Dendrobium humboldtense J.J.Sm., Repert. Spec. Nov. Regni Veg. 11 (1912) 131; Nova Guinea 12, 4 (1916) 297, t. 108, fig. 193.
Type: Gjellerup 574 (holo BO; iso L?, possible, Bogor cult., s.n., no loc, no coll.).
Stems elongated, in basal part slender for 2-4.5 cm, then swollen into 2-10 cm long, 0.7-0.85 cm wide pseudobulbs, these in cross section transversely rhombic, above the pseudobulbs with a longer and narrower section, c. 40 cm long, which is leafy in the basal part and covered with scale-leaves in the upper part; internodes 1.5-2 cm long. Leaf sheaths strongly laterally compressed. Leaves erect, laterally compressed, slightly falcate, lanceolate, 4.4 by 0.87 cm, apex very sharply acuminate. Inflorescences arising in fascicles from the bare upper part of the stem, 1-flowered, very short. Pedicel and ovary 1.5 cm long. Flower c. 1.9 cm long. Dorsal sepal 0.57 cm by 4 mm, margins strongly recurved; mentum 1.35 cm long, obtuse. Petals 0.6 cm by 2.3 mm, margins recurved. Lip 3-lobed, 0.9 by 0.4 cm, for c. 0.58 cm adnate to the column-foot. Column 0.17 cm long; column-foot 1.4 cm long, inside with a distinct keel.
(after Smith, 1916).
Colours: Flower pale greenish with thin dull purple lines, lip whitish at the apex.
Habitat: Epiphyte in hill forest along the coast. Altitude 50 m.
Flowering time in the wild: July.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua (Jayapura Regency).
Notes: Dendrobium humboldtense belongs in the affinity of Dendrobium macfarlanei, from which it is said to be distinguished by the strongly recurved margins of the sepals and petals.
Cultivation: Warm growing epiphyte.