Banksia foliosissima is a species of erect shrub that is endemic to Western Australia. It has densely crowded, pinnatifid leaves, golden yellow flowers in heads of up to one hundred, and egg-shaped follicles. It is only known from two small areas in the south-west of the state.
Banksia foliosissima is a shrub that typically grows to a height of but does not form a lignotuber. It has hairy branchlets and linear pinnatifid leaves long and wide on a petiole up to long, with between 25 and 45 triangular teeth on each side. The flowers are borne on a head containing between ninety and one hundred flowers in each head. There are oblong to lance-shaped involucral bracts up to long at the base of the head. The flowers have a golden yellow perianth long and a cream-coloured pistil long. Flowering occurs in May or August and the fruit is a hairy, egg-shaped follicle long.[1]
This species was first formally described in 1964 by Charles Austin Gardner who gave it the name Dryandra foliosissima and published the description in the Journal of the Royal Society of Western Australia from specimens he collected near Ravensthorpe.[2] [3]
In 2007, Austin Mast and Kevin Thiele transferred all the dryandras to the genus Banksia and this species became Banksia foliosissima.[4] [5] The specific epithet (foliosissima) is a Latin word meaning "leafy".[6]
Banksia foliosissima is only known from two disjunct areas, one near Tarin Rock and the other near Ravensthorpe, where it grows in dense kwongan.
This banksia is classified as "Priority Four" by the Government of Western Australia Department of Parks and Wildlife, meaning that is rare or near threatened.[7]