Leaf linear, terete, smooth, 150–300 × 4–5 mm, hollow, dark green, very stiff, tip often blackish. Flower stem 300–1000 mm tall, stiff, 2–8-flowered. Flowers 25–40 mm across, lilac-blue to deep mauve or reddish mauve with dark veins and spots. Dorsal sepal broadly elliptic, 18–20 × 7–9 mm, erect or recurved. Lateral sepals ovate, 18–20 × 10–12 mm, divergent. Petals ovate, 16–18 × 7–10 mm, spreading or recurved. Labellum shortly stalked, oblong, 13–15 × 10–12 mm, flat or concave, base with 2 rounded, ridge-like calli (separate or often fused) adorned with a tuft of dark, ribbon-like appendages with curled, white, clubbed tips. Column with prominent, broad, blue-spotted wings which hood column.