Dendrobium atroviolaceum

Dendrobium atroviolaceum Rolfe, Gard. Chron. (1890, I) 512; (1892, I) 214; Hook. f. Bot. Mag. (1894) t.73.

Type: Veitch cult. (XII-1894, New Guinea) (holo K).

An epiphytic herb. Pseudobulbs clustered, erect, subclavate, 3-6-noded below leaves, 11-31 by 0.4-0.8 cm, yellow, 2-leaved at apex. Leaves spreading, coriaceous, elliptic-ovate to narrowly elliptic, minutely emarginate at rounded or obtuse apex, 5-12 by 2-3.8 cm. Inflorescence erect or arcuate, few-flowered, 7-15 cm long; bracts ovate, acute or apiculate, 5-9 by 4-6 mm. Flowers subnutant, large; pedicel and ovary 2-3.5 cm long. Dorsal sepal ovate, acute, 2-2.8 by 0.9-1.3 cm; lateral sepals falcate, obliquely ovate-lanceolate, acuminate, 1.5-2.5 by l-1.3 cm; mentum obliquely conical, 0.8-1 cm long. Petals obovate, obtuse to subacute, 2.5-3 by 1.3-1.8 cm. Lip strongly recurved, 3-lobed, 1.3-2 by 1.8-2.6 cm; side-lobes erect, semi-elliptic, rounded at apex; midlobe much longer than side-lobes, broadly ovate, acute; callus 3-ridged, running onto base of midlobe. Column 4 mm long; foot 0.8-1 cm long.
(after Cribb, 1983).

Colours: Sepals and petals cream-coloured, marked with violet spots; lip yellow, heavily veined with violet.

Habitat: Epiphyte on large trees e.g. Castanopsis in rainforests. Altitude 300-750 m.

Flowering time in the wild: July to December.

Distribution: New Guinea (islands off the eastern coast); Louisiade Archipelago.

Distribution in New Guinea: Papua (Jayapura Regency); Papua New Guinea (D'Entrecasteaux Islands and Louisiades only).

Map: ATROVMAP.JPG [Dendrobium atroviolaceum Rolfe, distribution map, redrawn from P. Cribb, Kew Bull. 38 (1983) 234, map 2, with new record added.]

Notes: Its nodding flowers, distinctive flower colour and short strongly recurved lip serve to distinguish Dendrobium atroviolaceum from allied species such as Dendrobium convolutum and Dendrobium engae. It has also found favour with hybridists despite the nodding habit of its flowers. Dendrobium Nellie Slade, a hybrid of this species with Dendrobium rhodostictum, has an extended flowering period, grows vigorously and has attractively coloured flowers. Van Bodegom (1973) gives a surprising record from the Cyclop Mountains near Jayapura.
(largely after Cribb, 1983).

Cultivation: Warm growing epiphyte.