Orchids of New Guinea

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Dendrobium wentianum

Dendrobium wentianum J.J.Sm., Bull. Dép. Agric. Indes Néerl. 45 (1911) 6; Nova Guinea 8, 3 (1911) 573, t. 95B.

Type: Nouhuys, van 4 (holo BO).

Synonyms:

Dendrobium obtusisepalum J.J.Sm., Bull. Jard. Bot. Buitenzorg, sér. 2, 2 (1911) 13 (as 'obtusipetalum'); Nova Guinea 12, 1 (1913) 61, t. 17, fig. 49.
- Type: Kock, de 208 (holo BO).
Pedilonum obtusisepalum (J.J.Sm.) Rauschert, Feddes Repert. 94 (1983) 462 ('obtusipetalum').
Dendrobium deflexum Ridl., Trans. Linn. Soc. London, Bot. 9 (1916) 169.
- Type: Kloss s.n. (Camp 11 to 12, 8300 to 11000 ft.) (holo BM).
Pedilonum deflexum (Ridl.) Rauschert, Feddes Repert. 94 (1983) 459.
Chromatotriccum deflexum (Ridl.) M.A.Clem. & D.L.Jones, Orchadian 13 (2002) 494
Dendrobium vacciniifolium J.J.Sm., Nova Guinea 18 (1935) 53, pl. 11, 33.
- Type: Docters van Leeuwen 10839 (syn L); 10898 (syn L).
Pedilonum wentianum (J.J.Sm.) Rauschert, Feddes Repert. 94 (1983) 465.
Chromatotriccum wentianum (J.J.Sm.) M.A.Clem. & D.L.Jones, Orchadian 13 (2002) 496
Chromatotriccum obtusisepalum (J.J.Sm.) M.A.Clem. & D.L.Jones, Orchadian 13 (2002) 495 ('obtusipetalum')
Chromatotriccum vacciniifolium (J.J.Sm.) M.A.Clem. & D.L.Jones, Orchadian 13 (2002) 496

(Roots thick.) Stems flexuose, (pendulous), branching, to c. 65 cm long, internodes 0.7-1 cm long. Leaves (reflexed,) ovate, 1.8-3.4 by 1.1-1.8 cm, thick coriaceous, apex obtuse. Inflorescences lateral, racemose, 1.25 cm long; peduncle 0.6 cm long, 2-3-flowered. Floral bracts cucullate-ovate, to 0.9 cm long, apex acuminate. Pedicel and ovary 2.3 cm long, sigmoid, 6-ribbed, the ribs paired. Flowers 2.7 cm long. Dorsal sepal oblong-ovate, 1.43 cm by 7 mm; mentum curved, 1.7 cm long, obtuse. Petals narrowly oblong, 1.4 cm by 5 mm. Lip clawed, spathulate, when flattened 2.35 by 1.6 cm, base claw for 0.53 cm adnate to the column-foot, apex cucullate, margins densely short-laciniate, apex emarginate. Column 0.6 cm long; column-foot 1.7 cm long.
(after Smith, 1911 & 1916).

Colours:

Not described for the type collection, flowers now known to be uniformly bright orange, sometimes tinged red. The roots have orange tips.

Habitat:

Epiphyte in montane forest, often on trunks of Nothofagus. Altitude 1850 to 3250 m, mainly above 2500 m.

Distribution:

New Guinea (endemic).

Distribution New Guinea:

Papua (Jaya Wijaya Regency); Papua New Guinea (Sandaun, Southern Highlands, Enga, Western Highlands, Eastern Highlands, and Central Provinces).

Cultivation:

Cool growing epiphyte, keep in shade.

Flowering time in the wild:

February, April-August, October.

Literature:

Smith, J.J. 1916. Nova Guinea 12, 3: 348.
Royen, P. van. 1979. Alp. Fl. New Guinea 2: 337, fig. 116, pl. 87; Ibid. 350, fig. 121; Ibid. 360, fig. 125.

Notes:

Dendrobium wentianum is a common, widespread and variable species from the high mountain forests. It may be recognised by the thick, branching, pendulous stems, with relatively broad, reflexed leaves, and uniformly orange flowers.

Note: Originally published as obtusipetalum, but this should be considered a mistake, as both the manuscript and the more detailed redescription in Nova Guinea have obtusisepalum. Besides, in the first description (1911) explicit mention is made of the conspicuously obtuse sepals, while the petals are only described as being oblong.