An epiphytic or occasionally lithophytic herb. Leaves 5–8, ligulate, rounded at asymmetric apex, up to 45 cm long, 4–7.5 cm wide, green. Inflorescence arcuate to suberect, 30–50 cm long, (2–)3–9-flowered; peduncle densely pubescent, 20–26 cm long, pale green, white-pubescent; bracts large, conduplicate, broadly elliptic, obtuse to subapiculate, 3–4 cm long, 2–3.5 cm wide, margins undulate. Flowers 9-10.5 cm across, up to 13.5 cm long; sepals cream to green with darker veins; petals green below and spotted with blackish-maroon, dark maroon on margins and in apical half; lip yellowgreen to green or purplish flushed; pedicel and ovary 5 cm long, green, pubescent. Dorsal sepal elliptic, obtuse, 3.5–5.2 cm long, 1.8–3.5 cm wide, basal margins recurved, apical margins incurved. Synsepal ovate, acute, 2.6–4.1 cm long, 1.5–3.5 cm wide, with recurved margins, 2-keeled on outer surface. Petals decurved-pendent, linear-tapering, rounded at apex, 7–11.2 cm long, 0.6–1.6 cm wide, spirally twisted in apical half; basal margins undulate, maroon spots on lower basal margin, ciliate. Lip tapering to rather narrow apex, 3–4.5 cm long, 1.5–2.3 cm wide. Staminode obcordate, 11–14 mm long, 7–9 mm wide, umbonate at base, cream with dark green venation. 2n = 26.