572 GRAMINE^. (grass FAMILY.) 



§ 2. VAHL6DEA, Fries. — Glumes more boat-shaped, lonyet- than the Jloioers; 

 lower palea of a firm or coriaceous texture, nerveless, the truncate-obtuse tip moslti/ 

 entire ; tlie avm borne at or aliove the middle : grain grooved, flattish, free. 

 3. A. atropiirpurea, Wahl. Ctdms 8'-15' high, weak; leaves flat or 



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

 the palese. % — Alpine tops of the White Mountains, and those of N. New 

 Yorlc. August. (Eu.) 



48. DANTIIONIA, DC. Wild Oat-Gkass. 



Xiower palea (oblong or ovate, rounded-cylindraceous, T-'g-neiTed) 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 Avena. Glumes longer than the imbricated flowers. (Named for 

 Danthoine, a French botanist.) 



1. n. spickta, Beauv. Culms tufted (1° -2° high); 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. 

 % — Dry and sterile or rocky soil. July. 



49. TBISIITUM, Persoon. Tkisetum. 



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 Ms, three, and seta, a bristle) : other- 

 wise nearly as in Avena. 



1. T. subspicatum, Beauv., var. mfille. Minutely soft-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 exserted. (Avena mollis, 

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

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



2. T. palustre, Torr. Smooth; pani'de 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 

 rliachis, and bears a slender spreading or bent awn next the short 2-pointed tip, 

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

 palustris, Michx. Aira pallens, Muhl. ) — 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, panicled; the flowers herbaceo-chartaceous, or 

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

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

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



