Plants annual, biennial, or perennial; loosely cespitose or tufted. Culms 30–120 cm tall, 2–4 mm thick, erect or decumbent. Sheaths densely, often retrorsely, hairy, hairs sometimes confined to the throat; auricles absent; ligules 1–4 mm, glabrous or pilose, obtuse, lacerate to erose; blades 4–30 cm long, 3–10 mm wide, flat, glabrous or hairy on both surfaces. Panicles 9–28 cm, usually open, erect or nodding; lower branches shorter than 10 cm, 1–4 per node, spreading or ascending, with up to 5 spikelets variously distributed. Spikelets (17)20–40 mm, shorter than at least some pedicels and branches, elliptic to lanceolate, strongly laterally compressed, not crowded or overlapping, with 4–12 florets. Glumes smooth or scabrous, glabrous or pubescent; lower glumes 7–12 mm, 5–7(9)-veined; upper glumes 9–17 mm, 7–9(11)-veined, shorter than the lowest lemma; lemmas 11–20 mm, lanceolate, laterally compressed, strongly keeled, usually glabrous, sometimes pubescent distally, smooth or scabrous, 9–13-veined, veins often raised and riblike, margins sometimes conspicuous, hyaline, whitish or partly purplish, apices entire or toothed, teeth acute, shorter than 1 mm; awns absent or to 10 mm; anthers 0.5–1 mm in cleistogamous florets, 2–5 mm in chasmogamous florets. 2n = 42.
Leon E. Pavlick and Laurel K. Anderton
Plants annual or biennial; tufted. Culms 30120 cm, erect or decumbent. Sheaths densely, often retrorsely, hairy, hairs sometimes confined to the throat; ligules1–4 mm, glabrous or pilose, erose; blades 4–26 cm long, 3–10 mm wide, glabrous or hairy on both surfaces. Panicles 9–28 cm, open, erect or nodding; lower branches 1–4 per node, spreading or ascending, with 1–5 spikelets. Spikelets 20–30 mm, with 6–12 florets. Lower glumes 5–7-veined; upper glumes 9–13 mm, (7)9(11)-veined; lemmas 11–20 mm, glabrous or scabrous, sometimes pubescent distally, (9)11–13-veined; awns absent or to 3.5 mm; anthers about 0.5 mm in cleistogamous florets, 2–4 mm in chasmogamous florets. 2n = 42.
Bromus catharticus var. catharticus is native to South America. It has been widely introduced in the Flora region as a forage crop and is now established, particularly in the southern half of the United States. It usually grows on disturbed soils.