60. Dendrobium trigonopus H. G. Reichenbach, Gard. Chron., ser. 3,. 2: 682. 1887.
翅梗石斛 chi geng shi hu
Callista trogonopus (H. G. Reichenbach) Kuntze; Dendrobium velutinum Rolfe.
Stems clustered, golden yellow when dry, fusiform or sometimes clavate, 5-11 cm, 12-15 mm in diam. at middle, thick and fleshy, unbranched, with 3-5 nodes, internodes ca. 2 cm. Leaves 3 or 4, subterminal, oblong, 8-9.5 × 1.5-2.5(or more) cm, thickly leathery, abaxially sparsely black hairy on midvein, midvein concave adaxially, with short clasping sheaths, apex acute. Inflorescences 1 or 2, distal on latest or older mature leafy pseudobulbs, arcuate, 2- or 3-flowered; peduncle 1-4 cm; floral bracts ovate-triangular, ca. 5 mm, fleshy, apex acute. Pedicel and ovary yellowish green, 3-4 cm; ovary triquetrous. Flowers nodding, thick; sepals and petals waxy yellow, lip yellow, disk tinged with pale green. Dorsal and lateral sepals subsimilar, narrowly lanceolate, ca. 30 × 10 mm, strongly keeled, both margins ascending above middle, midvein on abaxial surface slightly raised and wing-shaped, apex acute; lateral sepals with base only partly adnate to column foot; mentum subglobose, ca. 4 mm. Petals ovate-oblong, ca. 25 × 11 mm, 8-veined, apex acute; lip erect, nearly parallel to column, ca. 25 mm, base shortly clawed, apex 3-lobed; lateral lobes embracing column, subobovate, upper margin denticulate, apex rounded; mid-lobe orbicular, smaller than width between 2 lateral lobe apices; disk densely papillose. Column ca. 6 mm, upper margin of teeth with several shallow indentations; anther cap conic, ca. 5 mm, glabrous.
Epiphytic on tree trunks in mountain forests; 1100-1600 m. S Yunnan [Laos, Myanmar, N Thailand, Vietnam].