Perennials; culms solid; root-primordia present at the base of nearly all internodes, in 2-9-rows. Ligule and collar well-developed; blade linear, sometimes very much reduced in width, leaving scarcely more than a midrib, just behind ligule on both sides with a group of long hairs, the margins serrate, the midnerve not or only slightly decurrent into the sheath. Inflorescence a large, silky panicle, composed of spike-like racemes. Spikelets in pairs, the one pedicelled, the other sessile, dorsally compressed, oblong, the base hairy, with hairs much longer than spikelets; glumes as long as spikelet, obtuse, or upper glume mucronate, glabrous; lower glume with margins inflexed, mostly with an even number of nerves without midnerve, sometimes with a shorter or longer midnerve; upper glume 1-5-nerved; lower lemma slightly shorter, hyaline; lower palea absent; upper lemma wanting, or hyaline, muticuous; upper palea small, hyaline; lodicules 2, cuneate, obliquely emarginate, hairy or hairless; stamens 3; ovary glabrous, the styles 2, about free, the stigmas plumose, exserted laterally, purplish-red or white.
About five species distributed in the tropical and subtropical regions of the world.
Four species and one variety are found both in cultivation and wild, S. spontaneum is extremely common in river beds.