Dendrobium speciosum, commonly known as the Sydney rock orchid or rock lily, is a highly variable Australian native orchid that forms a species complex. Its varieties can be found in a range of habitats as an epiphyte (on branches or trunks of trees) or a lithophyte. It has a continuous distribution along the east coast of Australia and in distinct populations along the Tropic of Capricorn. As a lithophyte, it forms gigantic spreading colonies on rocks and cliff faces, often exposed to full sun, with its roots forming dense, matted beds across the rock that anchor the plant. It can be found at altitudes from sea level to 900 metres (3,000 ft).

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There are two to five thick, leathery leaves originating from the top of each pseudobulb. These leaves can remain on the plant for up to 12 years. The erect or curved pseudobulbs are large, up to 45 cm (18 in) long. They are thickest at their base, measuring 5 to 7 cm (2.0 to 2.8 in), and taper towards the apex (3 cm (1.2 in)). The showy flowers grow in long racemes on straight or slowly arching, long, starchy stems. Some varieties produce 100 or more 2 to 5 cm (0.8 to 2.0 in), sweetly fragrant flowers per raceme in winter or spring. Flower colour, depending on variety, can be white, cream, yellow or dark yellow. Some cultivars have golden hued flowers. The (predominantly) white labellum is covered with purple dots and veined with red and purple.
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