Bulbophyllum unitubum J.J.Sm., Nova Guinea 14 (1929) 478, pl. 78, fig. 122
Type: Thomsen 875 (holo BO, also alc.; iso L sterile)
Rhizome elongated, creeping, rooting, terete, slightly more than 0.3 cm diam. Pseudobulbs c. 2-3 cm apart, making an acute angle with the rhizome, sublinear, to the apex gradually attenuate, in cross-section rhombic, in front longitudinally bichannelled, c. 5.3 by 0.9 cm; 1-leaved. Leaf shortly petiolate, lanceolate, apex recurved (deficiente); base narrowed in an acuminate petiole; midrib above grooved, underneath obtuse prominently, margins slightly recurved acutisque, coriaceous, in total c. 12-14.5 cm long; petiole 1.4-1.7 by 2.85 cm. Inflorescences from the nodes of the rhizome, fascicled, erect, 1-flowered; peduncle terete, c. 13.7 cm long; in basal half small sheaths c. 5 tubular upper enlarging laxioribup to the with. Floral bract tightly tubular, acuminate, acute, c. 1.2 cm long. Flower large. Median sepal from base oblong-ovate concave in tail elongatedm, margins incurved and contiguous tubular extended; nerves 7 outer branched inside prominent marginsque densely puberulous, dorsally papillose, almost 9 cm long; wide part c. 2.5 by distinctly 1 cm, tail 0.2 cm diam. Lateral sepals shortly decurrent on the column-foot, obliquely linear, gradually narrowed to the apex ; base somewhat dilated, channelled, inside marginsque shortly patent puberulous, dorsally papillose, 4-nerved, c. 7 by 0.6 cm in the basal part. Petals very small, between Sepals inserted, porrect, appressed to the column, somewhat decurrent along the column-foot on; base obliquely triangular convex 3-nerved gradually thinly filiform-extended globule fairly conspicuous echinulato without hairs 0.1 cm diam. terminata, 0.9 cm long. part wide 0.4 by 0.2 cm. Lip small, mobile, curved, fleshy, weakly 3-lobed, callus triangular convex not acute margin to base, keels 2 longitudinal rather inconspicuous in mid-lobe, margins parallel decurrent and in front apex obsolete confluent1.bus, fascia longitudinal wide pilorum rigidrum in the basal part shortum appressed torumque above longerum erect-patentumque between ribs up in the middle mid-lobed, hairs upper with the apex apex lobe almost reaching, above entirely papillose; underneath a thickening convex in base triangular-dilated applanataque with, when not flattened 0.5 cm long; to lateral lobes 0.37 cm wide,lower part transversely quadrangular with lateral lobes very short incurved rounded concave papillose, mid-lobe, recurved, with lateral lobes angles obtuse, making, subelliptic-oblong with, margins lateral slightly curved, apex rounded-truncate, transversely rugulose, when not flattened 0.38 by 0.26 cm. Column short, thick, especially with the apex slightly incurved, laterally compressed, dorsally convex; underneath strongly concave with, margins a the middle of the stigma up in the middle Column-foot conspicuously roundeddilated, rib longitudinal obtuse in a hollow, 0.4 cm long; clinandrium deeply concave, apex oblong, truncate sinibus high oblong, ab auricles as long as trapezoids obliquely truncate angulo posterior acute anguloin front rounded the middle with a tooth acute instructis separated by. Anther cucullate, subglobose, apex in appendage large, saddel-shaped tranverse quadrangular with the apex slightly recurved, underneath concave extended; base bilobed, 0.18 cm long. Pollinia 4, strongly unequal; outer ones semiovate, apex obliquely truncate, outside convex, inside flat, 0.12 cm long; the inner ones much smaller.; stigma deeply concave, longitudinal, elliptic; column-foot making an obtuse angle with the ovary, apex free, slightly incurved, on either side rounded-dilated, truncate, 0.5 by 0.28 cm wide apex. Ovary terete, high, 6-grooved, c. 1.25 cm long; pedicel terete, c. 2.5 by 0.85 cm above the base articulate. (After Smith, 1929)
Colours: Flower yellow with red streaks.
Habitat: Epiphyte in lowland forest.
Flowering time in the wild: September.
Distribution: Malesia (New Guinea).
Distribution in New Guinea: Papua (Indonesia); see map 96-1931M.jpg.
Cultivation: Warm growing epiphyte.