Description from Flora of China
Didissandra kingiana Craib, Notes Roy. Bot. Gard. Edinburgh 11: 259. 1919; Corallodiscus grandis (Craib) B. L. Burtt; D. grandis Craib; D. rufa King ex J. D. Hooker, not C. B. Clarke.
Petiole to 5.5 cm, adaxially glabrous, rarely rust brown centrally, abaxially densely rust-brown woolly; leaf blade rhombic-lanceolate to lanceolate, rarely ovate, 1.6-11 X 0.8-4 cm, flat to bullate, adaxially glabrous, rarely rust-brown woolly near base of midrib, abaxially densely rust-brown woolly, margin subentire to crenulate, rarely serrulate, apex narrowly acute to acute, seldom obtuse or acuminate; lateral veins 4 or 5 on each side of midrib, adaxially impressed, abaxially prominent. Cymes (5-)7-20-flowered; peduncle (3.5-)4.5-17 cm, densely rust-brown woolly. Calyx 4-5 mm, outside densely rust-brown woolly. Corolla purplish to blue and white, inside with 2 deep brown spotted striae on abaxial lip, (1-)1.3-16 (-1.8) cm, outside glabrous; tube 8-12 X 3-7 mm; adaxial lip lobes 1-3 mm; lobes abaxial lip 3-5 mm. Adaxial stamens 3-4 mm, abaxial ones 5-6 mm; staminode ca. 1.5 mm. Pistil glabrous; ovary ca. 3 mm. Style 3-6 mm. Capsule ovoid to oblong, rarely narrowly oblong, 6-10(-20) mm. Fl. Jun-Sep, fr. Jun-Sep.
Corallodiscus kingianus and C. grandis are treated as a single species because the large number of specimens now available shows that the variation between them is continuous and correlates with elevation throughout their range. Corolla and pedicel length and number of flowers per inflorescence tend to decrease with increasing elevation. Calyx indumentum becomes denser with greater elevation.
Rocks on slopes or in forests; 2800-4800 m. S Qinghai, SW Sichuan, S Xizang, NW Yunnan [Bhutan, Sikkim].