72 SPECIES OF LAEGEE GENEEA. [Chap. II. 



species greater than the average are now manu- 

 facturing, many of the species already manufactured 

 still to a certain extent resemble varieties, for they 

 differ from each other by less than the usual amount of 

 difference. 



Moreover, the species of the larger genera are 

 related to each other, in the same manner as the 

 varieties of any one species are related to each other. 

 No naturalist pretends that all the species of a genus 

 are equally distinct from each other ; they may 

 generally be divided into sub-genera, or sections, or 

 lesser groups. As Fries has well remarked, little 

 groups of species are generally clustered like satellites 

 around other species. And what are varieties but 

 groups of forms, unequally related to each other, and 

 clustered round certain forms — that is, round their 

 parent-species. Undoubtedly there is one most im- 

 portant point of difference between varieties and 

 species ; namely, that the amount of difference between 

 varieties, when compared with each other or with their 

 parent-s s, is much less than that between the 

 species of the same genus. But when we come to 

 discuss the principle, as I call it, of Divergence of 

 Character, we shall see how this may be explained, 

 and h'W the lesser differences between varieties tend 

 to increase into the greater differences between species. 



There is one other point which is worth notice. 

 Varieties generally have much restricted ranges : this 



ttement is indeed scarcely more than a truism, for, if 

 a variety were found to have a wider range than that 

 of its supposed parent-species, their denominations 

 would be reversed. But there is reason to believe 

 that the species which are very closely allied to other 



