page_title: Banksia petiolaris
section_title: Taxonomy
hierarchical_section_title: Banksia petiolaris / Taxonomy
caption_attribution_description: Foliage of Banksia petiolaris, in cultivation, Kings Park, Perth, Western Australia
context_page_description: Banksia petiolaris is a species of flowering plant of the family Proteaceae native to Western Australia, where it is found in sandy soils in the south coastal regions from Munglinup east to Israelite Bay. It was first described by Victorian state botanist Ferdinand von Mueller in 1864, and no subspecies are recognised. B. petiolaris is one of several closely related species that all grow as prostrate shrub, with horizontal stems and thick, leathery upright leaves. Those of this species can be viable for up to 13 years—the longest-lived of any flowering plant recorded. It bears yellow cylindrical flower spikes, known as inflorescences, up to 16 cm high in spring. As the spikes age, they turn grey and develop up to 20 woody seed pods, known as follicles, each.
  Insects such as bees, wasps and ants pollinate the flowers. B. petiolaris is nonlignotuberous, meaning that it regenerates by seed after bushfire. B. petiolaris adapts readily to cultivation, growing in well-drained sandy soils in sunny locations. It is suitable for rockeries and as a groundcover.
context_section_description: 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 monographs. The placement of B. petiolaris in George's 1999 arrangement may be summarised as follows:
  Banksia
  B. subg. Banksia
  B. sect. Banksia
  B. ser. Salicinae (11 species, 7 subspecies)
  B. ser. Grandes (2 species)
  B. ser. Banksia (8 species)
  B. ser. Crocinae (4 species)
  B. ser. Prostratae
  B. goodii
  B. gardneri
  B. gardneri var. gardneri
  B. gardneri var. brevidentata
  B. gardneri var. hiemalis
  B. chamaephyton
  B. repens
  B. blechnifolia
  B. petiolaris
  B. ser. Cyrtostylis (13 species)
  B. ser. Tetragonae (3 species)
  B. ser. Bauerinae (1 species)
  B. ser. Quercinae (2 species)
  B. sect. Coccinea (1 species)
  B. sect. Oncostylis (4 series, 22 species, 4 subspecies, 11 varieties)
  B. subg. Isostylis (3 species)
  Since 1998, American botanist Austin Mast has been publishing results of ongoing cladistic analyses of DNA sequence data for the subtribe Banksiinae, which includes Banksia. With respect to B. petiolaris, Mast's results have some semblance to George and Thiele's. It is somewhat basal in a group with the other prostrate species as well as species in series Tetragonae, and B. elderiana, B. baueri, and B. lullfitzii. However, B. repens, B. chamaephyton and B. blechnifolia form a closely knit group within this group, and the overall inferred phylogeny is very different from George's arrangement. Early in 2007, Mast and Thiele initiated a rearrangement of Banksiinae by publishing several new names, including subgenus Spathulatae for the species of Banksia that have spoon-shaped cotyledons; in this way they also redefined the autonym B. subgenus Banksia. They have not yet published a full arrangement, but if their nomenclatural changes are taken as an interim arrangement, then B. petiolaris is placed in subgenus Banksia. In a 2013 cladistics study, evolutionary scientists Marcell Cardillo and Renae Pratt found that its closest relative is B. brevidentata.
caption: Foliage
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