Bulbophyllum ustusfortiter J.J.Verm., Blumea 38 (1993) 155, fig. 1
Type: Leiden cult. (Schuiteman, Mulder & Vogel 90-609) 31721 (holo L, alc. only)
Rhizome creeping, 3-4 mm diam. Pseudobulbs ovoid, close together, 1.6-1.8 by 0.6-0.8 cm, somewhat flattened. Petiole 17-20 mm. Leaf blade elliptic, 11-16 by 1,6-2 cm, index 6.5-8, tip obtuse, finely cuspidate. Inflorescences many together on a short sympodium, 1.3-1.7 cm, 1-flowered. Peduncle 0.2-0.3 cm; 1 bract at its base, 7-10 mm long. Floral bracts elliptic, c. 10 mm, tip acuminate. Pedicel and ovary c. 4 mm, with the node c. 0.2 mm from the floral bract. Flowers opening only with a small lumen at the top. Median sepal adherent to the upper margins of the lateral sepals except at the extreme tip, obovate, c. 11 by 7 mm, index 1.5-1.6, tip subacute; margins glabrous; thick; adaxially glabrous; abaxially papillose-pubescent. Lateral sepals connate along their lower margins from base to tip, oblique, c. 11.5 by 5.5 mm, index 2-2.1, tip acuminate; otherwise as the median sepal. Petals oblique, obovate, c. 3 by 1.8 mm, index 1.6-1.7, tip slightly emarginate; rather thin; glabrous. Lip curved, general outline obovate, c. 3 by 2.3 mm, index c. 1.3 (not spread), tip rounded; margins halfway with fine, elongated papillae; thick; adaxially concave towards the base, with a transverse ridge close to the base and with 2 distinct, convergent ridges over most of its length, surface glabrous but somewhat wrinkled towards the margins; abaxially with a distinct, retuse median ridge, with a central patch of elongated papillae in the basal half and a larger central patch of scattered verrucae in the top half. Column from ovary' to the tip of the stelidia c. 2 mm; stigma not protruding at its base, slit-like; column foot not widened, with a slight central swelling. Stelidia triangular, c. 1 mm; tip acute; with an inconspicuous, subacute tooth along the upper margin. Anther abaxially with a wide ridge; front margin somewhat protruding. Pollinia 4; the inner pair more than half as long as the outer pair. Stipes absent. (After Vermeulen, 1993)
Colours: Entire flower very dark purple, at first sight black.
Habitat: Epiphyte in lower montane forest; 440-900 m.
Flowering time in the wild: February, September.
Distribution: Malesia (New Guinea).
Distribution in New Guinea: Papua New Guinea; see map 96-1937M.jpg.
Cultivation: Intermediate growing epiphyte.