Plants herbs to soft-wooded trees; monoecious; glabrous throughout. Leaves alternate, stipulate and petiolate; stipules united to form a sheath which quickly falls off; petioles glandular at base; blades peltate, palmately lobed, 2 glands present at junction with petiole. Inflorescences leaf-opposed or subterminal racemes, with clusters of male flowers below more open clusters of female flowers towards the tip. Male flowers: calyces 3-5-lobed, lobes valvate; petals and disc absent; stamens up to 1000, united into bundles by their filaments; pistillode absent. Female flowers: buds conical; sepals 5, valvate, soon falling; petals and disc absent; ovaries 3-celled, with 1 ovule each; styles 3, free 2-fid, papillose plumose. Fruits 3-lobed capsules, oblong, usually spiny; seeds more or less compressed-ovoid, smooth, with a caruncle.
Ricinus has only 1 species. Ricinus communis, which fossil evidence shows to be native to northest Africa. It is now cultivated and/or escaped throughut the tropics and warm temperate regions.
Note: GBIF records include introduced and cultivated plants. Consequently, the distribution shown often differs from statements about a taxon's native distribution.