Description from Flora of China
Loxotis obliqua (Wallich) Bentham; Rhynchoglossum hologlossum Hayata; R. obliquum f. albiflorum Kuntze; R. obliquum f. coeruleum Kuntze; R. obliquum var. hologlossum (Hayata) W. T. Wang; R. obliquum var. parviflorum C. B. Clarke; R. zeylanicum W. J. Hooker; Wulfenia obliqua Wallich.
Annuals, not rhizomatous. Stems 18-100 cm, glabrous to sparsely puberulent. Petiole 0.5-1.5(-3.5) cm; leaf blade oblique, 1 side elliptic, other side ovate, 4-12 X 2-6 cm, adaxially glabrous, sometimes minutely sparsely puberulent, abaxially glabrous, base strongly oblique, cuneate to narrowly cordate on smaller side, cordate on other, margin entire to undulate, apex acuminate. Cymes 3-24 cm, 10-30-flowered, appressed puberulent, glabrescent; peduncle 2-5.5(-8) cm, glabrous. Calyx often tinged blue, 3-8 mm; lobes 1-3 mm. Corolla pale to dark purple or blue, 8-11 mm, inside puberulent near mouth; tube 5-6 X 1.5-2 mm; adaxial lip 1.5-2.5 mm; abaxial lip 3.5-5 mm, 3-lobed to undivided. Stamens 2; anthers 0.7-1 mm, thecae nearly parallel; staminodes 2, ca. 0.8 mm. Disc ca. 1 mm. Pistil ca. 6.5 mm, glabrous. Style 4-6 mm. Capsule 3-4.5 mm. Fl. Jul-Nov, fr. Aug-Nov.
In recent treatments of Rhynchoglossum in China two varieties were recognized. However, the only character that separates them is lobing of the abaxial corolla lip, which varies from entire to deeply 3-lobed even on the same specimen. The entire-lipped variety was described from and previously reported only from Taiwan. Entire abaxial corolla lips have been observed in W Guangxi, SW Guizhou, SW Sichuan, S & W Yunnan, India, Philippines, and Thailand.
Forest margins, forests, caves, shaded cliffs; 100-2800 m. W Guangxi, SW Guizhou, SW Sichuan, Taiwan, E Xizang, Yunnan [Cambodia, India, Indonesia, Malaysia, Myanmar, Nepal, Philippines, Sri Lanka, Thailand, Vietnam].