Description from Flora of China
Gomphostemma insuave Hance, J. Bot. 22: 231. 1884; Microtoena esquirolii H. Léveillé.
Herbs or subshrubs. Stems 1-2 m tall, appressed pubescent. Petiole 3-8.5 cm; leaf blade ovate to broadly ovate, 6-10 × 4.5-7.5 cm, papery, pubescent, densely so on veins, base broadly truncate-cuneate, decurrent into a winged petiole, margin serrate-crenate, apex acute. Cymes dichotomous with 1-sided branches, in open terminal panicles. Calyx ca. 2.5 × 1.5 mm, puberulent; teeth triangular-lanceolate, ca. 1/2 as long as calyx, posterior tooth somewhat longer; fruiting calyx dilated. Corolla red, purple on upper lip, ca. 1.4 cm, throat to ca. 3 mm wide; upper lip ca. 7 mm, base truncate, apex emarginate; lower lip longer, middle lobe ligulate, lateral lobes triangular. Nutlets ca. 1.2 × 1 mm in diam., slightly corrugate. Fl. Oct-Dec, fr. Dec-Jan.
Forests, forest margins; 700-1000 m. Guangdong, Guizhou, Yunnan [Indonesia, Vietnam].