Description from Flora of China
Herbs, perennial. Rhizomes usually very short, sometimes obliquely and shortly creeping, rarely stoloniferous and spreading. Stems usually tufted, rarely scattered. Leaves basal or sub-basal; basal leaf sheaths persistent and usually prominent; blade with midrib not distinct abaxially (margin involute, sometimes filiform), or with midrib distinct abaxially (flat, sometimes folded). Inflorescence terminal, paniculate to spicate, sometimes unisexual; lowest involucral bract leafy or glumelike, sheathless; branches of inflorescence sessile. Spikelets subtended by glumes, unisexual or bisexual; bisexual spikelets with 1 female flower at base and 1 to several male flowers at distal parts enclosed by prophylls; unisexual spikelets with a solitary female flower within prophylls. Sterile rachilla in female spikelet usually present. Flowers unisexual. Female flowers reduced to naked pistils; ovary 2- or 3-carpellate; style elongated; stigmas 2 or 3. Male flowers subtended by male glumes; stamens 1-3; filaments free, longer than glumes, slender; male glumes usually distinct in shape from glumes of female spikelets. Nutlets trigonous or flattened, usually included in prophylls, beaked or not, stipitate or not.
About 54 species: mainly in temperate regions of the N Hemisphere; 44 species (16 endemic, one unconfirmed) in China.
(Authors: Zhang Shuren (张树仁); Henry J. Noltie)