1918] DEVRIES—MASS MUTATIONS 305 
hybrids of ochracea X Cockerelli had broad leaves (6-7 cm.) and were 
stout green plants, whereas those of the reciprocal cross were still 
pale. I compared them with the hybrids of O. grandifloraxX 
Cockerelli and with those of O. grandiflora loreaXCockerelli which 
grew quite near to them. In the beginning of August they began to 
flower and almost all of the plants of both cultures reached this 
phase before the end of the month, reaching a height of 1.50 m. 
They were uniform groups and in all respects like the laeta of the 
corresponding crosses, with the exception of the paleness of one of 
the two sets; but this diminished gradually as the summer 
advanced. The leaves and bracts of the inflorescence were still 
very broad and flat. There were no specimens like the velutina 
of the crosses with O. grandiflora and O. lorea. 
C. UNIFORM HYBRIDS 
O. grandifloraXO. syrticola—The hybrids derived from the 
pollen of O. syrticola (O. muricata) have often the type described 
as gracilis in my Gruppenweise Artbildung. This is especially the 
case with those of O. Lamarckiana, and the hybrids to be described 
here simply duplicate these latter. I made the cross twice, in 
1913 and 1914, and had the first generations of 80 and 30 plants in 
1914 and 1915. From the latter I derived a second generation from 
two self-fertilized individuals of the first. They were uniform lots 
when they flowered, embracing 7 and 44 specimens with the slender 
stature and characteristic foliage and stature of gracilis, but many 
seedlings had been yellow and died before making their leaves, 
exactly as in the first generation. In this the uniformity of the 
type was already evident in the beginning of June, before the full 
development of the stems, by the brownish color of the stems and 
foliage and the narrow, almost linear, leaves. The resemblance to 
O. biennis Xsyrticola increased during the growth of the stems and 
the development of the spikes. At the time of flowering the plants 
measured only 80-120 cm.; their top was curved sideward as in 
O. syrticola; the flowers were small and 3-5 of them opened every 
evening; lobes of the stigma short and thick; leaves narrow, slightly 
kennel-shaped, and bluish green. It is easily seen that the charac- 
ters of the father prevailed in the hybrid. 
