Description from Flora of China
Callista strongylantha (H. G. Reichenbach) Kuntze; Dendrobium ctenoglossum Schlechter.
Stems erect, cylindric or ± narrowly fusiform, 3-27 cm, with sheath 4-10 mm in diam., fleshy, many noded, current ones enclosed in leaf sheaths, previous year’s stems golden yellow. Leaf blade distichous, alternate on entire stem, oblong, 4-10 × to 1.7 cm, thin, base dilated into gibbous sheaths, apex acute and unequally bilobed; leaf sheaths sparsely clasping when dry, herbaceous, sheath mouth obliquely truncate. Inflorescences 1-4, subterminal or lateral on upper part of stem, suberect, to 13 cm, much taller than leaves, densely 20- or more flowered; rachis slender; floral bracts ovate-lanceolate, 2-4 mm, apex acuminate. Pedicel and ovary ca. 5 mm. Flowers yellowish green, sepals purplish red at base, petals pale yellowish green with purplish red stripes, lip violet, column pale purple. Dorsal sepal narrowly ovate-lanceolate, ca. 11 × 2 mm, 3-veined, long acuminate; lateral sepals falcate-lanceolate, to 14 × ca. 4.3 mm, 4- or 5-veined, base oblique, abruptly contracted above middle, apex caudate; mentum broadly conic, ca. 4 mm. Petals ovate-lanceolate, slightly smaller than dorsal sepal, 3-veined, apex acute; lip ca. 8 × 4 mm, 3-lobed above middle; lateral lobes ovate-triangular, margin with comb-shaped teeth, apex sharply toothed; mid-lobe triangular, margin wrinkled and crestlike, apex acute; disk with 2 or 3 lamellate ridged projections, ridges thickly fleshy, terminating at base of mid-lobe, apex enlarged. Column subterete, ca. 2 mm, foot margin densely finely papillate; anther cap subglobose, front margin lacerate.
Epiphytic on tree trunks in mountain forests; 1000-2100 m. Hainan (Bawangling), S and W Yunnan [Myanmar, N Thailand, N Vietnam].