Including Chailletiaceae R.Br., Hirtellaceae Horan. (p.p.)
Habit and leaf form. Trees, shrubs, and lianas. 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 recorded; represented by 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. Wood parenchyma apotracheal, or paratracheal.
Reproductive type, pollination. Hermaphrodite, or monoecious.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in `inflorescences'; in cymes and in fascicles. The terminal 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); 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). 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, or 3(-4); 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; with ventral raphe (micropyle superior); arillate (often carunculate), or non-arillate; anatropous.
Fruit fleshy (rarely), or non-fleshy; indehiscent; a drupe (the stone 1(-3) locular). Seeds non-endospermic. Embryo well differentiated. Cotyledons 2. Embryo straight.
Seedling. Germination cryptocotylar.
Physiology, biochemistry. Alkaloids present, or absent. Saponins/sapogenins absent. Aluminium accumulation not found.
Geography, cytology. Sub-tropical to tropical. Pantropical. X = 20, 24.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren's Superorder Malviflorae; Euphorbiales. Cronquist's Subclass Rosidae; Celastrales. Takhtajan's Subclass Dilleniidae; Malvanae; Euphorbiales. Species 200. Genera 3; Dichapetalum, Stephanopodium, Tapura, (Gonypetalum, Falya).
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