12. Urena Linnaeus, Sp. Pl. 2: 692. 1753.
梵天花属 fan tian hua shu
Herbs perennial or shrubs, stellate. Leaves alternate; leaf blade orbicular or ovate, palmately lobed or sinuate, with 1 or more prominent foliar nectaries on abaxial surface. Flowers solitary or nearly fascicled, rarely racemelike, axillary or rarely aggregated on twig tips. Epicalyx campanulate, 5-lobed. Calyx 5-parted. Petals 5, stellate puberulent abaxially. Staminal column truncate or slightly incised; anthers numerous, on outside of staminal column only, nearly sessile. Ovary 5-loculed; ovule 1 per locule; style branches 10, reflexed; stigma discoid, apically ciliate. Fruit a schizocarp, subglobose; mericarps 5, ovoid, usually with spines, these each with a cluster of short barbs at tips. Seed 1, obovoid-trigonous or reniform, glabrous.
About six species: in tropical and subtropical regions; three species (one endemic) in China.
Some authorities have restricted Urena to the taxa with barb-tipped setae, sometimes treating these as a single, very variable, pantropical species, and placed other species, including U. repanda, in Pavonia. Some species of Triumfetta (Tiliaceae s.l.) are superficially rather similar and have been confused with this genus.