Tufted to robustly erect perennial herbs, dioecious or polygamous, glabrous; stem base surrounded by old leaves. Leaves conspicuously transverse-septate, simple or divided, often pungent-pointed. Inflorescence a terminal, compound umbel with alternate, subopposite or whorled lateral compound umbels; female inflorescence more robust than male; bracts usually shorter than the compound umbels, lowermost leaf-like, uppermost reduced. Flowers bisexual or unisexual, creamy white to pink; sepals very small; petals obovate, apex slightly inflexed; ovary and style rudimentary in male flowers; small staminodes present in female flowers; nectary prominent and conical in female and bisexual flowers. Fruit dorsally compressed, ovoid to oblong-elliptic; mericarps with 4 or 5 narrowly winged ribs, often unequally developed; carpophore bipartite.
About 40 species, in Australia, New Zealand and Antarctic islands; 3 species in Australia, all endemic.