Dendrobium shiraishii

Dendrobium shiraishii T.Yukawa & M.Nishida, Lindleyana 7 (1992) 127, fig. 1.

Type: Yukawa 1911 (holo CBM).

Epiphytic plant to 65 cm tall. Pseudobulbs clustered, erect, clavate, strongly sulcate, about 5-noded below leaves, 17-43 by 2-2.8 cm, 2- to 4-leaved at apex. Leaves suberect, coriaceous, oblong-elliptic, 15-29 by 4-12 cm, obtuse to subacute. Inflorescences erect, terminal, 28-37 cm long, about 10-flowered; peduncle bearing three sheaths; fertile bracts lanceolate, 1.5-2 cm by 3.5-7.5 mm, acute. Pedicel and ovary muricate, 3.7-5.1 cm long, ovary terete. Flowers fleshy, widely-opening, 5-7 cm across, sometimes weakly fragrant. Sepals short-muricate on outer surface, keeled on mid-vein; dorsal sepal narrowly-triangular, 3-3.5 cm by 11-12 mm, acute; lateral sepals obliquely-lanceolate, 2.7-3 cm long by 10-16 mm, acute; mentum incurved-conical, 1.2-1.3 cm long. Petals obovate-spathulate, 2.9-3.3 cm by 14-16 mm, apiculate, deflexed. Lip obscurely 3-lobed, somewhat recurved, 2.5-3 by 2.8-3.5 cm; callus 3-ridged, with a 4 mm tall free apical part, the lateral ridges extending 2 mm past the apex; side-lobes erect-incurved, triangular; midlobe ovate, apiculate. Column 4-5 mm long, with two hook-like apical appendages; column-foot 1-1.1 cm long; pollinia 4 in 2 pairs. (after Yukawa & Nishida, 1992, and van Bodegom, 1973).

Colours: Pseudobulbs dark greenish brown. Leaves dark green. Sepals and petals greenish yellow, outside of sepals spotted maroon, petals with dark blackish brown markings outside at the base, lip dull red, greenish yellow at apex, callus white. Column light yellowish green with purple spots. Anther dull purple. Pollinia yellow.

Habitat: Not known. Probably epiphyte in lower montane forest. Altitude not recorded.

Flowering time in the wild: Not known.

Distribution: New Guinea (endemic).

Distribution in New Guinea: Papua (Manokwari and Jayapura Regencies).

Map: SHIRAMAP.JPG [Dendrobium shiraishii T.Yukawa & M.Nishida, map of distribution (original).

Notes: Dendrobium shiraishii is closely related to Dendrobium macrophyllum, from which it differs in the striking colour pattern and in the callus which is almost forked at the apex. Although formally described recently, and said to be discovered by Shigeru Shiraishi, this species was in fact already known for a long time to Dutch residents of New Guinea. A photograph of a plant collected by Stüber (who also discovered Dendrobium lasianthera) in the vicinity of Hollandia (now Jayapura) was illustrated as early as 1935 in the journal De Orchidee 4: 287. In 1973, van Bodegom illustrated and informally described this species as a nameless variety of Dendrobium macrophyllum, suggesting it may be better to regard it as a new species. Van Bodegom specified the Cyclop Mountains near Hollandia as place of origin. The type locality of Dendrobium shiraishii was given as 'the vicinity of Manokwari'. In our opinion this locality needs confirmation.

Cultivation: Warm growing epiphyte.