1918] DEVRIES—MASS MUTATIONS 401 
and measure approximately 4X17 cm. The combination of this 
foliage with the thick stems and branches of O. Lamarckiana con- 
stitutes the most striking mark; the hybrid is obviously interme- 
diate between its parents. The flower buds resemble those of 
Lamarckiana and have a tinge of brown, which is subjected to some 
amount of fluctuating variability. The flowers are large and the 
Fic. 6 
Fie. § 
—Fig. 5, O. grandifloraXO. Lamarckiana mut. nanella: branches of 
eh lobe shortly before flowering; O. ovata (about 50 per cent); L. lutea, and 
B. brunnea (each about 25 per cent of offspring); fig. 6, O. grandifloraXO. Lamarckiana 
mut. nanella: flowering spikes (deprived of flowers just open), showing characteristic 
Position of flower buds; to left, O. hybr. lutea; to right, O. hybr. ovata. 
petals cover one another by the margins, but this mark is also 
variable, and sometimes the petals are seen to have a wedge-shaped 
base. The fruits are stout and of an intermediate form. 
O. hybr. lutea differs little from ovata in form, but its color is 
strikingly yellowish instead of pure green. This is seen in the 
foliage and very evident in the flower buds, but may disappear when 
the season advances. The leaves are almost as large. I measured 
