Description from Flora of China
Herbs mostly dioecious, rarely monoecious or polygamous. Rhizome scales imbricate, densely woolly pubescent. Stem simple or branched, terete, hollow except at nodes. Leaves usually closely appressed to stem, persistent; leaf sheath open, margin sometimes scarious, apex elongate; ligule usually absent; leaf blade absent. Inflorescences narrowly paniculate; spikelets very small, clustered, male ones pedicellate, female ones sessile, sometimes spicate; glumes subtending spikelets imbricate. Perianth segments 4--6 or sometimes indefinite, variously shaped. Male flowers: stamens (1 or)2 or 3; filaments ligulate to filiform, free; anthers dorsifixed, 1-loculed, introrse, apex apiculate; ovary (when present) rudimentary. Female flowers: staminodes 3 or absent; ovary superior, 1-loculed; styles usually 3, free or connate at base, free parts entirely stigmatic. Bisexual flowers: stamens 1--3; pistil 1. Fruit narrowly ellipsoid, ovoid, or obovoid; pericarp thin and opening on 1 side or thick and splitting at angles.
Four species: Cambodia, China, Indonesia (Aru Islands), Laos, Malaysia, New Guinea, Thailand, Vietnam; Australia; one species in China.