410 GRAMINEiE. (GRASS FAMILY.) 



* * Panicle loose and open. 



6. M. pungens, Thurb. Stems erect, from 1 to U feet high: leaves very- 

 pale green, hard and rigid, terminated by a hardened point : panicle very open, 

 its solitary rays fasciculately branched just above the base into long 1-flowered 

 divisions: outer glumes half as long as the floret, pointed by a distinct bristle: 

 flowering glume acute, the awn a line long or less : palet with 2 setose teeth, which, 

 nearly equalling the awn, give the appearance of an undeveloped Aristida. — 

 Proc. Philad. Acad. 1863, 78. From S. California to Arizona, Colorado, and 

 Nebraska. 



7. M. gracillima, Torr. Cespitose, glabrous : stem simple, 6 to 12 inches 

 high : leaves very narrow, involute, short, mostly in radical tufts : panicle 5 to 

 6 inches long, pyramidal, capillary ; branches sub-solitary, widely spreading : 

 spikelets lanceolate, mostly purplish : outer glumes acute, scarcely twice shorter 

 than the palets : flowering glume glabrous, 3-nerved, minutely bifd, with a straight 

 awn of equal length: callus naked. — Whipple, Pacif. R. Rep. iv. 155. Colorado 

 and southward. 



8. M. Texana, Thurb. Stems geniculaiely decumbent, branching: panicle 

 few-flowered, rays solitary or in pairs, naked below, at last widely spreading . 

 outer glumes shorter than the floret, 1 -nerved, setaceously mucronate: flowering 

 glume and palet pilose, the former terminated by an awn thrice its length and 

 equalled or exceeded by the latter: callus conspicuous, glabrous. — Gram. 

 Mex. Bound, ined. From Colorado to Arizona and Texas. 



9. M. debilis, Trin. Stems 3 to 18 inches high, ascending from a genicu- 

 late base, branching from the lower nodes: leaves mostly flat, acuminate, puberu- 

 lent on both surfaces, and with the whole plant purple tinged or dark purple 

 throughout : panicle 2 to 6 inches long, the few mostly solitary rays spreading, 

 distant, a little longer than the interspaces, included below by the upper 

 sheath ; floret very early deciduous : outer glumes £ to £ its length, equal or 

 the lower slightly shorter, the upper or both eroded at the obtuse or truncate apex: 

 flowering glume scabrous throughout, terminated by a slender awn 1 to 1| inches long. 

 — S. California to Northern Mexico and extending into S. Colorado and 

 eastward. 



17. PHLEUM, L. Cat's-tail Grass. Timothy. 



Perennials, with spikes very dense and harsh. 1 



1. P. alpinum, L. Culms 1 to 2 feet high: sheaths of the upper leaves 

 very loose or inflated, the lower ones close ; ligule short : spike ovoid or ob- 

 long, rarely more than an inch long, usually purplish : outer glumes strongly 

 fringed on the back, bearing an awn about their own length. — In alpine 

 regions throughout N. America, Europe, and Asia. 



18. S P O R O B O L U S, R. Rr. Drop-seed Grass. Rush Grass. 



Stems wiry or rigid. Leaves usually involute and bearded at the throat, 

 their sheaths often enclosing the panicles. Includes J7//a, Beauv. 



1 P. pratense, L., the cultivated "Timothy" and frequently naturalized, can be distin- 

 guished from P. alpinum by its close sheaths, long ligule, much longer spike (1 to 6 inches), 

 and glumes with scarious margins and green keel, which is ciliate with stiff hairs and pro- 

 longed into a rigid rough awn shorter than itself. 



