Australian Tropical Rainforest Orchids
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Durabaculum mirbelianum

Dark-stemmed Antler Orchid

Durabaculum mirbelianum (Gaud.) M.A.Clem. & D.L.Jones, Orchadian 13(11): 488 (2002).

Dendrobium mirbelianum Gaud. in Freycinet, Voy. Uranie 423, t. 38 (1826); Callista mirbeliana (Gaud.) Kuntze, Revis. gen. pl. 2: 655 (1891). Type: In insulis Moluccis (Rawak), Gaudichaud Dupre s.n. (holo P).

Dendrobium rosenbergii Teijsm. & Binnend., Natuurk Tijdschr. Ned.-Indie 24: 317 (1862). Type: Ambon, Rosenberg s.n. (holo BO).

Dendrobium polycarpum Rchb.f., Gard. Chron. 2: 492 (1883). Type: cult. London, J. Veitch & Sons. ex Sondaic area [Sunda Islands], Curtis s.n. (holo W).

Dendrobium giulianettii Bailey, Queensland Agric. J. 3: 158 (1898). Type: On trees, Holdicott Bay, New Guinea, 1898, A. Giulianetti ex Lamington 21 (holo BRI; iso K).

Dendrobium aruanum Kraenzl. in Engl., Pflanzenr. Orch.-Mon.-Dendr. 1: 242 (1910). Type: Papuanische Provinz: Neu-Guinea, Aru-Iseln, O. Beccari s.n. (holo FI).

Dendrobium buluense Schltr., Repert. Spec. Nov. Regni Veg., Beih. 1: 549-550 (1912) & Fig. Atlas t. 185, f. 694 (1923-28). Type: Kaiser-Wilhelms-Land: On trees in the coastal forest near Bulu, alt. c. 30 m, Dec. 1908, R. Schlechter 19038 (holo B).

Dendrobium buluense var. kauloense Schltr., Repert. Spec. Nov. Regni Veg., Beih. 1: 550 (1912). Type: Kaiser-Wilhelms-Land: On trees in the mountain forests near the Kaulo Base, alt. c. 400 m, Nov. 1907, R. Schlechter 16833 (holo B).

Dendrobium wilkianum Rupp, North Queensland Naturalist 10(67): 4 (1941). Type: Babinda, North Queensland, Oct. 1941, J.H. Wilkie s.n. (holo NSW).

Distribution

Occurs north-eastern in Queensland from the Daintree to Innisfail, and disjunctly on Moa Island in Torres Strait.

Altitude: 2-150 m.

Also found in Indonesia, New Guinea and the Solomon Islands.

Description

Epiphytic or lithophytic herb forming small clumps. Pseudobulbs erect, cylindrical, slightly thicker in middle, dark blackish brown, 20-100 cm x 2-3 cm, upper half leafy. Leaves 4-10, scattered along stem, erect to prostrate, distichous, sessile, bases sheathing stem; lamina ovate, 8-15 cm x 3-4 cm, dark green, often suffused with brown or dark red, leathery, apex emarginate. Inflorescence an axillary raceme, erect to arching, 100-300 mm long, from upper nodes of stem; pedicels 10-20 mm long. Flowers numerous, resupinate, porrect, star-shaped, 25-35 mm x 30-40 mm, pale brown to dark brown with yellow labellum. Sepals and petals spreading widely or remaining nearly closed, straight or slightly twisted. Dorsal sepal erect to recurved, narrowly triangular, 25-30 mm x 7-9 mm, apex obtuse. Lateral divergent, sepals triangular, 25-28 mm x 7-9 mm, bases fused to column foot, apex acute. Petals obliquely erect, slightly twisted, spathulate, 28-32 mm x 7-8 mm, apex acute. Labellum 3-lobed, curved, 30 mm x 20 mm, yellow with dark red veins, with 5 ridges, 3 extending onto midlobe; lateral lobes erect or incurved; midlobe with undulate margins. Column broad, 4-5 mm long. Column foot 7-9 mm long, nearly at right-angles to column. Capsules porrect to pendulous, dehiscent.

Ecology

Occurs in mangroves and coastal swamps in humid, high light situations growing on trees and less often on rocks. There are two flowering forms; one with insect-pollinated flowers opening widely, the other self-pollinating with flowers opening narrowly, if at all.

Locally common.

Flowering period: August-November.

Name Changes

Until recently known as Dendrobium mirbelianum.

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