Diplocaulobium isthmiferum (J.J.Sm.) P.F.Hunt & Summerh., Taxon 10 (1961) 109.
Basionym: Dendrobium isthmiferum.
Rhizome short. Pseudobulbs crowded, 1-leaved, stem-like, slightly thickened towards the base, 19-32 cm long, at the apex 0.7-0.8 cm wide. Leaves oblong, 6.75-10 by 2.4 cm, coriaceous, apex obtuse, obtusely bilobulate. Inflorescences 1-flowered, spathe narrowly triangular, 1-1.5 cm long; peduncle 0.6-1.4 cm long. Pedicel 2.2 cm long; ovary 0.4 cm long. Flower c. 5 cm across. Dorsal sepal 3.2 cm by 5 mm. Lateral sepals 3.3 cm by 8.5 mm; mentum 0.65 cm long, obtuse. Petals 2.7 cm by 2.4 mm. Lip 3-lobed, 1.35 by 1.1 cm, with two keels, disc papillose between the undulating part of the keels; midlobe 0.8 by 1.1 cm. Column 0.37 cm long; column-foot 0.6 cm long.
(after Smith, 1935).
Colours: Sepals and petals light yellow, darker yellow towards the tips, lip bordered white, centre yellow, with red streaks, base red.
Habitat: Epiphyte in hill forest. Altitude 150 m.
Flowering time in the wild: August.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua (Nabire Regency: Rouffaer River).
Notes: Diplocaulobium isthmiferum probably belongs in the affinity of Diplocaulobium mekynosepalum, but the lip is very different.
Cultivation: Warm growing epiphyte.