Creeping annual or perennial herbs with mixed stellate and simple hairs. Leaves alternate; stipules present, ± persistent. Flowers bisexual, solitary in axils; epicalyx of 3 free segments; calyx 5-lobed, the lobes about equal to the broadly campanulate tube, expanding in fruit; petals 5, free; stamens numerous, at the mouth of the obconical staminal tube; style-branches and locules c. 20, stigmas capitate; ovules 2 per locule. Fruit a schizocarp, the mericarps maturing 1 or 2 seeds, usually remaining attached to receptacle until seeds shed.
A single species, native to tropical and near-tropical America, widely naturalized.