No. 50. 



ELYMUS SITANION Schultes. (Sitanion elymoides Raf. Polyanthrix 



Hystrix Nees.) 



Plant annual, or short-lived perennial, from rather bulbous base. 



Culms tufted at base with many radical shoots, erect, unbranched, terete, hol- 

 low, nearly smooth,- 6 to 18 inches tall. 



Radical leaves mostly membranaceous scales, or leafless sheaths, those from 

 radical shoots numerous, striate, often pubescent, or nearly glabrous on sheaths 

 and blades below; blade flat or slightly involute, rigid, hispid above, H lines wide, 

 4 to 6 inches long; leaves of culm 3, rarely 4; sheaths longer than internodes; 

 blades like those of radical shoots, ligule an inconspicuous, narrow, membrana- 

 ceous line, often auriculate on one or both sides. 



Inflorescence a rather loose spike 2 to 3 inches long; rachis articulate at base 

 of each flattened internode, and easily separating. 



Spikelets 2 at each node of the rachis, nearly sessile, lanceolate, 5 to 6 lines 

 long, not including the awns, 1- to 5-flowered; upper flowers sterile; first and sec- 

 ond glumes nearly equal, side by side in front of the spikelet, narrow, 2-nerved at 

 base, terminating in a divergent hispid awn 2 to 4 inches long; floral glumes ovate- 

 lanceolate, acute, round on back, enveloping seed and palet, finely scabrous, indis- 

 tinctly 5-nerved, terminating in a hispid awn 2 to 2% inches long, the upper 

 imperfect glumes short-awned^ palet lance-linear, obtuse, hispid on the two nerves, 

 margins reflexed, flat, one-half line wide, folded. 4 to 4^ lines long. 



Grain dull brown, linear, wrinkled lengthwise, 2% lines long, adherent to palet 

 and enveloping glume. 



Extensively diffused over the arid and desert districts of the West, from the 

 Missouri to the Pacific, and from Dakota to Texas, presenting great diversity of 

 size and appearance. Sometimes the empty glumes are divided into three parts. 



PLATE L; a, spikelet; 6, floral glume; c, palet. 



