Branchlets terete, with conspicuous longitudinal ridges and sparse lanate tomentum when young, then becoming glabrescent; tendrils bifurcate, leaf-opposed. Leaves simple; stipules brownish, lanceolate, 2.5-6 × 1.5-3 mm, membranous, glabrous, margin entire, apex acute or obtuse; petiole 2-6.5 cm, with arachnoid tomentum when young, then glabrescent; leaf blade oval or ovate-elliptic, undivided or 3-lobed, 4-12 × 3.5-9 cm, abaxially densely tomentose when young, then hairs falling off and only veins pubescent or nearly glabrous, adaxially pubescent and with sparse arachnoid tomentum when young, then glabrescent, basal veins 5, lateral veins 4-6 pairs, veinlets slightly raised abaxially, base cordate or subtruncate, rarely subrounded on upper leaves, margin 15-25-toothed on each side, teeth sharp, apex acute or acuminate. Panicle leaf-opposed, with well-developed basal branches, loose, 4-15 cm, with arachnoid tomentum when young, then nearly glabrescent. Pedicel 1.5-3 mm, glabrous. Buds obovoid, 1.5-2 mm, apex rounded. Calyx ca. 0.2 mm, margin membranous, entire. Filaments filiform, 1-1.5 mm; anthers yellow, elliptic, ca. 0.4 mm. Ovary oval; style short. Berry purple-black at maturity, globose, 8-10 mm in diam. Seeds obovoid, apex rounded, chalazal knot rounded or elliptic, ventral holes furrowed upward 2/3-3/4 from base.