Terrestrial herb 20–60(80) cm tall; tubers to 3.5 × 2 cm, ellipsoid or ovoid, woolly.Stem leafy.Leaves 9–15, sometimes distichous, the lowermost 1–2 sheath-like, the middle ones suberect or spreading, the largest 2–10 × 0.7–4.5 cm, linear to ovate, the uppermost grading into the bracts.Inflorescence 5–19 cm long, laxly to densely few to many-flowered; bracts leafy, to 27 mm long.Flowers green or yellow-green, the lip occasionally white.Pedicel and ovary 18–28 mm long.Dorsal sepal erect, 5–16 × 4–8 mm, ovate, convex; lateral sepals deflexed, 6–16 × 5–10 mm, obliquely ovate, rolled up lengthwise.Petals 2-lobed almost to base, upper lobe 6–15 mm long, ± filiform, adnate to dorsal sepal; lower lobe 20–50 mm long, 1–2 mm wide at base, horn-like, usually curling up but occasionally erect and straight.Lip 3-lobed from undivided base 1–2 mm long; mid-lobe 9.5–19 mm long, to 1 mm wide, linear; side lobes diverging, 8–18 mm long, the basal part flattened, 1–2.5 mm wide, usually with 1–6 short teeth, the apical part tapering; spur 14–28 mm long, very slender but suddenly swollen in apical 5 mm.Anther erect, 3–7.5 mm long; canals 4.5–8.5 mm long.Stigmas 3–8 mm long, porrect, slender, widened and truncate at apex.Rostellum mid-lobe triangular, c. 1 mm long.
