Dendrobium rhodostictum

Dendrobium rhodostictum F.Muell. & Kraenzl., Österr. Bot. Zeitschr. 44 (1894) 300.

Type: Sayer s.n. (1887, Bourawarri (camp 9), New Guinea) (holo HBG).

An erect epiphytic or terrestrial herb. Pseudobulbs clavate, often markedly dilated above, 3-5-noded below leaves, 9-25 by 0.3-1.2 cm, yellow, 2-4-leaved at apex. Leaves suberect or spreading, coriaceous, ovate-lanceolate to linear-lanceolate, minutely emarginate at acute to obtuse apex, 5-11 by 1-2.5 cm. Inflorescences apical or subapical, erect to arcuate, few-flowered; bracts elliptic, acute, 3-4 mm long. Flowers subnutant, white with purple spots on side margins of lip; pedicel and ovary 2.5-3.5 cm. Dorsal sepal ovate, acute or acuminate, 1.8-2.5 by 1 cm; lateral sepals falcate-lanceolate, acuminate, 1.8-2.2 by 1-1.1 cm; mentum obliquely conical, 8-10 mm long. Petals obovate-spathulate, obtuse to apiculate, 3-3.5 by 1.5-2.4 cm. Lip obscurely 3-lobed towards apex, broadly obovate in outline 1.9-2.6 by 1.8-2.8 cm; side-lobes erect-incurved, semicircular, often overlapping and larger than midlobe ; midlobe often obscure, transversely oblong to ovate, apiculate; callus 3-ridged above, raised and 3-lobed at base. Column 2.5 mm long; foot 7-9 mm long.
(after Cribb, 1983).

Colours: Flowers white with purple spots on side margins of lip.

Habitat: Epiphyte in montane forest on Castanopsis, Nothofagus, etc. or terrestrial on steep wet mossy slopes; 800-1200 m.

Flowering time in the wild: January, May, June.

Distribution: New Guinea, Bismarck Archipelago, Solomon Islands.

Distribution in New Guinea: Papua New Guinea (Karkar Island; Milne Bay Province; New Britain; New Ireland).

Map: RHODOMAP.JPG [Dendrobium rhodostictum F.Muell. & Kraenzl., distribution map, redrawn from P. Cribb, Kew Bull. 38 (1983) 250, map 4.]

Notes: Characteristic for Dendrobium rhodostictum is the broad lip, which is three-lobed, apiculate, difficult to flatten and has rose-purple spots on the side margins.

Specimens from New Britain have somewhat larger flowers with a more markedly three-lobed lip than those from New Guinea or Bougainville. They also have pseudobulbs less abruptly dilated in the apical half. However they do not warrant, in Cribb's (1983) opinion, separate taxonomic recognition.
(after Cribb, 1983).

Cultivation: Intermediate growing epiphyte.