450 



THE AMERICAN NATURALIST 



[Vol. XLVII 



of when this plant is discussed. Lamarckiana then, like 

 many species, has its minor strains which may be iso- 

 lated. 



Heribert-Nilsson ('12) in his recent extended analyt- 

 ical studies on CE. Lamarckiana reaches the same con- 

 clusion that Lamarckiana is not a simple species but, on 

 the contrary, polymorphic. His investigations are the 

 first serious attempts to bring forward evidence that will 

 explain the ''mutants" and minor varieties as deriva- 

 tives from a hybrid through the segregation and recom- 

 bination of characters on Mendelian principles. These 

 studies form a very important contribution to the re- 

 search upon this interesting plant. 



I have not as yet among my hybrids of biennis and 

 grandiflora obtained any plant that matches in all re- 

 spects any one of the biotypes of Lamarckiana. On the 

 other hand, there is, I believe, no important character of 

 taxonomic value presented by Lamarckiana through its 

 various biotypes that has not appeared in some of my 

 hybrids. I have, as it were, surrounded the group of 

 biotypes, which we call the species Lamarckiana, with a 

 circle of hybrids that in various characters agree with 

 the plants that have come down to us through the cul- 

 tures of De Vries. If the group of biotypes of Lamarck- 

 iana is enlarged to include certain of its so-called 

 ''mutants" the number of my hybrids with points of 

 resemblance to this larger assemblage is correspondingly 

 increased. 



My studies have now reached a stage where I have data 

 to present on the behavior of hybrids between biennis 

 and grandiflora in the F 2 and F 3 generations. These 

 later hybrids have a two-fold interest ; first with respect 

 to their possible interpretation in relation to Mendelian 

 principles of inheritance, and second, with respect to the 

 behavior of certain types in the F 2 generation, which 

 types repeat in the F, the history of the F 1 parent 

 hybrid in throwing the same marked variants, and thus 

 exhibit a behavior similar to that of Lamarckiana when 



