Chap. IL] DOMINANT SPECIES VAEY MOST. 67 



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 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 nourishing, 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. And this, perhaps, 

 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 

 species which are already dominant will be the most 

 likely to yield offspring, which, though in some slight 

 degree modified, still inherit those advantages that 

 enabled their parents to become dominant over their 

 compatriots. In these remarks on predominance, it 

 should be understood that reference 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 



