366 



OENOTHERA RUBRINERVIS, A HALF MUTANT. 



deserens and mut. velutina. The latter has been described under the 

 synonym 0. blandina. I made the following combinations: 



Cross 



Year 



Number 

 of plants 



Percentage of 



lucida subrobusta velutina 



O. deserens x Lamarckiana 

 O. rubrinervis x blandina . 

 O. blandina xrubrinervis . 

 O. deserens x blandina . . . 

 O. blandina x deserens ... 



1915 

 1915 

 1913 

 1915 

 1915 



49 

 70 

 70 

 70 

 49 



18 

 

 

 

 



82 



50 



53 



100 



100 







50 



47 











The expectation for these crosses was: 



O. deserens x Lamarckiana=0. deserens x(typ.+ velutina)=lucida-f subro- 

 busta 



O. blandina x rubrinervis=0. blandina x (deserens -f- ve!utina)=subrobusta-f 

 velutina 



O. blandina xdeserens=0. blandina x(deserens)= subrobusta 



Apart from the figure for lucida, which is too small, the results 

 of the experiments directly confirm the expectation. I have deter- 

 mined the amount of empty seeds for the four last named crosses, 

 and found almost none: 



Cross Percentage of 



germs in seeds 



O. rubrinervis x blandina 97 



O. blandina xrubrinervis 91 



O. deserens x blandina 100 



O. blandina x deserens 90 



Moreover, I made the same determinations for the hybrids from 

 the two first named of these crosses, self-fertilizing them in 1916. 

 For the two latter crosses it was evident that the hybrids would 

 hardly have any empty grains, and I did not think it necessary to 

 control this. 



