672 GRAMINKyE. (OKASS FAMILY.) 



2. VAHLC-DEA, Fries. ( Humes more Ixjul-sfta/xd, lonyer than (lie jL 

 lower palea of a Jinn or coriaceous texture, nerveless, the truncate-obtuse lift mostly 

 entire ; the awn borne at or above the middle : yrain grooved, JlattisJi, fiee. 

 3. A. atl'Oplirpurea, Wahl. Culms 8'-15' high, weak; loaves flat or 



rather wide ; panicle of few spreading brunches ; awn stout, twiee the length of 



the paleae. 1J. Alpine tops of the White Mountains, and those of N. Ne\v 



York. August. (Eu.) 



48. I> A NTH ONI A, DC. WILD OAT-GRASS. 



Lower palca (oblong or ovate, roundcd-cylindraceous, 7 -9-ncrved) bearing 

 between the sharp-pointed or awn-iike teeth of the tip an awn composed of tiie 

 3 middle nerves, which is flattish and spirally twisting at the base : otherwise 

 nearly as in Avena. Glumes longer than the imbricated flowers. (Named lor 

 Dant/toine, a French botanist.) 



1. D. Spicata, Beauv. Culms tufted (l-2high); leaves short, nar- 

 row and soon involute ; sheaths bearded at the throat; panicle simple, raceme- 

 like (2' long) ; the few spikelets appressed, 7 -flowered ; lower palea broadly 

 ovate, loosely hairy on the back, much longer than its lance-awl-shaped teeth. 

 1J. Dry and sterile or rocky soil. July. 



49. TRISETUM, Pcreoon. TRISETUM. 



Spikelets 2 - several-flowered, often in a contracted panicle ; the lower palea 

 compressed-keeled, of about the same membranaceous texture as the glumes, 

 bearing a bent or flexuous (rarely twisted) awn below the sharply 2-toothed or 

 2-pointcd apex (whence the name, from tris, three, and $>ta, a bristle) : other- 

 wise nearly as in Avena. 



1. T. Sllbspicatlllll, Beauv., var. molle. Minutely soft-downy ; pani- 

 cle dense, much contracted, oblong or linear (2 ; - 3' long) ; glumes about the length 

 of the 2 -3 smooth flower?; awn diverging, much exscrted. (Avena mollis, 

 Michx.) y. Mountains and rocky river-banks, N. New England to Wisconsin, 

 and northward; rare. July. About 1 high: leaves flat, short. (Eu.) 



2. X. pallistrt?, Torr. Smooth; panicle rather long and narrow (5' long), 

 loose, the branches capillary; spikelets flat (3" long) ; glumes shorter than the 2 

 smooth lanceolate flowers, of which the upper is on a slightly naked joint of the 

 rhachis, and bears a slender spreading or bent awn next the short 2-pointcd tip, 

 while the lower one is commonly awnless or only mucronate-pointed. 1J. (Avena 

 palustris, Alichx. Aira pullcns, Mnhl.) Low grounds, S. New York to Illinois, 

 and southward. June. Culm slender, 2 -3 high : leaves flat, short. Spike- 

 lets yellowish-white, tinged with green. 



. 50. AVENA, L. OAT. 



Spikelets 2 -many-flowered, pnniHcd : the flowers horbaoco-chartaoeous, or 

 becoming harder, of firmer texture than the large and mostly unequal glumes; 

 the uppermost imperfect. Lower palea rounded on the back, mostly 5-11- 

 nerved, bearing a long usually bent or twisted awn on the back or below the 



