Annuals or perennials; culms tufted, solid. Leaf sheaths strongly compressed, blades linear, with broad base. Inflorescence a spike-like raceme, at apex of culm. Spikelets oblong, in alternate pairs, one shortly pedicelled and the other sessile, the uppermost pair forming a triad with terminal spikelet of raceme; spikelets dorsiventrally arranged. Sessile spikelets in the upper part of the raceme fertile, narrowly terete and shortly hairy, with geniculate awn of at least 60 mm, with glossy brown-hairy pungent base. Staminate spikelets larger, dorsally compressed, muticous twisted in such a way, that tops get side by side with tops of sessile spikelets. Fertile spikelets with lower glume short-hairy, with longitudinal fold which embraces base of awn; lower lemma small, membranous; upper lemma consisting of awn with membranous, narrow, usually stipe-like base, epaleate; lodicules 2; stamens 0-3; styles 2, with rudiment of a third, the stigmas long. Caryopsis long, crowned by base of styles. Staminate spikelets with lower glume many-nerved, green, margins membranous, sharply inflexed, usually winged; upper glume few-nerved, membranous; lemmas membranous, narrow; lodicules 2; stamens 3.
About 12 species distributed in tropical regions.
One species, H. contortus is found growing gregariously in the southern parts of Taiwan.