ARISTIDA | GRAMINEZ 739 
PHLEUM 
clothed with long white hairs 144 lines long, terminating in an awn 2 lines 
long .whicb falls at maturity: palet conical, smooth, hard, brown. On 
sandy plains. Eastern Oregon to California, Texas and Brit. Columbia. 
@. exigua Thurber Bot. Wilkes 481. Stems slender, erect, 6-15 inch- 
-es high, hispid, the nodes black, scarcely constricted: leaves of sterile 
shoots numerous with close striate hispid sheaths and narrow involute 
wiry scabrous blades 4-7 inches long, of the stem usually 4, lower 2 with 
short overlapping sheaths and blades like the radical ones, next sheath 
above much shorter than the internodes with blades 2-4 inches long: 
ligules acute, 1-2 lines long: panicle narrow, secund, 2-3 inches long, ‘its 
branches usually ip pairs, erect: unequal: empty glumes oblong-ovate, 
barely acute, or abruptly acuminate, membranous, minutely scabrous, 
equal, 2-214 lines long flowering glumes herbaceous, becomiug chartaceous, 
obtuse or with purple teeth at the apex, short-pubescent throughout, 5 
nerved. the nerves united above: awn persistent, minutely hispid, 2-3 lines 
long: palet equalling the glume, obtuse or bidentate at the apex. In the 
mountains of Oregon and Washington. 
0. Hendersoni Vasey Contrib. U. S. Nat. Herb. 7, 267. Stems 
densely tufted, 7-10 inches high: lower sheaths rather loose: leaves scab - 
rous, conduplicate, rigid pungent 4-5 inches long: panicle narrow 24g-4 
inches long, its branches mostly in twos, the longest 114-24 inches long 
bearing 2-4 spikelets near the ends: empty glumes broadly oblong, obtuse 
and toothed, the first 3-nerved, the second 5-nerved : flowering glume linear, 
oblong, 2 lines long, smooth, coriaceous, obscurely 5-nerved, bearing 2 lateral 
teeth : awn curved, caducous, 5-6 lines long. Washington. 
23 ARISTIDA L. Sp. 82. 
Annual or perennial grasses with narrow leaves and various 
inflorescence. Spikelets narrow, one-flowered. Glumes 3, narrow, 
the 2 otter empty, carinate, the third rigid and convolute, bearing 3 
awns, sometimes united at hase, the lateral ones rarely wanting 
or reduced to rudiments. Palet 2-nerved. Stamens 3. Styles 
distinct. Stigmas plumose. Grain free, tightly enclosed in the 
glume. 
A. purpurea Nutt. Trans. Am, Phil. Soc. (II) v, 145. Stems slen- 
der, tufted, erect, nearly smooth, 1-2 feet high: lower leaves with narrow 
close sheaths and slender involute blades 4-10 inches long: lower sheaths 
_Jonger than the internodes, the upper ones much shorter: ligules a line 
of fine short hairs: panicle rather loose, narrow, 4-6 inches long, its bran- 
_ ches 2-3 at each node, unequal the lower 1-2 inches long, naked below: 
spikelets 5-6 lines long, first glume narrowly lanceolate-linear, emargin- 
ate, mucronate, hispid on the keel, 1-nerved, 4-5 lines long; the second 
similar but nearly 2 lines longer, stipe hairy: flowering glume linear-lan- 
ceolate, recurved, slightly hispid on the nerves above, 4 lines long, termina- 
ing in 3 separate slender awns 1-2 inches long: palet obovate, thin, about 
24 line long. On prairies and ridges, eastern Washington to Brit. Colum- 
bia, Idaho and Texas. . 
A. oligantha Michx. Fl i, 41.. Glabrous annual: stems slender, 1-2 
feet high, erect, dichotomously branched, smooth or roughish: sheaths 
loose, longer than the internodes: ligules very short, minutely ciliate: 
leaves 1-6 inches long, 4-1 line wide, smooth, the larger ones attenuate 
into a long slender point: spikelets few, borne in a lax spike-like panicle: 
first glume 5-nerved, an inch long, attenuate or short-awned equalling or 
shorter than the second which bears an awn 2-4 lines long: flowering 
glume shorter than the first one, bearing 3 slender divergent or spreading 
awns, the middle one 1-3 inches long, the lateral ones somewhat shorter. 
