Dendrobium pseudoglomeratum

Dendrobium pseudoglomeratum T.M.Reeve & J.J.Wood, Orchadian 7 (1982) 115, fig. 6, 7.

Type: NGF (Frodin) 28527 (holo LAE; iso L).

A robust epiphytic herb up to 1.1 m high. Pseudobulbs slightly swollen at the base then uniformly fusiform except for the lower part which is sometimes distinctly slender, older stems slightly sulcate and covered with scarious leaf sheaths, new stems leafy for their whole length, 10-110 by 0.5-1.8 cm, nodes 1-4.2 cm apart. Leaves semi-erect, ovate to oblong-lanceolate, 2.5-13 by 0.8-3.0 cm, subacute to obtuse, sometimes obliquely emarginate, amplexicaul. Inflorescences usually fairly dense, many-flowered, arising from the upper nodes of defoliated stems; peduncle with rachis up to 3.5 cm long. Bracts rotund to obovate-spathulate, often apiculate, concave, membranous, 0.3-1 cm long. Flowers non-resupinated, with lip uppermost, usually widely opening, glabrous, size variable even on a single raceme, 2-4 by 1.5-3.6 cm. Pedicel and ovary 6-grooved, 13-32 mm long. Dorsal sepal ovate, 1.0-1.8 cm by 6-10 mm, obtuse; lateral sepals with basal section fused to column foot, free part ovate, 1.8-3.6 cm by 7-14 mm, obtuse. Petals obovate, 0.9-1.8 cm by 5-9 mm, obtuse. Lip clawed, spathulate, entire, 1.8-3.1 cm by 9-15 mm when expanded, with a prominent V-shaped cross-ridge two-thirds of the way down, the basal third strongly saccate and adnate to the column foot, apical margin slightly involute and often erose-denticulate. Column c. 0.4 cm by 4 mm; rostellum triangular, projecting downwards over the stigmatic area; column foot / mentum 10-20 mm long with enclosed spur-like part of the mentum 5-10 mm long, apex obtuse. Anther cucullate, quadrangular, c. 2x2 mm; pollinia c. 2 mm long.
(after Reeve & Wood, 1982).

Colours: Sepals and petals bright mauve-pink, lip bright orange near apex, whitish below. Column and anther white, pollinia greyish green.

Habitat: Epiphyte in lowland swamp forest and montane forest. Altitude 0 to 2000 m.

Flowering time in the wild: April to November. Flowers last 2 to 5 weeks.

Distribution: New Guinea (endemic).

Distribution in New Guinea: Papua (Jaya Wijaya Regency); Papua New Guinea (Gulf, Sandaun, Enga, Southern Highlands, Western Highlands, Eastern Highlands, and Morobe Provinces).

Map: PSGLOMAP.JPG [Dendrobium pseudoglomeratum T.M.Reeve & J.J.Wood, distribution map.]

Notes: Specimens cultivated in the highlands of Papua New Guinea were observed to be pollinated by the honeyeater Melidectes belfordi (Reeve & Wood, 1992), a nectar-eating bird which is c. 25 cm long. Dendrobium pseudoglomeratum is an attractive species with its many-flowered inflorescences of rather large purple-pink, not resupinated flowers with an orange lip. It has been confused with Dendrobium glomeratum (syn. Dendrobium sulawesiense), hence the name. The latter, which probably only occurs in the Moluccas despite published records from Sulawesi and New Guinea, has fewer-flowered inflorescences and a more distinctly hooded lip.

Cultivation: Warm to intermediate growing epiphyte, requires light shade and excellent drainage. Should not be allowed to dry out for too long.