22 



Mutability and Individual Variation. 



and distinct under cultivation. The extent of these dif- 

 ferences is sufficiently indicated by a series of the most 

 important forms, in Fig. 3. 



A heated controversy in which Jordan and Godron 

 played the most prominent parts has raged over the ques- 



Fig. 3. Subspecies of Draba verna. i. D. violacea ; 2., 3. 

 and 4. D. scabra; 5. D. subnitens ; 6. D. majuscula ; 7. D. 

 obconica ; 8. D. glaucina \ 9. D. clongata ; 10. D. graminea. 

 (After F. Rosen, Bot. Zeitung, 1889. Plate VIII.) 



tion as to whether these smaller perfectly circumscribed 

 types should be called species or not. Jordan and the 

 advocates of the smaller species based their views on 

 the results of cultures ; and in this way they have en- 



