AVENA. CLXI. GRAMMES. 60D 



2. A. c;espit6sa. (A. aristulata. Torr.) 



Coespitose, glabrous ; si. 18 — 30' high ; Ivs. narrow-linear, scabrous above, 

 smooth beneath, flat; jO«?«'c/e pyramidal, capillary, oblong, finally diffuse; avms 

 straight, about as long as the paleee which arc longer than the bluish glumes. — 

 % Swamps, Free States and Can. May. 



3. A. PUMiLA. Pursh. 



Sts. scarcely 1' high, erect, growing in tufts, scarcely longer than the 

 leaves; Ivs. flat, smooth; panicle small, tastigiate, few-flowered; pedicels short; 

 palecc awnless, obtuse, twice the length of the glumes ; glmnes with a mem- 

 branaceous margin. — % In barren, clayey soils, near brickyards, Penn. 

 Pursh. Jn. 



29. TRISETUM. 



Lat. tria, three, setum, a bristle ; a characteristic term. 



Spikelet 2 — 5-flowered ; glumes 2, as long as the flowers ; lower 

 palea with 2 bristles at the apex and a soft, flexuous awn from above 

 the middle of the back ; scales ovate ; fruit coated, furrowed. 



1. T. PALUSTRE. Torr. (Avena. M.v. Aira pallens. Muhl.) 



St. erect, contracted at the nodes, slender, smooth, about 2f high ; lis. 

 lance-linear, about 3' long, roughish, on smooth, striate sheaths ; panicle oblong, 

 contracted, nodding, yellowish-green ; spikelets 2—3 flowered, middle flower 

 abortive, upper one pedicellate, its lower palea ending in 2 setose teeth, and 

 awned below the tip, lower one m'ostly awnless. — % Wet meadows, Mass., 

 JN. Y. to Flor. May— July. 



2. T. PURPURASCEMS. Torr. (Avena striata. Mkhx. ?) 



St. lealy, 2f high ; Ivs. narrow-linear, keeled,-4— 6' long, and with the 

 sheaths smooth; panicle very simple, almost a raceme, few-flowered, 4 — 6' long; 

 glumes 3-flowered, very unequal, entire; spikelets lanceolate, terete, often purple, 

 smooth; lower palea 7-veined, 2-cleft at the extremity; atvn geniculate.— 'Zj. 

 Mountain bogs, N. Eng., N. Y., Can. June. 



3. T. susPiCATUM. Brown. (T. aroides. Palis. Aira. Linn.) 



St. a foot high ; Ivs. narrow, 2 — 4' long ; panicle contracted into a spike 2 

 ong; awn at length deflexed, longer than the glume.— 9]. Rocks and moun- 

 ^ins. Little Falls, N. Y. Gray. White Mts., N. H. Pickering. Jn. 

 30. AVENA. 

 Spikelets 2 — 5-flowered; glumes 2, loose and membranaceous, 

 -mbequal, longer than the flowers ; paleae 2, mostly hairy at base, the 

 lower one bifid, with a twisted or bent awn at the back. 



1. A. ELATioR. (Arrhenatherum. Palis.) 



,§/. 2— 4f high, geniculate, smooth; Ivs. lance-linear, rough on the margin 

 and upper surface ; panicle loose, equal, nodding, branches in pairs or ternate ; 

 spikelets 2-flowered; awn twice as long as the palea; upper jlovxr $, mosilv 

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

 May, June. 



2. A Pennsylvanica. (Arrhenatherum. Torr.) 



St. erect, smooth; Ivs. linear-lanceolale ; paiiide slender, with short, alter- 

 nate branches ; avni twice as long as the flowers, geniculate, from the base of 

 the lower palea; upper flower awnless.—® Fields and open woods, N. Eng. to 

 Car. and 111., rare. July. 



3. A. PRJECox. Palis. (Aira. LAnn:) , , i , , 

 CJBspitose ; St. erect, a few inches high ; Ivs. \—V long, rough ; slieam deeply 



striate • panicle dense, racemose ; spikelets ovate, 2-flowered, glumes as long as 

 the flowers ; lower palea with a bent awn from the lower part of the back twice 

 its length.—® N. Y. to Virg. Jn. 



4 A. sATiVA. ^Commo?;. Oat.— St. smooth, 2— 4f high; hs. linear-lanceo- 

 late veined roTigh, with loose, striate sheaths; slip, lacerate; panicle loose; 

 spikcMs pediinculate, pendulous, 2-flowered, both flowers perfect, the lower one 

 mostly awned ; palete somewhat cartilaginous, closely embracing the caryopsis. 



