Flora of the Palouse Region 3 1 



and the variety are frequently found growing together. Under some con- 

 ditions the plants may produce long stolons as in the following species. 



A. elmeri Scrib. & Smith. Culms erect, 60-120 cm. tall, smooth, from 

 elongated creeping rootstocks: culm leaves 4, the blades becoming involute, 

 rather narrow, ascending, strigose above, smooth- beneath, the sheath loose, 

 exceeding the internodes: spikes erect, 15-25 cm. long: spikelets not crowded , 

 3-3.5 cm. long, 6-10-flowered: flowering glumes sparsely pubescent, tipped 

 with a very short awn. Common on the dry sandy bars of Snake River. 



A. pseudorepens Scrib. & Smith. Perennial from creeping rootstocks: 

 culm erect, 30-100 cm. high, rather slender, glabrous: culm leaves 3 or 4, 

 the blades becoming involute, scabrous on both sides; the sheaths glabrous 

 and shorter than the internodes: spike 10-20 cm. long, narrow, the spikelets 

 densely crowded: flowering glumes linear-oblong, 5-nerved, scabrous, acum- 

 inate, or short-awned. Common in low ground. 



51. HORDEUM. 



Inflorescence a terminal cylindrical spike: spikelets 1 -flowered, 

 usually in threes at each joint of the rachis, the lateral generally 

 short-stalked and imperfect; rachilla produced beyond the 

 flower; lower empty glumes often reduced to awns and form- 

 ing an apparent involucre around the spikelets: empty glumes 

 rigid: flowering glumes rounded on the back, 5-nerved at the apex, 

 awned; palet scarcely shorter than the flowering glume: grain 

 usually adherent to the flowering glume, hairy at the summit. 



Floret of the central spikelet sessile. 



Empty glumes 2.5-6 cm. long, capillary: lateral flowers long-awned. 



H. JUBATUM. 

 Empty glumes broader at the base, less than 2-5 cm. long: lateral flow- 

 ers sterile, the glumes subulate. H. nodosum. 

 Floret of the central spikelet stalked. H. murinum. 



H. jubatum L- Annual, tufted, erect. 30-60 cm. high, glabrous or some- 

 times pubescent: leaf blades flat, becoming involute, the sheaths shorter than 

 the internodes: spike-like panicle pale green or yellowish, 7-10 cm. long, read- 

 ily breaking apart; central spikelet sessile, fertile, the lateral ones peduncled 

 and sterile: empty glumes all subulate, 3-6 cm. long. In moist places, not 

 plentiful. 



H, nodosum L. Annual or perennial, 30-90 cm. high, erect: leaf blades 

 flat orjn volute, the sheaths smooth or hairy: panicle spike-like, 3-8 cm. long, 

 narrow, usually fiexuous, readily separating into joints: central spikelet 

 sessile, fertile, the lateral ones peduncled and sterile: empty glumes all sub- 

 ulate, 2 cm. or less in length. Common in moist ground. 



H. murinum h- Culms 15-30 cm. tall: leaf blades 2-12 cm. long, 

 2-6 mm. wide: spikes 5-10 cm. long, thick: spikelets mostly in threes, all 

 stalked: both empty glumes of the central spikelet and the inner empty 

 glume of the lateral spikelets ciliate and flattened, bearing awns 20-25 mm. 

 long; outer empty glumes of lateral spikelets neither flattened nor ciliate: 

 flowering glume scabrous at the apex, long awned. A troublesome weed, 

 sparsely introduced. 



