The Origin of Crepis and Related Genera 17 



has been similarly helpful in determining the proper classifica- 

 tion of certain dubious sections of Hieracium. The section 

 Crepidisperma, in particular, is characterized by having the 

 achenes more or less attenuate toward the summit, as in Crepis, 

 and the pappus white as in most species of Crepis. Because of 

 these features of fruit and pappus, certain species were originally 

 described as Crepis, for example, C ambigua A. Gray. Cyto- 

 logical examination of this plant showed the haploid number 

 to be 9, which is characteristic of Hieracium and not of Crepis, 

 and it is probable that the other species of this section have the 

 same base number. Thus cytology supports the inclusion of these 

 species in Hieracium. 



There exists a very puzzling group of high alpine Himalayan 

 plants which have come to be known as the "Glomeratae" from 

 the type species, Prenanthes glomcrata Dene., although this 

 species and four or five similar ones have long been known as 

 Crepis. The evidence from comparative morphology, however, 

 strongly supports Decaisne's original classification in Prenan- 

 thes, and now it is known that the haploid number of chromo- 

 somes in P. glomerata is 8, a number not found in Crepis except 

 in certain polyploids. For the present, however, this group may 

 be considered as intermediate between Prenanthes and Crepis. 



The occurrence of 5 as a base number in several species of 

 ChondrillcT raises a special problem concerning the relationship 

 of this genus to Crepis. It has long been considered as closest to 

 Taraxacum because of the similarly specialized achenes in the 

 two genera. Although the base number for Taraxacum is 8, both 

 genera might have sprung from primitive Crepis stock. This is 

 only one of many similar problems awaiting investigation. 



Without going into further detail concerning the evidence 

 from comparative morphology and cytology, and as a first step 



