1915] BARTLETT—MASS MUTATION 449 
mutations. As in the case of progenies from f. typica, mut. angusti- 
folia, and mut. latifolia, the predominating form among the muta- 
tions was mut. setacea. 
and 187 
cauline plants, Sieg E-5-196 — 
4 
t.—Mut. albicans: 2 
pee ert the F, progeny of f. typica; no. 187 is shown also in fig 
Mut. albicans.—This mutation reproduces itself in only a small 
proportion of its progeny, but can be said to come true in the sense 
