Description from Flora of China
Herbs annual. Leaves alternate, sessile, linear to lanceolate, complanate, semiterete, or terete, membranous or fleshy, densely hairy. Flowers solitary or forming a spike, sessile, without bracts or bractlets, bisexual. Perianth discoid, 5-lobed, hairy; segments equal; abaxial appendages uncinate, subulate, or triangular in fruit. Stamens 5. Ovary broadly ovoid; style short; stigmas 2 or 3. Utricle depressed ovoid; pericarp membranous, free from seed. Seed horizontal, depressed globose; embryo annular.
Between ten and twelve species: warm-temperate and subtropical zones of the Old World; three species in China.