Bulbophyllum atroviride J.J.Verm., Nordic J. Bot. 26 (2008) 177, fig. 26
Type: Leiden cult. 20031539 (holo L), from PNG, Gulf Prov.
Roots sprouting near the base of the rhizome, growing backwards along it until reaching the substrate. Rhizome up to 20 cm long, c. 1.5 mm in diameter, sections between pseudobulbs 0.4-0.9 cm long, pendulous, bracts rather persistent. Pseudobulbs 0.3-0.45 by 0.2-0.3 cm, obliquely recurved, distant, oblong, deeply furrowed on the adaxial side, the new shoot arising at the base of the pseudobulb. Leaves dark green, sessile, blade 2-3.2 by 1-1.6 cm, index (length/width) 1.6-2, elliptic, acute, usually distinctly convex. Inflorescence c. 1.6 cm long, 1-flowered; peduncle c. 3.5 cm long, porrect; non-floriferous bract 1, c. 3 mm long; floral bract c. 2.3 mm long, tubular, acute. Flowers wide open. Pedicel-with-ovary 6-8 mm long, basal node on a c. 1.2 mm long stump. Dorsal sepal c. 10 by 4 mm, index c. 2.5, spreading, ovate, acute, margins entire, base rather broadly attached, rather thin, surface glabrous. Lateral sepals c. 9.5 by 3.2 mm, index 2.9-3, free, base rather narrowly attached, otherwise as the dorsal sepal. Petals c. 4.2 by 1.7 mm, index 2.4-2.5, spreading, ovate-triangular, acute, margins finely erose, base narrowly attached, thin, surface glabrous. Lip c. 3.8 by 1.5 mm, index c. 2.5, only slightly recurved, oblong, rounded, margins distinctly ciliate except near the very base, thick; adaxially concave near the base, with two high, rather sharp keels starting near the base, close to the margins and gently converging but leaving a deep furrow in between up to two fifths of the length of the lip, distal part somewhat convex, adaxial surface glabrous but with a finely papillose seam towards the margins; abaxially convex and deeply furrowed, surface papillose and with long hairs except near the tip. Column c. 3.2 mm long; stigma ovate, without keels inside; foot widened distally; stelidia c. 2 mm long, slightly downwards falcate, triangular-subulate, acute; rostellum not protruding; anther-cap abaxially with a crest, surface papillose, front margin drawn out into a rounded beak; pollinia 4, more or less obovoid, the outer slightly flattened, the inner slightly shorter than the outer, distinctly flattened; no appendages. (After Vermeulen, 2008)
Colours: Sepals and petals translucent yellow, the sepals with greenish tips, lip orange-yellow, bright red at the base, column greenish, foot red, anther-cap pale yellow.
Distribution: Malesia (New Guinea).
Distribution in New Guinea: Papua New Guinea; Papua New Guinea; see map 96-2268M.jpg.