Plants polygamo-dioecious. Branchlets terete, with longitudinal ridges, gray or brown lanate; tendrils bifurcate. Leaves simple; stipules brown, ovate-lanceolate, 3-5 × 2-3 mm, membranous, entire, apex acuminate, rarely obtuse; petiole 2.5-6 cm, with dense arachnoid tomentum; leaf blade sometimes 3-lobed to -cleft, 4-12 × 3-8 cm, abaxially densely grayish or brown tomentose, gradually becoming less so, abaxial veins tomentose, sometimes pilose or lanate, adaxially with sparse arachnoid tomentum when young, then glabrate, adaxial veins glabrous or sometimes sparsely pubescent, basal veins 3-5, lateral veins 4-6 pairs, base cordate to subcordate, notch obtuse, rarely acute, margin 9-19-toothed on each side, teeth sharp, apex acute or acuminate. Panicle leaf-opposed, 4-14 cm, basal branches developed; peduncle 1-2 cm, with gray or brown arachnoid tomentum. Pedicel 1-3 mm, glabrous. Buds obovoid or elliptic, 1.5-2 mm, apex rounded. Calyx ca. 0.1 mm, subentire. Filaments filiform, 1-1.2 mm; anthers yellow, elliptic or broadly so, ca. 0.5 mm. Ovary oval; style short. Berry purple-black at maturity, globose, 1-1.3 cm in diam. Seeds obovoid, apex rounded, chalazal knot rounded, ventral holes furrowed upward ca. 1/4 from base.