672 GRAMINEvE. (GRASS FAMILY.) 



| 2. VAHLODEA, Fries. Glumes more boat-shaped, lonaer than the flouers 

 lower palea of a Jirin or coriaceous texture, nerveless, the truncate-obtuse, tij) mostly 

 entire; the awn borne at or alwve the middle : grain grooved, flatfish, fiee. 



3. A. atropurpurca, Wahl. Culms 8' -15' high, weak; leaves flat or 

 rather wide ; panicle of few spreading branches ; awn stont, twice the length of 

 the paleae. 1|. Alpine tops of the White Mountains, and those of N. New 

 York. August. (Eu.) 



48. D ANT HO N I A, DC. WILD OAT-GRASS. 



Lower palca (oblong or ovate, rounded-cylindraccous, 7 -9-nerved) bearing 

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

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

 nearly as in A vena. Glumes longer than the imbricated flowers. (Named for 

 Danthoine, a French botanist.) 



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

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

 like (2' long) ; the few spikelcts apprcssed, 7-ilowered ; lower palca broadlj 

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

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



49. TRISETUlfl, Persoon. TRISETUM. 



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

 compressed-keeled, of about the same merabranaceous 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 seta, a bristle) : other- 

 wise nearly as in Avena. 



1. T. Sllbspicatlim, Beauv., var. mo He. Minutely so ft -downy ; pani- 

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

 of the 2 -3 smooth flowers; awn diverging, much cxserted. (Avcna mollis, 

 Michx.) 1|. Mountains and rocky river-banks, N. New England to Wisconsin, 

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



2. T. pa lustre, Torr. Smooth; panicle rather long and narrow (5' long), 

 loose, the brandies cafiillary ; sptkdets flat (3" long) ; glumes shorter than the 2 

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

 rhaehis, and hears a slender spreading or bent awn next the short 2-pointed tip, 

 while the louxr one is commonly awnless or only mucronate-pointed. 1|. (Avena 

 palustris, Miclix. Aira pal lens, Mulil.) 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. 



Spikelcts 2 -many-flowered, panic-led; the flowers hcrbaceo-chartaccous, or 

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

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

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



