The Origin of Crepis and Related Genera 



27 



Throughout the genus there is close correspondence between 

 chromosome numbers and external morphology of the plants. 

 Although the most primitive species have 10 chromosomes, there 



CREPIS 



EVOLUTIONARY POSITIONS OF THE SUBGENERA 

 CHROMOSOME NUMBER AND PHYLOGENY 



BARKHAUSIA 

 16^ 8 (10-18) 



8^' 



EUCREPIS 

 44' 55? 88 



22^ (15-24) 



CATOIMIA 

 12^ 10^ 8® 



PROGEMIAL\STOCK, 10 



Fig, 5. Distribution of chromosome numbers in the subgenera of Crepis. 



are some fairly primitive 8-chromosome types. In both 10- 

 chromosome and 8-chromosome series there is abundant evi- 

 dence of progressive development from the woody-based peren- 

 nials vsdth large lyrate or entire leaves, few large heads, large 

 florets, and large unspecialized fruits to the short-lived annual 

 types with small leaves, numerous small heads, small florets, and 



