38. DESCHÁMPSIA, Beauv. ([Pl. 12.])
Spikelets small, panicled, of 2 perfect flowers and the hairy pedicel or rudiment of a third (rarely staminate); rhachis hairy. Empty glumes persistent, membranaceous and shining, carinate, acute, nearly equal; flowering glumes toothed or erose-denticulate at the truncate summit, usually delicately 3–5-nerved, with a slender twisted awn near or below the middle. Grain oblong, free.—Root perennial. (Named for Loiseleur-Deslongchamps, a French botanist.)
[*] Empty glumes somewhat shorter than the flowers.
1. D. flexuòsa, Trin. (Common Hair-Grass.) ([Pl. 12], fig. 1–3.) Culms slender, nearly naked (1–3° high) above the small tufts of involute bristle-form root-leaves (1–6´ long); branches of the small spreading panicle capillary; awn longer than the palet, at length bent and twisted. (Aira flexuosa, L.)—Dry places; common. June. (Eu.)
2. D. cæspitòsa, Beauv. Culm tufted (2–4° high); leaves flat, linear; panicle pyramidal or oblong (6´ long); awn straight, barely equalling the glume. (Aira cæspitosa, L.)—Shores of lakes and streams; N. Eng. to Penn., Mich., and northward. June, July. (Eu.)
[*][*] Empty glumes longer than the flowers, 2–2½´´ long.
3. D. atropurpùrea, Scheele. Culms 8–15´ high, weak; leaves flat, rather wide; panicle of few spreading branches; awn stout, twice longer than the nerveless truncate ciliolate-denticulate glume. (Aira atropurpurea, Wahl.)—Alpine summits of N. H. and N. Y., to Lab. and northward. Aug. (Eu.)
39. TRISÈTUM, Persoon. ([Pl. 12.])
Spikelets 2–several-flowered, often in a contracted panicle; the flowering glume compressed-keeled, of about the same thin-membranaceous texture as the empty glumes, bearing a bent or flexuous (rarely twisted) awn at or below the sharply 2-toothed or 2-pointed apex (whence the name, from tris, three, and seta, a bristle); otherwise nearly as in Avena. Ours are perennials.
1. T. subspicàtum, Beauv., var. mólle, Gray. ([Pl. 12], fig. 1, 2.) Minutely soft-downy; panicle dense, much contracted, oblong or linear (2–3´ long); glumes about the length of the 2–3 smooth flowers; awn dorsal, diverging, much exserted.—Mountains and rocky river-banks, N. New Eng. to L. Superior, and northward. July.—About 1° high; leaves flat, short. (Eu.) (Addendum)—Trisetum subspicatum, var. molle, is reported from Roan Mt., N. C. (Scribner), and probably occurs on the higher Alleghanies northward.