Habit and leaf form. Shrubs, or herbs; laticiferous (latex usually reddish). Plants succulent, or non-succulent. Herbs perennial. Mesophytic, or xerophytic. Leaves medium-sized; alternate; spiral, or distichous; ‘herbaceous’, or leathery, or fleshy; petiolate; non-sheathing; gland-dotted, or not gland-dotted; simple. Leaf blades dissected (often lobed), or entire; pinnately veined, or palmately veined. Leaves with stipules. Stipules in J. gossypiifolia reduced to a cluster of much-branched, filiform, gland-tipped segments; caducous, or persistent. Leaves without a persistent basal meristem. Leaf anatomy. 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 usually monoecious. Male flowers without pistillodes. Entomophilous.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in cymes (each with lateral male flowers and a single terminal female flower). Inflorescences terminal. Flowers bracteate, or ebracteate; minute to small; regular. Floral receptacle developing an androphore, or with neither androphore nor gynophore (? depending on interpretation). Free hypanthium absent. Hypogynous disk present; of separate members (5 free glands), or annular. Perianth with distinct calyx and corolla, or sepaline (rarely); 10, or 5 (rarely); 2 -whorled, or 1 -whorled; when two-whorled, isomerous. Calyx 5; 1 -whorled; more or less polysepalous, or gamosepalous (often shortly connate towards the base); regular. Corolla present, or absent (rarely); when present, 5; polypetalous, or gamopetalous (shortly connate towards the base); regular. Fertile stamens present, or absent (female flowers). Androecium 6–12. Androecial members branched, or unbranched; free of the perianth; free of one another (if filaments interpreted as arising from an androphore), or coherent (filaments connate towards the base into a central column). Androecium exclusively of fertile stamens. Stamens 6–12; diplostemonous; 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 2–3(–5) carpelled. The pistil 2–3(–5) celled. Gynoecium syncarpous; synovarious, or synstylovarious (depending on interpretation of partially connate styles); superior. Ovary plurilocular; 2–3(–5) locular. Styles 3; free, or partially joined (connate at the base); often forked; apical. Stigmas 6; 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; anatropous.
Fruit and seed features. Fruit non-fleshy; a schizocarp (subglobular); elastically dehiscent (schizocarpic capsules often splitting elastically), or passively dehiscent. Seeds 1 per mericarp. Seeds ovoid; endospermic. Endosperm oily. Seeds arillate. Cotyledons 2 (usually 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. Adventive. Australian states and territories: Western Australia, Northern Territory, and Queensland. Northern Botanical Province.