Description from Flora of China
Didymocarpus grandifolius (A. Dietrich) F. G. Dietrich; Henckelia grandifolia A. Dietrich (1831), not H. macrophyllla (Wallich ex D. Don) Sprengel (1817).
Perennials. Rhizome internodes inconspicuous. Stems absent or erect to prostrate, to 15(-37) cm, sparsely appressed puberulent. Basal leaves ca. 2, stem leaves 1-3 pairs, opposite, widely spaced, strongly unequal in each pair, larger ones similar to basal leaves, but smaller; petiole 1.3-4 cm X 1-4 mm; leaf blade ovate to elliptic, 9.5-19 X 6-14 cm, herbaceous, adaxially appressed puberulent, eglandular, abaxially sparsely pubescent, base oblique, cordate to rounded, margin dentate to serrate, apex abruptly acuminate to rounded; lateral veins 6-9 on each side of midrib, conspicuous. Cymes (1 or)2-6-flowered; peduncle 6.5-15(-25) cm, sparsely pubescent; bracts 2, free, ovate or elliptic to suborbicular, 0.4-2 cm X 1-10 mm, sparsely pubescent, margin entire to dentate, apex acute to rounded. Pedicel 0.7-2.3 cm, pubescent to glabrous. Calyx 1.5-2.2 cm, 5-lobed from above to near middle; tube 7-11 mm; lobes unequal, narrowly triangular, 5-8 X 3-4 mm, glabrous or outside sparsely puberulent, margin entire, apex acute to attenuate. Corolla white to yellow, sometimes purplish to bluish, 4.4-5.5 cm, glabrous; tube tubular, 3-4 X ca. 1 cm; adaxial lip ca. 9 mm; abaxial lip ca. 1.1 cm. Filaments ca. 1 cm, glabrous; anthers fused by entire adaxial surfaces, 3-4 mm, glabrous; staminodes 3, central ca. 2 mm, laterals 3.5-5.5 mm. Pistil ca. 2.3 cm, puberulent; ovary ca. 1.5 cm. Stigma flabellate, ca. 3 mm, 2-lobed. Capsule often at to 90 to peduncle, 8-13 cm. Fl. May-Sep, fr. Aug-Dec.
Rocks in forests; 1300-3100 m. SW Guizhou (Zhenfeng Xian), S Yunnan [Bhutan, NE India, N Myanmar, Nepal, Thailand].