40 POACEAE. 



spike 8-15 cm. long, compact; spikelets 7-13-flowered, 12-20 mm. long, 

 glabrous; lemma firm, awn-pointed, the nerves faint. Introduced along the 

 railway, probably from Montana. 



Agropyron repens L. ( Couch or Quack Grass.) Stems erect, 100-150 cm. 

 high; leaf blades green, pilose above, the nerves not prominent; spike 5-15 cm. 

 long; spikelets 5-flowered; lemma glabrous or nearly so, strongly nerved, 

 usually awn-pointed. A dangerous weed sparingly introduced from Europe. 



62. ELYMUS. RYEGRASS. 



Perennial or annual grasses with spike-like inflorescences which 

 do not readily break up into segments; spikelets 1-7-flowered, 

 2-4 at each joint of the rachis or rarely solitary; glumes entire, 

 equal, rigid, narrow; lemmas acute, acuminate or awned, entire. 



Annual; awns 5-10 cm. long. E. caput-medusae. 



Perennials; awns short or none. 



Plants spreading by rootstocks; lemma glabrous. E. triticoides. 



Plants tufted. 



Culms very stout, 1-2 m. high. E. condensatus. 



Clums slender, seldom 1 m. high. 



Lemma pubescent; spike nodding. E. canadensis. 



Lemma not pubescent; spike erect. 



Glumes lanceolate. E. glaucus. 



Glumes subulate. E. leckenbyi. 



Elymus caput-medusae L. Glabrous annual; stems 20^50 cm. high, 

 erect or geniculate at base; leaves 1-2 mm. broad, becoming involute; spike 

 stout, erect, green or becoming purplish, 1-4 cm. long without the awns; 

 spikelets 2 at each node, 1 or rarely 2-flowered; glumes subulate, rigid, 2-2.5 cm. 

 long; lemma lanceolate, very scabrous, tipped with a stout awn 5-10 cm. long. 

 Introduced from Europe about Steptoe Butte and spreading rapidly. 



Elymus triticoides Buckl. Stems erect, about 1 m. tall, not densely tufted; 

 leaves 4-6 mm. wide, sometimes scabrous; panicle spike-like or with some of 

 the lower branches elongated, usually purplish, rather loose; lemma acuminately 

 short-awned. Moist places. 



Elymus condensatus Presl. Stems 1-2 m. tall, stout, densely tufted; 

 leaf blades flat, glaucous, smooth except the scabrous margin, usually 1-2 cm. 

 broad; spikes 3-30 cm. long, erect; spikelets 3-6-flowered, usually several at 

 each node, commonly densely crowded; lemmas mucronate-pointed. Abun- 

 dant in moist soil. 



Elymus canadensis L. Stems stout, about 1 m. tall, pale and somewhat 

 glaucous throughout; leaf blades flat or involute, nearly smooth; spike pale- 

 green, flexuous or nodding, 10-15 cm. long; spikelets 3-5-flowered, mostly in 

 pairs, somewhat divergent; lemma pubescent, the awn 2-3 cm. long, usually 

 spreading. Not common. 



Elymus glaucus Buckl. Stems 50-100 cm. tall, erect; leaf blades spreading 

 or drooping, 10-30 cm. long, 6-16 mm. wide; spike-like panicle narrow, erect 

 or rarely nodding above, 5-15 cm. long, greenish or purplish, glaucescent; 

 spikelets usually appressed, mostly in pairs, 3-6-flowered; glumes lanceolate; 

 lemma not pubescent but rough near the apex, tipped with an awn about twice 

 as long. Common and variable; some forms approach E. canadensis. 



