Dendrobium platygastrium Rchb.f., Otia Bot. Hamburg. 1 (1878) 55.
Type: Wilkes expedition (possibly Rich, Pickering or Agati) s.n. (Faunu-levu nr. 23363; putative iso AMES nr. 4744; 4745).
Rhizome very short, roots elongated, filiform, flexuose, glabrous. Pseudobulbs crowded, 3-4-leaved, erect, strongly laterally compressed, elliptic oblong, at the base much narrower, terete, 5-8 by 0.4 (at the base) to 2.5-3 cm (near the middle), shiny. Leaves oblong, 5-7 by 1.8-2.5 cm, apex unequally obtusely bilobulate, thin-coriaceous, soon deciduous. Inflorescences lateral, racemose, 2.5-3.5 cm long, laxly 2-3-flowered. Floral bracts small, deltoid, apex acuminate, much shorter than the pedicel. Pedicel and ovary 1.5 cm long, clavate, glabrous. Flowers resupinated, c. 2 cm wide. Dorsal sepal oblong, 1 cm long, apex subacute. Lateral sepals strongly obliquely oblong, 1 cm long, apex subacute; mentum c. 10 mm long, obtuse. Petals obliquely oblong, c. 2.8 cm long, apex very shortly acuminate. Lip 3-lobed above the middle, 2 by 1 cm, with a long narrow claw at the base, with two parallel keels extending from the base to the apex; lateral lobes broadly triangular, obtuse, patent, short; midlobe much longer than lateral lobes, oblong, apiculate. Column short, clinandrium 3-lobulate, the lateral lobules obtuse, fleshy, longer than the tooth-like median lobule; column-foot c. 1 cm long. Anther cucullate, glabrous.
(after Schlechter, 1905 - as Dendrobium lamprocaulon).
Colours: Flower white tinged pink.
Habitat: Epiphyte in lowland to lower montane forest. Altitude 0 to 1200 m (fide O'Byrne).
Flowering time in the wild: April-September, December.
Distribution: New Guinea, Bismarck Archipelago, Solomon Islands, Vanuatu, New Caledonia, Fiji, Tonga.
Distribution in New Guinea: Papua (Manokwari and Jayapura Regencies); Papua New Guinea (Gulf, Madang, Morobe, Central, Milne Bay, and Provinces; New Ireland, New Britain).
Notes: This is probably the only representative of section Platycaulon in New Guinea, and as such easily recognised by the broad, strongly flattened, fleshy stems. O'Byrne (1994) noted the extensive variability exhibited by this species.
Cultivation: Warm to intermediate growing epiphyte, should be watered throughout the year and be kept in light shade.