Rhizome stout. Leaves elongate, lanceolate, acuminate, long petiolate, 3–4 ft. long, 3–4 in. broad. Scapes 8–16 ft. high, with numerous sheaths below; racemes 1–1 1/2 ft. long, 20–30-flowered. Bracts oblong or obovate-oblong, obtuse or apiculate, concave, 3/4–1 3/4 in. long. Pedicels 1 1/4–2 in. long. Flowers light purple, with yellow keels to the lip. Sepals oblong or obovate-oblong, obtuse, and sometimes incurved and concave, 9–10 lin. long, light green. Petals broadly elliptic-oblong, obtuse or apiculate, 1 1/4–1 1/2 in. long, light purple. Lip trilobed, 1 1/4–1 1/2 in. long, light purple; side lobes broadly rounded; front lobe quadrate-suborbicular, obtuse or emarginate; disc with 3 somewhat thickened keels in the middle; spur broadly conical, 5–6 lin. long, somewhat narrowed and subacute at the apex.
