132 
W. C. Etheridge 
leaves colored as the sheaths, narrow, margins glabrous; panicles equi- 
lateral, wide-spreading, lax, drooping, the branches drooping from the 
middle outward; spikelets 2-3-grained, although the inner and middle 
grains often drop at maturity; glumes light green and barely glaucous 
at period of full heading, 20-25 mm. long, usually 9-nerved; grains black, 
brown, yellow, or gray, elongate; awn present on all grains, twisted and 
geniculate; lemma covered with long, stiff hairs; basal hairs present in a 
bushy ring; rhachilla covered with hairs; basilar articulation of the grains 
distinct, all grains of the spikelet readily separating from their axes. 
Plants 8-12 dm. tall; medium late in maturing. (Plate I, 2, and fig. 12.) 
A form of A. fatua transitional between the wild and the cultivated 
species is found in A. fatua glabrata, received from the Office of Cereal 
Investigations, United States Department of Agriculture. In this form 
the basilar articulation of the grains is much reduced, although still dis- 
tinct. The grains are of three colors — black, yellow, and gray (Plate 
X); the lemma is usually glabrous and the basal hairs are much reduced; 
the awn is as strong as in the wild form, although frequently wanting 
on the inner grains of the black and the gray type ; and the rhachilla is 
haired in the yellow type, but usually glabrous in the black and 
the gray. 
AVENA SATIVA 
Avena sativa and Avena sativa orientalis, the two groups that include 
the great majority of cultivated varieties, are distinguished from the 
foregoing groups by a combination of the following characters: (1) the 
close investment of the kernel by the hull, as contrasted with the loose 
kernel of A. nuda; (2) the single, more or less abrupt, point of the lemma, 
as compared with the toothed or awn-pointed lemma of A. brevis, A. stri- 
gosa, and A. abyssinica; and (3) the easy separation of the upper grains 
from their rhachillas, and the solidified articulation of the lower grain, 
as compared with the persistent upper grains and the slightly articulate 
lower grain of the cultivated forms of A. sterilis. (Plates II, 2, and III, 1.) 
The A. sativa and A. sativa orientalis groups differ specifically only by 
the unilateral form of panicle of the latter group. There is another char- 
acter, the non-ligulate and non-auriculate leaf occurring within the A. 
sativa orientalis group, which is not found among varieties of A. sativa; 
but this is not a group characteristic, as it occurs only in a few varieties. 
Other characters, such as the abnormal node, previously discussed, 
