Diplocaulobium auricolor

Diplocaulobium auricolor (J.J.Sm.) A.D.Hawkes, Lloydia 20 (1957) 127.

Basionym: Dendrobium auricolor.

Rhizome short. Pseudobulbs crowded, 1-leaved, at the base fusiform, with a much longer very slender upper part which is angular-subterete basally, in apical part slightly widened, transversely elliptic in cross-section, ribbed, 40-50 cm long, the swollen base 3.5-4 cm long, at the base 12-15 mm wide, in the middle 3-3.3 mm wide, at the apex 8-8.5 mm wide. Leaves narrowly lanceolate, 16 by 2.5 cm, coriaceous, keeled below, base conduplicate, undulate, apex bidentate. Inflorescences arising in succession from the apex of the pseudobulb, fasciculate, 1-flowered; peduncle 0.8 cm long, peduncle-scales few. Floral bract triangular, very short. Pedicel 2.5 cm long; ovary 0.4 cm long, 6-grooved, together with the pedicel slightly sigmoid. Flower resupinated, 3.7 cm wide. Dorsal sepal strongly recurved, elliptic-oblong, 2 cm by 8.5 mm, strongly convex, apex narrowly obtuse. Lateral sepals obliquely oblong, 2.15 cm by 8 mm in the middle, at the base 9.3 mm wide, apex lightly recurved, subacute; mentum oblongoid, 0.73 cm long, curved, obtuse. Petals recurved, widely patent, obliquely ovate, shortly convexly clawed at the base, 2.25 cm by 12 mm, apex broadly obtuse, apiculate. Lip 3-lobed below the middle, at one third above the base recurved, 1.55 by 0.97 cm, elastically attached to the column-foot, with two papillose basal keels diverging towards the apex, extending to the base of the midlobe, in the basal 2/3 of the midlobe with an oblong hairy cushion-like callus, transversely rugulose on either side of the callus; lateral lobes erect, falcate-triangular, concave, subacute; midlobe narrowly oblong, constricted near the middle, 0.8 by 0.48 cm, slightly widened in upper part, margins recurved, apex subtruncate. Column obliquely conical, 0.4 cm long, clinandrium 3-lobulate, the lobules triangular, the laterals weakly denticulate, stigma 5-angled-elliptic; column-foot at an acute angle with the ovary, 0.7 cm long, strongly incurved, obtuse. Anther transversely cucullate, in front obtuse, glabrous. Pollinia oblong, 1 mm long.
(after Smith, 1911).

Colours: Flower orange-yellow, the keels on the lip pale yellow with red spots, with confluent red spots between the keels, lateral lobes lemon-yellow.

Habitat: Epiphyte in lowland and montane forest, altitude 250 to 2300 m.

Flowering time in the wild: May, June, September to December.

Distribution: New Guinea (endemic).

Distribution in New Guinea: Papua (Nabire, Puncak Jaya, Merauke, and Jayapura Regencies); Papua New Guinea (Sandaun, Madang, and Morobe Provinces).

Map: AURCOMAP.JPG [Diplocaulobium auricolor (J.J.Sm.) A.D.Hawkes, distribution map, redrawn after N.H.S. Howcroft, Orchadian 7 (1981) 7.]

Notes: Diplocaulobium auricolor belongs to a trio of very showy species, all characterised by the broad petals, but each quite distinct in the shape of the lip. The other members are Diplocaulobium regale and Diplocaulobium centrale.

Cultivation: Intermediate growing epiphyte.