Description from Flora of China
Didymocarpus sesquifolius (C. B. Clarke) H. Léveillé.
Herbs. Stems 12-38 cm, sparsely villous, glabrescent. Leaves 2, at stem apex, strongly unequal; petiole absent to 3 mm; leaf blade ovate to very broadly ovate, 8.5-29 X 5.2-21 cm and (1-)3-6.5 X (0.6-)2-4.6 cm, pubescent to villous, base rounded to cordate, margin serrate to dentate-serrate, often doubly so, apex obtuse to acuminate. Cymes 1- or 2(-4)-flowered; peduncle 0.5-1(-3.5) cm, densely villous; bracts 2, often deciduous, lanceolate to oblanceolate, 4-5 X 0.5-2, margin entire. Calyx 1-2 cm, 5-lobed from below to above middle; lobes lanceolate to broadly triangular, 3-14 X 2-3 mm. Corolla purple to purple-blue, 4.8-7 cm; tube 3.5-5.7 cm; adaxial lip 8-10 mm; abaxial lip ca. 1.2-1.5 cm. Adaxial stamens 0.9-1.1 cm, abaxial ones 1.2-1.6 cm; anther thecae confluent; staminode 1, ca. 0.6 mm. Pistil 2.8-3.4 cm; ovary sparsely villous to puberulent. Style 6-7 mm, sparsely pubescent, glabrescent; adaxial stigma oblong, ca. 2 mm, abaxial stigma obovate, ca. 3 mm, 2-lobed. Capsule 5.5-7 cm. Fl. Jul-Aug, fr. Aug-Oct.
* Under forests, near roads, cliffs in montane regions; 900-1600 m. SW Sichuan.