Tufted or stoloniferous perennials, rarely annuals. Culm internodes solid or spongy. Ligule a membrane, sometimes fringed. Inflorescence a panicle of 2–several racemes. Spikelets dorsiventrally flattened, subsessile, arranged in 2 rows, each row along 1 side of the 3-angled raceme, 2-flowered, the lower floret neuter, the upper floret bisexual; lower glume not developed; sterile lemma membranous, as long as the spikelet; fertile lemma firm, slightly shorter than or equal to the spikelet, its dorsal surface facing away from the axis.
Around 110 species, mostly from tropical South America; 2 naturalised in Australia, 1 in Victoria.