Orchids of New Guinea

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Dendrobium wulaiense

Dendrobium wulaiense Howcroft, Orchadian 6 (1981) 284, fig.

Type: NGF (Howcroft) 64079 (holo LAE); para

Synonyms:

Durabaculum wulaiense (Howcroft) M.A.Clem. & D.L.Jones, Orchadian 13 (2002) 489

An epiphytic or rarely lithophytic herb. Stems usually erect, cane-like, swollen at base, up to 1.7 m tall, l.2-1.75 cm in diam. Leaves coriaceous, ovate to elliptic, obtuse at bilobed apex, 6.5-17 by 3-13 cm, articulated to sheathing bases 2.5 cm long, often striped with maroon. Inflorescences 1-3, 13-47 cm long, 4-c. 30-flowered; bracts triangular, acute, about 3-1 mm long. Flowers fragrant, nutant; pedicel and ovary up to 3.5-6 cm long. Dorsal sepal recurved and inrolled, narrowly oblong, obtuse or subacute, 2.7 by 0.7 cm, with slightly undulate margins, lateral sepals obliquely oblong-triangular, acute or apiculate, 2.5 by 1-1.3 cm; mentum incurved-conical, 1.2 cm long. Petals spathulate, subacute, 3.3-3.5 by 0.5-0.8 cm, once-twisted. Lip 3-lobed, obovate in outline, 2.6 by 2 cm, side-lobes elliptic, rounded in front; midlobe broadly ovate, obtuse; callus of five ridges, the central three dilated at apex on base of midlobe. Column 7 mm long, bidentate on each side at apex.
(after Cribb, 1986).

Howcroft (1981) suggests that it is more closely allied to Dendrobium odoardii Kraenzl., a little-known species from mainland New Guinea. Dendrobium wulaiense differs in having a midlobe which is as long as broad, its callus with three (rather than one) ridges raised at the apex, petals which are subacute to apiculate but never emarginate, and bifid stelidia at the apex of the column.
(after Cribb, 1986).

Colours:

Leaf sheath yellow. Flowers creamy white or ivory-white lined with violet on the lip.

Habitat:

Epiphyte on several species of tree but notably on Terminalia catappa and Calophyllum inophyllum often overhanging the sea. Also lithophytic on coral cliffs.

Distribution:

Bismarck Archipelago.

Distribution New Guinea:

Wulai Island off the coast of New Britain.

Map: Dendrobium wulaiense Howcroft, distribution map, redrawn from P. Cribb, Kew Bull. 41 (1986) 658, map 6.

Cultivation:

Warm growing epiphyte.

Flowering time in the wild:

July to September.

Literature:

Cribb, P.J. 1986. Kew Bull. 41: 661, fig. 9, pl. 10C, map 6.
O'Byrne, P. 1994. Lowland Orchids of Papua New Guinea: 248, fig., pl.

Notes:

This attractive orchid differs from Dendrobium lineale in having more densely flowered inflorescences, a shorter rachis and flowers with a shorter and broader incurved mentum, a broad lip with a broadly ovate to almost circular midlobe and a column which has bifid rather blunt stelidia at its apex.