A large monoecious glabrous annual or perennial herb. Leaves alternate, petiolate, stipulate, peltate, palmately-lobed, the lobes glandular-serrate, penninerved. Petioles glandular at apex and base. Stipule united to form a caducous sheath. Inflorescences paniculate, subterminal or leaf-opposed, ♂ in the lower half and ♀ in the upper or else all ♀; bracts membranous, soon caducous. Male flowers: pedicels articulate, bibracteolate; buds globose, closed, later splitting into 3-5 valvate lobes; petals 0; disc 0; stamens up to 1000 with the filaments variously united, anthers basifixed, the cells globose, longitudinally dehiscent; pistillode 0. Female flowers; pedicels extending in fruit; buds conical; sepals 5, valvate, soon caducous; petals 0; disc 0; ovary 3-celled, with 1 ovule per cell, echinate or smooth; styles 3, ± free, bipartite, papillose-plumose, dark red. Fruit trilobate, echinate or smooth, dehiscing into 3 bivalved cocci. Seeds dorsiventrally compressed-ovoid, smooth, carunculate, testa crustaceous, albumen fleshy; cotyledons broad, flat.