poa GRAM1NE.E 759 



feet high, smooth or slightly scabrous, from stout creeping perennial root- 

 stocks: sheaths smooth, the lowerones short but exceeding the internodes: 

 ligules obtuse, 1 line long or less, or often nearly obsolete : panicle oblong, 

 1-3 inches long: leaves flat or involute, 2-6 inches long, 1-2 lines wide: 

 panicle 1-3 inches long, its branches hispid, 2-4 at each of the 5-7 nodes, 

 1 inch long or less, nearly erect or somewhat spreading: spikelets rather 

 turgid 3-5-flowered: empty glumes ovate, acute or acutish, smooth, l>£-2 

 lines long: flowering glumes lance-ovate, minutely scabrous, hispid-ciliate 

 on the keel, purple with scarious tips. 5 nerved, 23^-3 lines long: palet 

 oblong, obtuse or retuse, 2 lines long, ciliate on the keels. On the highest 

 peaks of the Cascade Mountains, Washington to California. 



P. pratensis L. Sp. 67. Stems slender, erect, simple, 1-4 feet high, 

 from long running rootstocks : sheaths often longer than the internodes: 

 ligules truncate, % line long, or less : leaves 2-10 inches long, flat or invo- 

 lute l%-3 lines wide : panicle 2-8 inches long, usually pyramidal, its bran- 

 ches spreading or ascending, 1-3 inches long: spikelets 3-5-flowered, 2-2)^ 

 lines long : empty glumes unequal, glabrous, rough on the keel, the lower 

 1-nerved, the upper 3-nerved : flowering glume \% line long, acute, 5-ner- 

 ved, webbed at the base, the marginal nerves and midnerve silky-pubescent 

 below. Common everywhere. 



P. compressa L. Sp. 69. Pale bluish-green and glabrous: stems 6-24 

 inches long, decumbent at base, from long horizontal rootstocks, smooth, 

 much flattened : sheaths loose, mostly shorter than the internodes : ligules 

 % line long: leaves 1-4 inches long, about 1 line wide, smooth, beneath, 

 rough above: panicle usually contracted, its branches erect or ascending, 

 1 inch long or less : spikelets 3-9-flowered, l%-3 lines long : empty glumes 

 acute, 3-nerved; flowering glumes 1-1 l ^ lines long, obscurely 3-nerved, the 

 nerves slightly pubescent toward the base. In fields and waste places: 

 naturalized from Europe. 



P. Wheeleri Vasey Rothr. Pep. Bot. U. S. Surv. vi, 291. Stems 

 10-30 inches high, from perennial running rootstocks : ligules about 1 line 

 long: leaves of sterile shoots 7-10 inches long, 1-2 lines wide, rigid, condu- 

 plicate or involute, with a firm oblique point: panicle open, 4-6 inches 

 long, ovoid, its slender branches mostly in pairs, the longer about 2 inches 

 long, spikelets lance-elliptical, 2-4 lines long, 3-flowered : empty glumes 

 subequal, ovate-lanceolate 3-nerved; the second one 2 lines long; flowering 

 glumes not webbed, 2 lines long, ciliate on the lateral nerves and on the 

 lower part of the keel, oval, subacute, with scarious margins : palets trun- 

 cate very nearly as long as the glumes, ciliate on the keel. Eastern 

 Washington to Colorado. 



P. acutiglumis Scribn. U. S. Dept. Agr. Div. Agrost. Cir. 9, 4. A 

 loosely tufted perennial : stems smooth or somewhat roughened at the 

 nodes, about 2 feet high, sheaths shorter than the internodes: ligules 

 about 2 lines long, often more or less fimbriately divided: stem leaves 2-3, 

 minutely roughened on both sides: panicle ovate in outline, about 4 inches 

 long, its branches in twos or threes, rough-hispid, ascending, the lower 

 ones 1-2)^ inches long: spikelets lanceolate, acute, 5-7 lines long loosely 

 4-7-flowered : empty glumes unequal, hispid on the back, the lower long- 

 acuminate, 3-nerved, the upper lanceolate, acute, more or less distinctly 

 5 nerved. 2 lines long; flowering glumes narrowly oblong-lanceolate, acute, 

 5-nerved, hispid on the back : palets oblong-linear, acute, a little shorter 

 than the glumes, ciliate on the keels. Near Grave Creek, southern Oregon. 



P. epilis Scribn. I.e. A closely cespitose perennial with numerous 

 basal leaves from intravaginal shoots: stems slender, smooth, sheaths most- 

 ly shorter than the internodes: ligules of the stems leaves acute, 1% line 

 long: leaves smooth, flat or convolute, 2-10 inches long, panicle contracted, 

 its smooth branches erect or ascending, 1-2 inches long: spikelets ovate- 



