432 GRAMINACE^E. 



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

 ones in threes, at length spreading. Spikeleis clustered at the extremity of tho 

 branchlets. A some what 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. Agrostis scabra Willd. A. laxiflora var. scabra Torr. N. Y. Fl. 



Woods. Can. to Car. July, Aug. 1J.. 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 stiffly erect ; leaves narrow-linear, flat, sca- 

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

 nearly equal. Agrostis dispar Mich. 1 



Sandy swamps. N. J. to Car. Aug. %. Culm 23 feet high. Panide 

 purple, exserted. Tall Thin-grass. 



21. VILPA. Adans. Vilfa. 



(Origin unknown.) 



Glumes carinate; the lower one smaller. Paleae awnless; 

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

 2-keeled. Stigmas simply plumose. Caryopsis deciduous. 

 Panicle diffuse or contracted and spike-like. 



1. V. vaginfeflora 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 palese. 

 Agrostis Virginica Muhl. \ 



Sandy soils. N. Y. to Virg. Sept., Oct. (p. Culms about a foot high, ces- 

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

 Panicle oblong, compressed, few-flowered. Antiiers 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. Agroslis aspera Mich. 



Sandy fields and hill sides. N. Y. and Mass, to Car. Sept., Oct. %.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. serolina Torr. <$ Gr. : culm filiform, much compressed ; leaves 

 very narrow, keeled, erect ; panicle elongated, capillary, somewhat diffuse ; 

 glumes ovate, unequal, about half as long as the awnless palese. Agrostis 

 serotina Torr. FL 



Sandy swamps. N. Y. and N. J. Sept. 1\..Culm 1218 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 



