1915] BARTLETTI—MUTATION IN OENOTHERA 99 
whether or not mut. mummularia is really as nearly self-sterile as 
this comparison would indicate. At any rate, only 403 seeds, 
many of them obviously too unripe to germinate, were obtained 
from 3 plants of the mutation. The seeds have given an F; progeny 
of 135 plants which is now (April 1914) in the early seedling stage. 
The F; generation from mut. nummularia consists in part of 
plants which exactly reproduce the parental type and in part of 
secondary mutations. At the time: this article is being written 
the plants are still young, but it is nevertheless clear (1) that the 
Fic. 8.—Flowers and buds of (a) Oenothera pratincola mut. nummularia, and 
(0) typical 0. pratincola, showing especially the difference in the rupture of the calyx. 
F, generation includes no typical O. pratincola; (2) that the second- 
ary mutations (with one possible exception) are narrower leaved 
than O. pratincola and therefore even more sharply distinguished 
from mut. nwmmularia than the latter is from O. pratincola; and 
(3) that all of the secondary mutations (again with the single excep- 
tion noted above) appear to be quite identical with certain primary 
mutations which have appeared simultaneously with mut. num- 
mularia in various cultures of typical O. pratincola. 
The secondary mutations fall into three well marked groups 
which have been called mut. tortuosa, mut. rubricentra, and mut. 
