POA GRAMINE^E 763 



bia and North Dakota. 



P. laevigata Scribn. P. Ixvis Vasey, not Barb, Stems tufted, pale, 

 slender, erect, smooth, 2-3 feet high, with 2 or 3 distant leaves; sheaths 

 smooth : ligules acute : leaves of sterile shoots narrow, 5-8 inches long, 

 those of the stem shorter : panicle narrow, rather loose 4-8 inches long, 

 sometimes interrupted below, its branches erect or appressed the lower in 

 twos or threes, unequal, the longest 1-2 inches long: spikelets linear, 3-5 

 lines long, about 5- flowered : empty glumes nearly equal, linear-lanceolate, 

 acute, thin, pale and scarious except on the minuetly scabrous midrib: 

 flowering glumes 2-2% lines long, linear-oblong, subacute,5 nerved, minute- 

 ly scabrous, slightly pubescent on the keel and marginal nerves near the 

 base, the apex scabrous and yellowish-tinged in age, somewhat erose : palets 

 equalling the glumes, scabrous on the keels. Eastern Washington to 

 Brit. Columbia, Montana and Arizona. 



P. longilignla Scribn. U. S. Dept. Agr. Div. Agrost. Cir. 9, 3. A 

 cespitose glaucous perennial : stems rather stiff, 16-20 inches high: basal 

 sheaths persistent and rather crowded : ligules conspicuous, 2-5 lines long : 

 leaves of sterile shoots erect or spreading, usually 6-10 inches long, flat or 

 conduplicate, with conspicuous decurrent ligules : cauline leaves shorter, the 

 upper ones sometimes reduced to a mere mucro, all rather rigid and mucron- 

 ate-pointed : panicle ovate in outline, 3-5 inches long, its lower branches 1-2 

 inches long : spikelets compressed, ovate-lanceolate, rather acute, 4-6-flow- 

 ered, 3-6 lines long: empty glumes unequal, more or less rough-hispid on 

 the back, the lower lanceolate, acute or acuminate, 1-nerved, 3 lines long; 

 the upper much broader, 3-nerved; flowering glumes ovate-oblong, obtuse, 

 5-nerved, more or less scabrous above, woolly-pubescent on the lower half 

 of the keel and marginal nerves, with broad hyaline margins, 2%-3 lines 

 long: palets much shorter than the glumes, hyaline with green hispid- 

 pubescent keels. Oregon to South Dakota and Arizona. 



P. Lettermanl Vasey Contrib. Nat. Herb, i, 273. A dwarf densely 

 tufted perennial: stems 2-4 inches high: sheaths loose, longer than the 

 internodes : ligules rather conspicuous, acute : radical leaves flat, 1-2 inches 

 long, %-l line wide; those of the stem 1 or 2, about 1 inch long: panicle 

 6-12 lines long, oblong, rather dense, its branches mostly in twos, short, 

 erect, with 1-3 spikelets at the extremities : spikelets 1^-2 lines long, 2-4- 

 flowered, purplish: empty glumes nearly as long as the spikelets, oblong- 

 lanceolate, acute, nearly equal, smooth; flowering glumes 1-1 K lines long 

 ovate-oblong, acute, or'subobtuse, obscurely nerved, smooth, scarious at 

 the apex: palet nearly equalling the glume, acutely 2 toothed at the apex. 

 On mount Rainier Washington at 9000 feet altitude, and Gray's peak Col. 



P. Pringlei Scribn. Bull. Torr. Bot. Club x, 31. Stems tufted, 5-10 

 inches high, slender, wiry, with 1 or 2 leaves : ligules conspicuous, 2 lines 

 long: leaves mostly basal, 1-2 inches long, convolute, rigid, those of the 

 stem with very short or nearly obsolete blades : panicle 6-12 lines long, 

 compact, oblong, the few branches mostly in pairs, erect, with 1-2 spikelets 

 each : spikelets 3 lines long, mostly 2-flowered, oblong, turgid, purplish : 

 empty glumes thin, membranous, ovate-lanceolate nearly as long as the 

 florets ; flowering glumes about 3 lines long, oblong-lanceolate, subulate, 

 scarious at the apex, smooth, obscurely 5-nerved, ; palets a little shorter, 

 acutely 2-toothed. On the high mountains, California to Washington. 



P. Leiberg-ii Scribn. U. S. Dept. Agr. Div. Agrost. Bull. 8, 6, t. 11 

 A densely cespitose fibrous-rooted glabrous perennial: stems slender, 2-6 

 inches high, the base clothed with loose scarious sheaths : ligules hyaline, 

 about 1 line long: radical leaves numerous, 1-2 inches long, about % line 

 wide, those ot the stem 6-12 lines long, conduplicate when dry, minutely 

 scabrous along the margins and at the apex, otherwise smooth: panicle 

 simple, of 1-7 spikelets, its lower branches usually in pairs, each branch 



