Banksia, and was divided into three sections, one of which was Oncostylis. Oncostylis was further divided into four series, with B. brownii placed in series Spicigerae because its inflorescences are cylindrical. In 1996, Kevin Thiele and Pauline Ladiges published a new arrangement for the genus, after cladistic analyses yielded a cladogram significantly different from George's arrangement. Thiele and Ladiges' arrangement retained B. brownii in series Spicigerae, placing it in B. subser. Occidentales along with B. occidentalis (red swamp banksia), B. seminuda (river banksia), B. verticillata (granite banksia) and B. littoralis (swamp banksia). This arrangement stood until 1999, when George effectively reverted to his 1981 arrangement in his monograph for the Flora of Australia series. Under George's taxonomic arrangement of Banksia, B. brownii's taxonomic placement may be summarised as follows: Genus Banksia Subgenus Banksia Section Banksia Section Coccinea Section Oncostylis Series Spicigerae B. spinulosa - B. ericifolia - B. verticillata - B. seminuda - B. littoralis - B. occidentalis - B. brownii Series Tricuspidae Series Dryandroidae Series Abietinae Subgenus Isostylis The closest relative to B. brownii is held to be B. occidentalis, which differs in having smaller, deep red flowers and narrow, sparsely serrate leaves. Since 1998, Austin Mast has been publishing results of ongoing cladistic analyses of DNA sequence data for the subtribe Banksiinae, which comprises Banksia and Dryandra. With respect to B. brownii, Mast's results are somewhat at odds with those of both George and Thiele and Ladiges, finding it to be more closely related to B. nutans (nodding banksia) and B. quercifolia (oak-leaved banksia) than to many of the Spicigerae. Overall, the inferred phylogeny is very greatly different from George's arrangement, and provides compelling evidence for the paraphyly of Banksia with respect to Dryandra. Early in 2007, Mast and Thiele initiated a rearrangement of Banksia by transferring Dryandra into it, and publishing B. subg. Spathulatae for the species having spoon-shaped cotyledons. They foreshadowed publishing a full arrangement once DNA sampling of Dryandra was complete; in the meantime, if Mast and Thiele's nomenclatural changes are taken as an interim arrangement, then B. brownii is placed in B. subg. Spathulatae. Three genetically distinct forms of B. brownii are recognised: the better known forms are a "mountain form" with a shrubby habit, short thin hard leaves, and a squat inflorescence; and a "Millbrook Road form", with a tree habit and longer, wider, soft leaves. Some horticulturists also recognise an intermediate form.