Description from Flora of China
Lianas woody, to 10 m tall. Branchlets glabrous or pilose, ferruginous scaly. Leaves opposite, subopposite, or alternate, rarely 3-whorled; petiole 6-13 mm, pilose and ferruginous scaly; leaf blade usually elliptic or oblong-elliptic, 6-15(-18) × 3-7(-9) cm, both surfaces glabrous, or pilose and glabrescent with age but remaining pilose on veins, ferruginous minutely scaly, more densely so abaxially, not verruculose, base obtuse-rounded or attenuate, apex acute or cuspidate to caudate-acuminate; lateral veins in 6-12 pairs. Inflorescences terminal and axillary, simple, narrowly cylindric spikes 4-10 cm, sometimes grouped at branchlet apex and forming a panicle; axes pilose and ferruginous scaly; bracts persistent at anthesis, filiform-linear, 3-7 mm, pilose. Calyx tube in middle part narrowly funnelform, distally cupular, 5.5-7 mm, abaxially glabrous, densely ferruginous scaly, adaxially with a ring of dense, coarse hairs not or only slightly exserted; lobes 4, erect, deltoid, ca. 1 mm, apex acute or subacute. Petals 4, white to yellow or yellowish green, 2-2.5 mm, clawed; limb obovate or oblanceolate. Stamens 8, exserted, 3-5 mm. Fruit brown, globose, 4-winged, 2-3.5 × 2-4 cm, glabrous, densely white and/or brown minutely scaly. Fl. Apr-Jun, fr. Jul-Dec.
Forests, sparse forests, woods, thickets by streams, mountain slopes and valleys, ravines, riversides; 500-1600(-2000) m. S and W Yunnan [Bangladesh, Bhutan, India, Laos, Malaysia, Myanmar, Thailand, Vietnam].