Cultivated Elementary Species 91 



the real systematic units in elementary species 

 play the same part as in ordinary wild species. 

 The inference that the origin of the cultivated 

 plants is multiple, in most cases, and that more 

 than one, often many separate elementary 

 forms of the same species must originally have 

 been taken into cultivation, throws much light 

 upon many highly important problems of culti- 

 vation and selection. This aspect of the ques- 

 tion will therefore be the subject of the next 

 lecture. 



