JORDAN'S SPECIES 9 



It has already been pointed out that Linnaeus him- 

 self distinctly deprecated this process of splitting. 

 ' Varietates levissimas non curat botanicus,' said 

 Linnaeus. Jordan, however, applied the method of 

 experiment to many of the species of his own defini- 

 tion, and having transplanted them from a variety 

 of localities to the uniform soil of a garden, found that 

 they preserved their distinctive characters and came 

 perfectly true to seed. 



It appears then that Jordan's species are just such 

 true and constant groups as those of Linnaeus. They 

 are separated from one another by definite features of 

 form and structure, only these differences are not so 

 wide as those which separate Linnaean species. The 

 latter are, indeed, to be looked upon as more or less 

 artificial groups or aggregates of these physiological 

 species, as Jordan's species have also been called. The 

 problem of the origin of the smaller groups is clearly 

 to be placed before that of the origin of the larger 

 species. 



It is true that in the case of certain groups of 

 animals and plants there would appear to be no possi- 

 bility of drawing hard and fast lines between the 

 species, which thus seem to shade gradually one into 

 the other. There is, however, a great difference 

 between the admission that certain nearly related 

 species are difficult or impossible to separate definitely, 

 and the statement that there is no true distinction 

 between them, and the latter statement is one which 

 few are bold enough to make. The case stands thus. 

 We know that great numbers of large groups (classes 



