Dendrobium flagellum Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1912) 481; 21 (1923) t. 162, fig. 608.
Type: Schlechter 18402 (holo B, lost; iso AMES, BO, G, L).
Rhizome to 50 cm long, stem-like, rooting at the base, flexuose, pendulous, covered with closely appressed scales; roots elongated, filiform, flexuose, glabrous. Pseudobulbs 6-10 cm apart, 1-leaved, cylindrical, 0.5 by 0.25 cm. Leaves terete, whip-like, pendulous, 30-37 by 0.25 cm, apex subacute, carnose. Inflorescences racemose, slender, 8-13 cm long, somewhat laxely many-flowered. Floral bracts minute, deltoid, much shorter than the pedicel. Pedicel and ovary 2.5 cm long, pedicel filiform, ovary subclavate, glabrous. Flowers resupinated, c. 2.5 cm wide. Dorsal sepal oblong-lanceolate, 1.4 cm long, apex acute. Lateral sepals obliquely oblong-lanceolate, abruptly widened to the base, 1.4 cm long, apex acute; mentum 3.5 mm long, obtuse. Petals obliquely linear-subspathulate, 1.4 cm long, apex acute. Lip 3-lobed below the middle, 1.3 by 0.45 cm, cuneate at the base, with two keels extending from the base of the lip to a little below the apex of the midlobe, initially subparallel and straight, on the midlobe slightly divergent and undulate, the midlobe with an additional straight median keel extending to the apex; lateral lobes short, obliquely triangular, subacute; midlobe much longer than lateral lobes, lanceolate, margins undulate, apex acuminate. Column short, clinandrium 3-lobulate, the lateral lobules a little shorter than the tooth-like median lobule. Anther rhomboid, helmet-shaped, in front minutely papillose, truncate.
(after Schlechter, 1912).
Colours: Flowers snow-white, anther light yellow.
Habitat: Epiphyte on solitary trees in grassland. Altitude 150 m.
Flowering time in the wild: October.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua New Guinea (Malia River area).
Notes: Possibly conspecific with Dendrobium chordiforme.
Cultivation: Warm growing epiphyte, prefers light position.