Habit and leaf form. Trees, or shrubs; evergreen; bearing essential oils, or without essential oils; leptocaul. Mesophytic. Leaves alternate; spiral; leathery; petiolate; non-sheathing; gland-dotted; aromatic; simple. Leaf blades entire; pinnately veined; cross-venulate. Leaves without stipules; without a persistent basal meristem. Stem anatomy. Nodes unilacunar (with two traces). Secondary thickening developing from a conventional cambial ring.
Reproductive type, pollination. Fertile flowers functionally male, or functionally female. Unisexual flowers present. Plants dioecious. Female flowers with staminodes (5–16). Male flowers with pistillodes (ovary rudimentary), or without pistillodes.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in umbels (a reduced cyme or umbellule). The terminal inflorescence unit racemose, or cymose. Inflorescences axillary; pedunculate, often arranged in racemes; with involucral bracts. Involucral bracts persistent. Flowers pedicellate, or sessile; small; regular; 2–4 merous; cyclic. Free hypanthium present. Hypogynous disk present, or absent. Perianth sepaline (relatively undifferentiated), or of ‘tepals’, or absent; when present, 1–8; 1 -whorled, or 2 -whorled; when more than one, isomerous; joined (usually connate into a campanulate or funnel shaped, 4–6-lobed tube with caducous lobes); green to cream; fleshy, or non-fleshy; persistent, or deciduous; accrescent, or non-accrescent. Calyx 1–8. Fertile stamens present, or absent (female flowers). Androecium 5–20. Androecial members free of the perianth (on the hypanthium); all equal, or markedly unequal; free of one another; 3 -whorled. Androecium exclusively of fertile stamens (usually), or including staminodes. Staminodes 1–2. Stamens 5–20. Filaments appendiculate (those of the inner whorl usually with a pair of basal glands). Anthers basifixed; non-versatile; dehiscing by longitudinal valves; introrse; four locular, or bilocular (rarely). Fertile gynoecium present, or absent (male flowers). Gynoecium 1 carpelled (ostensibly), or 3 carpelled (theoretically); ostensibly monomerous; of one carpel (or at least, ostensibly so); superior. Carpel stylate; apically stigmatic (stigma peltate, conspicuous, sometimes 2-lobed); 1 ovuled. Placentation apical. Ovary sessile. Stigmas dry type; papillate; Group II type. Ovules pendulous; non-arillate; anatropous.
Fruit and seed features. Fruit fleshy. The fruiting carpel indehiscent; baccate (resting on an enlarged, flat or concave hypanthium). Fruit 1 seeded. Seeds non-endospermic. Embryo well differentiated; straight. Seedling. Germination phanerocotylar, or cryptocotylar.
Physiology, biochemistry. Aluminium accumulation demonstrated.
Geography, cytology, number of species. Native of Australia. Australian states and territories: Western Australia, Northern Territory, and Queensland. Northern Botanical Province.