Description from Flora of China
Shrubs or trees, erect; bark gray. Branchlets terete, with small rounded to elliptic lenticels, sparsely puberulent when young, glabrescent. Petiole 1-2.5 cm; leaf blade black and shiny when dry, ovate-oblong to ovate, 8-12 X 4-6 cm, papery, subglabrous to pubescent along veins, base broadly cuneate to subrounded, margin entire, apex acuminate to acute; veins 4 or 5 pairs, curve apically along margins and anastomose. Inflorescences 3-7 X 5-13 cm, sparsely puberulent; branches 3-5 pairs; bracts linear, ca. 6 mm. Calyx cup-shaped, ca. 1.5 mm, slightly 2-lipped, 5-dentate, pubes-cent and subglandular when young, glabrescent. Corolla ca. 4 mm, slightly 2-lipped, 4-lobed; lower lip 3-lobed, lobes subequal or middle lobe slightly longer; upper lip entire or emarginate, outside subglabrous, long villous in throat with hairs usually exserted. Ovary glabrous, without glands. Style longer than stamens. Fruit obovate to globose, 3-5 3-4 mm, tuberculate. Fl. and fr. Aug-Nov.
* Mixed forests on mountain slopes or in open places; 200-800 m. Hainan.