Orchids of New Guinea

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Dendrobium lasianthera

Dendrobium lasianthera J.J.Sm., Repert. Spec. Nov. Regni Veg. 31 (1932) 78.

Type: Stüber cult.?, locality not known (holo BO).

Synonyms:

Durabaculum lasianthera (J.J.Sm.) M.A.Clem. & D.L.Jones, Orchadian 13 (2002) 488 ('lasiantherum')
Dendrobium ostrinoglossum Rupp, Austral. Orchid Rev. 18 (1953) 58.
- Type: Slade (Blood) s.n. (holo NSW; iso K).
Dendrobium stueberi Hort. ex Zurowetz, Orchid Rev. 42 (1934) 204 (nomen, in syn.).
- Type: Stüber s.n. (Dutch N. New Guinea).

An epiphytic herb. Stems up to 2.7 m long, cane-like, leafy in upper half. Leaves coriaceous, elliptic, rounded at unequally bilobed apex, articulated to tubular sheaths about 2-3 cm long. Inflorescences 24-50 cm long, c. 8-30-flowered; bracts elliptic, acute or subacute, 4-6 mm long. Flowers very showy, large; pedicel and ovary 4-4.6 cm long. Dorsal sepal erect, lanceolate, acute, 2.5-3.2 by 1.1 cm, spirally twisted; lateral sepals recurved, obliquely sublinear-triangular, obtuse or subacute, to 4 by 1.3 cm, spirally twisted; mentum narrowly conical, 1.7-1.9 cm long, pointing backwards at acute angle to ovary. Petals suberect-spreading, linear-spathulate, obtuse or rounded, 3.5-4.4 by 0.4-0.65 cm, three- or four times spirally twisted. Lip porrect, convex, 3-lobed, 3.6-4.75 by 1.75-1.9 cm; side lobes narrowly elliptic, rounded and spreading in front; midlobe spathulate, apiculate, 8 by 6-8 mm, side margins recurved; callus of 3 or rarely 5 parallel keels onto base of midlobe, central keel longest and sometimes slightly raised at apex. Column 9-9.5 mm long, truncate at apex.
(after Cribb, 1986).

Colours:

Flowers pink with a whitish mentum and glossy dark purple or maroon on petals and apical parts of sepals or yellow variously flushed with purple; tip and column purple.

Habitat:

Epiphyte on small trees along rivers and streams and in swamp forest. Altitude 0-100 m.

Distribution:

Malesia: New Guinea, endemic.

Distribution New Guinea:

Papua (Sorong, Fak-Fak, Nabire, Jayapura, and Merauke Regencies); Papua New Guinea (tributaries of the Sepik River, also reported from the Ramu Valley).

Map: Dendrobium lasianthera J.J.Sm., distribution map, redrawn from P. Cribb, Kew Bull. 41 (1986) 650, map 5, with new records added.

Cultivation:

Warm growing epiphyte, requires a continually humid atmosphere and a light position, while the roots should be protected from direct sunshine (fide O'Byrne).

Flowering time in the wild:

Throughout the year. Flowers last 6-12 weeks (fide O'Byrne).

Classification:

Family Orchidaceae
Subfamily Epidendroideae
Tribe Dendrobieae
Subtribe Dendrobiinae
Genus Dendrobium
Section Spatulata
Species Dendrobium lasianthera

Literature:

Cribb, P.J. 1986. Kew Bull. 41: 670, fig. 12, pl. 12E, map 5.
O'Byrne, P. 1994. Lowland Orchids of Papua New Guinea: 244, fig., pl.
van Bodegom, J. 1973. Enige orchideeën van West Nieuw Guinea: 130.

Notes:

Dendrobium lasianthera J.J.Sm. is one of the finest species in sect. Spatulata, unfortunately it is generally considered to be a tricky subject in cultivation. It may be recognized by the spirally twisted petals in combination with the relatively very small, apiculate midlobe of the lip, which is grooved below. Perhaps the nicest of the several colour forms is popularly known as the 'Sepik Blue', even though this form does not grow along the Sepik River itself and certainly is not blue.