Dendrobium planum

Dendrobium planum J.J.Sm., Orchid. Java (1905) 352.

Type: Blume s.n. (Java, Salak); van Hasselt s.n. (Leuwiboenger); Collector ? s.n. (Tjihanjawar); (Poentjak) H.L.B. 902, 322-1491 -1494; 903, 348-97 (syntypes L).

Stems strongly compressed, 3.3 mm wide, internodes 2.1-2.3 cm long. Leaf sheaths 0.5 cm wide, tapering to the base, tubular, strongly laterally compressed, slightly shorter than the internodes, at apex truncate and lightly transversely rugulose. Leaves lanceolate, 3.7-5.6 by 0.75-1.1 cm, coriaceous, base half-twisted, abruptly contracted, apex broadly bilobed. Inflorescences arising laterally from the stem, short, 2-flowered; peduncle 0.25 cm long, spathe membranous. Floral bracts minute. Pedicel and ovary 0.5 cm long, 6-grooved. Flowers c. 1.6 cm wide. Dorsal sepal erect, recurved in upper part, lanceolate-triangular, 1 cm by 2.5 mm, convex, 5-nerved, apex acute. Lateral sepals obliquely triangular, falcate, 1 cm by 7.3 mm, 5-nerved, front margins free, apex acute; mentum conical, curved, obtuse. Petals linear, 0.95 cm by 1.3 mm, 3-nerved, apex acute. Lip 3-lobed above the middle, 1 by 0.73 cm, erect, curved, with a basal keel extending to the base of the midlobe, the keel thickened towards the apex, 3-dentate at its apex, on the midlobe with 3 strongly interrupted keels; lateral lobes erect, obliquely ovate-triangular, obtuse; midlobe ovate, 0.48 by 0.44 cm, acuminate, margins crenate-undulate, in apical part incurved. Column dorsally compressed, 0.25 cm long, clinandrium with obtuse lateral lobules, stigma suborbicular; column-foot at an acute angle to the ovary, 0.6 cm long, curved, linear. Anther cucullate, truncate, 1.3 mm wide. Pollinia linear.
(after Smith, 1911, as Dendrobium planum var. collinum).

Colours: Flower pale yellowish green, shiny outside, midlobe and margins of lateral lobes of the lip with red spots and stripes, column-foot pale orange at the apex.

Habitat: Epiphyte in lowland forest. Altitude 0 to 800 m.

Flowering time in the wild: July, October.

Distribution: Sumatra, Java, New Guinea.

Distribution in New Guinea: Papua (Merauke and Jayapura Regencies); Papua New Guinea (Southern Highlands and Madang Provinces).

Notes: A species of sect. Grastidium with conspicuously flattened stems, but not closely related to Dendrobium eriopexis and its allies, which also have strongly flattened stems.

Cultivation: Warm growing epiphyte.