Including Chailletiaceae R.Br., Hirtellaceae Horan. (p.p.)
Habit and leaf form. Trees, shrubs, and lianas; non-laticiferous and without coloured juice. Self supporting, or climbing. Mesophytic, or xerophytic. Leaves alternate; spiral; ‘herbaceous’, or leathery; petiolate; non-sheathing; simple. Lamina entire; pinnately veined; cross-venulate. Leaves stipulate. Stipules intrapetiolar; caducous. Lamina margins entire. Leaves without a persistent basal meristem. Domatia occurring in the family; manifested as pits.
Leaf anatomy. Mucilaginous epidermis present. Stomata present; mainly confined to one surface (abaxial); paracytic. Hairs present; eglandular (with wartlike papillae).
Adaxial hypodermis present, or absent. Lamina usually dorsiventral. The mesophyll containing mucilage cells, or not containing mucilage cells.
Stem anatomy. Cork cambium present; initially superficial. Secondary thickening developing from a conventional cambial ring. Xylem with fibre tracheids. Vessel end-walls simple, or scalariform and simple. Vessels with vestured pits. Wood parenchyma apotracheal, or paratracheal.
Reproductive type, pollination. Plants hermaphrodite, or monoecious.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes and in fascicles. The ultimate inflorescence unit cymose. Inflorescences axillary (to petiolar), or epiphyllous; dichotomous cymes or fascicles. Flowers small; regular, or somewhat irregular; cyclic. Free hypanthium absent. Hypogynous disk present; of separate members, or annular (when a corolla tube present).
Perianth with distinct calyx and corolla; 8, or 10; 2 whorled; isomerous. Calyx (4–)5; 1 whorled; polysepalous, or gamosepalous (sometimes basally connate); imbricate. Corolla (4–)5 (the petals usually two-lobed or bifid); 1 whorled; polypetalous (usually), or gamopetalous (rarely with a basal tube). Corolla lobes markedly longer than the tube. Corolla imbricate; regular, or unequal but not bilabiate. Petals broadly clawed, or sessile; deeply bifid, or bilobed, or entire (rarely).
Androecium (4–)5. Androecial members free of the perianth, or adnate (sometimes epipetalous); all equal; free of one another, or coherent; 1 whorled. Androecium exclusively of fertile stamens (usually), or including staminodes (rarely). Staminodes when present, 2 (then with three fertile stamens); in the same series as the fertile stamens. Stamens 3, or 5; reduced in number relative to the adjacent perianth, or isomerous with the perianth; oppositisepalous; filantherous, or with sessile anthers. Anthers dehiscing via longitudinal slits (the connective often dorsally thickened). Pollen grains aperturate; 3 aperturate; colporate.
Gynoecium 2 carpelled, or 3(–4) carpelled. The pistil 2 celled, or 3(–4) celled. Gynoecium syncarpous; synovarious, or synstylovarious; superior to inferior. Ovary 2 locular, or 3(–4) locular. Styles 1 (usually), or 2–3(–4) (rarely); free (rarely), or partially joined; apical. Placentation apical. Ovules 2 per locule; pendulous; epitropous (micropyle superior); with ventral raphe; arillate (often carunculate), or non-arillate; anatropous.
Fruit fleshy (rarely), or non-fleshy; indehiscent; a drupe. The drupes with one stone (1–3 locular). Seeds non-endospermic. Embryo well differentiated. Cotyledons 2. Embryo straight. Micropyle not zigzag.
Seedling. Germination cryptocotylar.
Physiology, biochemistry. Alkaloids present, or absent. Saponins/sapogenins absent. Aluminium accumulation not found. Sugars transported as oligosaccharides + sucrose (in Tapura).
Geography, cytology. Sub-tropical to tropical. Pantropical. X = 20, 24.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae; Euphorbiales. Cronquist’s Subclass Rosidae; Celastrales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Malpighiales.
Species 200. Genera 3; Dichapetalum, Stephanopodium, Tapura, (Gonypetalum, Falya).
• Technical details: Dichapetalum (Thonner).
• Technical details: Dichapetalum spp. (Lindley).