Diplocaulobium obyrnei W.K.Harris, Lasianthera 1 (1997) 148, fig. 1, pl. 1A-D.
Type: Canberra cult. (Clements s.n.) s.n. (6 Nov. 1989) (holo CANB 7901448, iso BRI, CANB, NCBG).
Rhizome creeping, becoming patent with age. Pseudobulbs 0.5-1.2 cm apart, fusiform, 2.5-4 cm long, 4-5 mm diameter in the widest part, 1.5-2 mm at apex, 1-leaved. Leaf erect, linear, 8-11 by 0.3-0.5 cm, thin coriaceous, prominently channelled, apex acute, minutely unequally bilobed. Inflorescence terminal, 1-flowered. Spathe lanceolate, 0.6-2.5 cm by 2 mm. Peduncle 2 cm long. Pedicel and ovary 4-5.5 cm long, erect to suberect. Flower c. 2.5 cm across, ephemeral. Dorsal sepal lanceolate, 1.2-1.6 cm by 3 mm, acuminate. Lateral sepals obliquely triangular, 1.5-2 cm by 12-15 mm, acute; mentum ellipsoid, 1.2-1.5 cm long, laterally compressed, obtuse. Petals filiform, slightly widened at base, margins inrolled, 1.1-1.3 cm by 1 mm, acute. Lip erect in basal half, porrect in upper half, oblong, 1.9-2 by 0.4-0.7 cm, with two almost straight, smooth keels extending from the base to c. 3 mm from the acute apex. Column 2 mm long, stelidia short, bidentate; column-foot 13-15 mm long, slightly incurved, 3-ribbed at apex. Stigma transversely ovate, c. 0.8 mm across, sunken. Anther ovate in outline, c. 1 by 1.5 mm. Pollinia obovoid, c. 0.5 mm long.
(after Harris, 1997, and O'Byrne, 1994).
Colours: Pseudobulbs light green to yellow-green. Sepals and petals translucent pale yellow-green to cream with yellow tips. Lip creamy white with yellow tip, margins near the middle wine red to purple, keels purple. Unlike many species of Diplocaulobium, the flowers do not turn pink as they close. Pollinia white.
Habitat: Epiphyte in (seasonally dry) rainforest. Altitude 80 to 300 m.
Flowering time in the wild: July, November. Flowers last one day.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua New Guinea (Central and Milne Bay Provinces).
Notes: Diplocaulobium obyrnei may be recognised by the relatively very large mentum and the lip which lacks distinct side-lobes.
Cultivation: Warm growing epiphyte.