Grevillea williamsonii, also known as Williamson's Grevillea, is a shrub which is endemic to a restricted area in the Grampians Ranges in western Victoria. It was first described from a single plant in 1893, which was destroyed by bushfire four years later. It was then feared extinct and went unrecorded until 1992, where 12 plants were found.[1] The taxonomic validity of this grevillea has been disputed, and many sources treat it as synonymous with G. aquifolium.[2] [3]
Grevillea williamsoni is a spreading shrub that grows 0.6–1 m tall. Leaves are elliptic to narrow, 1.5–4.0 cm long, 3–8 mm wide, entire or (occasionally on adults, commonly on juveniles) with 2–4 spreading triangular teeth; margins shortly and angularly refracted; lower surface subsericeous to subvillous with straight hairs. The perianth is lime-green becoming yellowish; style pale orange yellow becoming pale pink at about anthesis then darker reddish pink. Flowering occurs August-October.
Grevillea williamsonii was first described in 1893. It is named after its discoverer, H.B. Williamson.[4]
Many sources, including the National Herbarium of Victoria and the Australian Plant Census treat G. williamsonii as synononymous with G. aquifolium, with recent studies suggesting it is a sterile variant.
The species is known only from a single area in the Grampians Ranges in western Victoria.