Fls minute, unisexual, cymose; per. 4-5-lobed, imbricate or valvate. Stamens 4-5, opp. per.-lobes, inflexed in bud. ♀ with per. often enlarged in fr.; staminodes present or absent; ovary superior, rarely inferior, 1-celled; ovule 1, erect. Fr. an achene or drupe. Herbs, subshrubs or small soft-wooded trees, with alt. or opp., simple, stipulate lvs. About 40 genera, mainly tropical, some widespread.

Herbs, shrubs, soft-wooded trees, or rarely climbers, often with stinging hairs; latex 0. Lvs opposite or alternate, simple, usually stipulate. Fls usually unisexual, apetalous, in cymes. Perianth 4-5-merous, often persistent. ♂ fls with (1)-4-5 stamens opposite the perianth segments and usually inflexed in bud, sometimes straight, often with rudimentary ovary; anthers 2-celled. ♀ fls often with small staminodes. Ovary superior, 1-locular, free or adnate to perianth; style simple; ovule solitary, erect. Fr. usually an achene, rarely a drupe. Seeds usually with endosperm; embryo straight.