Stephania Lour.

Scientific Description

Family Menispermaceae.

Habit and leaf form. Lianas, or herbaceous climbers; non-laticiferous and without coloured juice (in Australia). ‘Normal’ plants. Leaves well developed. Plants with roots; autotrophic. Climbing. Mesophytic. Not heterophyllous. Leaves medium-sized; alternate; spiral; with blades; membranous (‘chartaceous’); petiolate; simple; peltate; epulvinate. Leaf blades neither inverted nor twisted through 90 degrees; entire; flat; ovate to orbicular (‘circular’). Mature leaf blades adaxially glabrous (in Australia); abaxially glabrous (sparsely), or pubescent (or glaucous). Leaves without stipules. Leaf blade margins entire; flat. Leaf anatomy. Hairs present, or absent (rarely).

Reproductive type, pollination. Fertile flowers functionally male and functionally female. Unisexual flowers present. Plants dioecious. Plants homostylous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in cymes. Inflorescences compound. The terminal inflorescence unit cymose. Inflorescences axillary. Flowers pedicellate; minute (in Australia); regular; not resupinate; 3 merous, or 4 merous; cyclic. Perianth with distinct calyx and corolla; 9, or 12; 3 -whorled; isomerous. Calyx present; 6, or 8; 2 -whorled; polysepalous; glabrous, or hairy (sometimes ‘puberulous’ on outer sepals only). Sepals obovate (or spathulate). Corolla present; 3, or 4; 1 -whorled; polypetalous; glabrous abaxially; glabrous adaxially; green, or white, or yellow. Petals broadly obovate, or orbicular (‘circular’). Androecium present, or absent. Fertile stamens present, or absent. Androecial members definite in number. Androecium 2–6. Androecial members coherent (connate into a peltate disc-like synandrium). Androecium exclusively of fertile stamens. Stamens 2–6; isomerous with the perianth, or diplostemonous; with sessile anthers. Anthers cohering (connate around the margin of the synandrium); dehiscing via longitudinal slits; tetrasporangiate. Fertile gynoecium present, or absent. Gynoecium 1 carpelled. Carpels isomerous with the perianth. Gynoecium monomerous; of one carpel. Carpel stylate, or non-stylate; apically stigmatic; 2 ovuled (‘but only 1 developing’).

Fruit and seed features. Fruit ca 4–6 mm long; subsessile, or sessile; an aggregate. The fruiting carpel indehiscent; drupaceous. Dispersal unit the seed. Fruit 1 seeded.

Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, Queensland, and New South Wales. Northern Botanical Province. A genus of ca 40 species; 1 species in Western Australia; S. japonica (Thunb.) Miers; 0 endemic to Western Australia.

Additional comments. The leaves of S. japonica are reportedly toxic to stock in Australia.