Plants perennial; not rhizomatous. Culms 80-150 cm, erect; nodes 9-20, glabrous, usually concealed by the leaf sheaths; internodes usually glabrous, sometimes hairy just below the nodes. Sheaths overlapping, densely to moderately retrorsely pilose or glabrous over most of their surface, throats and collars densely pilose; auricles 1-2.5 mm on most lower leaves; ligules 0.8-1.4 mm, hirsute, ciliate, truncate, erose; blades 20-30 cm long, 5-15 mm wide, flat, usually glabrous, rarely pilose, with 2 prominent flanges at the collar. Panicles 10-22 cm, open, nodding; branches spreading to ascending. Spikelets 15-30 mm, elliptic to lanceolate, terete to moderately laterally compressed, with 4-9 florets. Glumes pubescent or glabrous; lower glumes 4-7.5 mm, 1(3)-veined; upper glumes 6-9 mm, 3-veined, sometimes mucronate; lemmas 8-14 mm, elliptic to lanceolate, rounded over the midvein, backs glabrous or pilose to pubescent, margins long-pilose, apices obtuse to acute, entire; awns 3-4.5(7) mm, straight, arising less than 1.5 mm below the lemma apices; anthers 2-3 mm. 2n = 14.
Conn., N.J., N.Y., Del., D.C., Wis., W.Va., Kans., N.Dak., Nebr., S.Dak., N.H., N.C., Pa., Alta., B.C., Man., N.B., Ont., Que., Sask., Va., Vt., Ill., Ind., Iowa, Maine, Md., Mass., Ohio, Mo., Minn., Mich., Mont., Tenn., Ky.
Bromus latiglumis grows in shaded or open woods, along stream banks, and on alluvial plains and slopes. Its range is mainly in the north-central and northeastern United States and adjacent Canadian provinces. Specimens with decumbent, weak, sprawling culms, densely hairy sheaths, and heavy panicles can be called Bromus latiglumis i. incanus (Shear) Fernald.