Rhizomes about 2 mm thick. Culms 12–70 cm. Basal blades 10–31 cm long, 3–8 mm wide. Spikes 5–13(16) cm, with 3–14 nodes. Glumes 9–14(21) mm long, 1.5–2.5 mm wide, often longer than the lemmas, villous. 2n = 28.
Leymus mollis subsp. villosissimus is an arctic taxon found primarily in eastern Siberia, Alaska, and northwestern Canada. It grows mostly on arctic coasts, but is also known from a few inland locations.