Monoecious herbs, trailing or climbing, bristly or pubescent with glandular hairs. Leaves simple, shallowly to deeply palmatifid; tendrils 2–5-branched. Male flowers in simple or branched racemes or head-like clusters. Female flowers in heads or solitary (not in Victoria). Calyx 5-lobed; corolla deeply 5-lobed; hypanthium broadly bell-shaped; stamens 2–5, inserted at base of hypanthium, filaments united to form a column, anthers fused into a head, rarely free, locules flexuose; disc absent. Female flowers without staminodes; ovary ovoid, ovule solitary. Fruit ovoid, dry, bristly; seed solitary, ovate, compressed.
About 50 species, from North and South America, Hawaii, New Zealand, eastern Australia and the south-west Pacific; 1 species in Australia.