The Origin of Crepis and Related Genera 1 1 



possible to compare these cultivated species and forms when 

 grown under fairly uniform conditions. Although this can never 

 take the place of thoroughgoing field study, yet it does compen- 

 sate to a degree for the inability to see the plants growing in the 

 wild. For there is no doubt that the inherent morphological and 

 physiological peculiarities which distinguish species are faith- 

 fully reproduced under cultivation, often with an obviousness 

 that is not found in the study of herbarium material alone or 

 even in limited field observations. 



In the two decades during which the writer has applied part 

 of his time to the study of Crepis, fully half of all the known 

 species have been introduced into cultivation and many of them 

 have been maintained for use in genetical and cytological re- 

 search extending over a long period. Some of these species have 

 been represented by accessions from many localities throughout 

 the range of distribution, and of others only one or a few acces- 

 sions have been obtained. Every species in the collection has 

 been examined cytologically, and several reports have been pub- 

 lished on the chromosomes in relation to taxonomy and phy- 

 logeny in this genus.^' ^' *' "' '^^ Meanwhile, the taxonomic litera- 

 ture on the genus has been reviewed and most of the species have 

 been studied critically by the use of herbarium material, at least. 

 In the second part of this paper, the data on geographic distribu- 

 tion in this genus will be summarized and compared with the 

 evidence from chromosome relations with reference to phylo- 

 geny. Let us first consider the general aspects of the genus and 

 its position with reference to other most nearly related genera. 



Crepis and Some Related Genera 



The genus Crepis is a natural group of more than two hundred 

 species, being the second largest genus of the sub tribe Crepidinae 



