Description of the genus
Annual, glabrous or pubescent, small herbs. Leaves usually 1-pinnate, pinnae toothed or lobed. Inflorescence terminal or axillary leaf-opposed umbels. Peduncles glabrous or pubescent. Rays 3-10, glabrous or pubescent. Bracts 3-5, margins scarious, ciliate; bracteoles 5-6, papery, margins ciliate. Flowers white or pale purple. Calyx-teeth reduced, adnate to ovary wall. Corolla with 5 petals, obovate or obcordate, emerginate with long pointed tip. Stamens 5, filaments long, anthers bithecous, hairy at base. Fruits oblong, oblanceolate, pubescent or glabrescent, ridges obscure, unwinged furrows, vittae usually one carpophore, bifid, mericarps dorsally compressed, hairs simple intermixed with a few T-shaped.