Annuals or perennials. Leaf-blades flat or filiform; ligule a ciliate rim. Inflorescence a panicle with capillary branches (very rarely the primary branches raceme-like). Spikelets ± asymmetrical in profile, laterally compressed, often silky hairy; lower glume small, sometimes distant from the upper; upper glume as long as the spikelet, firmly membranous to subcoriaceous, becoming thinner towards the tip, 5-nerved, ± gibbous below the middle and sometimes tapering to a beak above, emarginate to bibbed (rarely entire), often awned from the sinus; lower floret usually male, its lemma resembling the upper glume or somewhat narrower and less gibbous, the palea present (except in the African R. scabridum (K. Schum.) Chiov.) and usually ciliate on the margins; upper lemma smaller than the lower, often deciduous before the rest of the spikelet, cartilaginous, smooth, laterally compressed and ± enfolding the palea. Caryopsis oblong-ellipsoid.