Bulbophyllum rubipetalum P.Royen, Alp. Fl. New Guinea 2 (1979) 224, fig. 81
Type: Vink 16035 a (holo L)
Prostrate, up to 30 cm long. Rhizome stemlike, slender, glabrous, branched, densely covered with roots in the basal part, top part with bracts. Pseudobulbs relatively close together, glabrous, 3-10 mm apart, subparallel to rhizome, at base enveloped by bracts, ovoid-cylindric, 8-11 by 2.5-3.5 mm, ribbed, glabrous. Leaves erect, coriaceous, glabrous, linear-spathulate or linear-ovate, 3.8-8 by 0.4-0.8 cm, acute, base narrowly cuneate, midrib a little prominent above, prominent below, margin slightly revolute, crinkled. Inflorescence 1-flowered, in bundles of 2-5. Peduncle glabrous, 8-12 cm long, with 2-3 cylindric, 4-10 mm long, obliquely truncate, acute, 1-nerved glabrous bracts. Pedicels glabrous, slender, 9-13 mm long. Ovary glabrous, short claviform, 1.5-2.5 mm long, 6-grooved, ribs very scattered warty. Flowers pendant. Sepals with incurved margins. Median sepal linear-ovate, c. 13 by 2 mm, obtuse, 3-nerved, nerves prominent on outside mainly in basal part and scattered warty, but midrib warty almost to the tip, margin scattered fimbriate. Lateral sepals obliquely linear-ovate, connate at base and forming a slight pouch, 13-15 by c. 3 mm, obtuse at tip, 3-nerved, but 5-nerved at very base, nerves prominent on outside, irregularly warty-bullate, margin papillate-ciliate except for basal part. Petals very finely papillate along margins, otherwise glabrous, obliquely quadrangular-orbicular, c. 3 by 2.5 mm, acute, 1-nerved and nerve sigmoid. Lip glabrous, mobile, ligulate, 8 by 2.5 mm when expanded, obtuse, base cordate and curved, margin in apical part markedly revolute, in basal part erect and wavy, deeply lobed at its very end, between the two basal marginal lobes with an oblong flattish callus which expands distally, deeply longitudinally 2-grooved on underside at tips of basal marginal wings, upper side of apical half irregularly bullate, entire lip 5-nerved, and at base connate to tip of column-foot by an oblong, curved, c. 1 by 1.5 mm large, membranous claw. Column broad and short, cone-shaped, c. 1 by 1.5 mm. Stelidia sigmoid-falcate, curving downwards, reaching beyond the anther. Anther oblong-cordate-cucullate, c. 1.2 mm long, lateral and apical parts curved upwards, finely papillate along apical margin. Pollinia 4, unequal, ellipsoid, c. 0.4 mm long, light yellow. Capsule not seen. (After van Royen, 1979)
Colours: Flower with light yellow sepals, scarlet petals with black dots at tip and scarlet lip with light yellow base and minute scarlet dots.
Habitat: Epiphyte in montane forest.
Distribution: Malesia (New Guinea).
Distribution in New Guinea: Papua New Guinea; see map 96-1606M.jpg.
Cultivation: Cool growing epiphyte, requires shaded position.