Annual or perennial herbs or shrubs (rarely arborescent), glabrous or variably pubescent, occasionally glandular. Leaves alternate or opposite, simple, often fleshy, sometimes much reduced. Inflorescence cymose, paniculate, or of solitary axillary flowers. Flowers small, usually greenish, bisexual or unisexual; perianth segments (tepals) 1–5, in one whorl, or sometimes lacking; stamens equal to or fewer than tepals; ovary superior or semi-inferior (Beta), unilocular, with 2–3 carpels, stigmas 2 or 3. Fruit a nut, berry or utricle with membranous, hardened or succulent pericarp; perianth or bracteoles often enlarged in fruit and developing spines, wings or tubercles; seed often lenticular, testa membranous to crustaceous.
Over 100 genera and 1500 species, cosmopolitan, many halophytic; 26 genera and c. 325 species in Australia (c. 120 species in Victoria).
Recent molecular studies suggest that some generic rearrangements are warranted and that the fruit types (e.g. spiny, fleshy, winged) that define many Australian genera are a result of convergent evolution and mask deeper underlying relatinships. Some new combinations exist, but until there is wide acceptance of new generic circumscription, we retain 'old' concepts here.