432 GRAMINACE^. 



form. Panicle purp.e, very loose, the lower branches in fives or sixes, the upper 

 ones in threes, at length spreading, Spikelets clustered at the extremity of "the 

 branchlels. A somewhat variable species. Loose-flowered Thin-grass. 



2. T. scabrum Muhl. : culm geniculate at base, assurgent, branched ; 

 leaves linear-lanceolate, flat, scabrous on .the margin ; panicle oblong ; 

 branches spreading or divaricate, the divisions trichotomous ; glumes un- 

 equal. Agrostls scabra Willd. A. laxijlora var. scabra Torr. N. Y. Fl. 



Woods. Can. to Car. July, Aug. %. — Culm 12 — 18 inches high, often 

 somewhat decumbent and branching. Leaves 4 — 6 inches long. Panicle pale 

 green, the branches slender, but shorter than in the preceding. Spikelets not 

 clustered. Rough Thin-grass. 



3, T. elatum Pursh. : culm stiflly erect ; leaves narrow-linear, flat, sca- 

 brous, the sheaths smooth ; panicle verticillate, somewhat spreading ; glumes 

 nearly equal. Agrostis dispar Mich. 7 



Sandy swamps. N. J. to Car. Aug. %.. — Culm 2 — 3 feet high. Panicle 

 purple, exsertedt Tall Thin-grass. 



21. VILFA. Adans.—YiUsi. 



(Origin unknown.) 



Glumes carinate; the lower one smaller. Paleae awnless; 



the lower one rather acute, longer than the glumes ; the upper 



2 -keeled. Sligraas simply plumose. Caryopsis deciduous. — 



Panicle diffuse or contracted and spike-like. 



1. V. vaginceflora Torr.: culms numerous, assurgent; leaves distichous, 

 involute, rigid ; panicles lateral and terminal, spike-form ; the lateral ones 

 concealed in the sheaths ; glumes equal, about as large as the paleae. 

 Agrostis Virginica Muhl. 



Sandy soils. N. Y. to Virg. Sept., Oct. (!)• — Cuifms about a foot high, ces- 

 pitose, geniculate at base. Leaves with a slender point, the sheaths tumid. 

 Panicle oblong, compressed, few-flowered. Anthers purple. 



Hidden-flowered Vilfa. 



2. V. aspera Beauv. : leaves very long, filiform and recurved towards the ' 

 apex; panicle contracted, spiked, partly exserted from the uppermost 

 sheath ; paleae much longer than the glumes, subequal, smooth or hairy, 

 without awns. Agrostis aspera Mich. 



Sandy fields and hill sides. N. Y. and Mass. to Car. Sept., Oct. Tj.. — Culm 

 2 — 4 feet high, simple, terete. Leaves 1 — 2 feet long, tapering to a filiform ex- 

 tremity, rough on the margin. Panicles lateral and 'terminal, the former more 

 or less exserted. Rough-leaved Vilfa. 



3. V. serotina Torr. <^ Gr. : culm filiform, much compressed ; leaves 

 very narrow, keeled, erect ; panicle elongated, capillary, somewhat diff'use ; 

 glumes ovate, unequal, about half as long as the awnless paleae. Agrbstis 

 serotina Torr. FL. 



Sandy swamps. N. Y. and N. J. Sept. %.~Culm 12 — 18 inches high. 

 Leaves short, almost filiform. Panicle slender, with the branches flexuous. 



Late-flowering Vilfa. 



4. V. heterolepis Gray: leaves setaceous; panicle pyramidal, sparsely 

 flowered; lower glume subulate; the upper one ovate, cuspidate, about 



