Habit and leaf form. Lianas (woody or semi-woody); laticiferous (clear, colourless or pale yellow, occasionally milky). Plants unarmed. Leaves cauline. To 2–30 m high. Climbing; stem twiners (mostly), or root climbers, or scrambling. Not heterophyllous (in adult plants), or heterophyllous (in jeuvenile plants). Leaves small to large; opposite; ‘herbaceous’, or leathery; petiolate; simple. Leaf blades dorsiventral; entire; linear, or ovate, or oblong, or elliptic, or triangular; pinnately veined; cordate, or attenuate at the base, or cuneate at the base, or rounded at the base. Mature leaf blades adaxially glabrous, or pubescent; abaxially glabrous, or pubescent. Leaves without stipules. Leaf blade margins entire. Leaf anatomy. Hairs present; glandular hairs absent. Unicellular hairs absent. Complex hairs present. Branched hairs absent. Complex hairs peltate.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’. Inflorescence few-flowered, or many-flowered. Flowers in cymes, or in panicles. Inflorescences compound; terminal, or axillary; pedunculate cymes arranged in panicles. Flowers pedicellate, or subsessile, or sessile; bracteate; small; regular; 5 merous (commonly), or 4 merous (occasionally); tetracyclic. Hypogynous disk present; more or less annular. Perianth with distinct calyx and corolla; 10 (commonly), or 8 (occasionally); 2 -whorled; isomerous. Calyx present; 5 (commonly), or 4 (occasionally); 1 -whorled; gamosepalous; lobed (lobes are deeply divided); lobulate. Calyx lobes markedly longer than the tube. Calyx erect; hairy; exceeded by the corolla; regular. Calyx lobes ovate, or obovate. Corolla present; 5 (commonly), or 4 (occasionally); 1 -whorled; appendiculate (with corolline corona), or not appendiculate; gamopetalous; lobed (lobes mostly spreading or recurved, rarely erect or incurved); lobulate. Corolla lobes about the same length as the tube, or markedly longer than the tube. Corolla contorted (dextrorse in bud), or valvate; sub- rotate, or funnel-shaped, or hypocrateriform (rarely); regular; glabrous abaxially (commonly), or hairy abaxially (occasionally); hairy adaxially (at top); plain, or with contrasting markings (spots; apical or marginal streaks; lobes and throat are different colours); green, or white, or cream, or yellow, or orange, or red, or pink, or brown. Corolla lobes oblong, or ovate, or obovate, or linear. Androecial members definite in number. Androecium 5 (commonly), or 4 (occasionally). Androecial members adnate (epipetalous); united with the gynoecium (anthers adherent to style-head); all equal; 1 -whorled. Stamens 5 (commonly), or 4 (occasionally). Staminal insertion midway down the corolla tube. Stamens all inserted at the same level; becoming exserted (partly or fully); all more or less similar in shape; isomerous with the perianth; oppositisepalous; all alternating with the corolla members. Filaments glabrous; filiform. Anthers connivent, or cohering (in a cone around style-head); all alike; dehiscing via longitudinal slits; appendaged. The anther appendages basal (sterile lobes). Gynoecium 2–5 carpelled. The pistil 2 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary plurilocular; 2 locular. Ovary summit glabrous. Gynoecium stylate. Styles 1; bearing an ‘indusium’ beneath the stigma; hairless. Stigmas 1; truncate, or clavate. Placentation axile. Ovules 2–50 per locule (‘many’).
Fruit and seed features. Fruit 40–230 mm long; non-fleshy; hairy, or not hairy; dehiscent; a capsule (separating into 2 follicle-like segments). Capsules valvular. Dispersal unit the seed. Fruit 30–50 seeded (‘many’). Seeds not compressed; conspicuously hairy; with a tuft of hairs (long silky hairs at the micropylar end).
Geography, cytology, number of species. World distribution: from south-east Asia to Australia, New Caledonia, New Zealand and other parts of the south-western Pacific. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, Queensland, New South Wales, Victoria, Australian Capital Territory, and Tasmania. Northern Botanical Province, or South-West Botanical Province. A genus of c. 130 species; 2 species in Western Australia; 1 endemic to Western Australia.
Additional comments. Etymology: named after James Parsons, (1705–1770), a London doctor, authors of works on pharmacology and on seeds.
Etymology. After James Parsons (1705–1770), a London doctor, author of works on pharmacology and on seeds.