Robust terrestrial herb 30–70 cm tall.Perennating organs subterranean, tuberous, 5–10 × 2–2.5 cm, potato-like, forming a long chain; roots 1.5 mm in diameter.Leaves 2–3, 30–80 × 1.5–5 cm, lanceolate, acute, ribbed, absent or just starting to develop at flowering time.Inflorescence short and dense, almost capitate, many-flowered; scape stout, with several loose, papery sheaths up to 10 cm long, sometimes overlapping.Pedicel and ovary 10–20 mm long; bracts 20–50 mm long, lanceolate, long acuminate, spreading or reflexed.Flowers lemon-yellow with a deep purple, orange or brown blotch on the mid-lobe of the lip, side lobes purplish.Sepals 28–40 × 10–16 mm, elliptic-lanceolate, acuminate, the laterals very slightly longer than the dorsal.Petals slightly shorter than the sepals, 28–35 × 10–14 mm, elliptic-lanceolate, acuminate.Lip 23–30 × 12–22 mm, 3-lobed; side lobes small, rounded; mid-lobe c. 15 × 15 mm, suborbicular, obtuse or emarginate; callus of 2 basal ridges turning to long papillae on the basal half of the mid-lobe.Spur 2–5 mm long, straight, conical to cylindrical.Column 6–7 mm long; foot 3 mm long.Capsule pendent, c. 20 mm long.