Annual or perennials with a simple or branched stem and with finely dissected leaves. Flowers solitary, terminal on the main stem or on lateral branches. Sepals 5-8, usually thin, pellucid. Petals 5 to numerous, petaloid, red or yellow, rarely white. Stamens numerous. Carpels arranged in a subglobose to cylindrical spike, developed as 1-seeded nutlets, rugose with a distinct beak at maturity.
Most of the species are poisonous.