1918] DEVRIES—MASS MUTATIONS 393 
culture for the Jaefa. In this the types were exactly the same as in 
the previous year. There were 57 /aeta and 12 velutina, as counted 
in July, when the differences were most sharp. 
O. grandiflora lorea XO. Cockerelli.—Apart from the appearance 
of a few individuals of the Jorea type, this cross gives the same result 
as the analogous cross of the species itself, and the hybrids are just 
the same, not showing the least influence of the almost linear leaves 
of the mutant mother. I made the cross twice, in 1914 and 191s. 
The first one gave 80 specimens with 60 per cent laeta and 4o per 
cent velutina, but without lJorea.. The second gave 81 flowering 
plants, among which 23 were /aefa and 58 velutina. Two weak 
specimens had the leaves of O. grandiflora lorea. If we wish to 
explain their occurrence we must, perhaps, take into consideration 
that in culture of hybrids of O. Cockerelli with other species weak 
specimens with linear leaves are seen from time to time. In the 
second generation I expected to find some specimens of /orea, but 
only one appeared among the Jaeta. The culture embraced 64 
plants, with 49 laeta and 14 velutina. also derived a second genera- 
tion from the velutina of the first; it had the same number of speci- 
mens, all of which flowered, but they were wholly uniform and like 
those just described. 
O. grandiflora XO. biennis Chicago (cross of 1913).—First genera- 
tion in 1915 with 4o flowering specimens, among which 12 were 
weaker than the others from the very beginning, and proved in 
August, when they flowered, to belong to the type of velutina, hav- 
ing narrower leaves. There were still some doubts concerning this 
identification, but they disappeared when the second generations 
were cultivated in 1916. These embraced the offspring of two 
Specimens of Jaeta, each consisting of 70 flowering plants, and that 
of two velutina, with 47 and 60 specimens. 
The differences were evident by May, since the leaves were 
broad and clear green in the /aefa, but narrower and darker in the 
velutina. The velutina were quite uniform, but among both groups 
of laeta some specimens showed the broad leaves, pale color, and 
low stature of the mut. ochracea (7 and 12 specimens). The two 
main types were both intermediate between their parents and much 
resembled the corresponding twins of O. Lamarckiana x Chicago. 
