Banksia aemula

Found from Bundaberg south to Sydney on the Australian east coast, it is encountered as a shrub or a tree to 8 m (26 ft) in coastal heath on deep sandy soil, known as Wallum.

It has wrinkled orange bark and shiny green serrated leaves, with green-yellow flower spikes, known as inflorescences, appearing in autumn.

However, the former name, originally coined by Richard Anthony Salisbury, proved invalid, and Banksia aemula has been universally adopted as the correct scientific name since 1981.

A wide array of mammals, birds, and invertebrates visit the inflorescences and are instrumental in pollination; honeyeaters are particularly prominent visitors.

[4] Conversely, individual wallum banksias have been measured at 8.3–12.1 m (27–40 ft) high, with a maximum diameter at breast height of 44 cm (17 in) in forest on North Stradbroke Island.

[4] Banksia aemula closely resembles B. serrata, but the latter can be distinguished by a greyer, not orange-brown, trunk, and adult leaves wider than 2 cm (0.8 in) in diameter.

Inflorescences of serrata are generally a duller grey-yellow in colour, and have longer (2–3 mm), more fusiform (spindle-shaped) or cylindrical pollen presenters tipping unopened flowers.

[11] Banksia aemula was collected by Scottish botanist Robert Brown in June 1801 in the vicinity of Port Jackson, and described by him in his 1810 work Prodromus Florae Novae Hollandiae et Insulae Van Diemen.

[11] Brown also collected a taller tree-like specimen from Sandy Cape, which he called Banksia elatior; the specific name is the comparative form of the Latin adjective ēlātus meaning "elevated".

Banksia verae was renamed Eubanksia by Stephan Endlicher in 1847, and demoted to sectional rank by Carl Meissner in his 1856 classification.

[4] John White had sent material to James Edward Smith now held in the Linnean Society marked as B. serratifolia Salisb.

[18] The only contemporary specimen labelled B. serratifolia in the Linnaean Herbarium is a branchlet with juvenile leaves which cannot be definitely identified as B. aemula or B. serrata.

[24] In 2005, Mast, Eric Jones and Shawn Havery published the results of their cladistic analyses of DNA sequence data for Banksia.

They inferred a phylogeny greatly different from the accepted taxonomic arrangement, including finding Banksia to be paraphyletic with respect to Dryandra.

[26] Banksia aemula is found along the east coast of Australia from around 70 km (43 mi) north of Bundaberg in central Queensland down to Sydney.

Almost all populations are within a few kilometres of the coast, except for one at Agnes Banks in western Sydney, and two just north and south of Grafton at Coaldale and Glenreagh, and a last around 30 km (19 mi) southwest of Bundaberg.

[28] In Cooloola National Park, it is an occasional emergent plant (along with Melaleuca quinquenervia and Eucalyptus umbra) in closed graminoid heathland, a community of shrubs 0.5–2 m (1.6–6.6 ft) high containing Xanthorrhoea fulva, Empodisma minus, Petrophile shirleyae, and Hakea and Leptospermum species.

Other plants it grows in association with include Ricinocarpos pinifolius, Brachyloma daphnoides, Dillwynia glaberrima, D. retorta, Allocasuarina distyla, Bossiaea ensata, Aotus ericoides, Phyllota phylicoides, and Empodisma minus.

[30] At the southern end of its range, B. aemula is a component of the Eastern Suburbs Banksia Scrub, designated an endangered ecological community.

[31] The Agnes Banks Woodland in western Sydney has been recognised by the New South Wales Government as an Endangered Ecological Community.

Here Banksia aemula is an understory plant in low open woodland, with scribbly gum (Eucalyptus sclerophylla), narrow-leaved apple (Angophora bakeri) and B. serrata as canopy trees, and B. oblongifolia, Conospermum taxifolium, Ricinocarpus pinifolius, Dillwynia sericea and nodding geebung (Persoonia nutans) as other understory species.

[35] A 1998 study in Bundjalung National Park in northern New South Wales found that B. aemula inflorescences are foraged by a variety of small mammals, including marsupials such as yellow-footed antechinus (Antechinus flavipes), and rodents such as pale field rat (Rattus tunneyi), Australian swamp rat (R. lutreolus) and grassland melomys (Melomys burtoni) and even the house mouse (Mus musculus).

Grey-headed flying foxes (Pteropus poliocephalus) were also observed visiting B. aemula and their heads and bellies were noted to contact stigmas while feeding.

[36] Bird species that have been observed feeding at the flowers of B. aemula include rainbow lorikeet and scarlet[37] and Lewin's honeyeaters.

[38] Intervals of 10–15 years are recommended for the Eastern Suburbs Banksia Scrub, as longer leads to overgrowth by Leptospermum laevigatum.

Overall, seedlings grow slowly over the first 21 weeks of life compared with other plant species, the reasons for which are unclear, although it may be that it offers an increased chance of survival in a nutrient- or water-poor environment.

[45] Similarly in field work on North Stradbroke Island, B. aemula was noted to shed its winged seeds over time between (as well as after) fire, and germinate and grow readily with little predation by herbivores.

[49] Its shiny green leaves, showy flower spikes, huge follicles, and wrinkled bark are attractive horticultural features.

Grey spike in foreground on left with three huge seed pods. An ageing flowerhead in background turning brown.
B. aemula , showing large follicles, Cranbourne Annexe, RBG Melbourne
A green-yellow cylindrical flower spike is made up of many small flowers. The flowers are unopened and tipped with conical swellings
Inflorescence in late bud, showing more conical pollen presenters on the tips of the styles
A pale yellow flowerhead nestles among green foliage
Inflorescence after anthesis, with all flowers fully opened
Map of Australia with a green stripe straddling the eastern coastline
Range of B. aemula