The families of flowering plants.
Habit and leaf form. Slender shrubs, or lianas; bearing essential oils (in the wood), or without essential oils (?the leaves). Climbing; tendril climbers (with axillary tendrils representing modified peduncles). Leaves alternate; long petiolate; simple. Lamina entire; pinnately veined (3–5 nerved at the base); cross-venulate. Leaves exstipulate. Lamina margins entire.
Reproductive type, pollination. Fertile flowershermaphrodite. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes. The ultimate inflorescence unit cymose. Inflorescences axillary; loose, axillary dichotomous cymes. Flowers bracteate (the bracts subulate); very small; regular; 5 merous; cyclic; tetracyclic. Free hypanthium present (the tube becoming enlarged, enclosing the fruit).
Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; gamosepalous; blunt-lobed (the lobes short and broad); regular; persistent; accrescent; (sub-) imbricate. Corolla 5; 1 whorled; polypetalous; valvate; deciduous.
Androecium 5. Androecial members adnate (to the corolla); free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 5; isomerous with the perianth; alternisepalous; opposite the corolla members; shortly filantherous. Filamentsappendiculate (with two lateral, bearded scales at the base). Anthers ovate, introrse. Pollen grains aperturate; 3 aperturate; colpate.
Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 1 celled, or 3 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; inferior. Ovary 3 locular (at first), or 1 locular (later, by disappearance of thin septa). Epigynous disk present (shortly cupular, pentagonal). Gynoecium shortly stylate. Styles 1; apical. Stigmas 1, or 3 (stigma shortly trifid). Placentation apical. Ovules 1 per locule; pendulous; anatropous; unitegmic; tenuinucellate. Embryo-sac development Polygonum-type. Antipodal cells formed; 3; not proliferating; small.
Fruit fleshy; dehiscent; a drupe (with crustaceous endocarp, completely enclosed in the subpyriform, thin, red-brown, long-stipitate hypanthium-plus-calyx, which finally splits into 3–5 reflexed valves). The drupes with one stone. Fruit 1 seeded. Seeds endospermic. Embryo minute. Testa blue.
Geography, cytology. Paleotropical. Tropical. Indomalayan.
Taxonomy.Subclass Dicotyledonae; dubiously Crassinucelli. Dahlgren’s Superorder Santaliflorae; Santalales. Cronquist’s Subclass Rosidae; Santalales. APG 3 core angiosperms; core eudicot; Superorder Santalanae; Order Santalales (as a synonym of Olacaceae).
Species 2. Genera 1; only genus, Erythropalum.