Disa aperta N.E.Br.

A terrestrial herb 2–4.5 dm. high, glabrous except for the roots.. Tubers ovoid or ellipsoid, 1.5–2.5 cm. long, 1–1.5 cm. in diameter, ± densely tomentose.. Roots slender, flexuous, pubescent.. Sterile stems only slightly developed at time of flowering, very short, with several overlapping sheaths and a single narrow leaf.. Flowering stems erect, rather slender, terete, leafy throughout their length; leaves 4–6, the lowest 1 or 2 sheath-like, obtuse, the remainder erect, ± adpressed to the stem, lanceolate, acute, the largest 4.5–8 cm. long and 5–14 mm. broad, the uppermost often much smaller than the others.. Inflorescence 4–17 cm. long, 3–4.5 cm. in diameter, rather loosely 6–25-flowered.. Bracts thin in texture, lanceolate, acuminate, 8–16 mm. long, shorter than the flowers.. Flowers half-spreading, whitish with purple or mauve markings or spots; pedicel with ovary straight, 10–14 mm. long.. Dorsal sepal erect or tilted backwards, convex, broadly elliptical in front, spurred at the back below the middle, 7–11 mm. long, the mouth ± 7 mm. broad when spread out, the spur at right angles, shortly cylindrical from a broader base, total length from base of sepal 6–7 mm.; laterals projecting forwards, oblong-elliptical, rounded, 10–13 mm. long, 4–5 mm. broad, apex shortly mucronate.. Petals inside the dorsal sepal, erect, very obliquely oblanceolate or almost subhastate, acute, 5–7 mm. long, ± 3 mm. broad, attached to the column by a thin keel or ridge.. Lip projecting forwards in a straight line with the ovary, narrowly oblong from a narrower base, obtuse or rounded at the apex, 6–11 mm. long, ± 2 mm. broad.. Column short, erect; anther reflexed or horizontal, ± 2 mm. long, canals short, turned upwards; stigma almost orbicular, 2 mm. in diameter.