Erect or ascending herbs, annual or perennial, sometimes woody at the base. Leaves alternate, stipulate or not, simple, petioled, serrate or serrate-dentate, biglandular at the base or not, herbaceous. Flowers in the Malaysian species solitary in the leafaxils or in terminal racemes, actinomorphic, ♀, homostylous or heterodistylous, ephemerous. Calyx gamophyllous, 5-fid, after anthesis circumsciss at the base; segments imbricate in bud. Petals 5, inserted in the throat of the calyx-tube, contorted in bud, free, shortly clawed or subsessile, deciduous after anthesis. Stamens 5, inserted on calyx-tube, alternating with the petals; filaments filiform-subulate, free; anthers introrse, 2-celled; cells opening longitudinally. Ovary superior, sess...