AoRosTis. CLXl. GRAMINEiE. 597 



larger, sometimes longer, often shorter than the palca) ; paleao 2, 

 unequal, lower one larger, awnless or awned, larger than the glumes, 

 coating the caryopsis. 



§ 1. Glumes longer than the palect. 



1. A. VULGARIS. Sinilh. (A. polyinoipha. (irny.) licd-top. I3ent Grass. 



St. erect, 1 — '21" hij^h ; ptin'uic spreading, with the branches finally divari- 

 cate; lis. linear-laneeulate, veined, scabrous, with smooth, striate sheaths, and 

 short, truncate stipules ; lower palca twice as largo as the upper, and nearly as 

 long as the lanceolate, acute glumes.— 'Z|. U. S. A common and very valuable 

 grass, .spread over hills, vales, and meadows, forming a solt, den.se turf. Flow- 

 ers very numerous, purplish. July. 



2. A. Ai-BA. (A. decumbens. Miihl.) Wkit^-tnp. Florin Grass. 



St. decumbent, geniculate, rooting at the lower joints, .sending out stolons; 

 Ivs. linear-lanceolate, smooth, those of the stolons erect and subulate; sheaths 

 smooth, with a long, membranaceous stipule; panicle dense, narrow, at length 

 spreading, whitish, sometimes purplish; lower palca 5-veined, rarely awned. — 

 (1) N. Eng. to Ohio, in meadows, or in dry soils; hence its characters are vari- 

 able, being often nearly erect. June. ^ 



3. A. sTRicTA. Willd. Bcvt Grass. 



S/. erect, smooth, with black nodes; lis. linear-lanceolate, scabrous on 

 the margin, with cleft, while stipules; panicle elongated, strict, the branches 

 about 5, tlexuous, scabrous, erect; flumes equal, lanceolate; paleee unequal, 

 smaller than the glumes, with an awri at the base of the outer one twice longer 

 than the flower.— 2|. Fields, N. Eng., N. Y. June. 



4. A. CANiNA. Dog's Bent Grass. 



St. prostrate, somewhat branched, rooting at the lower nodes, about 2f 

 long ; panicle at length spreading, with angular, rough branches ; glutncs elon- 

 gated ; lower palecB furnished with an incurved awn upon the beak twice its 

 length. — %. Introduced and common in wet meadows. July. ^ 



5. A. PiCKERiNGii. Tuckm. (A. canina, /?. alpina. Oakes.) 



St. erect; Ivs. flat, linear; pan. ovate, diffuse, branches verticillate, rather 

 erect, scabrous ; gl. subequal, keel of the lower mucronate at tip, upper acutr^ 

 smoothish ; loicer palea ovate-lanceolate, acute or erose, veined, upper ovate, 

 veinless ; awn from the middle of the back, contorted, twice longer than the 

 fls.— White Mts. 



0. rnpicola. Tuckm. Smaller ; pan. contracted, smoothish, often purplish. — 

 Mountains, Vermont. 



§ 2. ViLFA. Glumes not longer than the subequal, awnless paleee. 



6. A. ViRGiNiCA. (Vilfa vaginiflora. Gray.) 



S's. numerous, assurgent, procumbent and hairy at base, nearly simple, 

 about a foot long ; Ivs. somewhat 2-rowed, involute, rigid, erect, 2^3' long, 

 with smooth sheaths which are hairy at the throat and swollen with the en- 

 closed panicles ; panicles spike-form, terminal and lateral, the lateral ones con- 

 cealed; (riinnes nearly equal, about as long as the subequal paleee. — (I) Sandy 

 soils, Middle States. Sept., Oct. 



7. A. coMPREssA. Torr. (Vilfa compressa. Trinius.) Flat-stemmed 

 Aurostis. — Glabrous ; sf. erect, compres.sed, simple, leafy, branched at base, 



1 2f high; lis. narrowly linear, compressed, scarcely shorter than the stem; 



keel prolonged into the open sheath ; stip. very short ; panicle purple, subsimple, 

 contracted, the branches few and erect ; glumes equal, acute, snorter than the 

 palese, the upper emarginate, rarely mucronate ; j)atc(e ovate, obtuse, smooth, 

 sometimes deeply cleft ; stig. purple. — Sandy swamps, N. J. Sept. 



8. A. sEROTiNA. Torr. (Vilfa serotina. cjusdcm.) 



St. 12 — 18' high, filiform, compressed, growing in patches, smooth, often 

 viviparous at the nodes ; Irs. 2 — 3' by i", keeled, smooth ; sheaths open ; stip. 

 ovate, short; panicle 3 — 10' long, capillary, diffuse, branches fle.xuous, alter- 

 nate ; spikdr's elliptical, scarcely i" long; glume ovate, 1-veined, unequal, half 



