Description from Flora of China
Curanga amara Jussieu; C. felterrae (Loureiro) Merrill.
Herbs, to 1 m tall, rooting from lower nodes. Branches divaricate, striate. Petiole 0.5-2 cm; leaf blade ovate to sometimes suborbicular, to 5.5 X 3 cm, abaxially hispid on veins, adaxially short hispid, base cuneate, rounded, or truncate, margin crenate-serrate, apex acute; lateral veins 4 or 5 on each side of midrib. Racemes 4-8-flowered. Pedicel to 1 cm. Calyx lobes oblong-ovate, to 1.4 X 1 cm in fruit, veins conspicuously reticulate; lower lobe smaller than upper; upper lobe often apically 2-lobed; 2 lateral lobes linear. Corolla white or red-brown, ca. 1.2 cm; tube ca. 6.5 mm, constricted at middle; lower lip ca. 6.5 mm; upper lip erect, ca. 4.5 mm, base wide, apically narrowly suboblong, emarginate. Anterior filaments puberulent. Capsule ovoid, 5-6 mm.
Sparse forests, fields; 700-1400 m. Guangdong, Guangxi, Guizhou, S Yunnan [India, Indonesia, Laos, Malaysia, Myanmar, Philippines, Thailand, Vietnam].