GRAMINE^E. (GKASS FAMILY.) 411 



* Seed adherent to the pericarp : panicle spiked or contracted. VILFA. 



1. S. CUSpldatUS, Torr. Root perennial: stems and leaves very narrow, 

 the latter awl-shaped: panicle exserted, very simple and narrow: outer glumes 

 very acute : flowering glume cuspidate. Vdfa cuspidata, Torr. Colorado 

 and northward ; eastward through northern latitudes to Canada and Maine. 



2. S. depauperatus, Torr. Stems tufted, very slender, 3 inches to 2 feet 

 long, often much branched : leaves very minutely scabrous on the upper surface : 

 panicle ^ to 2 inches long, very narrow, of few solitary distant erect rays, which 

 are branched and flower-bearing nearly to the base : outer glumes obtuse, nearly 

 equal: flowering glume and palet nearly equal, the former obscurely 3-nerved, 

 often with a minute mucro. Vilfa depauperata, Torr. Varying greatly with 

 the locality. From W. Texas and Mexico to the Saskatchewan, Oregon, and 

 California. 



3. S. Wolfii, Vasey. Stems erect, 1 to l inches high, very slender, branched 

 at the base : leaves mostly radical, short, strongly nerved : spifces simple, few- 

 flowered, terminal and lateral, the lateral ones partly enclosed in the loose 

 sheaths ; flowers alternate, pointed : outer glumes membranaceous, obtuse : flow- 

 ering glume and palet nearly equal in length. Vilfa minima, Vasey, Bot. 

 Wheeler Exped. 283. About T\yiu Lakes, Colorado. 



4. S. tricholepis, Torr. Stems erect, simple, terete, 9 to 18 inches high, 

 tufted: leaves glabrous: branches of the oblong rather dense panicle alternate; 

 pedicels longer than the spikelets : outer glumes nearly equal, acutish, % shorter 

 than the nearly equal pilose flowering glume and palet: flowering glume 

 3-nerved. Vilfa tricholepis, Torr. Colorado and southward. 



* * Seed free from the pericarp : panicle generally open. 

 *- Outer glumes very unequal. 



5. S. cryptandrus, Gr. Sterns 2 or 3 feet high, usually geniculate and 

 branched below : leaves flat, acuminate, scabrous especially above ; sheaths 

 strongly bearded at throat: panicle narrowly pi/ramidal, more or less enclosed 

 by the upper sheath, 4 to 8 inches long, its rays mostly in pa.\rs,Jloiver-bearing 

 to the base : spikelets lead-colored, short-pedicelled : outer glumes somewhat 

 acute. Vilfa cryptandra, Trin. From Texas and New Mexico to Colorado 

 and Oregon, and eastward to New England. 



6. S. airoidas, Torr. Stems forming large tufts, clothed below by the 

 dead sheaths, 2 to 3 feet high, somewhat rigid, smooth : leaves very pale, con- 

 volute and tapering to a filiform apex ; sheaths with a few long hairs at the 

 throat: panicle broadly pyramidal, soon exserted, 6 to 12 inches long, its rays 

 solitary or in pairs, naked below: spikelets brownish, on rather long pedicels: 

 outer glumes rather obtuse. Marcy's Rep. 300. Vilfa airoides, Steud. 

 California to Nebraska and southward to New Mexico and Texas. 



H_ H_ Outer glumes nearly equal. 



7. S. ramulosus, Kunth. Stems tufted, 3 to 8 inches high, very slender 

 and branched below : leaves flat or involute, scabrous on the margins : panicle very 

 long for the size of the plant, constituting f of its height, the capillar if few-flowered 

 mostly solitary rays rather distant and spreading, the secondary branches 1 to 

 ^.-flowered : spikelets less than \ line long: outer glumes mostly ciliate-f ringed on 

 the margin. Vilfa ramulosa, HBK. From Colorado to Texas, New Mexico, 

 and California. 



