AvENA. CLXI. GRAMINEiE. 009 



2. A. c^spiTosA, (A. .nristulata. Torr.^ 



Coespitosc, -^'lalnous ; .</. 18— :$()' liif^'h ; (vs. narrow-linear, scabrous above, 

 smooth beneath, flat ; /w/j/V/tpyramiil.il, capillary, oblong, finally diffuse; awns 

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

 %. Swamp.s, Free Stales and Can. May. 



3. A. PUMiLA. Pursh. 



Sis. scarcely 1' high, erect, growing in tufis, scarcely longer than the 

 leaves; Irs. flat, smooth; panicle small, lastigiate, few-flowered; ;>ty//a7.s short; 

 paiecc awnless, obtuse, twice the lengtli of the glumes; ghoiws with a mem- 

 branaceous margin. — IJ. In barren, clayey soils, near brickyards, Pcnn. 

 Purs/i. Jn. 



29. TRISETUM. 



Lat. tria, three, sctum, a bristle ; n characteristic term. 



Spikelet 2 — r)-flowcred ; glunics 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.c. Aira pallens. Muhl.) 



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

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

 contracted, nodding, yellowish-green ; spikclcts 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. — IL Wet meadows, Mass., 

 N. Y. to Flor. May— July. 



2. T. puRPLRAscENs. Torr. (Avena striata. Michx. ?) 



Si. leafv, 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 S-flowered, very unequal, entire; spikclds lanceolate, terete, often purple, 

 smooth ; loiccr paka '7-veined, 2-cleft at the extremity ; aivn geniculate. — 7|. 

 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 

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

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



30. AVENA. 



S pikelets 2 — 5-flowered ; glumes 2, loose and membranaceous, 

 subeepal, 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.) 



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

 and upper surface ; particle loose, equal, nodding, branches in pairs or tcrnate ; 

 spikelets 2-flowered ; awn twice as long as the palea ; vpper fiotcer ^ , mostly 

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

 May, June. 



2. A Pennsylvanica. (Arrhenatherum. Torr.) 



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

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

 the lower palea; vpper Jlowcr awnless. — (i) Fields and open woods, N. Eng. to 

 Car. and 111., rare. July. 



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



Caespitose; st. erect, a few inches high ; Ivs. h — V long, rough ; S/^fc^/t*; deeply 

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

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

 its length.—® N. Y. to Virg. Jn. 



4. A. SATivA. Co'imnon Oat. — St. smooth, 2 — 4f high; Ivs. linear-lanceo- 

 late, veined, rough, Avithloo.se, striate sheaths; slip, lacerate; punirle loose; 

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

 mostly awned; pale(s somewhat cartilaginous, closely embracing the caryopsis. 



