Description from Flora of China
Herbs or subshrubs. Stem erect or ascending. Leaves opposite, petiolate, margin entire. Flowers clustered in cymose partial inflorescences, 1-3 in each cluster, hermaphroditic, partly accompanied by sterile ones. Bracts ovate, membranous, often spiny. Tepals 5, nearly equal, membranous. Stamens 5; anther 2-loculed, oblong; filaments connate into a short cup at base, alternating with dentate or lacerate staminodes. Ovary obovoid; ovule 1, pendulous from a long funicle; style filiform, persistent; stigma capitulate. Utricles included in persistent perianth, globose, ellipsoid, or obovoid, membranous, indehiscent. Seeds oblong or ellipsoid.
Cyathula semirosulata Masamune (Trans. Nat. Hist. Soc. Taiwan 33: 111. 1943) was described from Hainan, but we have seen no specimens and are therefore unable to treat it in this account. Further revisionary study is necessary.
About 27 species distributed in Asia, Pacific Islands, Africa, and North and South America; four species in China.