Plants 50-70(-120) cm tall. Rhizome ca. 1 cm in diam., fleshy. Pseudobulbs cylindric-ovoid to clavate, 4-5 × 1-3 cm, several noded, usually enclosed by leaf sheaths. Leaves 5-10, nearly distichous, well developed at anthesis, not deciduous; blade oblong-elliptic to oblanceolate, 40-95 × 4-9 cm, glabrous, apex acuminate; petiole-like base to 20 cm, ca. 1 cm in diam., articulate. Scape arising from base of pseudobulb, 30-45 cm, with several tubular sheaths below middle; rachis 10-15 cm, densely many flowered; floral bracts caducous, narrowly lanceolate, 2.5-3.5 cm, membranous, glabrous. Flowers yellow; pedicel and ovary 15-20 mm, glabrous. Sepals similar, ovate-lanceolate, 9-12 × 4-5 mm, 5-veined, apex acuminate. Petals ovate-elliptic, 9-12 × 4-6 mm, 7-veined, apex subacute; lip adnate to entire length of column wings, 8-9 × 5-6 mm, 3-lobed above base; lateral lobes subsquare to ovate-triangular, ca. 2.5 × 2.5 mm, ca. 5 mm across their apices; mid-lobe flabellate or sometimes subobovate-cuneate, ca. 5 × 5-6 mm, margin undulate, apex truncate and mucronate; disk with 2 lunar calli between lateral lobes, though sometimes inconspicuous; spur slightly arcuate, clavate, 7-9 mm. Column ca. 5 mm, thick, dilated toward apex; rostellum triangular, ca. 3 mm, unlobed; pollinia clavate, subequal in size, ca. 2.1 mm, with conspicuous caudicles; viscidium sublinear, ca. 2.2 mm. Fl. (Apr-)Jul-Oct. 2n = 20*, 40*.
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