Emmenosperma F.Muell.

Scientific Description

Family Rhamnaceae.

Habit and leaf form. Trees, or shrubs. ‘Normal’ plants. Leaves well developed. Plants with roots; non-succulent; unarmed; autotrophic. To 25 m high (in Australia). Self supporting. Not heterophyllous. Leaves medium-sized; alternate, or opposite (occasionally); with blades; petiolate; with ‘normal’ orientation; simple; not peltate. Leaf blades entire; ovate, or elliptic; pinnately veined. Mature leaf blades adaxially glabrous, or pubescent (on veins only); abaxially glabrous, or pubescent (on veins only). Leaves with stipules. Stipules scaly. Leaf blade margins entire; flat. Leaf anatomy. Hairs present, or absent.

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

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in cymes, or in umbels, or in racemes. Inflorescences compound. The terminal inflorescence unit racemose. Inflorescences axillary. Flowers shortly pedicellate; minute; regular; 5 merous; cyclic; tetracyclic. Free hypanthium absent. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; lobed; glabrous, or hairy (outside); valvate; regular. Calyx lobes ovate to triangular. Epicalyx absent. Corolla present; 5; 1 -whorled; alternating with the calyx; polypetalous; regular; white to cream. Petals hooded. Androecium present. Fertile stamens present. Androecial members definite in number. Androecium 5. Androecial members adnate (to the base of the sepals); free of the gynoecium; free of one another; 1 -whorled. Stamens 5; all more or less similar in shape; isomerous with the perianth; alternisepalous; filantherous. Anthers separate from one another; dehiscing via longitudinal slits; bilocular; tetrasporangiate. Fertile gynoecium present. Gynoecium 2 carpelled, or 3 carpelled. The pistil 1 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synstylovarious; superior. Ovary plurilocular; 2 locular, or 3 locular. Gynoecium stylate. Styles 1; apical. Stigmas 2 - lobed, or 3 - lobed. Ovules 1 per locule (in WA); ascending; anatropous.

Fruit and seed features. Fruit aerial; 6–9 mm long (in WA); a schizocarp. Dispersal unit the seed, or the fruit. Seeds 1 per locule.

Geography, cytology, number of species. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia, Northern Territory, Queensland, and New South Wales. Northern Botanical Province. A genus of 4 species; 1 species in Western Australia; E. cunninghamii Benth.; 1 endemic to Western Australia.