iQoS] SHULL^MENDELIAN INHERITANCE 115 



summer of 1Q06. The 



results then stood as follows : 



- No. 0446, y X y, 75( ?) y 



No. 0447, w X w, 53 w 



No. 0448 X 47, w X y, 8 y 



No. 0448 X self, y X y, ( ?) y (number unrecorded) 



Among the members of these families all possible combinations 

 were again made. The offspring of these crosses were mostly induced 

 to bloom the first season by starting early and giving the seedlings 

 the best possible conditions. The results of the second generation 

 were thus secured during the summer of 1907, and showed the follow- 

 ing composition: 



No. 06241, D X R, 



26 y 



Expected, 



26 V 



No. 06244, DR X DR, 



5y: 7w 



Expected, 



9y: 3W 



No. 06243, R X DR, 



13 y:i8\v 



No. 06245, J^R X R, 



5y: 8w 



Total, 



18 y: 26 w 



Expected, 



22y:22 w 



No. 06242, R X R, 



90 w 



Expected, 



90 w 



Although some of these ratios depart rather strongly from the 

 theoretical limiting ratio, this is due entirely to the small numbers of 

 obser\'ations, as pointed out above in the discussion of Lychnis. It 

 is plain therefore that the color-forms of Verbascum Blattaria consti- 

 tute a :Mendelian pair, and that the bright yellow is dominant over 

 the pale. The dominance of yellow in this cross is just the reverse 

 of the behavior of yellow in Polemonium and Matthiola, and teaches 

 that there are two kinds of yellows in plants, one of which is dominant 

 to white, the other recessive to white. A microscopic examination 

 of the petals of Verbascum shows that BA^ES0^-'s3 distinction between 

 plastid-colors and sap-colors is probably fxmdamental, as the }t11ow 

 color in this species proves to be a sap-color, and its behavior in com- 

 binations with white is the same as that of the blue, purple, and red 



3 Loc. cit. 



