INHERITANCE OF SEX IN LYCHNIS 1 



GEORGE HARRISON SHULL 



(WITH TWO FIGURES) 



Since CORRENS (4) made his brilliant investigations with Bryonia, 

 in which he showed that crosses between the monoecious B. alba 

 and the two sexes of the dioecious B. dioica do not give equiva- 

 lent results in regard to the sex of the offspring, and since DON- 

 CASTER and RAYNOR (6) published their equally interesting studies 

 with the currant moth, Abraxas grossulariata, and its variety 

 lacticolor, in which it was found that reciprocal crosses were not equal 

 with respect to sex, but that the Mendelian color character of the 

 variety lacticolor is sex-limited, the interest of all students of genetics 

 has been more or less strongly directed toward the problems of sex 

 inheritance, and toward the attempt to describe or explain the heredity 

 of sex on the basis of Mendelian inheritance. 



It has been of great interest to find that these two classic cases of 

 Bryonia and Abraxas apparently lead to opposite conclusions as to 

 which sex determines the sex of the offspring, but both seem to favor 

 the conception that one sex is homozygous with respect to sex, and 

 the other heterozygous. BATESON (i) attempts to make the results 

 with Bryonia agree with those in Abraxas, but his interpretation is 

 certainly not as simple as that of CORRENS. BATESON'S explanation 

 would require that Bryonia alba be gynodioecious, having larger 

 numbers of pure females than of monoecists, instead of being 

 wholly monoecious as described in the manuals. It does not seem 

 likely that so striking a relation as this would have been over- 

 looked by the taxonomists. Moreover, in the attempt to bring 

 harmony between -Bryonia and Abraxas, BATESON introduces fully 

 as fundamental inharmony between the two species of Bryonia, when 

 he assumes that the males of B. dioica are pure males with pollen 

 bearing only the male character, while the pollen of B. alba is all 

 female. Certainly we are justified in expecting a more complete 



1 Read by invitation before the American Society of Naturalists, Boston, Decem- 

 ber 28, 1909. 



Botanical Gazette, vol. 49] [no 



