Habit and leaf form. Small trees, or shrubs; often glutinous, laticiferous, or non-laticiferous and without coloured juice, or with coloured juice. Plants succulent, or non-succulent. Mesophytic, or xerophytic. Leaves minute to medium-sized; alternate; spiral; ‘herbaceous’, or leathery, or fleshy; shortly petiolate; non-sheathing; gland-dotted, or not gland-dotted; simple. Leaf blades entire; flat, or rolled; pinnately veined, or palmately veined. Leaves without stipules. Leaf blade margins flat, or revolute. Leaves without a persistent basal meristem. Leaf anatomy. Hairs present, or absent; complex hairs present, or absent. Complex hairs when present, 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 sub- dioecious, or monoecious. Male flowers without pistillodes. Entomophilous.
Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’ (then few together); when solitary, axillary. Inflorescences axillary. Flowers pedicellate to sessile; bracteate. Bracts few, calyx-like. Flowers minute, or small; regular; 5 merous. Floral receptacle developing an androphore, or with neither androphore nor gynophore (? depending on interpretation). Free hypanthium absent. Hypogynous disk absent. Perianth sepaline; 4, or 5; 1 -whorled. Calyx present; 4, or 5; 1 -whorled; gamosepalous; imbricate; regular; red to brown, or white to pink, or green; accrescent, or non-accrescent. Corolla and glands absent. Fertile stamens present, or absent (female flowers). Androecium 20–50 (i.e. ‘numerous’). Androecial members branched, or unbranched; free of the perianth; free of one another (if filaments interpreted to arise from an androphore), or coherent (the filaments united in a staminal column). Androecium exclusively of fertile stamens. Stamens 20–50; polystemonous; erect in bud, or inflexed in bud. Anthers dehiscing via longitudinal slits; 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; sessile. Styles 3; free, or partially joined (shortly united at the base); forked to more than 4-branched (2–7-fid); apical. Stigmas 6–21; dry type; papillate, or non-papillate; Group II type. Placentation apical. Ovules 1 per locule; pendulous; epitropous; with ventral raphe, or with dorsal raphe; arillate; anatropous.
Fruit and seed features. Fruit non-fleshy; dehiscent, or indehiscent, or a schizocarp; a capsule (ovoid or oblong, obtuse or acute); elastically dehiscent, or passively dehiscent; 1 seeded (by abortion). Seeds oblong to almost globose; endospermic. Endosperm oily. Seeds arillate. Cotyledons 2 (longer but scarcely wider than the radicle). Embryo linear, straight, or curved. Testa smooth. Seedling. Germination phanerocotylar, or cryptocotylar.
Physiology, biochemistry. Mustard-oils present, or absent.
Geography, cytology, number of species. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia, South Australia, Queensland, New South Wales, and Victoria.