Plants perennial; rhizomatous. Culms 10-150 cm, erect, glabrous. Sheaths usually closed for up to 1/5 their length; auricles absent; ligules membranous, obtuse, erose or lacerate; blades usually flat, glabrous, scabrous. Inflorescences terminal panicles, loose and open to narrow and contracted; branches 0.5-27 cm, scabridulous. Spikelets 3-6.5 mm, pedicellate, laterally compressed, usually with 1 floret, rarely with 2; rachillas hairy or scabrous, sometimes prolonged beyond the base of the single floret or terminating in a well-formed or vestigial floret; disarticulation above the glumes, beneath the floret(s). Glumes usually shorter than the lemmas, upper glumes sometimes equaling the lemma(s), ovate to lanceolate, glabrous, sometimes scabridulous, 1-3-veined, acute to obtuse, unawned; calluses weakly developed, glabrous; lemmas scabrous or puberulent, 3-5-veined, lateral veins sometimes obscure, not reaching the apices, apices obtuse to acute, sometimes mucronate, unawned; paleas about as long as the lemmas, folded along 1 prominent vein, the second vein faint; lodicules 2, glabrous; anthers 3; ovaries glabrous. Caryopses 1.7-3 mm, shorter than the lemmas, concealed at maturity; hila 1/4-1/3 the length of the caryopses. x = 7.
Distribution
Alta., B.C., Greenland, Nfld. And Labr. (Nfld.), Man., N.W.T., Nunavut, Ont., Que., Yukon, Alaska
Discussion
Arctagrostis is a circumpolar genus with one species and two subspecies.