Plants perennial; cespitose. Culms 5-150 cm, erect. Sheaths open nearly to the base; auricles absent; ligules about as long as wide, membranous, truncate to rounded, ciliate-erose; blades convolute or involute, adaxial surfaces ribbed over the veins. Inflorescences narrow panicles or racemes; disarticulation above the glumes and beneath the florets. Spikelets laterally compressed, with (1)2-8 florets; rachillas pilose on all sides, terminating in reduced florets. Glumes equaling or exceeding the adjacent lemmas, exceeded by the distal florets, 1-3(5)-veined; calluses acute, strigose; lemmas pilose or glabrous, 3-5-veined, apices acute, toothed, awned from about midlength, awns geniculate, twisted and terete below the bend; paleas shorter than the lemmas, wings more than 1/2 as wide as the intercostal region; lodicules 2, lobed; anthers 3; ovariespubescent distally. Caryopses with a solid endosperm, longitudinally grooved, with a terminal tuft of hairs; hila more than 1/2 as long as the caryopses, linear. x = 7. Name from the Greek helictos, twisted, and trichon, awn, referring to the lemma awn.

Perennial; spikelets erect or spreading; first glume 1-3-veined, the second 3(5)-veined; otherwise like Avena. (Avena in part; Avenula) 90, Old World.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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