Plant slender, (15-)20-50(-70) cm tall with (2-)3-12(-17) flowers in a (relatively) lax spike. Sepals violet to white, narrowly ovate to lanceolate-oblong, 11-17 × 5-9 mm; dorsal sepal boat-shaped, straight to slightly incurved, from the base reflexed. Petals yellowish green to rose-coloured, sometimes suffused with red, triangular (often auriculate) with recurved margins, 1-3(-7) × 1(-2) mm, shaggy, spreading. Lip with (dark) brown ground colour, straight with strongly recurved margin, deeply (to moderately) three-lobed close to the base, 8-14 × 10-16 mm, velvety to shaggy along the margin (otherwise nearly glabrous); side lobes converted into obliquely conical bulges; mid-lobe much longer than the side lobes, rounded, provided with a downward pointing, more or less rectangular to rhomboid appendage (often hidden under the strongly vaulted lip); mirror distinct (rarely obscure), consisting of a more or less H-shaped or often slightly more complicated figure, the basal arms of which are connected to the base of the lip (occasionally, there are also a few isolated markings towards the apex), dull greyish violet with a cream border. Column extended into a sigmoidly curved apex, not tapering towards the base (in side view); stigmatic cavity approximately as wide as long and approximately twice as wide as the anther, with dark, lateral, eye-like knobs at base; pollinia with flaccid stalks.