Description from Flora of China
Thunbergia adenophora W. W. Smith; T. chinensis Merrill; T. lacei Gamble.
Vines to 10 m or longer, woody. Stems 4-angled, sulcate, pubescent. Petiole 1-7 cm, grooved, pubescent; leaf blade ovate to triangular-ovate, 5-10 × 4-8 cm, papery, both surfaces pubescent, palmately 3-7-veined, base subcordate to truncate, margin undulate, irregularly angular on basal half, or rarely entire, apex acuminate to acute. Flowers solitary, paired in leaf axils, or arranged in terminal racemes with 2-4 flowers per node; peduncle 4-7 cm, sulcate, pubescent; rachis pubescent with large cyathiform glands; apical inflorescence bracts subulate to linear-subulate, 2-6 × 1-1.5 mm, pubescent; bracteoles oblong to ovate, 2.5-4 × 1.5-2.2 cm, both surfaces pubescent, 5-7-veined, base truncate, margin entire or ciliate, apex acute with a short mucro. Calyx ca. 2 mm, annular, unlobed, densely pubescent. Corolla bluish with a yellowish throat, 4-6 cm, outside glabrous; tube basally cylindric and ca. 3 mm wide for ca. 7 mm then gradually widened to ca. 5 cm at throat; limb subactinomorphic; lobes ovate, ca. 3 × 2.5 cm. Staminal filaments 7-9 mm; anther thecae pubescent, basally appendaged. Style glabrous; stigma with 2 subequal lobes. Capsule 1.2-1.5 cm, pubescent, basal part 1.3-1.8 cm in diam., beak ca. 2.5 cm. Seeds ovate in outline, compressed, verrucose. Fl. Aug-Jan, fr. Nov-Mar. 2n = 56.
Thunbergia grandiflora is naturalized in tropical regions worldwide.
Thickets; 400-1500 m. Fujian, Guangdong, Guangxi, Hainan, Yunnan [India, Myanmar, Thailand, Vietnam].