Erythroxylum P.Browne

Scientific Description

Family Erythroxylaceae.

Habit and leaf form. Trees, or shrubs. Mesophytic. Leaves alternate; spiral; ‘herbaceous’; petiolate; non-sheathing; simple. Leaf blades entire; pinnately veined. Leaves with stipules. Stipules intrapetiolar; concrescent (either entirely connate or rarely 2-lobed); caducous (usually). Leaf blade margins entire. Leaves without a persistent basal meristem. Leaf anatomy. Hairs absent. Stem anatomy. Nodes unilacunar. Secondary thickening developing from a conventional cambial ring.

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

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; when solitary, axillary; when aggregated, in fascicles. Inflorescences axillary. Flowers small; regular; 5 merous; cyclic; pentacyclic. Free hypanthium absent. Hypogynous disk absent. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx 5; 1 -whorled; polysepalous, or gamosepalous; imbricate (quincuncial), or valvate; regular; persistent. Corolla 5; 1 -whorled; appendiculate (nearly always with an emarginate or 2–3-lobed ligule inserted towards the base on the inner petal surface); polypetalous; imbricate; regular; green to white (in E. ellipticum); deciduous. Androecium 10. Androecial members free of the perianth; all equal; coherent (united into a tube at the base); 1 - adelphous; 2 -whorled. Androecium exclusively of fertile stamens. Stamens 10; diplostemonous; alternisepalous and oppositisepalous. Anthers dorsifixed; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate. Gynoecium 2 carpelled, or 3 carpelled. The pistil 2 celled, or 3 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synovarious to synstylovarious; superior. Ovary plurilocular; 2–3 locular (usually only one fertile). Gynoecium stylate. Styles 3; free to partially joined; apical. Stigmas 3; flattened or clavate; dry type; papillate; Group II type. Placentation axile. Ovules 1(–2) per locule; funicled; pendulous; epitropous; non-arillate; anatropous, or hemianatropous.

Fruit and seed features. Fruit fleshy; indehiscent; a drupe (one-loculed); 1 seeded. Seeds endospermic, or non-endospermic; with starch. Cotyledons 2. Embryo straight.

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.

Economic uses, etc. Cocaine is extracted from the leaves of coca (Erythroxylum coca).