Strong, tufted, bright green, rarely glaucous, summer annuals, with stout culms, usually ± prostrate at first, particularly in open situations, becoming erect at flowering. Leaf-sheath light green or purplish, chartaceous, keeled, glabrous, or occasionally with soft tubercle-based hairs just inside margin and scattered elsewhere. Ligule 0; ligular area glabrous, rarely faintly pubescent. Leaf-blade 15-50 cm × 5-15 mm, soft, flat, linear, glabrous, or sometimes with scattered soft, tubercle-based hairs, midrib distinct; margins and sometimes midrib scabrid, tapering to acute tip. Culm (20)-30-130 cm, slender to stout, often branching and compressed below, internodes glabrous. Panicle (6)-10-20 cm, erect, ± open, very variable in shape and in presence or absence of awned florets, with few to many spike-like racemes borne singly, or in pairs or clusters at nodes; rachis 3-angled, scabrid. Racemes (1)-2.5-6 cm, erect or spreading, distant or approximate, but not extremely close-set, bearing spikelets crowded in clusters of 2 or 3; rachis 3-angled, scabrid, hairs few to many, bristle-like tubercle-based hairs clustered at base; pedicels scabrid, 0.5-1 mm. Spikelets 3-5 mm, greenish or often purplish, ovate-elliptic, acute to acuminate. Glumes quite unequal, submembranous, acute to cuspidate, scabrid; lower 1.2-1.7 mm, 3-5-nerved, broadly ovate, enwrapping base of spikelet, upper 3-4 mm, 5-nerved, very convex, with bristle-like, tubercle-based hairs on nerves, very rarely slightly awned. Lower floret: lemma similar to upper glume, 5-7-nerved, flat or dorsally depressed with central nerves often obscure, nerves, especially lateral nerves, with tubercle-based spinules, apex acute, cuspidate or distinctly awned (2-25 mm) in some florets; palea < lemma, hyaline, broad, keels finely ciliate. Upper floret: lemma 2.7-3.5 mm, ovate-elliptic, very convex, whitish or yellowish, glabrous, shining, thinly crustaceous, cuspidate, apex greenish, scabrid, submembranous, deltoid; palea ≈ lemma, apex subobtuse, soft; anthers 0.5-0.7 mm, brownish yellow or greyish; caryopsis 1.2-2 × 1.4-1.8 mm, orbicular, greenish or whitish, not turgid.