Habit and leaf form. Herbs, or herbaceous climbers, or shrubs (subshrubs); laticiferous, or non-laticiferous and without coloured juice. Autotrophic. Herbs perennial; plants with neither basal nor terminal concentrations of leaves. Trailing or climbing, or self supporting; stem twiners. Helophytic, mesophytic, and xerophytic. Leaves alternate; spiral; petiolate to subsessile; non-sheathing; simple. Leaf blades entire; pinnately veined, or palmately veined; cross-venulate; cordate, or attenuate at the base (or obtuse). Leaves without stipules; without a persistent basal meristem. Leaf anatomy. Hairs usually present (hairs 3-branched), or absent. Stem anatomy. Nodes unilacunar. Secondary thickening anomalous, or developing from a conventional cambial ring; via concentric cambia, or from a single cambial ring.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.
Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; when solitary, axillary; in cymes, or in heads. The terminal inflorescence unit cymose. Inflorescences axillary; sometimes umbel-like; with involucral bracts, or without involucral bracts. Flowers bracteate; bi- bracteolate; small to medium-sized; regular to somewhat irregular. The floral asymmetry (when noticeable) involving the perianth (K only). Flowers 5 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present; annular. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx 5; 1 -whorled; polysepalous; hairy, or glabrous; imbricate; regular to unequal but not bilabiate (with the 2 outer ones often large); persistent; slightly accrescent; with the median member posterior. Corolla 5; 1 -whorled; gamopetalous; slightly lobed to entire. Corolla lobes markedly shorter than the tube. Corolla funnel-shaped to campanulate; regular; white, or pink, or purple, or blue, or yellow (rarely). Androecium 5. Androecial members adnate (to the corolla in lower half); all equal to markedly unequal (actually subequal); free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 5; usually remaining included; oppositisepalous. Anthers dehiscing via longitudinal slits; introrse; tetrasporangiate. Pollen grains psilate. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous (depending on interpretation of stigmatic area); superior. Ovary plurilocular; 2 locular. Gynoecium median. Styles 1; simple (filiform); apical; not becoming exserted. Stigmas 1; 2 - lobed; dry type; papillate; Group II type. Placentation basal. Ovules 2 per locule; ascending; apotropous; non-arillate; anatropous.
Fruit and seed features. Fruit non-fleshy; not hairy; dehiscent; a capsule. Capsules loculicidal (via 4–8 valves). Fruit 2 locular; 4 seeded. Seeds trigonous; endospermic. Endosperm oily. Seeds not conspicuously hairy (although minute hairs sometimes present); often very narrowly winged, or wingless. Cotyledons 2. Embryo chlorophyllous; straight, or curved. Seedling. Germination phanerocotylar.
Physiology, biochemistry. Aluminium accumulation not found. Photosynthetic pathway: C3.
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.
Additional characters Stigmas the stigmatic area globose, or linear.