1924] 



Collins: Inheritance in Crepis capillaris (L,) Wallr. 



261 



Plants of these two races when crossed showed almost the entire group 

 of H6 characters (rib hairs excepted) in the F^, while in<Fo (21.141) 

 there appeared the parental types and in addition some composite 

 types that showed some characters from each parent. When each 

 character pair was considered separately-, however, a peculiar sit- 

 uation was presented. Six of the character pairs gave 9 to 7 ratios, 

 and a seventh pair, rib hairs vs. smooth ribs, gave a 15 to 1 ratio. 

 The data for these characters are included in table 7. It is quite 

 probable that these six character pairs as given are the result of not 

 more than three sets of genes, since the two characters, black edging 

 of the leaves and anthocyanin of the midribs, are both concerned with 

 the distribution of anthocyanin pigment in the plant. The shape of 

 the terminal and of the lateral lobes is probably conditioned by the 

 same pairs of genes, while the crimping of the wing of the midrib 

 and the constriction of the base of the lobes also probably result from 

 the action of the same gene. The Berkeley plants were evidently 

 homozygous for the dominant complementary genes of all three 

 character couples. This genotype may be expressed as AA'BB'CC, 

 the simultaneous presence of both the primed and unprimed dominant 

 genes being necessary to cause the development of the respective 

 characters. The Eureka race w^ould then have the genotype aa'bb'cc' 

 wdth respect to these characters. 



TABLE 7 



Segregation of Six Pairs of Characters in the Fo from the Cross 

 H6 X ScALARis e28. (Culture 21.141) 



Segregation 



162 black edge : 103 green edge 



166 anthocyanin : 109 none 



142 angular lobes : 112 round 



150 narrow lobes : 104 broad lobes 



135 constricted lobes : 118 non-constricted 

 165 crimped wing : 101 flat wing 



REVOLUTE (r) 



Plate 47, figure 2 

 This race appeared in 1919 among offspring of a plant of the 

 Eureka stock, which had been self -pollinated. The plants are char- 

 acterized by a definite downward curling of the edge of the leaf 



