Dendrobium acuminatissimum (Blume) Lindl. var. papuanum J.J.Sm., Nova Guinea 12, 4 (1916) 303.
Type: Gjellerup 871 (Gautier Mountains.) (syn BO); Sitanala 11203 (Aru Isl.) (iso? L, probable).
(Stems crowded, very slender, terete, more than 60 cm long, c. 2 mm wide, often with clusters of adventitious roots. Leaves erect-patent, linear, narrowing towards the apex, 9-12 by 0.4 cm, apex strongly oblique. Inflorescences lateral, 2-flowered, spathe 0.6 cm long.) Sepals c. 5 cm long.
Colours: Flower white, outside at the base with faint purple dots.
Habitat: Epiphyte in lowland and lower montane forest. Altitude 0-800 m.
Flowering time in the wild: January, November.
Distribution: Aru Islands, New Guinea (var. acuminatissimum known from Sumatra, Java, Borneo, and the Philippines).
Distribution in New Guinea: Papua (Jayapura and Merauke Regencies); Papua New Guinea (Madang Province).
Notes: According to Smith (1916), var. papuana differs from typical Java forms of Dendrobium acuminatissimum only in the longer sepals, which are 3.4 cm long in the typical variety, 5 cm long in var. papuana.
Cultivation: Intermediate growing epiphyte.