Cyathostemma Griff.

Scientific Description

Family Annonaceae.

Habit and leaf form. Lianas. ‘Normal’ plants. Leaves well developed. Plants with roots; unarmed; autotrophic. Perennial; to 10 m high (in Australia). Climbing. Mesophytic. Not heterophyllous. Leaves medium-sized; alternate; distichous (in Australia); with blades; petiolate (in Australia); simple; not peltate; epulvinate. Leaf blades neither inverted nor twisted through 90 degrees; entire; flat; oblong and elliptic (in Australia). Mature leaf blades adaxially sparsely pubescent, or glabrous; abaxially sparsely pubescent, or glabrous. Leaves without stipules. Leaf blade margins entire; flat. Leaf anatomy. Hairs present, or absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Plants homostylous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’, or solitary. Inflorescence few-flowered. Flowers in cymes. Inflorescences compound, or simple. The terminal inflorescence unit cymose. Flowers shortly pedicellate; bracteate; small; regular; not resupinate; 3 merous; cyclic; pentacyclic. Perianth with distinct calyx and corolla; 9; 3 -whorled; isomerous. Calyx present; 3; 1 -whorled; gamosepalous; lobed. Calyx lobes markedly longer than the tube (‘connate at the base’). Calyx hairy, or glabrous; valvate; regular. Calyx lobes broadly ovate. Corolla present; in Australia 6; 2 -whorled; polypetalous; imbricate and valvate; hairy abaxially, or glabrous abaxially; hairy adaxially, or glabrous adaxially; orange, or unknown. Petals elliptic. Androecium present (in Australia). Fertile stamens present. Androecial members indefinite in number. Androecium 100 (‘numerous’). Androecial members free of one another. Androecium exclusively of fertile stamens. Stamens 100 (‘numerous’); polystemonous; with sessile anthers, or filantherous (subsessile). Anthers separate from one another; dehiscing via longitudinal slits; tetrasporangiate. Fertile gynoecium present (in Australia). Gynoecium 100 carpelled (‘numerous’). Carpels increased in number relative to the perianth. Gynoecium apocarpous; eu-apocarpous; partly inferior. Carpel stylate; 3–100 ovuled (‘few to many’).

Fruit and seed features. Fruit 5–10 mm long (in Australia); hairy, or not hairy. The fruiting carpel indehiscent. Dispersal unit the seed. Fruit 3–100 seeded (‘few to many’).

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 8 species; 2 species in Western Australia; C. micranthum (A.DC.) J.Sinclair; C. sp.A Kimberley Flora (G.J.Keighery 1873); 0 endemic to Western Australia.