Dendrobium triangulum J.J.Sm., Bull. Jard. Bot. Buitenzorg, sér. 2, 13 (1914) 65; Nova Guinea 12, 4 (1916) 314, t. 113, fig. 207.
Type: Janowsky 107 (holo BO).
Stems elongated, rooting and branching, in upper part flexuose, laterally compressed, ancipitous, 25 cm by 2.3 mm, internodes 0.7-0.9 cm long. Leaf sheaths 0.28-0.33 cm wide, much longer than the internodes, minutely transversely rugulose. Leaves erect-patent, twisted at the base so as to lie in one plane, obtuse, 1.45-2.2 by 5.5-7.7 cm, carnose-coriaceous, apex slightly unequally rounded-bilobulate, apiculate. Inflorescences laterally from the stems, very short, 2-flowered. Pedicel and ovary 0.45 cm long. Flowers c. 1 cm across. Dorsal sepal 0.73 cm by 3.8 mm. Lateral sepals 0.7 cm by 0.6 mm, mentum c. 0.4 cm long. Petals 0.63 cm by 2 mm. Lip 3-lobed, when flattened 0.59 by 0.87 cm; midlobe very short, 3-lobulate. Column 0.2 cm long; column-foot 0.4 cm long.
(after Smith, 1916).
Colours: Flower yellow.
Habitat: Epiphyte in lowland rainforest.
Flowering time in the wild: July.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua (Nabire Regency: Giriwo River).
Map: TRIANMAP.JPG [Dendrobium triangulum J.J.Sm., distribution map.]
Notes: Dendrobium triangulum belongs to a group of species that includes Dendrobium ingratum, Dendrobium erubescens, and Dendrobium setosum. Most of these resemble sect. Biloba in habit, while clearly belonging in sect. Grastidium.
Cultivation: Warm growing epiphyte.