Dendrobium convolutum

Dendrobium convolutum Rolfe, Bull. Misc. Inform. Kew (1906) 375.

Type: Sander cult. s.n. (XI-1898, New Guinea) (holo K).

An epiphytic herb. Pseudobulbs clustered, subclavate, up to 30 by 1.3 cm, 4-5-noded below leaves, yellow, 3-leaved at apex. Leaves subcoriaceous, spreading or suberect, elliptic-lanceolate, acute, up to 13.5 by 5 cm. Inflorescences suberect, few-flowered, 10-12 cm long; bracts ovate, apiculate, 6 by 3 mm. Flowers opening widely; ovary and pedicel 2.5 cm long. Dorsal sepal ovate, acute, 1.6-1.8 by 0.8 cm; lateral sepals obliquely triangular, acute, 1.5 by 1.2 cm; mentum obliquely conical, 1 cm long. Petals narrowly elliptic-oblanceolate, acute or subacute, 1.4 by 0.5 cm. Lip 3-lobed, recurved, 1.6-1.8 by 1.7-2.3 cm; side-lobes erect, subquadrate, slightly dilated above; midlobe transversely oblong-reniform, apiculate; callus 3-ridged, outer ridges longer than mid-ridge. Column dentate at apex, 2 mm long; foot 1 cm long.
(after Cribb, 1983).

Colours: Sepals and petals apple green; lip with maroon veins on side lobes and heavily suffused maroon on midlobe; callus glossy, maroon.

Habitat: Epiphyte in rainforest near the coast. Altitude 0 to 650 m.

Flowering time in the wild: June.

Distribution: New Guinea.

Distribution in New Guinea: Papua New Guinea (Madang, Morobe and Milne Bay Provinces).

Map: CONVOMAP.JPG [Dendrobium convolutum Rolfe, distribution map, redrawn from P. Cribb, Kew Bull. 38 (1983) 250, map 4, with new records added.]

Notes: The flowers of Dendrobium convolutum resemble those of Dendrobium macrophyllum but are smaller, distinctively coloured, lack any hairs on the outer surface and have a distinctive callus on the lip. It was described by Rolfe from a plant sent to him by F. Sander which arrived in a batch of Dendrobium atroviolaceum. As the latter is found only in Milne Bay Province, this may well be the type locality of Dendrobium convolutum as well.
(after Cribb, 1983).

Cultivation: Warm growing epiphyte.