Coca

Trees or shrubs. Young branches distinctive, flattened, with raised lines decurrent from the petiole bases (particularly distinctive in E. emarginatum) Stipules persistent to caducous, completely united. Petals white to cream-yellow. Nectary appendage usually exceeding the calyx. Ovary (2-)3-locular. The two species of Erythroxylum are quite unlike each other in general appearance. Apart from the characters in the key, E. emarginatum has dark green, relatively thick, coriaceous leaves which are brittle and can be heard to crackle when folded and held against the ear. E. zambesiacum has thinly-textured leaves which are not brittle.

Erythroxylum (Erythroxylon) is a genus of tropical flowering plants in the family Erythroxylaceae. Many of the approximately 200 species contain the substance cocaine, and two of the species within this genus, Erythroxylum coca and Erythroxylum novogranatense, both native to South America, are the main commercial source of cocaine and of the mild stimulant coca tea. Another species, Erythroxylum vaccinifolium (also known as catuaba) is used as an aphrodisiac in Brazilian drinks and herbal medicine.

Erythroxylum species are food sources for the larvae of some butterflies and moths, including several Morpho species and Dalcera abrasa, which has been recorded on E. deciduum, and the species of Agrias.