Description from Flora of China
Herbs, annual or perennial. Leaves basal; leaf blade flat. Involucral bracts leaflike. Spikes 2-7, fascicled into a capitulum or rarely single, with many bractlets and spikelets; bractlets spirally arranged, each with a spikelet. Spikelet with 2 glumes (sometimes absent) and a bisexual flower; rachilla very short, articulate at base, deciduous at article when mature; glumes alternate, membranous, several veined; basal glume without a flower; apical glume with a bisexual flower. Perianth bristles absent. Stamens 2. Stigmas 2. Nutlet 3-sided, biconvex, or plano-convex, included by subtending glume.
About 35 species: warm temperate and subtropical regions; four species in China.
(Authors: Dai Lunkai (戴伦凯); Gordon C. Tucker)