the seed body sits adjacent to it in the follicle. The first pair of leaves produced by seedlings, known as cotyledons, are cuneate (wedge-shaped) and measure long by wide. They are dull-green with a faint net-like pattern. The auricle at the base of the cotyledon leaf is pointed and measures long. The first pair of leaves to appear after the cotyledons are long and oval in shape, with 2–3 lobes or teeth on each side. The next set are long with 7–10 teeth. B. petiolaris is fairly uniform across its range, though plants may vary in leaf size. Its yellow flower spikes and white leaf undersurface distinguish it from other prostrate banksias. Taxonomy Banksia petiolaris was first described by Victorian state botanist Ferdinand von Mueller in 1864, its specific name Latin for "with petioles", referring to the species' long petioles. The type specimen was most likely collected in 1861 by G. Maxwell between Cape Le Grand and Cape Arid and is housed in Melbourne. George Bentham published a thorough revision of Banksia in his landmark publication Flora Australiensis in 1870. In his arrangement, Bentham defined four sections based on leaf, style and pollen-presenter characteristics. B. petiolaris was placed in section Cyrtostylis, a group of species which did not fit easily into one of the other sections. No further subspecies or varieties of B. petiolaris have been described, and it has no taxonomic synonyms. Its only nomenclatural synonym is Sirmuellera petiolaris (F.Muell.) Kuntze, which arose from Otto Kuntze's unsuccessful 1891 attempt to transfer Banksia into the new name Sirmuellera. In his 1981 monograph on the genus, Australian botanist Alex George placed B. petiolaris in B. subgenus Banksia because its inflorescence is a typical Banksia flower spike shape, in B. section Banksia because of its straight styles, and Banksia series Prostratae, because of its prostrate habit, along with five other closely related species. George held it to be most closely related to B. blechnifolia. In 1996, botanists Kevin Thiele and Pauline Ladiges published an arrangement informed by a cladistic analysis of morphological characteristics. Their arrangement maintained B. petiolaris in B. subg. Banksia and series Prostratae. They found it to be basal (the earliest offshoot) to the other prostrate banksias. Questioning the emphasis on cladistics in Thiele and Ladiges' arrangement, George published a slightly modified version of his 1981 arrangement in his 1999 treatment of Banksia for the Flora of Australia series of