The Origin of Crepis and Related Genera 35 



not of the most primitive category. C. tectorum is one of the 

 most widespread annuals, whereas C. nicaeensis is a biennial 

 (sometimes annual) of rather restricted distribution and prob- 

 ably a more recent species. C. parviflora and C. capillaris are 

 closely related species with similar distributional areas in differ- 

 ent geographic regions. Thus far, C. capillaris and C. fuliginosa 

 are the only 3-paired species found in the genus, but they are 

 not very closely related. It is believed that they were derived 

 from different 4-paired ancestors. The four species at the top of 

 the chart are very closely related. C neglecta is of comparatively 

 wide distribution, whereas cretica and fuliginosa are endemics 

 and Suffieniana is very restricted. The last three are more re- 

 duced or highly specialized than neglecta, and undoubtedly 

 they are comparatively recent in origin. These four species are 

 of special interest because they illustrate the tendency of some 

 of the recent Eucrepis species to merge into Bar]{hausia. This is 

 indicated by their more or less definitely beaked achenes, espe- 

 cially in the three more recent species. Finally, this whole group 

 of species is of unusual interest because of the probability that 

 they have been derived from a 5-paired progenial line (see fig. 

 10). 



By application of this method of comparing chromosome rela- 

 tions with the evidence from external morphology, the phyletic 

 relations of all the Crepis species thus far studied cytologically 

 have been v/orked out. These are represented in figures 9-1 1. 

 The distribution of these various groups of related species may 

 now be considered. 



In Catonia (fig. 9) only three lo-chromosome species have 

 thus far been obtained, but two of them, sibirica and pontana, 

 are the most primitive types in the whole genus. The first is dis- 

 tributed from central Europe to Mongolia and southward to 



