Bulbophyllum corrugatum J.J.Verm., Nordic J. Bot. 26 (2008) 142, fig. 8
Type: Jongejan cult. 101 (holo L), from PNG, New Ireland
Roots sprouting near the base of the rhizome, growing backwards along it until reaching the substrate. Rhizome up to 40 cm long, 3-5 mm in diameter, sections between pseudobulbs 1-1.6 cm long, patent to pendulous, bracts persistent. Pseudobulbs 0.6-1 by 0.3-0.6 cm distant, ellipsoid. Leaves: petiole 0.2-0.3 cm long; blade 3.5-5.5 by 2.1-2.9 cm, index (length/width) 1.6-2.2, ovate, acute, abaxial surface finely and densely corrugated. Inflorescence c. 2 cm long, 1-flowered; peduncle porrect, 0.3-0.4 cm long; non-floriferous bract 1 (?), c. 3 mm long; floral bract c. 4 mm long, tubular, acute. Flowers widely opening. Pedicel-with-ovary c. 8 mm long, basal node on a c. 3 mm long stump. Dorsal sepal c. 9 by3.5 mm, index 2.5-2.6, spreading, ovate-triangular, acute, margins entire, base broadly attached, thick, surface glabrous. Lateral sepals c. 8.5 by 3 mm, index 2.8-2.9, free, ovate, otherwise as the dorsal sepal. Petals c. 1 by 3 mm, index c. 0.3, porrect or somewhat recurved, with a narrow seam along the side of the column margins, entire, surface glabrous; with two types of stalked, papillose appendages along the top margin; the first thick, flattened-ellipsoid to ovoid, 4-6 by 0.8-1 mm, obtuse, abruptly narrowed into a thread-thin, smooth stalk 1-2 mm long, the second type stalk-like, subulate, 2-2.5 mm long, passing into a 1-1.8 mm long stalk of equal thickness; these appendages divided in two groups, one along the upper and one along the lower edge of the petal, each group consisting of 2 thick appendages and one stalk-like, and one more stalk-like appendage in between the groups. Lip c. 3 by 1.8 mm, index 1.6-1.7, straight, more or less ovate, with a slightly narrowed basal part, subacute, margins entire, thick; adaxially with the margins spreading proximally, concave in between, the margins converging over the proximal surface as obtuse ridges at about quarter of the length of the lip, then running parallel and clasping two more, equally strong ridges which start slightly proximally of the point where they meet the margins, at two thirds of the length of the lip the ridges fuse pair-wise, and diverge a little to leave a deep slit in between, adaxial convex distally, surface coarsely papillose towards the margins; abaxially convex, deeply grooved along the median line and with a coarsely papillose surface distally. Column c. 2 mm long; stigma narrowly triangular, without keels inside; foot not widened distally; stelidia c. 0.6 mm long, triangular, acute, with a small, patent, deltoid, subacute tooth along the lower margin; anther-cap abaxially with a crest proximally, surface papillose, front margin drawn out into a retuse beak; pollinia not seen. (After Vermeulen, 2008)
Colours: Leaves dark green above, dark purple below. Sepals white with red-purple spots, petals with greyish green appendages, lip red-purple.
Distribution: Malesia (New Guinea).
Distribution in New Guinea: Papua New Guinea (New Ireland).