Plants not cespitose, strongly rhizomatous, occasionally slightly glaucous. Culms 12-170 cm tall, 3-6 mm thick, usually densely pubescent below the spikes for 10-40+ mm. Leaves exceeded by the spikes; auricles to 0.7 mm; ligules 0.2-2.5 mm; blades 10-94 cm long, 3-15 mm wide, adaxial surfaces scabridulous to scabrous, 20-40-veined, veins subequal, prominently ribbed, closely spaced. Spikes 5-34 cm long, 10-20 mm wide, with 3-33 nodes, usually with 2 spikelets per node; internodes 4.5-9.5 mm, surfaces and edges similar, soft, hairs on the surfaces 0.1-0.5 mm, on the edges to 0.7 mm. Spikelets 15-34 mm, with 3-6 florets. Glumes 9-34 mm long, 1.5-4 mm wide, lanceolate, tapering from midlength or above, flat or rounded on the back, flexible, usually strigillose to pilose or villous, rarely almost glabrous, the central portion scarcely thicker than the margins, 3(5)-veined at midlength, apices acute; lemmas 11-20 mm, densely hairy, hairs 0.5-1 mm, soft, apices acute, unawned; anthers 4-9 mm, dehiscent.
Leymus mollis is native to Asia and North America. It is treated here as having two very similar subspecies that have somewhat different ranges. The subspecies are sometimes treated as separate species, but they may be little more than environmentally induced variants. Both subspecies grow primarily on coastal beaches, close to the high tide line, and along some inland waterways, particularly in the arctic. Reports of Leymus ajanensis (V.N. Vassil.) Tzvelev from North America are based on specimens of L. mollis (D. Murray, University of Alaska, pers. comm. 2006).
Stout, erect, green or somewhat glaucous, 5-15 dm, from long, stout rhizomes; culms finely hairy under the spike, otherwise glabrous; sheaths crowded and overlapping at base; lvs 6-15 mm wide; ligule scarcely 1 mm; spike stout, erect, dense, 1-3 dm נ1-2 cm; spikelets coarse, 4-6-fld, mostly paired at the nodes; glumes lanceolate, 13-30 נ2-4 mm, strongly 3-5-nerved, about as long as the spikelet, evidently villous-hirsute; lemmas hairy like the glumes, or more so, tapering to a slender, awnless tip; anthers 5-9 mm; 2n=28. Sandy beaches and dunes; both coasts of n. N. Amer., s. to Mass. and Calif., on the shores of Lake Superior, and on the Arctic shore and the coast of ne. Asia. (Elymus m.) Ours is the relatively southern var. mollis.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.