Dendrobium acianthum Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1912) 572; 21 (1923) t. 192, fig. 719.
Type: Schlechter 16250 (holo B, lost; iso E, G, K, L, NY); para: Schlechter 19249 (B, lost; AMES, E, K, L).
Rhizome stem-like, roots elongated, filiform, flexuose, finely hairy. Stems reclining to pendulous, up to 50 cm long, densely many-leaved, branching. Leaf sheaths entirely covering the stem. Leaves bilaterally flattened, obliquely lanceolate, 1.3-2 by 0.3-0.45 cm, apex acute, thickly coriaceous. Inflorescences laterally from the leaf-axils, short, scales overlapping, acute, usually 1-flowered. Floral bracts ovate, longer than the ovary, apex acuminate, similar to the peduncle-scales. Ovary 0.4 cm long, cylindrical, glabrous. Flowers c. 0.7 cm long, fleshy. Dorsal sepal ovate to ovate-lanceolate, 0.6 cm long, apex acute; fleshy. Lateral sepals obliquely ovate to ovate-lanceolate, 0.6 cm long, apex acute; mentum very short, broadly obtuse. Petals obliquely ligulate, c. 0.5 cm long, apex acute. Lip oblong, 0.55 by 0.25 cm, minutely papillose-punctate except for a median ligulate shiny strip, below the apex with an obscure V-shaped thickening, fleshy, apex acute. Column very short, clinandrium 3-lobulate, the lateral lobules short, rounded, the median a little longer, subulate; column-foot oblong. Anther rounded-cucullate, in front truncate and densely papillose.
(after Schlechter, 1912).
Colours: Sepals greenish yellow; lip and anther dark red-brown.
Habitat: Epiphyte in lowland rainforest and riverine forest in savannah areas. Altitude 0-350 m.
Flowering time in the wild: Throughout the year.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua New Guinea (Madang, Morobe, and Central Provinces).
Cultivation: Warm growing epiphyte.