19221 



SetcheU-Goodspeed-Clausen : Nicotiaua Tahacum 



471 



thrown into the petiolate class if they were distinctly narrowed at the 

 base, and whether naked or winged. 



In Fo, then, there appears to be simple Mendelian inheritance in 

 only one pair of the original character contrasts of the parents, namely, 

 red versus pink corolla color. Here the hybrid is intermediate 

 and Fo segregates sharply into pink and red in the ratio 3 pink : 1 red. 

 Within the pink class there is a more or less evident segregation into 

 2 pink : 1 light pink, but the shades intergrade so that no distinct line 

 of demarcation exists between the classes. As respects leaf base char- 

 acters, the segregation is so complex that no reasonable genetic analysis 

 is possible. The numerical data for this latter character presented in 

 table 1 are of value only in that they indicate a close agreement in 

 segregation among Fo families, thereby furnishing a rough statistical 

 demonstration of the equivalence of the several families. The more 

 definite data on leaf base characters are derived from generations 

 subsequent to F2. 



TABLE 1 



CLASSIFICATION OF F2 PLANTS OF THE ANGUSTIFOLIA-MACROPHYLLA SERIES 

 ACCORDING TO COROLLA COLOR AND LEAF BASE CHARACTERS. 



