Shull 



Plate I 



Fig. 1. Bursa bursa-pastoris heteris. Dominant form from the F 2 of an artificial cross of B. bp. 



heteris X tenuis. The grandparents were sibs of the plants shown in text-figures 4 and 9. 



Fig. 2. Bursa bursa-pastoris tenuis. Recessive form from the same family as the plant shown in 

 figure 1 . 



