A plant with fine feathery leaves and large red-brown flower spikes, it usually grows as an upright bush around two metres (6.6 ft) high, but can also occur as a small tree or a low spreading shrub.

Banksia brownii occurs naturally only in two population clusters between Albany and the Stirling Range in southwest Western Australia.

It has been evaluated as critically endangered by the International Union for Conservation of Nature (IUCN); all major populations are threatened by Phytophthora cinnamomi dieback, a disease to which the species is highly susceptible.

Highly valued by Australia's horticultural and cut flower industries, B. brownii is widely cultivated in areas not exposed to dieback.

Dark green and hairless above but with a hairy white underside, they are easily recognised by their feather-like appearance, caused by the fact that they are finely divided almost back to the midrib, into as many as 70 thin tapered lobes.

The fruiting structure is a stout woody "cone", around five centimetres (2 inches) in diameter, with a hairy appearance caused by the persistence of old withered flower parts.

[4][5] Banksia brownii was first collected near King George Sound in 1829 by William Baxter, who named it in honour of botanist Robert Brown.

A formal description was published by Brown in his 1830 Supplementum Primum Prodromi Florae Novae Hollandiae;[8] thus the full botanic name of the species is Banksia brownii Baxter ex R.Br.

[10] When George Bentham published his 1870 arrangement in Flora Australiensis, he discarded Meissner's series, placing all the species with hooked styles together in a section that he named Oncostylis.

[16] 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.

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.

[7] Banksia brownii occurs between Albany (35°S) and the Stirling Range (34°24'S) in the southwest of Western Australia,[24] at the juncture of the Esperance Plains, Warren and Jarrah Forest biogeographic regions.

[6] As with other Banksia species, B. brownii is a heavy producer of nectar, and serves as a food source for a range of nectariferous birds, mammals and insects.

[28] Threats to B. brownii include loss of habitat due to land clearing, commercial exploitation, disease, and changes to the fire regime.

[34] A subsequent study by these authors, published in 2015, estimated that B. brownii has lost between 35–40% of its historical genetic diversity due to P. cinnamomi dieback.

[35] B. brownii has been assessed as having a high risk of extinction,[36] and that this would be "not only a tragedy in itself but may have unforeseen, and potentially disastrous, consequences for the functioning of the vegetation communities of which feather-leaved banksia is an integral part.

"[7] The species has been formally assessed for the IUCN Red List as "Critically Endangered (CR)";[1] populations are projected to decline by more than 80% within the next three generations.

[39] These acts provide legislative protection against a range of potential threats, including commercial harvesting of flowers and land clearing.

[37] A five-year interim management plan was put in place by the Western Australia's Department of Environment and Conservation in October 2005.

Actions under that plan include regular monitoring of populations, management of the threats of fire and P. cinnamomi, and the cold storage of seed.

Studies of the effect of P. cinnamomi on B. brownii have found it to be "highly susceptible" to dieback, with specimens "frequently and consistently killed in the wild".

"[28] A number of protective measures have been implemented, including site access restrictions, the collection and cold-storage of seed, and the treatment of plants with phosphite.

[46] Direct injection of phosphite into the stem of each tree appears to lack this disadvantage, but is costly to administer and restricted to known plants.

[7] If fire occurs too frequently, plants are burned before reaching maturity or before they have produced sufficient seed to ensure regeneration of the population.

[51] With large metallic red inflorescences and attractive feathery leaves that are perhaps the softest of all Banksia species,[16] B. brownii is highly valued by Australia's horticultural and cut flower industries.