756 GRAMINE.E poa 



conduplicate, %-3 inches long, less than 1 line wide: panicle 1-1% inches 

 long, oblong, loosely-flowered, with a pale silvery hue : spikelets oblong- 

 linear, 3-4 lines long, 3-5-flowered: empty glumes s unequal, 2-2% lines long, 

 3-, 4- or 5-nerved, obovate, with shining scarious margins : flowering glumes 

 nearly 3 lines long, oval or ovate, denticulate, 5-7-nerved: palets lanceo- 

 late, about as long as the glumes. On the top of Ashland Butte in the 

 Siskiyou Mountains, Oregon. 



P. macrantha Vasey Bull. Torr. Bot. Club, iv, 11. Stems stout 1 

 smooth, 15-20 inches high, from stout perennial creeping rootstocks? dioe- 

 cious : sheaths loose,, equalling or exceeding the internodes : ligules %M 

 line long : leaves folded or involute, the lower ones with sterile branches in 

 their axils, 6-10 inches long, blunt or abruptly acute at the apex : panicle 

 2-5 inches long, sometimes interrupted below, its branches in twos or threes, 

 erect, the longest l%-2}4 inches long: staminate spikelets 5-8 lines long, 

 compressed, 4-7-flowered, yellowish: empty glumes oblong-lanceolate, the 

 first, 4-5 lines long, 3-*§-nerved, ciliate on the midnerve ; second 4-6 lines 

 long, 3-7-nerved : flowering glumes 4-5 lines long, oval or lanceolate, with 

 soft hairs at base and minutely pubescent on the nerves, the apex notched, 

 awnless, 3-10-nerved : palet but very little shorter than its glume, linear, 

 ciliate on the keels ; pistillate spikelets rather smaller and more compact. 

 On sand-dunes along the coast of Oregon and Washington. 



§ 2 Eupoa Glumes usually acute, more or less prominently 

 carinate, with or without cobwebby hairs at the base of the flow- 

 ering glumes. 



P. annua L. Sp. 68. A soft depressed or sometimes erect annual : 

 stems weak, 2-12 inches long : sheaths shorter than the internodes : ligules 

 1-2 lines long: basal leaver %-% as long as the stem; those of the stems 3, 

 flat or conduplicate, abruptly acute, the upper %-2 inches long: panicle 

 ovoid or pyramidal, subsecund, 1-3 inches long, its branches mostly in pairSj 

 the longest 1-2 inches long, sometimes drooping: spikelets 2-3 lines long', 

 3-7-flowered, oval or ovate-lanceolate : empty glumes compressed ; the first 

 1-S-nerved, the second 3<herved, broadest at or above the middle, usually 

 1-2 lines long: flowering glumes ovate-oval, smooth, erose at the apex, 1-2 

 lines long, with soft hairs on the keel for half its length and on the lower 

 part of the lateral nerves: palet about 2% lines long, ciliate or pubescent 

 on the keels. Common everywhere: naturalized from Europe. 



P. subaristata Scribn. Macoun Cat. Can. PI. 4, 227, name only. A 

 slender densely tufted perennial 10-20 inches high : leaves of sterile shoots 

 conduplicate, scabrous, 2%-5 inches long: sheaths of the stem 2, smooth, 

 the upper one nearly half as long as the stem : ligules % hne long : upper 

 leaf pungent, %-2 inches long : panicle linear to oval, dense, somewhat in- 

 terrupted, l%-6 inches long: spikelets linear-lanceolate, 4-7-flowered, 3-5 

 lines long; empty glumes subequal, linear-lanceolate, 3 lines long, 1-nerved; 

 flowering glumes linear-lanceolate, 3 lines long, scabrous on the nerves, not 

 webbed : palet 2% lines long, ciliolate on the keels. Idaho to Wyoming. 



P. Cnsickii Vasey Cont. U. S. Nat. Herb, i, 271. A glabrous, tufted 

 perennial 16-20 inches high : leaves of the stem 2 : lower sheaths longer 

 than the internodes: ligules 1-1 >£ lines long: leaves flat or involute, acute, 

 2-2% inches long, less than 1 line wide : panicle more or less exserted, 

 narrow, 3-5 inches long, the branches mostly in pairs, the longest l%-2 

 inches long, bearing 4-8 spikelets on the outer half: spikelets 3-3% lines 

 long, 2-3-flowered : rachella hispidulous : empty glumes with broad char- 

 flaceo-hyaline margins, fir^t ovate-lanceolate, nearly 2 lines long, 1-nerved, 

 rarely 3-nerved, second oval erosely acute, about 2 lines long, 3-nerved : 

 towering glumes keeled 2-2-% lines long, scabrous, oval, subacute: palets 

 5 lines long, 2 toothed, ciliate on the keels. In the mountains of eastern 



