498 



University of California Publications in Botany [Vol. 5 



In this cross, corolla color behaved in exactly the same manner as 

 it did in the angustifolia-macrophylla series. The same remarks as 

 to sharpness of segregation apply here as in that series. Red was 

 nearly always readily distinguishable, but pink and light pink formed 

 a more or less completely intergrading series. Taking the results in 

 this way, we obtain 23 red ; 73 pink and light pink, which is substan- 

 tially in accord with Mendelian expectations. 



TABLE 9 



F2 SEGREGATION IN CALYCINA-VIRGINICA SERIES. 



With respect to corolla form some difficulty was encountered be- 

 cause the expression of the hose-in-hose character in the segregants 

 did not seem to be so extreme as it was in the parent, and a large 

 number of the plants showed slight traces of it, but sometimes in a 

 more pronounced form than in the F^ hybrids. Accordingly the classi- 

 fication of corolla form in table 8 is not a wholly satisfactory one. 



The classification for stature and leaf width is subject to similar 

 remarks as to its definiteness. Here there was also a more or less 

 completely intergrading series of forms and no accurate measurements 

 were taken. However, there is no doubt that there was segregation 

 with respect to these characters, and a range of forms was obtained 

 which completely bridged the gap between the parents. The behavior 

 of these characters is to be considered in the light of their segregation 

 in subsequent generations. 



In 1916 four additional Fo populations of the calycina-virginica 

 series w^ere grown in order to reexamine populations for the segrega- 

 tion of normal versus hose-in-hose flowers, and red versus pink flower 

 color. The method of classifying the flowers was that used in studies 

 of 1916 populations previously mentioned. The results of these studies 

 are given in table 9. 



