Plants perennial; not rhizomatous. Culms 50–100(110) cm, usually erect, sometimes decumbent at the base; nodes 3–5, pubescent, puberulent, or glabrous; internodes puberulent or glabrous. Sheaths and throats pilose or glabrous; auricles absent; ligules 0.5–1 mm, glabrous, truncate, erose; blades 10–17 cm long, 5–10 mm wide, flat, with prow-shaped tips, both surfaces glabrous or pilose or only the adaxial surfaces pilose. Panicles 8–13 cm, open, drooping; branches ascending to spreading, flexuous. Spikelets 15–25 mm, elliptic to lanceolate, terete to moderately laterally compressed, with 7–11 florets. Glumespubescent, margins often hyaline; lower glumes 5–7.5 mm, 3-veined; upper glumes 6.5–8.5 mm, 5-veined; lemmas 7–11 mm, elliptic to lanceolate, rounded over the midvein, backs more or less uniformly pilose or pubescent, margins densely long-pilose, apices acute to obtuse, entire; awns 1.5–3 mm, straight, arising less than 1.5 mm below the lemma apices; anthers 1.5–2.5 mm. 2n= 14.
Bromus kalmii grows in sandy, gravelly, or limestone soils in open woods and calcareous fens. Its range centers in the north-central and northeastern United States and adjacent Canadian provinces.