AN ECOLOGIC VIEW OF THE SPECIES 

 CONCEPTION 



PROFESSOR FREDERIC E. CLEMENTS 

 University of Minnesota 



I. Past and Present Practise in Species-making 



The species may be either a means or an end; prop- 

 erly it is both. In descriptive botany, these two uses 

 of the species have often been confused. The describing 

 of new species has come to be recognized as an end in 

 itself, while it should be nothing more than a necessary 

 preliminary to further and more important botanical 

 study. The interest of the ecologist in the proper recog- 

 nition and naming' of species is necessarily greater than 

 that of nearly all other botanists. To him species are 

 an indispensable means in the study of vegetation. On 

 the other hand, the search for the definite results of 

 adaptation and evolution, which is his final work, leads 

 him inevitably to the species as an end. It is this double 

 significance of the species for the ecologist that makes 

 him peculiarly concerned about its treatment. So long 

 as he uses the species only as a means, he is not greatly 

 confused, except as a consequence of the fact that >peeie> 

 are habitually made in the herbarium upon a small num- 

 ber of specimens, while he meets them as hundreds and 

 thousands of variable individuals. His serious troubles 

 begin with experimental work in adaptation and evolu- 

 tion. It quickly becomes evident that species so-called 

 are widely different in rank, origin and relationship. 

 Some are clearly species in the usual sense, while others 

 are merely variations and forms of these. The ecologist 

 thus comes to look with doubt upon all species. He 

 accepts them reluctantly and provisionally until they 

 meet successfully the test of experiment. 



