Growth form Epiphyte, scandent or scrambling, up to 80 cm high. Rhizome ca. 1 mm in diameter. Roots filiform, flexible, glabrous. Stem cylindrical, glabrous, branches horizontal, slightly drooping up to 40 cm long branches, proliferously leafed, entirely covered by leaf sheaths. Leaf ovate, in two vertical rows, patent, glabrous, midrib grooved above, prominently crested below, lateral nerves 3-6 on either side of midrib, with less developed ones in between, visible above, prominently crested below, margin erose, wavy; apex unequal 2-lobed, both lobes obtuse; lamina 0.3-2.4 cm long, 0.2-0.5 cm wide; sheath tight clasping, tubular, densely warty mainly on the ribs, many-ribbed, 0.2-2.2 cm long; apex toothed, with bristled margin, bristles 0.15-0.3 cm long, each scattered papillate-warty. Inflorescences terminal, one-flowered, when young enveloped by a spathe. Spathe obovoid-tubular, many-ribbed, midrib and larger nerves crested on outside, scattered papillate-warty, warts often hook-like retrorse, apex obtuse or rounded, 1 cm long, 0.4 cm wide; floral bracts tubular, many-ribbed, ribs less strongly developed than in spathe, papillate-warty as spathe but less dense, apex rounded, 1.2 cm long, 0.35 cm wide. Flowers upright, glabrous. Median sepal oblong or oblong-ovate, glabrous, 3-nerved at base, 9-nerved in higher parts, apex obtuse, 1.2-1.25 cm long, 0.4-0.45 wide. Lateral sepals free, slightly falcate oblong-ovate, glabrous, 3-nerved at base, 8-nerved in higher parts, apex obtuse, base oblong-ovate widened, 1.2-1.4 cm long, 0.3-0.45 cm wide. Petal narrowly obovate, glabrous, 3-nerved at base, 7-nerved in higher parts, apex rounded, 1-1.2 cm long, 0.4 cm wide. Lip adnate to the column, free part triangular, 7-nerved, 0.5 cm long, 0.5 cm wide; epichile 3-lobed, obtuse, with brown glands along margin and in narrow patch along latter; hypochile spurred; spur clavate, 1.1 -1.2 cm long, apex retuse-truncate, upper side shallowly and broadly grooved. Column stout, 0.2 cm long, 0.15 cm wide; clinandrium denticulate; stelidia not seen. Anther not seen; rostellum not seen; pollinia not seen; stigma not seen; viscidium not seen. Ovary narrowly clavate, slightly curved, glabrous, 9-ribbed, 6-ribbed on the sutures developed as twin ribs, 1.2 cm long Capsule not seen.
Distribution – Papua New Guinea.
Habitat and Ecology – Epiphyte in upper montane forest of Kubor Range (Nona-Minj-Divide). Altitude 3250 m. Flowering in July in the wild.
Notes - 1. Flowers green or white with green lip with black or grey margin and tip.
2. The epithet nigrimarginata refers to the black color of the lip margin of the species. (nigri- means black and-marginata means margin in Latin).
3. Specimen observed: Vink 16035.