Perennials; clums decumbent and stout. Leaf sheaths glabrous; ligule very short, ciliate; blades linear.
Inflorescence composed of spike-like racemes, alternately palced along a rather wider main axis,
which merges into a terminal raceme, usually longer than lateral racemes immediately below it; lateral
racemes erect and appressed to main axis, with a flattened axis, abaxial side with a zigzag keel. Spikelets
solitary, alternate along keel, very regularly 2-seriate, close together, elliptic, acute, nearly flat abaxially,
comvex on ventral side, unawned, 2-flowered, articulate with very short pedicels; upper spikelet
usually poorly developed; glumes shorter than spikelet; lower lemma as long as spikelet, 5-7-veined;
glumes and lower lemma thin; lower palea with broad, inflexed margins or absent; upper lemma as long
as spikelet or slightly shorter, acuminate, in older spikelets chartaceous, distinctly tuberculate or rugose,
with incurved margins; upper palea of same texture, embraced by margins of upper lemma; lodicules 2;
stamens 3; styles 2, free, stigmas plumose, exserted near apex. Caryopsis plano-convex.
About 40 species throughout tropics. Two species in Taiwan.