306 BOTANICAL GAZETTE [aay 
O. grandiflora XO. biennis.—This combination corresponds to 
the cross O. Lamarckiana X biennis, which gives uniform hybrids of a 
type in which the characters of the male parent largely dominate; 
but the results are very different, as we shall presently see. 
The two parents of the cross have both a large supply of good 
seeds. The character of O. Lamarckiana to produce at least one- 
half of empty grains is not present in either of them. There is no 
reason to expect this phenomenon among their crossed seeds, there- 
fore, and as a matter of fact I counted 85 good germs in 100 seeds 
from this cross; whereas the reciprocal cross, which produces the 
laeta and velutina as we have seen, had 79 germs in too seeds. The 
figures do not essentially differ.‘ 
I made the cross in 1914, and in 1915 had a set of 54 plants, 
among which 45, or 83 per cent, resembled their pollen parent in 
almost all respects, whereas 9, or 17 per cent, repeated the marks 
described for the mut. ochracea. All of the latter and the larger 
part of the former flowered in August. In the biennis type the 
leaves were narrower (3.011 cm.), with reddish midveins; whereas 
the ochracea had the ordinary broad leaves (3.5 X11 cm.) and white 
veins. The stature of the biennis exceeded that of the ochracea in 
July by 10-20 cm. (60 cm. as compared with 40-50 cm.). During 
August these differences gradually increased and the spikes with 
ripening fruits were compact in the one and loose in the other type, 
corresponding to those of the pollen parent and of the mutant. The 
hybrids of the biennis type became at the end very stout, reaching 
almost twice the height of the ochracea plants. In 1916 I cultivated 
a second generation from each of the two types, embracing 70 and 
51 specimens, most of which flowered. The offspring of the biennts 
plants were a uniform lot, exactly repeating the characters of their 
parent; those of the ochracea were dimorphic. Some plants made 
first a rosette of large radical leaves and from this produced a stout 
stem, whereas the others did not produce a rosette, but at once 
grew up, causing the stems to be thin and weak. It should be men- 
tioned that the initial rosettes are a character of biennis, whereas 
4 My determinations gave, as a mean from 7 countings of lots of 200 seeds each, 
75-76 per cent of seeds with normal germs for the cross O. Lamarckiana X biennis 
(see 4, p. 268). 
