Habit and leaf form. Small, Olea-like trees; non-laticiferous and without coloured juice. Leaves opposite; not gland-dotted; simple. Lamina entire; lanceolate; pinnately veined. Leaves exstipulate. Lamina margins entire.
Leaf anatomy. Stomata mainly laterocytic.
Cystoliths absent.
Stem anatomy. Nodes unilacunar (with one trace). Internal phloem absent. Secondary thickening developing from a conventional cambial ring. `Included' phloem absent. Xylem with vessels. Vessel end-walls horizontal; simple. Primary medullary rays mixed wide and narrow.
Reproductive type, pollination. Dioecious. Anemophilous.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in `inflorescences'; in cymes. The terminal inflorescence unit cymose. Inflorescences axillary. Flowers ebracteate; ebracteolate; small; regular. Free hypanthium absent.
Perianth sepaline; 3, or 4; 1 whorled. Calyx 3, or 4 (the sepals of the female flowers pinnately net-veined); 1 whorled; gamosepalous (at the base); regular; persistent; in the female flowers, slightly accrescent; of male flowers, valvate.
Androecium 6-9(-12). Androecial members free of the perianth; free of one another. Androecium exclusively of fertile stamens. Stamens 6-9(-12); diplostemonous to triplostemonous; erect in bud; filantherous (with very short filaments). Anthers dehiscing via longitudinal slits; elongate, the connective apiculate. Pollen grains aperturate; 3 - aperturate; colporate (colporoidate).
Gynoecium 1-3. Carpels reduced in number relative to the perianth to isomerous with the perianth. Gynoecium monomerous (usually), or apocarpous, or syncarpous; of one carpel (usually), or eu-apocarpous, or semicarpous (the carpels sometimes joined basally); superior. Carpel long stylate; apically stigmatic (the stigma decurrent on the long style); 1 ovuled. Placentation apical. Styles free; apical. Placentation when semicarpous, apical. Ovules 1 per locule; pendulous; anatropous; apparently unitegmic.
Fruit non-fleshy; multiple (when G 2 or 3), or not multiple (when monomerous). The fruiting carpel when apocarpous or monomeric, indehiscent; nucular (shortly beaked). Fruit when semicarpous, of 2-3 basally joined nucules(?). Seeds non-endospermic. Embryo well differentiated. Cotyledons 2. Embryo straight.
Physiology, biochemistry. Ellagic acid present.
Geography, cytology. Paleotropical. Sub-tropical. North East Africa, Arabia.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren's Superorder Malviflorae; Urticales. Cronquist's Subclass Hamamelidae; Urticales. Takhtajan's Subclass Hamamelidae; Hamamelidanae; Barbeyales. Species 1. Genera 1; Barbeya oleoides the only representative.