Habit and leaf form. Trees, or shrubs; laticiferous (latex milky, acrid). Plants succulent, or non-succulent. Mesophytic, or xerophytic. Leaves small to medium-sized; alternate, or opposite (or clustered); spiral, or distichous; leathery; petiolate to subsessile; non-sheathing; gland-dotted, or not gland-dotted; simple. Leaf blades entire; pinnately veined. Leaves with stipules. Stipules minute; caducous, or persistent. Leaves without a persistent basal meristem. Leaf anatomy. Hairs absent. Urticating hairs present, or absent. Stem anatomy. Nodes tri-lacunar, or unilacunar. Secondary thickening developing from a conventional cambial ring, or anomalous; from a single cambial ring.
Reproductive type, pollination. Fertile flowers functionally male, or functionally female. Unisexual flowers present. Plants dioecious (usually), or monoecious. Male flowers without pistillodes. Entomophilous.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’ (clustered along the axis, each flower or cluster subtended by a bract); in racemes, or in spikes. Inflorescences terminal, or axillary. Flowers bracteate; very small; regular. Floral receptacle developing an androphore, or with neither androphore nor gynophore (? depending on interpretation). Free hypanthium absent. Hypogynous disk absent. Perianth sepaline; 2, or 3; 1 -whorled. Calyx 2, or 3; 1 -whorled; polysepalous, or gamosepalous; regular. Fertile stamens present, or absent (female flowers). Androecium 2, or 3. Androecial members free of the perianth; free of one another, or coherent (then filaments basally fused). Androecium exclusively of fertile stamens. Stamens 2, or 3; isomerous with the perianth; erect in bud, or inflexed in bud. Anthers globular; dehiscing via longitudinal slits; extrorse, or introrse; bisporangiate, or tetrasporangiate. Fertile gynoecium present, or absent (male flowers). Gynoecium 2 carpelled, or 3 carpelled. The pistil 2 celled, or 3 celled. Gynoecium syncarpous; synovarious, or synstylovarious (depending on interpretation of partially connate styles); superior. Ovary plurilocular; 2 locular, or 3 locular. Styles 3; free, or partially joined (shortly connate); simple; apical. Stigmas 3; dry type; papillate, or non-papillate; Group II type. Placentation axile, or apical. Ovules 1 per locule; pendulous; epitropous; with ventral raphe, or with dorsal raphe; arillate (caruncle deciduous from seed and persistent on columella); orthotropous, or anatropous, or hemianatropous.
Fruit and seed features. Fruit non-fleshy (usually), or fleshy (rarely, when indehiscent); a schizocarp (usually), or indehiscent. Mericarps 3. Fruit a capsule, or a drupe; elastically dehiscent (schizocarpic capsules often splitting elastically), or passively dehiscent. Seeds globular to ovoid; endospermic. Endosperm oily. Cotyledons 2 (usually wider than the radicle). Embryo straight, or curved. Seedling. Germination phanerocotylar, or cryptocotylar.
Physiology, biochemistry. Mustard-oils present, or absent.
Special features. Mangroves (with spreading surface roots but no pneumatophores), or non-mangrove species.
Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, Queensland, and New South Wales.