Luisia tonkinensis Schlechter.

Stems ascending, to 30 cm, 4-5 mm in diam., rigid, with many distichous leaves. Leaves 9-13 cm × ca. 3 mm, obtuse. Inflorescences 1-3, 5-10 mm, usually 4-6-flowered; floral bracts broadly ovate-triangular, ca. 4 mm, fleshy. Flowers small, opening widely, sepals and petals yellowish green, tinged with purplish brown abaxially and purplish or purplish brown on lip, column purple, anther cap yellow; pedicel and ovary ca. 1 cm, yellowish green. Dorsal sepal elliptic, ca. 5.5 × 3.5 mm, slightly concave, obtuse; lateral sepals obliquely ovate, ca. 7 × 3.5 mm, dorsally carinate-winged toward apex and then becoming a tooth protruding from apex, apex obtuse. Petals subovate, ca. 5 × 3 mm, obtuse; lip 8-9 mm, with a distinct boundary between epichile and hypochile; hypochile embracing column, broader than epichile, slightly concave; epichile nearly reniform-triangular, abaxially with a conic wart, margin ± erose, apex emarginate. Column ca. 3 mm. Fl. Apr-May.

Epiphytic on tree trunks in forests; 300-1200 m. SW Guangxi, SW Guizhou, Hainan, S Yunnan [Laos, Thailand, Vietnam].