AvENA. CLXI. GRAMINEiE. G09 



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



Csespitose, g:labrous ; st. 18 — 30' high ; Ivs. narrow-linear, scabrous above, 

 smooth beneath, flat; j9a?w'cfe pyramidal, capillary, oblong, finally difi'use; auvis 

 straight, about as long as the palete which are longer than the bluish glumes. — 

 '2J. 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, I'astigiate, few-flowered ; pedicels short ; 

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

 branaceous margin.— 'Z(. 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, flesuous awn from above 

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



1. T. PALisTRE. Torr. (Avena. Mx. Aira pallens. Muhl.) 



SI. erect, contracted at the nodes, slender, smooth, about 2f high ; Ivs. 

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

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

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

 awned below the tip, lower one mostly awnless. — % "Wet meadows, Mass., 

 N. Y. to Flor. Maj'— July. 



2. T. puRPURAscENs. Torr. (Avena striata. Michx. 7) 



SI. 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-flowcred, very unequal, entire; spikelcts lanceolate, terete, often purple, 

 smooth ; lower palea 7-veined, 2-cleft at the extremity ; aion geniculate.— Ij. 

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



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



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

 long ; awn at length deflexed, longer than the glume.— Tj. Rocks and moun- 

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



30. AVENA. 

 Splkelets 2 — 5-flowered; glumes 2, loose and membi-anaceous, 

 subequal, longer than the flowers ; palefe 2, mostly hairy at base, the 

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



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



Sf., 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 ; tipper flower $ , mostly 

 av/nless.— A tall grass, introduced and naturalized in cultivated grounds. 

 May, June. 



2. A Pennsylvanica. (Arrhenatherum. Torr.) 



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

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

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

 Car. and 111., rare. July. 



3. A. pr;ecox. Palis. (Aira. Linn.) 



Crespitose ; St. erect, a few inches high ; Ivs. \—V long, rough ; 5/tmC/t5 deeply 

 striate; panicle dense, racemose ; spikelcts ovate, 2-flowered, o-Zimcs as long as 

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

 its length.—® N. Y. to Virg. Jn. 



4. A. sATlvA. Common Oat.— SI. smooth, 2— 4f high; Ivs. linear-lanceo- 

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

 spikelets pedunculate, pendulous, 2-flowered, both flowers perfect, the lower one 

 mostly awned; palea; somewhat cartilaginous, closely embracing the caryop.sis. 



