Studies on the Variability and Heritability of Pigmentation in Oenothera. 363 
F, (total 126 plants) O. Lamarckiana and O. rubricalyx. Since many 
of them remained rosettes, it is possible that some O. rubrinervis also 
occurred in the F,. But this point will have to be settled later. 
Fig. 5. O rubricalyx. O. rubricalyx and O. rubrinervis (Fig. 4) are identical in size 
and every other morphological character, but fig. 4 happens to have been a little 
farther from the camera. 
DE VRIES has shown (and in certain cases I have confirmed the 
result) that crosses between certain of the mutants produce in the 
F,, O. Lamarckiana in addition to one or both of the parent types. 
Similarly, I have found that O. rubricalyx = O. nanella gave in the 
