Description from Flora of China
Herbs, perennial, moderately robust to robust, rhizomatous [or stoloniferous]. Roots coarse. Culms central or lateral, if lateral then with cataphylls at base. Leaves 3-ranked, basal or cauline, ligulate; basal leaf sheath folded, adaxially open, cauline leaf sheath tubular; leaf blade leathery, glabrous. Involucral bracts leaflike or glumelike, basal bract usually longest. Inflorescence usually an open compound panicle or capitate, with 1 to many spikes. Spikes comprising many spirally imbricate glumelike bracts each subtending a bisexual spikeletlike unit with a much reduced axis (pseudospikelet). Pseudospikelets comprising a naked apparently terminal female flower and 2(or 3) glumes all subtending a male flower comprising 1 stamen; basal 2 glumes opposite, keeled. Perianth bristles absent. Stigmas 2 or 3. Nutlet with a sculptured hard outer surface, apex often conically rostrate or sometimes mucronate.
About 60 species: tropical and subtropical regions; four species (two endemic) in China.
(Authors: Dai Lunkai (戴伦凯); David A. Simpson, Gordon C. Tucker)