1923] Bau: Morphological Characters in Crepis Capillaris 237 



8. Number of lobes per leaf is constant for any given race of plants 

 and the character is determined by four sets of factors: 

 (a) The group of factors for presence of lobes. 

 (h) The group of factors for depth of the incisions. 



(c) The group of factors for number of lobes. 



(d) The group of factors for extension by which the secondary 



lobules are developed into lobes. 

 9. Of these the group of factors for number of lobes consists of 

 at least four interacting factors. The F^ in these crosses was found 

 to be intermediate and F, showed segregation. 



10, Races of Crepis capillaris with different diameters of capitula 

 were isolated and when crosses were made between such races the 

 diameter of the capitula of F^ was found to be intermediate between 

 the two parents. The work has not progressed far enough to study the 

 Fo plants and determine the type of segregation, 



11, As far as studied, environment, except moisture, has very little 

 influence on the size of capitula. 



LITERATURE CITED 

 Babcock, E. B. 



1920. Crepis, a promising genus for genetic investigations. Am. Naturalist, 

 vol. 54, pp. 270-276. 

 Babcock, E. B. and Collins, J. L. 



1920. Interspecific hybrids in Crepis. I. C. capillaris (L) Wallr. X C 



tectorum L. Univ. of Calif. Publ. in Agr. Sci., vol. 2, pp. 191-204. 

 Beer, Eudolf 



1912. Studies in spore development, 2. Annals of Botany, vol. 26, pp. 

 705-726. 

 Castle, W. E. 



1921a. On a method of estimating the number of genetic factors in cases 

 of blending inheritance. Science, n.s., vol. 54, pp. 93-96. 

 Castle, W. E. 



1921fe. An improved method of estimating the number of genetic factors 

 concerned in cases of blended inheritance. Science, n.s., vol. 

 54, p. 225. 

 Clausen, E. E. and Goodspeed, T. H. 



1921. Inheritance in Nicotiana tahacum II. On the existence of genetically 



distinct red-flowering varieties. Am. Naturalist, vol. 55, pp. 

 328-334. 

 Collins, J. L. 



1920. Inbreeding and crossbreeding in Crepis capillaris (L) Wallr. Univ. 

 Calif. Publ. Agr. Sci., vol. 2, pp. 205-216. 

 DiGBY, L. 



1914. A critical study of the cytology of Crepis virens. Archiv f. Zell- 

 forsch., Bd. 12, pp. 97-146. 

 East, E. M. 



1916, Studies on size inheritance in Nicotiana. Genetics, vol. 1, pp. 

 164-176, 



