Dendrobium piestocaulon Schltr., in K.Schum. & Lauterb., Nachtr. Fl. Deutsch. Schutzgeb. Südsee (1905) 173; Repert. Spec. Nov. Regni Veg. Beih. 21 (1928) t. 212, fig. 802.
Type: Schlechter 14632 (holo B, lost; iso AMES, BO, K).
Rhizome very short, roots elongated, filiform, glabrous. Stems crowded, erect, at the base terete, upwards laterally compressed, slender, 30-40 cm long, many-leaved. Leaf sheaths entirely covering the stem, ancipitous. Leaves erect to suberect, linear-ligulate, 6 by 0.6-0.8 cm, apex obtusely unequally bilobulate, coriaceous. Inflorescences arising laterally from the stem, 1-flowered, sessile. Floral bract shorter than or as long as the ovary. Pedicel and ovary 0.3 cm long, cylindrical, glabrous. Flower not resupinated, c. 1 cm across. Dorsal sepal ovate, 0.7 cm long, apex obtuse. Lateral sepals obliquely ovate, widened at the base, 0.7 cm by 6 at the base mm, apex obtuse. Petals obliquely subfalcate-lanceolate, 0.6 cm long, apex obtuse. Lip 3-lobed near apical fourth, fleshy, , hypochile oblong at the base; lateral lobes very small; midlobe oblong, margin subundulate, thickened along lateral and apical margins, apex obtuse. Column short, rather thick, clinandrium with a dorsal subulate teeth; column-foot elongated. Anther cucullate, broadly obtuse, in front subretuse.
(after Schlechter, 1905).
Colours: Sepals and petals white, lip yellowish.
Habitat: Epiphyte in hill forest. Altitude 550 m.
Flowering time in the wild: July.
Distribution: New Guinea, Bismarck Archipelago.
Distribution in New Guinea: Papua (Jayapura and Merauke Regencies); Papua New Guinea (New Ireland).
Cultivation: Warm growing epiphyte.
INFRASPECIFIC TAXA
Dendrobium piestocaulon Schltr. var. kauloense Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1912) 632.
Type: Schlechter 16831 (holo B, lost; iso BO, E, G, K, L, MO, NSW, S).
Differs from var. piestocaulon by the more robust habit, with leaves 10--14 by 0.7--0.8 cm.
Colours: Sepals and petals light yellow, lip with brown-red hypochile and light yellow epichile.
Habitat: Epiphyte in lowland forest. Altitude 0 to 250 m.
Flowering time in the wild: July, October, November.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua (Puncak Jaya and Jayapura Regencies); Papua New Guinea (Madang Province).
Cultivation: Warm growing epiphyte.