No distinct subspecies have been recognised by Banksia expert Alex George, who nonetheless concedes that further work is needed.

[6] Cylindrical in shape, they are composed of a central woody spike or axis, perpendicularly from which a large number of compact floral units arise.

[8] Pale yellow in colour, they are composed of up to 1,000 individual flowers (784 recorded in the Gibraltar Range[6]) and arise from nodes on branchlets that are at least three years old.

[8] In coastal and floodplain populations, these usually open spontaneously and release seed, while they generally remain sealed until burnt by fire in plants from heathland and montane habitats.

During his third voyage in January 1777, Captain James Cook reported a "most common tree [...] about ten feet high, branching pretty much, with narrow leaves, and a large, yellow, cylindrical flower, consisting only of a vast number of filaments; which, being shed, leave a fruit like a pine top.

"[17] The genus Banksia was named in honor of Sir Joseph Banks, a botanist who was with Captain Cook during his first voyage (1768–1771) in which he circumnavigated the world, including stops in New Zealand and Australia (Botany Bay).

[2][19] The species name is the Latin adjective marginatus ('bordered') and refers to appearance of the lower surface of the recurved margins of the leaves when viewed from underneath.

[22] He described Banksia australis R.Br., giving the location of the collection as Port Phillip Bay in Victoria in 1802 (having crossed out Van Diemen's Land 1804).

Meissner divided Brown's Banksia verae, which had been renamed Eubanksia by Stephan Endlicher in 1847,[8] into four series based on leaf properties.

Bentham observed that the characteristics Brown used to define B. australis, B. depressa, B. patula, and B. insularis were unable to distinguish separate forms as more specimens came to light, and hence declared them synonyms of B. marginata.

[27] The current taxonomic arrangement of the genus Banksia is based on botanist Alex George's 1999 monograph for the Flora of Australia book series.

In a morphological cladistic analysis published in 1994, Kevin Thiele placed it as the most basal member of a newly described subseries Integrifoliae, within the series Salicinae.

[3] George did concede that major work is needed on Banksia marginata, which shows such a high degree of variability over its range.

Banksia marginata resolves as the closest relative, or "sister", to B. saxicola, the two taxa part of a larger group containing B. paludosa and the three subspecies of B. integrifolia.

[35] A purported hybrid with B. integrifolia, thought to be from Cape Paterson on Victoria's south coast, was first described by Alf Salkin and is commercially available in small quantities.

He had collected this form from Revesby in New South Wales as well as Cape Paterson, and had received reports of similar plants at Marlo and Bemm Rivers.

[6] In the Sydney region, it grows in association with heath banksia (Banksia ericifolia), old man banksia (B. serrata), mountain devil (Lambertia formosa), lance-leaved geebung (Persoonia lanceolata) and dwarf apple (Angophora hispida) in heathland, and with silvertop ash (Eucalyptus sieberi), Blue Mountains ash (E. oreades), Sydney peppermint (E. piperita), scribbly gum (E. haemastoma), Blue Mountains mallee ash (E. stricta), brittle gum (E. mannifera), snow gum (E. pauciflora) and red bloodwood (Corymbia gummifera) in forested areas.

[44] It is a common shrub, sometimes small tree, in heathy and shrubby forests as well as coastal scrub and heath in part of its range.

[48] In Tasmania, Banksia marginata occupies a wide range of habitats, in mixed forest (where it grows as a small tree), buttongrass moorlands, flood plains of the Loddon, Franklin and Huon Rivers, as well as coastal regions.

[49] In parts of the west and southwest of Tasmania, the species is dominant within the threatened native vegetation community known as Banksia marginata wet scrub.

[10] Plants have been recorded at altitudes ranging from sea level to as high as 1,200 m (3,900 ft) AHD at Mount Field National Park.

[54] Ants, bees (both native and European honeybees), blowflies and brown butterflies have been recorded as visitors to flower spikes.

[35] The wasp Mesostoa kerri of the subfamily Mesostoinae within the family Braconidae causes stem galls on B. marginata in southeastern South Australia.

[43] All banksias have developed proteoid or cluster roots in response to the nutrient-poor conditions of Australian soils (particularly lacking in phosphorus).

During the winter months, segments around 30 cm (0.98 ft) in length develop vegetative buds capable of forming suckers.

A field study found that seeds were dispersed short distances, generally 8 m (26 ft) or less, with those closest to the parent plant faring the best.

[66] Tasmanian forms are frost tolerant at any time of year, which might explain some of their success in spreading and growing in different habitats around the island.

[72] A sample was prepared in Victoria in 1885 as part of a collection of local timber species under the direction of Government botanist Ferdinand von Mueller.

Salkin proposed this was necessary so that seed released in a summer or autumn bushfire would lie dormant over the winter months before germinating in the spring.

[77] Banksia 'Mini Marg' is a small form selected from the northeastern coast of Tasmania which reaches 30 cm (12 in) high and 1 m (3.3 ft) wide.