Growth form Epiphyte or terrestrial, erect, much branched, broom-like, densely bushy, branches slightly pendulous at tip, up to 35 cm long. Rhizome 2-3 mm in diameter. Root filiform, flexible, glabrous, up to 5 cm long. Stem branched, cylindric, glabrous, internodes 0.3-2.2 cm long. Leaf lanceolate-linear, sometimes slightly ovate or obovate, subcoriaceous, erect, glabrous, 5-nerved, midrib grooved above, prominent below, lateral nerves 2 on either side of midrib, prominent on underside only, margin membranous; apex unequally 2-lobed, both lobes obtuse; lamina 0.7-2.5 cm long, 0.1-0.2 cm wide; sheath tight, tubular, rather densely warty mainly on the ribs, many-ribbed; apex toothed, with bristled margin, bristles 0.1-0.3 cm long, scattered, papillate. Inflorescences terminal, one-flowered, when young enveloped by a spathe. Spathe widely obovoid-tubular, transparent, finely papillate on outside, with brown dots, 1-1.2 cm long, 0.4-0.6 cm wide, 5-nerved, apex acute, midrib crested at tip; floral bracts obovoid, glabrous, thin, transparent, with brown dots, 1.3 cm long, 0.78 cm wide, thinly 5-nerved, apex acute. Flower upright, glabrous. Median sepal oblong-ovate, glabrous, 3-nerved at base, 5-7 nerved in higher parts, 1.2-1.4 cm long, 0.4-0.5 cm wide, with silver dots; apex apiculate. Lateral sepal slightly obliquely oblong-elliptic, 3-nerved at base, 5-7-nerved in higher parts, 1.2-1.4 cm long, 0.35-0.4 cm wide, with silver dots; apex rounded, apiculate; base obliquely widened. Petals broadly elliptic, 3-nerved at base, 5-nerved in higher parts, glabrous, 1.1-1.2 cm long, 0.35-0.4 cm wide, 3-nerved, with silver spots; apex rounded, obtuse. Lip triangular, adnate to the base of the column, 0.55-0.6 cm long, 0.6-0.8 cm wide; epichile obtuse, with brown glands on both sides in a narrow strip along the apical part, 5-nerved, with silver dots; hypochile spurred; spur cylindrical, sigmoid, glabrous, 1.1-1.2 cm long, flattened and truncate at tip, broadly shallowly grooved above with a raised mid-rib in the groove. Column curved, without column foot, 0.3 cm long, 0.2 cm wide; clinandrium dentate-crenulate. Anther broadly ellipsoid, apex truncate-retuse, base subtruncate, emarginated, connective umbonate, 0.12 cm long, 0.2 cm wide; pollinia 4, pear-shaped, 0.06 cm long. Ovary oblong-clavate, glabrous, 3-ribbed, each rib double one, 1.1-1.3 cm long, 0.2 cm wide. Capsule ellipsoid, 1.2 cm long, 0.5 cm wide, 3-ribbed, glabrous.
Distribution –Papua New Guinea.
Habitat and Ecology – Terrestrial in upper montane forest in exposed positions on Imbuka Ridge. Altitude 3353-3600 m. Flowering in May and June in the wild.
2. The epithet nigricans refers to the black color or the leaf sheaths.
3. Specimen observed: L0061276.