Annuals or perennials. Leaf-blades flat or involute; ligule a line of hairs. Inflorescence a cylindrical spike-like panicle with an angular rhachis, each spikelet or cluster of spikelets enclosed by a deciduous involucre; involucre composed of 1 or more whorls of bristles, these ± flattened and often spiny, connate at the base for some distance along their length. Spikelets .lanceolate to ovate, dorsally compressed, acute to acuminate; lower glume up to half as long as the spikelet, sometimes suppressed; upper glume a little shorter than the spikelet; lower floret male or barren, its lemma as long as the spikelet, membranous; upper lemma as long as the spikelet, firmly membranous to coriaceous, the margins covering up to two-thirds of the palea. Caryopsis & elliptic to ovoid, dorsally compressed.