Monoclinous or diclinous (gynomonoecious, gynodioecious, or dioecious) Annuals or perennials; with or without downward or laterally tending cataphyllous shoots. densely to loosely tufted; tillers extravaginal, intravaginal, pseudointravaginal, or combinations of these. Culms 2--150 cm (rarely taller), 1--4 mm diam., hollow, terete or weakly to stongly compressed; nodes terete or compressed. Leaves; Leaf sheaths, basal sheaths sometimes bulbous, flag-leaf sheath margins fused at least at least at the base, but more often between 1/10 and the top; ligules membranous, upper margins entire to lacerate, smooth or asperous or ciliolate, apicies truncate to acuminate; blades linear, flat to folded, or involute, abaxially with a central keel, margins usually upturned or more or less inrolled when folded, adaxially usually with 2 central groves these flanking the mid-rib, tips acuminate or more often prow-tipped. Panicles 1--50 cm long, erect to nodding, contracted to diffuse, lanceoloid to pyramidal, with 10 to 100s of spikelets; axis with 1--7 (-- 25) branches per node; primary branches terete to prominently angled, smooth to strongly scabrous, pedicels 1/5 to longer than the spikelets. Spikelets 2.5--8 (--12) mm long, ovoid to lanceolate, laterally compressed, not or sometimes bulbiferous; florets (1--) 2--6 (--12); rachilla internodes terete, smooth, muriculate, or scabrous, glabrous or pubescent, joint tips without a beard or crown of hairs; Glumes 2, usually more than 1/3 the lower lemma in length, rarely exceeding the lower lemma, keeled, herbaceous chartaceous, without awns; lower glumes 1--3 veined; upper glumes 3 (--7)-veined; callus glabrous or pubescent, hairs in a dorsal tuft (rarely diffuse or arranged as a crown or short beard); lemmas 1.7--8 mm long, keeled (rarely rounded), subchartaceous to subcoreaceous, smooth, scabrous, or pubescent, 3--5 (--11) veined, margins smooth or scaberulous, distally scarious, apicies obtuse to acute (--acuminate), usually entire, awnless; paleas herbaceous, 2-keeled, keels smooth or scabrous, glabrous or pubescent, inter-keel surface broader than the marginal flanges. Flowers bisexual or unisexual (upper flowers sometimes pistillate in Turkey); lodicules 2, distally broadly membranous, usually lobed, glabrous; anthers (1, 2) 3, 0.1--4 mm long; ovaries glabrous, styles terminal, adjacent or slightly gapped (fused at the base in P. flabellata), lanceoloid, plumose, white; caryopsis 0.9--2.5 (--4) mm long, elliptical to fusiform in ventral veiw, laterally compressed to trigonous to nearly round in cross-section, ventrally sulcate, brownish, dull or sub-lustrous, hard, lipid present, free or adherent to the palea, embryo 1/5--1/3 the grain in length, hilum punctiform, or round to narrowly elliptical, less than 1/6 the grain in length. x = 7, polyploidy common.