Description from Flora of China
Petiole 1-11(-14.5) cm, densely brown appressed puberulent; leaf blade narrowly to broadly ovate or oblong, 4-18 X 2.5-8 cm, appressed puberulent, glabrescent, base oblique, cordate, margin entire to repand, apex abruptly acuminate to acute; lateral veins 5 or 6 on each side of midrib. Cymes 10-20-flowered; peduncle 14-18(-26) cm; bracts linear-lanceolate, 6-12 mm, margin entire or subentire. Pedicel 1-2 cm. Calyx 4-9 mm, 4-lobed; tube 1.5-2(-3) mm; lobes linear-lanceolate, 2.5-7 mm, margin sparsely denticulate. Corolla white, 5-8 mm, outside glabrous, 4-lobed from below middle; tube 2.5-3 mm; lobes oblong to ovate-oblong, 5-6 X 2-3 mm. Stamens 4, 8-11 mm. Pistil glabrous; ovary 4-7 mm. Style 2-3 mm. Capsule (1-)2-3.5 cm. Fl. Sep-Oct, fr. Oct-Nov and May.
* Streamside rocks, valley forests; 600-1000 m. Guangdong.