Habit and leaf form. Trees, or shrubs; non-laticiferous and without coloured juice. Plants succulent, or non-succulent. Mesophytic, or xerophytic. Leaves small to medium-sized; alternate, or opposite (rarely); spiral, or distichous; when opposite decussate; ‘herbaceous’, or leathery, or fleshy; petiolate; non-sheathing; gland-dotted, or not gland-dotted; simple. Leaf blades entire; pinnately veined, or palmately veined. Leaves with stipules. Stipules subulate, scaly, or leafy; caducous, or persistent. Leaves without a persistent basal meristem. Leaf anatomy. Hairs present; complex hairs present. Complex hairs stellate. 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). Male flowers without pistillodes. Entomophilous.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in panicles, or in racemes, or in spikes. Inflorescences terminal, or axillary; the flowers commonly in clusters along the rachis. Flowers bracteate, or ebracteate; minute to small; regular. Floral receptacle developing an androphore, or with neither androphore nor gynophore. Free hypanthium absent. Hypogynous disk absent (in pistillate flowers). Perianth sepaline; 2–5; 1 -whorled. Calyx 2–5; 1 -whorled; polysepalous, or gamosepalous; regular. Fertile stamens present, or absent (female flowers). Androecium 20–200 (i.e. ‘numerous’). Androecial members free of the perianth; free of one another (filaments on a common receptacle). Androecium exclusively of fertile stamens. Stamens 20–200; polystemonous; erect in bud, or inflexed in bud. Anthers dehiscing via longitudinal slits (the cells separated by a broad connective); extrorse, or introrse; bisporangiate, or tetrasporangiate. Fertile gynoecium present, or absent (male flowers). Gynoecium 3 carpelled. The pistil 3 celled. Gynoecium syncarpous; synovarious, or synstylovarious (depending on interpretation of partially connate styles); superior. Ovary plurilocular; 3 locular. Styles 3; free, or partially joined (very shortly connate at the base); simple (plumose); apical. Stigmas 3; dry type; papillate; Group II type. Placentation axile, or apical. Ovules 1 per locule; pendulous; epitropous; with ventral raphe, or with dorsal raphe; non-arillate; anatropous.
Fruit and seed features. Fruit non-fleshy, or fleshy (when endocarp succulent); a schizocarp. Mericarps 2, or 3. Fruit elastically dehiscent (schizocarpic capsules often splitting elastically), or passively dehiscent. Seeds 1 per mericarp. Seeds globular; endospermic. Endosperm oily. Seeds non-arillate. Cotyledons 2 (wider than the radicle). Embryo straight, or curved. Seedling. Germination phanerocotylar, or cryptocotylar.
Physiology, biochemistry. Mustard-oils present, or absent.
Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, and Queensland. Northern Botanical Province and Eremaean Botanical Province.