Bromus arenarius Labill.

Annual, caespitose. Culms 4–75 cm high. Leaves: basal sheaths pubescent to pilose (hairs dense) or occasionally glabrous; blade 4–24 cm long, 1–7 mm wide, usually densely pubescent to pilose or rarely glabrous to scabrous. Panicles nodding, open, 2.8–18 cm long; primary branches spreading. Spikelets erect or pendulous, oblong or elliptic, 13–45 mm long, with 4–14 bisexual florets; pedicel 4–45 mm long. Glumes unequal, keeled, with midnerve scaberulous to pilose and intercostal regions glabrous to densely pilose; lower glume 5.5–10 mm long, (1–) 3 (–5)-nerved; upper glume (7.8–) 8.2–11.5 mm long, 5–7 (–9)-nerved. Callus blunt, laterally scabrous. Basal lemma slightly laterally compressed, 9.3–18 mm long, ±dorsally rounded, 7-nerved; nerves scabrous to densely villous; intercostal regions glabrous to covered with dense, antrorse, spreading to appressed hairs, mostly c. 0.3 (–0.9) mm long; awn dorsal, arising 1.4–4 mm below lemma tip, (6.5–) 9–14 mm long (somewhat longer in upper florets), straight or curved (awns of lower floret usually straight, awn of upper florets not twisted at base and tending to recurve), entered by 3 nerves. Palea slightly shorter than lemma, ±reaching point of awn insertion on lemma, glabrous or puberulous. Anthers 0.8–1.5 mm long.

Commonly ingrasslands and shrublands on sand, sandy loam or cracking clay, along drycreeklines, lake beds or floodplains subject to periodic inundation; or in soilpockets in rocky outcrops.