i8 



E. B. Babcoc\ 



merely toward a better comprehension of the natural relation- 

 ships of the genera under discussion, we may represent their 

 phylogeny somewhat as in figure i. This arrangement is in 



CHROMOSOME NUMBER AMD PHYLOGEMY 

 IW THE CREPIDIIVIAE 



HICRACIUM 9 



CRCPiS 5.4 



LACTUCA 8.9 



Fig. I . Chromosome number and phylogeny in the Crepidinae. 



^nly one species reported with respect to 



chromosome number. 



general agreement with the natural system worked out by 

 Cassini" on the basis of comparative morphology. On the basis 

 of chromosome numbers alone, Crepis may not appear to have 

 had a common origin with Hieracium, Lactuca, Prenanthes, and 

 most of the other genera which have been examined cyto- 



