Dendrobium tampangii

Dendrobium tampangii O'Byrne, Malayan Orchid Rev. 35 (2001) 59, pl.

Type: O'Byrne SUL530 (holo SING).

Rhizome short, creeping, roots 2 mm wide, white, glabrous. Stems 1 cm apart, in the slender upper part many-leaved, at the base with 2-3 leafless, green, swollen nodes, the swollen part 2-4.5 by 1.3-1.5 cm, the wiry upper part 12-56 cm by 1.5-4 mm, rarely branching; internodes 1.6-2.6 cm long, decreasing in size upwards. Leaf sheaths a little shorter than the internodes, compressed-tubular. Leaves linear to narrowly ovate, decreasing in size upwards, the largest to 7.6 by 1.4 cm, thin, coriaceous, apex retuse, unequally bilobed. Inflorescences arising laterally from the slender part of the stem when defoliated, in fascicles of 1 to a few flowers, very short, at the base with 2-3 papery scales. Pedicel 2 cm long; ovary 0.6 cm long, cylindrical, obscurely 6-grooved. Flowers resupinated, c. 1.6 cm across, ephemeral, autogamous, somewhat thick and fleshy. Dorsal sepal erect, elliptic, 0.8 cm by 4.5 mm, convex, apex subacute, apiculate. Lateral sepals patent, oblong, 0.8 cm by 5 mm, convex, apex abruptly apiculate; mentum absent. Petals patent, linear-subfalcate, constricted at the base, 0.7 cm by 2 mm, apex subacute. Lip lanceolate, 0.7 by 0.25 cm, base in basal part cuneate with concave sides, with a single obscure median keel extending to the apex, fleshy, with slightly raised thinner margins, apex acute, apiculate. Column 0.2 cm long, with two lateral, broad, recurved, horn-like arms; foot deltoid, 2.5 mm long, not connected to the lateral sepals. Pollinia yellow, at anthesis fused to the stigma. Fruit cylindrical, 2 by 0.6 cm.
(after O'Byrne, 1994. Only referring to the New Guinea material, see notes).

Colours: White, the sepals with pale yellow tips.

Habitat: On solitary trees or on trees overhanging a river. Altitude 350-400 m.

Flowering time in the wild: November to May.

Distribution: Sulawesi, ?New Guinea.

Distribution in New Guinea: Papua New Guinea (Oro and Morobe Provinces).

Notes: Specimens from New Guinea agree well in habit with Dendrobium tampangii as described from Sulawesi. However, in New Guinea only peloric flowers have been observed so far. In these flowers the lip is petaloid and the column clearly abnormal, while the lateral sepals do not form a mentum as they are not attached to the column-foot. O'Byrne's suggestion that the New Guinea plants belong to D. tampangii must be considered a plausible conjecture.