Plants weakly cespitose, rhizomatous, strongly glaucous. Culms 50-150 cm tall, (2)3-6 mm thick, usually glabrous throughout, occasionally pub¬escent distally to 5 mm below the spike. Leaves exceeded by the spikes; ligules 0.3-2.5 mm; blades 3-11 mm wide, with 15-40 adaxial veins. Spikes 12-35 cm long, 15-25 mm wide, usually with 2 spikelets per node; internodes 8-12 mm, surfaces glabrous, edges ciliate. Spikelets 12-30 mm, with 2-5 florets. Glumes 12-30 mm long, 2-3.5 mm wide, lanceolate, tapering from below midlength, stiff, glabrous towards the base and usually distally, sometimes pubescent distally, the central portion thicker than the margins, 3(5)-veined at midlength, keeled or rounded over the midvein, midveins and sometimes the margins with hairs to about 1.3 mm, apices acuminate; lemmas 12-25 mm, densely villous, hairs 0.3-0.7 mm, 5-7-veined, acute, occasionally awned, awns to 3 mm; anthers 6-9 mm, dehiscent. 2n = 56.
Mich., Wis., N.Y., Ill., Ind., Greenland, N.W.T., Ont., Que., Conn.
Leymus arenarius is native to Europe. It has become established in sandy habitats around the Great Lakes and the coast of Greenland. It has also been found at a few other widely scattered locations. It is sometimes cultivated, forming large, attractive, blue-green clumps, but its tendency to spread may be undesirable.