Bulbophyllum sphaenopus J.J.Verm., Nordic J. Bot. 26 (2008) 167, fig. 23
Type: Yumte 116 (holo L), from Indonesia, Papua, Bird's head Peninsula
Roots sprouting mainly below the pseudobulbs. Rhizome 3.5-4 mm in diameter, sections between pseudobulbs 2.6-2.8 cm long, creeping, bracts not persistent. Pseudobulbs 2-3.7 by 0.7-1.1 cm, distant, erect, ovoid. Leaves: petiole 0.5-0.6 cm long; blade 4.7-6.3 by 1.3-1.6 cm, index (length/width) 3.6-4, elliptic to ovate, acute. Inflorescence c. 20 cm long, 1-flowered; peduncle 9.5-12 cm long, erect to patent; non-floriferous bracts c. 4, the longest c. 6 mm long; floral bract c. 7 mm long, tubular, acute. Flowers fully opening (?). Pedicel-and-ovary c. 53 mm long, basal node on a c. 4 mm long stump. Dorsal sepal c. 47 by 7.5 mm, index 6.2-6.3, ovate, acute, margins sparsely ciliolate, base narrowly attached, rather thin, surface shortly hairy. Lateral sepals c. 50 by 7 mm, index 7.1-7.2, free, oblique, ovate-triangular, upper margin entire, lower margin sparsely ciliolate, base rather narrowly attached, otherwise as the dorsal sepal. Petals c. 4.5 by 2 mm, index 2.2-2.3, porrect, obliquely ovate with the upper margin widely expanded in the proximal half, obtuse, finely papillose half-way along the upper margin, near the tip and along the lower margin, base rather broadly attached, very thin, surface more or less glabrous. Lip c. 14 by 2.5 mm, index c. 5.6, recurved near the base, with a triangular c. 3 by 2.5 mm basal part, grading into a linear top part of c. 1 mm wide, obtuse, margins glabrous, rather thick, surface glabrous; adaxially deeply concave near the base, with two rather high, obtuse ridges starting near the base and converging until they almost meet at two thirds of the length of the basal part, basal part otherwise convex, top part slightly convex to flat; abaxially convex near the base, slightly concave elsewhere. Column c. 2 mm long; stigma subtriangular, without keels inside, with a distinct callus well below its base which runs down the face of the column-foot as two separate ridges; foot distinctly widened, with distinct, triangular, obtuse lateral teeth just above the ligament; stelidia c. 0.9 mm long, triangular; anther-cap abaxially with a large, flattened crest overtopping the front margin, surface finely papillose, front margin not drawn out; pollinia 4, ellipsoid, the inner as long as the outer, all slightly flattened; no appendages. (After Vermeulen, 2008)
Colours: Flower entirely dark maroon.
Distribution: Malesia (New Guinea).
Distribution in New Guinea: Papua New Guinea; see map 96-2342M.jpg.