Bulbophyllum luteum J.J.Verm., Nordic J. Bot. 26 (2008) 165, fig. 21
Type: Yumte 213 (holo L), from Indonesia, Papua, Bird's head Peninsula
Roots sprouting mainly below the pseudobulbs. Rhizome creeping, 3-4 mm in diameter, sections between pseudobulbs 0.5-0.6 cm long, bracts not persistent. Pseudobulbs 1.1-1.8 by 0.7-0.9 cm, borne close together, erect, ovoid. Leaves: petiole 0.7-1 cm long; blade 4.5-6.3 by 1-1.4 cm, index (length/width) 3.2-6.3, elliptic, subacute. Inflorescence 4.5-6 cm long, 1-flowered; peduncle 3.2-4.5 cm long, erect to patent; non-floriferous bracts c. 4, the longest 3.5-5 mm long; floral bract c. 4.5 mm long, tubular, acute. Flowers fully opening. Pedicel-with-ovary c. 12 mm long, basal node on a c. 2 mm long stump. Dorsal sepal c. 9 by 3 mm, index c. 3, more or less porrect, ovate, acute-acuminate, margins finely erose-papillose, base rather broadly attached, rather thick ,but thin towards the margins, surface glabrous. Lateral sepals c. 10 by 3 mm, index 3.3-3.4, free, recurved, obliquely triangular, upper margin somewhat finely erose, lower entire, base broadly attached, otherwise as the dorsal sepal. Petals c. 4 by 2 mm, index c. 2, porrect, ovate with the margins folded outwards proximally, obtuse, margins finely papillose distally, thin, surface adaxially finely papillose towards the margins, abaxially glabrous. Lip c. 2.6 by 1.2 mm, index c. 2.2 (not flattened), recurved, oblong, rounded, margins with two inwards folded, ovate, rounded auricles near the ligament, elsewhere papillose but not so near top and base, very thick; adaxially concave except near the convex top, with two distinct ridges starting near the base, at the margins, and running up, close to the margin, to the convex top part of the lip, adaxial surface glabrous; abaxially with a deeply retuse median ridge up to three quarters of the length of the lip, surface papillose but less distinctly so near the base and the tip. Column c. 1.5 mm long; stigma sub-triangular, without keels inside; foot widened, with small, rounded lateral teeth just above the ligament; stelidia c. 0.8 mm long, triangular, acute; anther-cap abaxially with a large, rounded crest over almost its entire length, surface finely papillose, front margin drawn out, widely rounded, papillose; pollinia 4, obovoid, the inner as long as the outer, rather flat; no appendages. (After Vermeulen, 2008)
Colours: Sepals and petals greenish yellow, lip yellow, column and anther-cap greenish yellow.
Distribution: Malesia (New Guinea).
Distribution in New Guinea: Papua (Indonesia); see map 96-2340M.jpg.