Dendrobium chrysopterum

Dendrobium chrysopterum Schuit. & de Vogel, J. Orchideenfr. 8 (2001) 309.

Type: Schuiteman, Mulder & Vogel 58 (holo L).

Rhizome very short; roots 1-2 mm thick, branching, glabrous. Stems crowded, erect to pendulous, terete, becoming narrower towards the base and apex, flexuose in upper part, 20-50 cm by 3-7 mm, rather densely many-leaved in upper part. Leaf sheaths 2-2.5 cm by 3-7 mm, densely minutely warty. Leaves subpatent, short-lived, rather thin-textured but stiff, keeled below, narrowly ovate, 6-6.5 by 1.8-2.3 cm, margins entire, apex acute, minutely apiculate. Inflorescences arising laterally, usually from leafless stems, densely 1-5-flowered, very short, subsessile; rachis c. 0.5 cm long. Floral bracts concave, ovate, 0.4 by 0.25 cm, apex acute-acuminate, minutely warty outside. Pedicel and ovary 2.2-3.5 cm long, narrowly clavate, terete, glabrous, curved at the base. Flowers not resupinated, c. 3.5 cm long (smaller when newly opened), widely opening, pendulous. Dorsal sepal ovate-elliptic, 1.25 cm by 6 mm, glabrous, apex subacute, minutely cucullate. Lateral sepals patent, obliquely triangular, 1.33 cm by 22 mm, apex subacute, minutely cucullate; mentum narrowly conical, 2.2 cm long, obtuse, apical 4 mm tubular. Petals narrowly obovate-oblong, 1 cm by 3.8 mm, margins smooth, apex broadly obtuse, minutely cucullate. Lip strongly concave, narrowly spathulate in outline, 2.5 by 0.63 cm, with the basal 1.3 cm adnate to the column-foot, glabrous, without callus, apex cucullate, inflexed, 5-pleated, margins minutely serrate-laciniate, truncate. Column abruptly widened above the base, 0.45 cm long, clinandrium 3-lobulate, the lateral lobules triangular with a small uncinate apical tooth, the median lobule longer, narrow, tooth-like; column-foot narrowly linear, 2.2 cm long, c. 4 mm below the apex with a bilobed appendage. Anther quadrangular, 2.4 mm long, dorsally slightly emarginate, in front truncate and minutely pubescent, otherwise glabrous. Pollinia 1.5 mm long. Fruit not seen.

Colours: Dorsal sepal and petal bright yellow. Lateral sepals bright orange, dorsiscopic margin bright yellow. Lip bright orange. Column pale orange. Anther greenish grey, pollinia grey. Ovary orange.

Habitat: Epiphyte in disturbed submontane forest with Lithocarpus, mostly growing in rather shaded places. Altitude 900 m.

Flowering time in the wild: September.

Distribution: New Guinea (endemic).

Distribution in New Guinea: Papua New Guinea (Southern Highlands Province: Lake Kutubu).

Map: CHRYSMAP.JPG [Dendrobium chrysopterum Schuit. & de Vogel, distribution map.]

Notes: Dendrobium chrysopterum is a spectacular species, already widely cultivated but usually wrongly named as Dendrobium obtusisepalum, which we consider to be a synonym of Dendrobium wentianum. It may be recognized by the unbranching stems with circa 2 cm wide leaves and the 3.5 cm long widely opening orange-and-yellow flowers. The specimen illustrated on p. 309 in the original publication is wrongly stated there to be the holotype specimen.

Cultivation: Intermediate growing epiphyte, requires light shade and should be well watered throughout the year.