Grevillea robusta, commonly known as the southern silky oak, silk oak or silky oak, silver oak or Australian silver oak, is a species of flowering plant in the family Proteaceae and is endemic to eastern Australia. It is a tree with deeply dissected, divided leaves, golden yellow to orange flowers with red blotches and flattened, elliptic to oval fruit.
Description
Grevillea robusta is a fast-growing tree that typically grows to a height of 8–40 m (26–131 ft) with a single stem and dark grey, furrowed bark. Its leaves are 10–34 cm (3.9–13.4 in) long and 90–150 mm (3.5–5.9 in) wide and deeply dissected with 11 to 24 primary lobes, sometimes with up to five further divisions, the end lobes oblong to elliptic or almost triangular, 5–50 mm (0.20–1.97 in) long and 2–10 mm (0.079–0.394 in) wide. Many of the leaves are lost before flowering.
The flowers are arranged in one-sided, toothbrush-like groups, sometimes branched, 12–16 cm (4.7–6.3 in) long, each flower on a pedicel 7.5–16 mm (0.30–0.63 in) long. The carpel (the female part) of each flower has a stalk 21–28 mm (0.83–1.10 in) long. The flowers are glabrous and mostly yellowish orange, with reddish blotches. Flowering occurs from September to November and the fruit that follows is a glabrous follicle.
Taxonomy and naming
Grevillea robusta was first formally described in 1830 by Robert Brown after an unpublished description by Allan Cunningham. The type specimen was collected by Cunningham on the eastern edge of Moreton Bay in 1827. Brown's description was published in Supplementum primum Prodromi florae Novae Hollandiae. The specific epithet (robusta) is a Latin word meaning "strong like oak" or "robust".
Distribution and habitat
Silky oak occurs naturally on the coast and ranges in southern Queensland and in New South Wales as far south as Coffs Harbour where it grows in subtropical rainforest, dry rainforest and wet forests. It is now...
