Diplocaulobium regale (Schltr.) A.D.Hawkes, Lloydia 20 (1957) 129.
Basionym: Dendrobium regale.
Rhizome very short, roots elongated, filiform, flexuose, glabrous. Pseudobulbs crowded, 1-leaved, slender, to the base obclavate thickened, 40-60 by 2 (at the base) to 0.25-0.35 cm (near the apex). Leaves oblong-ligulate, 12-20 by 2.7-3.5 cm, apex obtuse, minutely bilobulate, shortly apiculate, coriaceous. Inflorescences arising in succession from the apex of the pseudobulb, 1-flowered; spathe laterally compressed, c. 2 cm long. Pedicel and ovary 5-6 cm long, slender, glabrous. Flower resupinated, c. 7 cm across. Dorsal sepal oblong-ligulate, 3.7 cm long, apex obtuse. Lateral sepals obliquely oblong-ligulate, 3.7 cm long, apex obtuse; mentum 7 mm long, obtuse. Petals obliquely elliptic, 3.7 cm long, almost twice as broad as the sepals. Lip 3-lobed above the middle, in outline very broadly rhombic, 1.2 by 1.4 cm, with two slightly diverging high keels extending from the base of the lip to the base of the midlobe; lateral lobes short, erect, rounded; midlobe broadly triangular, obtuse, apiculate. Column short, clinandrium lobulate; column-foot c. 0.7 cm long. Anther subquadrate-cucullate, truncate in front, glabrous.
(after Schlechter, 1912).
Colours: Sepals and petals deep pinkish red, the lip white with irregular purple-red stripes; column white.
Habitat: Epiphyte in montane forest. Altitude 700 to 2500 m.
Flowering time in the wild: January, March, April, May, September-December.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua (Manokwari, Paniai, and Timika Mimika Regencies); Papua New Guinea (Southern Highlands, Enga, Western Highlands, Madang, Morobe, and Milne Bay Provinces).
Notes: Diplocaulobium regale is a fine species with broad-petalled rose-red flowers.
Cultivation: Intermediate growing epiphyte.
INFRASPECIFIC TAXA
Diplocaulobium regale (Schltr.) A.D.Hawkes var. euanthum (Schltr.) A.D.Hawkes, Lloydia 20 (1957) 129.
Differs from var. regale by the elongated midlobe of the lip.
Colours: Flower purple-red, midlobe of the lip light yellow; column white.
Habitat: Epiphyte in lower montane forest.
Flowering time in the wild: December.
Distribution: New Guinea (endemic).
Distribution in New Guinea: Papua New Guinea (Madang Province: Kani Mountains).
Cultivation: Intermediate growing epiphyte.