410 GBAMINE^I. (GRASS FAMILY.) 



* * Panicle loose and open. 



6. M. pungens, Thurb. Stems erect, from I to l 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,^/a6rous.- 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 : Jlowering glume glabrous, 3-nerved, minutely bifid, with a straight 

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

 and southward. 



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

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

 outer glumes shorter than the Jloret, 1 -nerved, setaceously mucronate: Jlowering 

 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 fiat, 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: 

 Jlowering 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 Vilfa, Beauv. 



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

 guished from P. alpinum by it 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. 



