12 BOTANICAL GAZETTE [january 



not find any differences. The descriptions for the deserens laeta are 

 exactly the same as those given previously for the Lamarckiana 

 laeta. Although I have not made the cross O. syrticolaXO. rubri- 

 nervis, I have added the second experiment of the table. From 

 this and the result of O. syrticolaXO. blandina (mut. velutina) 

 described in my former article the result of the cross O. syrticola X 

 rubrinervis may be predicted, and so it would be in other cases 

 also. 



Summing up the results of these experiments, we see that in pro- 

 ducing twin hybrids O. rubrinervis is split in exactly the same way as 

 an artificial mixture of about equal parts of gametes of O. deserens 

 and O. mut. velutina would be. The conclusion that its gametes 

 really possess this dimorphy is thereby as clearly proven as might 

 be expected. 



Crosses of O. rubrinervis with O. Lamarckiana and its 

 DERIVATIVES. — In Gruppenweise Arthildung I have described the 

 first generation of these crosses as consisting of two types, O. La- 

 marckiana and 0. hybr. subrobusta. The latter is a rubrinervis in 

 which the brittleness fails, and thereby very similar to our new mut. 

 erythrina;'^ but this similarity is only an external one, since after 

 self-fertilization the hybrid subrobusta splits off, as a rule, brittle 

 rubrinervis plants, whereas the erythrina produces the decipiens, 

 which is not brittle. Shortly after publishing my book, however, 

 I discovered in the summer of 1 913, among the progeny of a cross of 

 O. rubrinervis and O. Lamarckiana, a slight difference among the 

 Lamar ckiana-like plants. Some of them were stouter and had 

 broader and less crinkled leaves than the others. I self-fertilized 

 them and got a culture, which, although not uniform, repeated the 

 deviating marks of the parental type in the majority of the indi- 

 viduals. I shall call this hybrid t}^e lucida. Moreover, in making 

 a large number of crosses of individuals of the same family of rub- 

 rinervis with Lamarckiana plants from various sources, as well as 

 different mutant strains, I discovered that the second hybrid type 

 is not always the solid subrobusta, but sometimes the brittle rubri- 

 nervis. I have not as yet discovered why this should be so. We 

 should expect the brittleness to be recessive to the production of 



'Zeitschr. f. Ind. Abst. 16:262. 1916. 



