790 Oedeb 156.— GKAMINB^. 



sheaths striate ; pan. oblong, dense, whitish, with a purple tinge ; fis. shorter than 

 the glumes; sterile one with a recurved, included awn. — y Common in wet 

 meadows, N. Eng., to the uplands of Ga. A beautiful grass, very soft with 

 whitish down. Jl. 



26. ArRA, L. (Gr. alpa, a deadly weapon ; originally applied to a 

 poisonous grass.) Spikelets 2-flowered, without abortive rudiments ; 

 glumes 2, membranaceous and shining, subequal ; one of the flowers 

 pedicellate ; palcs3_ subequal, pilous at base, the lower one lacerate at 

 apex and awned on the back. — Fls. in panicles of a silvery purplish 

 hue. 



§ Glumes much lonc^er than the pales. Awns long No. 1 



§ Glumes abtiut as long as the pales. Awns long or short Nos. 2, S 



1 A. atropurpiirea 'Wahl. Cajspitous, a foot high ; culms very slender ; Ivs. 

 flat ; pnn. thin, with spreading branches ; glumes much longer than the flowers ; 

 pales hairy at apex. — High Mts. of N. Eng. and N. Y. Aug. 



2 A. Cexuosa L. Culm smooth, 1 — 2f high, nearly naked ; Ivs. setaceous, 

 smooth, witli striate sheaths and truncate stipules ; pan. loose, spreading, triehoto- 

 mous, with long, fiexuous branches ; awns geniculate, twice longer than the pales. 

 — If Vales and hills, XJ. S. and Brit. Am., common. An erect, elegant grass, 

 growing in tufts. Jn. 



3 A. CEespitosa L. Casspitous, glabrous ; st. IS — 30' high ; Ivs. narrow-hnear, 

 scabrous above, smooth beneath, flat ; panicle pyramidal, capillary, oblong. Anally 

 diffuse ; atcns straight, about as long as the pales, which are longer than the bluish 

 glumes. — U Swamps, N. States and Can. May. (4. aristulata Terr.) 



27. DANTHO'NIA, DC. (In honor of M. Banthoine, a French botan- 

 ist.) Spikelets 2 — '7 -flowered ; glumes 2, subequal, longer than the 

 spikelct of flowers, cuspidate ; paleas hairy at the base, lower one bi- 

 dentate at the apex, with a twisted awn between the teeth, the upper 

 one obtuse, entire. 



D. Bpicata Bcauv. St. slender, nearly erect, 12 — 18' high, lovjer Irs. numerous, 

 4 — G' long, flat, hairy above, caullne Ivs. much shorter, subulate, erect, on very 

 short slieatlis; panicle simple, spicate, short, erect; spikelets 3 — 8 or 10, about 7- 

 floworcd ; glumes a little longer than the flowers ; lower palea hairy, about half as 

 long as its spirally twisted awn. — Pastures and open woods, common. June 

 — Aug.. (Avena, L.) 



28. AVE^NA, L. Oat. Spikelet 2 to 5-flowered ; glumes 2, loose 

 and membranous, awnless, often as long as the pales ; pales 2, herba- 

 ceous, at length subcoriaceous, the lower one bifid and usually with a 

 twisted or bent awn at the back. — Fls. paniculate. 



I AREITENATHEEUM. Gls. nnequ.al, 2-flo\verecl, with a rudiment ; lower fl. stam1nate.No. 1 



I AIROPSIS. Gib. subequal, 2-flo\vcic-tl, with no rudiment, fls. both perfect. Dwarf. No. 2 



5 AVKN.V proper. Gls. equal, longer than the 2 lis., and strongly striate. Cultivated No. 3 



1 A. elatior L. Culm 2 — if, geniculate, smooth ; Ivs. lance-linear, rough on the 

 margin and upper surface ; panicle loose, equal, nodding, branches in pairs or ter- 

 nate ; spikelets 2-flowered; cmn twice as long as the palea; upper flower 2, 

 mostly awnless. — y A tall grass, introduced and naturalized in cultivated 

 grounds. Hay, June. (Arrhenatherum avenaceum Beauv.) 



2 A. praioos Bcauv. Casspitous; culm erect, a few inches high; Ivs. I — 1' 

 long, rougli; sheaths deeply striata; panicle dense, racemous; spikelets ovate, 2- 

 flowered, glumes as long as the flowers ; lower palea with a bent awn from the 

 Iswer part of tlio back twice its length. — (1) N". Y. to Virg. Jn. (Aira, L.) 



3 A. BativaL. Common Oat. Culm smooth, 2 — 4fhigh; ?ts. linear-lanceolate, 

 veined, rongli, with loose, striate sheaths; sZip. lacerate ; panicle loose; spikeieti 

 pedunculate, pendulous, 2-flowered, both flowers perfeci;. the lower one mostly 

 awned ; j-uleca somewhat cartilaginous, closely embracing the caryopsis. — QD A 



