2i is 



THE AMERICAN NATURALIST [Vol. XL V 



The cultures of 1910 in the F, generation were hybrids 

 of three different combinations of parents, as follows: 



1. grandiflora B X biennis A (10.30), grown at the 

 Bussey Institution. 



2. grandiflora B X biennis B (10.18) and the recip- 

 rocal cross (10.19), grown at the Bussey Institution. 



3. grandiflora A X biennis B (10.17) and its recip- 

 rocal cross (10.20), grown at the Botanic Garden of Har- 



Bearing in mind that the biennis strains A and B are 

 practically indistinguishable and that the grandiflora 

 strains A and B are essentially similar, the cultures as 

 a whole would not he expected to differ markedly, which 

 was the case. 



The figures of hybrids published with this paper are 

 from two plants in the first culture (grandiflora B X 



