POACEAE. 2-] 



Agrostis pallens foliosa (Vasey) Hitchc. Perennial with running root- 

 stocks; stems slender, erect, about 60 cm. tall; radical leaves numerous, those 

 of the stem usually 2-3, the blades flat, 1-2 mm. broad, 7-10 cm. long, strongly 

 scabrous, the sheaths nearly smooth; panicle erect, narrow, purplish, 7-12 cm. 

 long, the branches scabrous, naked below. In moist soil, not common. 



Agrostis hyemalis (Walt.) B.S.P. Annual, tufted, 15-90 cm. tall; leaves 

 flat or involute, narrow, very scabrous; panicle very loose, 15-30 cm. long; 

 branches in whorls of 2-12, capillary, 5-15 cm. long, branched above the middle 

 and spikelet-bearing only near the tips. Common in both dry and moist 

 places. 



Agrostis idahoensis Nash. Delicate, loosely-tufted, glabrous, perennial, 

 10-30 cm. high; blades flat, narrow, 1-6 cm. long; panicle loose, green or 

 purple, 5-10 cm. long; rays capillary; spikelets about 1.5 mm. long; lower 

 glume scabrous on the keel, slightly larger than the upper; lemma truncate, 

 awnless, 1 mm. long; palea minute. In alpine woods, Craig Mountains. 



Agrostis exarata Trin. Perennial, tufted, the stems 30-90 cm. tall; leaves 

 erect, the blades flat, 2-6 mm. broad, 5-10 cm. long, scabrous, the upper 

 distant from the panicle; panicle strict, pale green, spike-like or interrupted, 

 the short branches appressed and spikelet-bearing to the very base; glumes 

 2.5-3.5 mm. long, usually scabrous on the back. Common in moist soil. 



Agrostis rossae Vasey. Tufted, 10-20 cm. high; leaves mostly basal, 

 2-5 cm. long, 1-2 mm. broad, flat or folded; panicle narrow, erect, 3-6 cm. 

 long, green or purple; glumes 2 mm. long, not scabrous. Meadows, on the 

 highest ridges of the Blue Mountains. 



44. HOLCUS. 



Annual or perennial grasses with densely-flowered terminal 

 panicles; spikelets deciduous, 2-flowered, the lower flower perfect, 

 the upper staminate; glumes membranous, keeled, the lower 1- 

 nerved, the upper 3-nerved and often short-awned; lemmas 2, 

 papery, that of the upper flower bearing a bent awn; palea 

 narrow; grain oblong, free, enclosed in the lemma. 



Holcus lanatus L. Velvet Grass or Mesquite. Perennial ; the whole plant 

 downy with pale pubescence; stems erect, 30-90 cm. high; leaf blades flat, 

 rather broad and short; sheath loose, shorter than the internodes; panicle 

 pale purplish, 5-10 cm. long, rather densely-flowered, the branches in twos 

 or threes; spikelets 4-6 mm. long; upper glume short-awned near the apex; 

 lemma of the staminate flower with a hook-like awn. Sparingly introduced. 



45. ARRHENATHERUM 



Tall perennials with long narrow panicles; spikelets 2-flowered, 

 lower flower staminate, upper perfect; rachilla extending beyond 

 the flowers; glumes thin-membranous, keeled, very acute or 

 awn-pointed, unequal, persistent; lemmas 2, rigid, 5-7-nerved, 

 deciduous, the first bearing a long bent and twisted dorsal awn 

 inserted below the middle, the second unawned; palea hyaline, 

 2-keeled; grain ovoid, free. 



Arrhenatherum elatius (L.) Beauv. Tall Meadow Oatgrass. Glabrous 

 perennial, 100-150 cm. high; stem leaves 3, the blades flat, minutely scabrous, 



