Durabaculum undulatum M.A.Clem. & D.L.Jones var. broomfieldii (Fitzg.) M.A. Clem. & D.L.Jones, Orchadian 13(11): 489 (2002).
Dendrobium broomfieldii (Fitzg.) Fitzg., Austral. orch. 2(3): back cover (1888); Dendrobium undulatum var. broomfieldii Fitzg., Austral. orch. 2(3): [t. 5] (1888); Dendrobium discolor forma broomfieldii (Fitzg.) Dockrill, Austral. Pl. 3: 28-30 (1964); Dendrobium discolor var. broomfieldii (Fitzg.) M.A.Clem. & D.L.Jones, Austral. Orch. Res. 1: 52 (1989). Type: cult. Sydney ex Northern Australia, Oct., Broomfield s.n. (holo BM).
Dendrobium undulatum var. carterae Bailey, Comp. Cat. Queensland Pls. 524 (1909). Type: cult. Brisbane ex Pine Islet, Percy Islands, T.W. Carter s.n. (holo BRI not found).
Occurs in Queensland on the Whitsunday Group.
Altitude: 1-10 m.
Epiphytic or lithophytic herb forming large clumps. Pseudobulbs erect to arching, elongate, cylindrical, slightly thicker in middle, 100-500 cm x 4-6 cm, green, becoming yellowish, sometimes striped, hard, covered in papery bracts when young. Leaves 10-35, scattered along upper two-thirds of stem, erect to prostrate, distichous, sessile, bases sheathing stem; lamina ovate, 8-16 cm x 3.5-5 cm, dark green to yellowish, often concave, leathery, apex emarginate. Inflorescence an axillary raceme, erect to arching, 200-600 mm long. Flowers 10-40, resupinate, porrect, opening sequentially, star-shaped, 40-80 mm x 40-80 mm, greenish yellow, bright golden-yellow or canary-yellow with varnished lustre and prominent white labellum callus. Sepals and petals widely spreading, strongly twisted, with undulate margins. Dorsal sepal recurved, narrowly oblong, 25-35 mm x 5-7 mm. Lateral sepals widely divergent, narrowly oblong to narrowly triangular, 25-35 mm x 5-7 mm bases fused to column foot. Petals obliquely erect, narrowly oblong to narrowly obovate, 35-40 mm x 7-8 mm. Labellum 17-24 mm x 11-15 mm, 3-lobed; lateral lobes, large, outcurved; midlobe decurved, 5-7 mm x 2-4 mm, with 3 main ridges, sometimes also accessory ridges, margins undulate. Column 3-6 mm. Column foot 5-12 mm. Capsules porrect to pendulous, dehiscent.
Occurs in coastal scrub. It is a very popular garden plant or pot plant in the tropics, with numerous horticultural varieties.
Flowering period: April-December.
Until recently known as Dendrobium undulatum var. broomfieldii or Dendrobium discolor var. broomfieldii.