Wallum banksia

Appearance

''Banksia aemula'' is generally a gnarled shrub or small tree to 8 m, although usually smaller. Conversely, individual wallum banksias have been measured at 8.3–12.1 m high, with a maximum diameter at breast height of 44 cm in forest on North Stradbroke Island.

The trunk has thick orange-brown wrinkled and warty bark, and the new growth is hairy but becomes smooth as it ages. New shoot growth is in spring and summer. The shiny green leaves are obovate to oblong in shape and measure 3–22 cm in length, and 1–2 cm in width.

The leaf ends are truncate and the margins flat and serrated. Flowering is in autumn, from March to June; the green-yellow flower spikes, known as inflorescences, are terminal, found on the ends of branches and emerging from the foliage. Measuring 4 to 20 cm in height and 8 to 9 cm in width, they are various shades of pale and greenish yellow.

Anywhere from 800 to 1700 individual small flowers arise from a central woody spike . Initially tipped with white conical pollen presenters, the flowers open sequentially from the bottom to the top of the flower spike over one to two weeks, in a process known as sequential anthesis. Each flower produces nectar for around seven days after opening.

The flower spikes turn grey as they age and up to 25 finely furred grey follicles appear, which can be very large, measuring 3–4.5 cm ong, 2–3.5 cm high, and 2–3.5 cm wide. They split open either after bushfire or spontaneously, and release oval seeds 4–4.7 cm in length, composed of a wedge-shaped body 1–1.5 cm long and 1.1–1.6 cm wide, and curved wing 2–3.2 cm wide. ''Banksia aemula'' resprouts from its woody lignotuber after fire.

''B. aemula'' closely resembles ''Banksia serrata'', but the latter can be distinguished by a greyer, not orange-brown, trunk, and adult leaves wider than 2 cm in diameter. Inflorescences of ''serrata'' are generally a duller grey-yellow in colour, and have longer , more fusiform or cylindrical pollen presenters tipping unopened flowers. Finally, the follicles are smaller.

Distribution

''Banksia aemula'' is found along the east coast of Australia from around 70 km north of Bundaberg in central Queensland down to Sydney. Specifically, its southernmost occurrence is at La Perouse on the northern side of Botany Bay.

It is also found on Fraser, Moreton and North Stradbroke Islands. 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 southwest of Bundaberg.

Habitat

''B. aemula'' is most commonly found in deep sandy soils, either on dunes or flattish areas which may be seasonally wet.

Cultural

Although ''Banksia attenuata'' was the common banksia in Australian children's author May Gibbs' own childhood in Western Australia, the old flower spikes of ''Banksia aemula'' with their large follicles are thought to have been the inspiration for the villains of her Snugglepot and Cuddlepie books, the "Big Bad Banksia Men".