Dendrobium sphenochilum F.Muell. & Kraenzl., Österr. Bot. Zeitschr. 44 (1894) 254.
Type: Bridge & Chalmers s.n. (N. Guinea, Cloudy Mountains.) (holo HBG).
Rhizome short. Stems crowded, pendulous, flexuose, branching, to 60 cm by 2-4 mm, leafy throughout when young, internodes 1.5-2.5 cm long. Leaves bilaterally compressed with rounded edges, narrowly triangular-linear, often slightly curved outwards, 3-5 by 0.4-1 cm, very thick and stiff, apex acute, apiculate. Inflorescences in fascicles of 1-3 from the apex, rarely lateral from the upper part of the stem; peduncle 0.2-0.3 cm long, at the base with a cylindrical cluster of 5-6 mm long dry scales. Pedicel 0.8-1.5 cm long; ovary 0.3-0.4 cm long, conical, 6-channeled. Flowers c. 2.5 cm long. Dorsal sepal oblong, somewhat widened at the base, 0.9 cm by 4 mm, apex acute. Lateral sepals obliquely oblong, falcate, apex rounded-acute; mentum incurved, 1.5 cm long, obtuse, apex bilobed. Petals oblong, 0.9 cm by 2.5 mm, upper margin erose, apex subacute. Lip oblong, with a 5 mm long narrow basal claw, total 2.2 by 0.8 cm, on the disc with two low narrow keels terminating below the apex, margins undulate, apical margins erose, apex bilobulate, with a small apicule between the lobules. Column 0.2 cm long, filament subulate; column-foot 1.8 cm long, incurved, 2-channeled.
(after O'Byrne, 1994).
Colours: Flower white, the keels on the lip yellow, terminating in a yellow spot near the lip apex.
Habitat: Epiphyte in rainforest and seasonally dry forest, often overhanging rivers. Altitude 0-500 m.
Flowering time in the wild: October to April.
Distribution: Sulawesi, Moluccas, New Guinea, Bismarck Archipelago.
Distribution in New Guinea: Papua (Manokwari Regency); Papua New Guinea (Central and East New Britain Provinces).
Notes: Dendrobium sphenochilum may be recognised by the elongated pendulous stems carrying laterally flattened leaves which have rounded, not sharp edges, and by the pure white flowers, usually with yellow markings on the lip.
Cultivation: Warm growing epiphyte.