2n = c. 40, 40

Plant at fl. to c. 100 cm. tall. Swollen rhizomes long-lived and extensively branched, individual parts to 25 × 5 cm. Stem erect, stout or slender. Scale lvs widely spaced. Raceme often long and fls ∞ (e.g. to 40 or more), erect to ± drooping. Per. c. 14 mm. long, brownish or greenish mottled with paler knobs, adjacent plants sts contrasting in colour; lobes slightly thickened marginally. Lateral sepals connate little above the gibbous base but their margins lying close together. Labellum ± oblong, long-adnate to per.-tube; long median calli crested; margin undulate and ± lobed, membr. above, thickened and twisted in the lower adnate part. Column very short, wing represented only by a minute ± curved process; anther short, operculate, filament transversely pleated at back; stigma immediately below anther and ultimately covered by it.