— ~s  e! T 
DANTHONIA GRAMINEA® 743 
AVENA 
stems slender 1-2 feet high: leaves of sterile shoots with crowded sheaths 
and narrow involute blades, sparsely pilose to glabrous, 4-12 inches long: 
sheaths of the stem shorter than the internodes, more or less pilose: 
ligules short, ciliate: inflorescence a short spicate panicle of 3-12 erect 
Spikelets: empty glumes lanceolate, acute or acuminate, keeled, smooth, 
4-5 lines long, exceeding the flowering glumes which are broadly lanceolate, 
2-3 lines long, acutish, 2-toothed, the awn more or less bent and twisted, 
4-6 lines long. On low prairies, eastern Washington to southern California 
Montana and Canada. 
Var. Cusickii Williams. Larger: leaves longer flatter, softer, less 
scabrous, quite destitute of pubescence, rather large spikelets and usually 
more open panicle. In the Blue Mountains of Oregon. 
D. unispicata Munro. Stems loosely tufted, 6-12 inches.high: sheaths 
shorter than the internodes, or the lower ones longer, pubescent with long 
white hairs: ligules very short or reduced to a row of white hairs: leaves 
flat or more or less involute with acuminate tips, 2-4 inches long, more or 
less pubescent: inflorescence a single terminal spikelet: empty glumes lan- 
ceolate, long-acuminate, exceeding the upper flowering one, glabrous, 6-12 
lines long: flowering glumes lanceolate, acute, 4-5 lines long, termina- 
ting in 2 usually dark-colored awns, ciliate on the margins: central awn 
twisted and bent below the middle, about 6lines long. In partially barren 
places, eastern Washington to California. 
D. Americana Scribn. U. S. Dept. Agr. Cir. 30,5. A slender dense- 
ly cespitose perennial 8-16 inches high, with short slightly inflated sheaths, 
narrow mostly involute leaves and simple panicles of 1=4 large spikelets: 
sheaths much shorter than the internodes, pubescent, at least the lower 
ones long-bearded at the throat: empty glumes acuminate-lanceolate the 
narrowed apex obtuse, 6-9 lines long, as long as or slightly exceeding the 
flowers: flowering glumes 5-4 lines long, rounded and glabrous on the back, 
densely silky villous on the margins from just above the base to’a little 
above the middle, abruptly 2-toothed, the teeth very slender bristles 2-3 
lines long: awn very slender twisted below, 3-5 lines long. Brit. Columbia 
to California and Chile. ihe 
27 AVENA L. 8p. 76. 
Annual or perennial grasses with usually flat leaves and num- 
erous spikelets in panicles. Spikelets one- to several-flowered, 
the lower flowers perfect, the upper often staminate or imperfect. . 
Glumes 3 to several the 2 outer empty, somewhat unequal, mem- 
branous, persistent. Flowering glumes deciduous, rounded on 
the back, acute, generally bearing a dorsal awn, the apex often 
2-toothed. Palet narrow, 2-toothed. Stamens 8. Styles short, 
distinct, with plumose stigmas. Grain oblong, deeply furrowed, 
-enclosed in the glume and palet, free or sometimes attached to 
the palet. 
A. Fatua L. Sp. 80. Stems stout, 1-4 feet high, erect, smooth: sheaths, 
smooth, or scabrous at the summit, sometimes sparingly hirsute, the lower 
often longer than the internodes: ligules 1-2 lines long: leaves 3-8 inches 
long, 1-4 lines wide: panicle open 4-12 inches long, the. branches ascend- 
ing : spikelets 2-4 flowered, drooping: empty glumes 9-12 lines long, smooth, 
flowering glumes 6-9 lines long, with a ring of stiff brown hairs at base, 
pubescent with long rigid brown hairs, bearing, a long bent and twisted 
awn. In fields and waste places: naturalized from Europe. 
VAR. GLABRESCENS Coss. Stems stout, pale, 144-21 feet high: sheaths 
equalling the internodes: leaves flat, 4-6 inches wide: flowering glumes 
