dominant over their compatriots. In these re- 

 marks on predominance, it should be understood that refer- 

 ence is made only to the forms which come into competition 

 with each other, and more especially to the members of the 

 same genus or class having nearly similar habits of life. 

 With respect to the number of individuals or commonness 

 of species, the comparison of course relates only to the 

 members of the same group. One of the higher plants may 

 be said to be dominant if it be more numerous in individuals 

 and more widely diffused than the other plants of the same 

 country, which live under nearly the same conditions. A 

 plant of this kind is not the less dominant because some 

 conferva inhabiting the water or some parasitic fungus is 

 infinitely more numerous in individuals, and more widely 

 diffused. But if the conferva or parasitic fungus exceeds 

 its allies in the above respects, it will then be dominant 

 within its own class. 



