Dendrobium dolichocaulon Schltr., Bot. Jahrb. Syst. 58 (1923) 117.
Type: Ledermann 8376; 9014 (syn B, lost).
Rhizome very short. Stems crowded, patent, terete, unbranched, to 200 cm by 6-7 mm, many-leaved. Leaf sheaths entirely covering the stem, lined with prominent veins. Leaves erect-patent, linear, 16-23 by 1.4-1.7 cm, apex acute, the very tip unequally bilobulate, coriaceous. Inflorescences arising laterally from the stem, sessile, fascicled. Floral bracts deltoid, minute. Pedicel and ovary 2.3 cm long, subclavate, minutely verruculose-glandulose. Flowers c. 2.5 cm across. Dorsal sepal lanceolate-ligulate, 1.4 cm long, apex obtuse. Lateral sepals ovate-triangular, falcate, widened at the base, 1.4 cm long, apex apiculate; mentum 0.5 cm long, obtuse. Petals obliquely ligulate, 1.3 cm long, apex subacute. Lip 3-lobed in apical third, 1 by 0.6 cm, with a linear callus which is rugose towards the apex, the midlobe densely verruculose-rugose; lateral lobes short, obliquely oblong, obtuse; midlobe subreniform-suborbicular, 0.35 by 0.4 cm, apex shortly apiculate. Column 0.45 cm long, clinandrium 3-lobulate, the lateral lobules obtusely triangular, sparsely dentate, the median longer, subulate; column-foot 0.5 cm long.
(after Schlechter, 1923).
Colours: Flower creamy white.
Habitat: Epiphyte in hill forest. Altitude 700-850 m.
Flowering time in the wild: August, October.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua New Guinea (East Sepik Province: Hunstein Mountains, Etappenberg).
Notes: This seems hardly distinct from Dendrobium pleianthum, of which we have examined many specimens. According to Schlechter, D. dolichocaulon should differ by the larger dimensions of the vegetative parts, larger flowers, and by the ovary covered with wart-like glands. We have found the size of the stems and leaves to be quite variable and the variation continuous, and this equally applies to the size of the floral parts. We have seen no specimen, among many, in which the ovary was glandular. This, then, might be a difference between D. pleianthe and D. dolichocaulon, but it could also be that Schlechter merely described an artefact, caused by fungi or insects.
Cultivation: Intermediate growing epiphyte.