Habit and leaf form. Lianas. Climbing; stem twiners, or scrambling. Leaves deciduous; alternate; long petiolate; non-sheathing; simple (sometimes), or compound (usually); usually ternate. Lamina when simple dissected (usually), or entire (rarely); when simple-dissected, palmatifid (trilobed); palmately veined, or pinnately veined (?); cross-venulate. Leaves exstipulate. Vegetative buds scaly.
Stem anatomy. Cork cambium present; initially deep-seated (in the inner pericycle). Nodes tri-lacunar. Primary vascular tissue comprising a ring of bundles (four large bundles, and eight smaller ones outside). Medullary bundles absent. Internal phloem absent. Secondary thickening developing from a conventional cambial ring, or anomalous (?). Xylem with tracheids; with vessels. Vessel end-walls simple. Primary medullary rays wide.
Reproductive type, pollination. Plants dioecious. Female flowers with staminodes (six). Gynoecium of male flowers vestigial. Floral nectaries present. Nectar secretion from the perianth (from the petals). Pollination entomophilous.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes. The ultimate inflorescence unit racemose. Inflorescences axillary; drooping racemes, from scaly axillary buds. Flowers bracteate; minutely bi- bracteolate; small; regular; 3 merous; partially acyclic. The gynoecium acyclic. Floral receptacle not markedly hollowed (elongated and becoming swollen and fleshy). Free hypanthium absent. Hypogynous disk absent.
Perianth with distinct calyx and corolla (the calyx green, but petaloid in texture); 12; 4 whorled; isomerous; petaloid. Calyx 6; 2 whorled (3+3); polysepalous; regular; imbricate. Corolla 6; 2 whorled (3+3); polypetalous (the petals very small, scalelike, nectariferous); regular; green.
Androecium in both male and female flowers, 6. Androecial members free of the perianth; free of one another; 2 whorled (3+3). Androecium of male flowers, exclusively of fertile stamens. Stamens 6; shortly filantherous. Anthers basifixed, or adnate (? — the thecae separated by a broad connective); non-versatile; dehiscing via longitudinal slits; extrorse; oblong, bilocular; appendaged. The anther appendages apical (the connective prolonged into a short, terminal projection). Pollen grains aperturate; (2–)3 aperturate; colporate (colporoidate).
Gynoecium 25–100 carpelled (‘many’). Carpels increased in number relative to the perianth. Gynoecium apocarpous; eu-apocarpous (the carpels imbricate and spiralled on the elongated torus); superior. Carpel non-stylate (the style subulate); 1 ovuled. Placentation apical to marginal (subapical to ventral). Ovules funicled; pendulous; hemianatropous to anatropous.
Fruit fleshy; an aggregate. The fruiting carpel indehiscent; baccate (the stipitate ‘berries’ becoming black and pruinose when ripe, and the receptacle becoming elongated and fleshy). Fruit 1 seeded. Seeds copiously endospermic. Endosperm fleshy, oily (and starchy). Seeds with starch. Embryo well differentiated (but minute). Cotyledons 2. Embryo straight (excentric).
Physiology, biochemistry. Aluminium accumulation not found.
Geography, cytology. Holarctic and Paleotropical. Temperate. Central China.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Ranunculiflorae; Ranunculales. Cronquist’s Subclass Magnoliidae; Ranunculales. APG 3 core angiosperms; peripheral eudicot; Superorder Ranunculanae; Order Ranunculales (as a synonym of Ladizabalaceae).
Species 1. Genera 1; only genus, Sargentodoxa.
• Sargentodoxa (Chittenden).