Climbers to 7 m tall. Branchlets ferruginous pubescent when young, glabrescent. Petiole 1-2.5 cm, blackish and minutely transversely wrinkled when dried, pubescent when young, glabrescent; leaf blade oblong-lanceolate, oblong-elliptic, or sometimes obovate-oblong, 7-24 × 2.4-6 cm, thinly leathery, abaxially ferruginous pubescent when young but glabrescent and grayish green with age, adaxially glabrous, secondary veins 10-14 on each side of midvein and adaxially flat, tertiary veins partly parallel and also often irregularly branched, reticulate veins inconspicuous, base rounded, obtuse, or sometimes broadly cuneate, apex obtuse to shortly acuminate. Inflorescences leaf-opposed or alternate, sometimes terminal, cymose, umbel-like, 3-7-flowered, ferruginous pubescent; peduncle short; bracts ovate, pubescent. Pedicel 0.3-2 cm, 1- or 2-bracteolate. Sepals ovate-triangular, ca. 3 × 2.3 mm, outside pubescent, inside glabrous. Petals leathery; outer petals ovate-oblong, 1.5-1.7 × ca. 0.7 cm, outside densely ferruginous pubescent, inside slightly puberulent; inner petals lanceolate, ca. 1.3 × 0.4 cm, inside basally glabrous and concave, apically puberulent. Stamens oblong; connectives ovoid. Carpels 2-6, densely pubescent; ovules 4 per carpel; styles cylindric, incurved; stigmas apically slightly 2-cleft. Monocarps subglobose, ca. 2.8 cm in diam., glabrescent. Fl. Mar-Nov, fr. Jul-Dec.