Herbs (in Victoria), sometimes with stinging hairs. Leaves simple, petiolate, stipulate. Inflorescence axillary, monoecious or dioecious, cymose, spicate or capitate. Flowers small, unisexual, rarely bisexual, actinomorphic, perianth segments 3–5, occasionally 1, 2 or absent, in 1 whorl, persistent. Male flowers wtih 3–5 stamens, rarely reduced to 2 or 1; anthers 2-locular, dehiscing by longitudinal slits; pistillode usually present. Female flowers with scale-like staminodes sometimes present; ovary superior, 1-locular, style 1. Fruit an achene, rarely a drupe.
About 52 genera and 1900 species, widely distributed around the world; 9 genera and 21 species in Australia.