Twining shrubs, 3-5 m tall; branchlets generally glabrous, rarely setaceous; winter buds small, ovate-globose, ca. 2 mm wide. Petiole 1-1.8 cm; leaf blade rectangular-elliptic, rarely rectangular-obovate, 6.5-12.5 × 3-6.5 cm, abaxially pubescent along veins, glabrous later, adaxially slightly green or light brown when dry, often membranous during flowering and leathery in fruit, base cuneate, widely cuneate to obtuse-orbicular, margin obtusely serrate, apex shortly acuminate to acute; secondary veins (4 or)5-7 pairs. Cymes axillary and lateral, 3-7-flowered; rachis 7-20 mm; pedicels 5-7 mm, with very short yellowish white setae, jointed below middle. Sepals subovate or subelliptic, 1-2 mm, margin slightly erose; petals rectangular-obovate, 3.5-4 × ca. 2 mm, margin erose. Disk shallowly cupuliform, lobe semicircular or approximately obtuse-triangular. Stamens slightly shorter than corolla; filament glabrous or papillate proximally; staminodes in female flowers ca. 1 mm. Pistils ampullaceous, ca. 3 mm, degenerate in male flowers; stigma revolute. Capsule globose, 6.5-8 mm wide; fructiferous stipe and fruit stipe glabrous, often with elliptic lenticels. Seeds adaxially flat, slightly crescentiform, 4.5-5.5 × 1.5-2 mm. Fl. Mar-May, fr. Aug-Oct.