Plants annual or perennial. Culms to 180 cm, erect or geniculate. Sheaths open, auricles absent; ligules elongate, membranous, becoming lacerate; blades flat or inrolled. Cleistogamous panicles often enclosed in the lower sheaths, the spikelets unawned, often with fewer florets and smaller anthers than the aerial spikelets. Terminal inflorescences panicles, open to spikelike. Spikelets 7-25 mm, laterally compressed, with 2-10 florets, occasionally cleistogamous florets intermixed with the chasmogamous florets, distal florets often reduced, staminate; rachillas pubescent, prolonged beyond the uppermost pistillate floret, empty or terminating in a reduced floret; disarticulation above the glumes and between the florets. Glumes subequal to unequal, shorter than the adjacent lemmas, ovate to lanceolate, scarious, acute to obtuse, often erose; lower glumes shorter and narrower than the upper glumes, (1)3(5)-veined; upper glumes 3-7-veined; calluses blunt, pubescent; lemmas chartaceous, smooth or scabrous, with 5-9 prominent veins, apices 2-4-toothed or -lobed, the outer lobes often smaller than the inner lobes, lobes aristate to obtuse, awns arising from just below the middle to near the apices, sometimes straight when young, geniculate at maturity, spreading or recurved; paleas subequal to or much shorter than the lemmas, bilobed; lodicules 2, free, glabrous, not lobed; anthers 3; ovaries glabrous. Caryopses terete, apices often with a few hairs; hila to 1/2 the length of the caryopses. x = unknown. Name of uncertain origin, perhaps in part from the Greek bromos, a kind of oats. Nees (1843) wrote "Habitus potius Avenæ quam Bromi [Appearance/habit rather/preferably of Avena than of Bromus ]", alluding to its similarity with Avena, not Bromus.