Banksia is a genus of about 75 species in the Protea family (Proteaceae). All species occur in Australia with one (B.dentata) extending to islands to Australia's north. Banksias can be found in most environments; the tropics, sub-alpine areas, the coast and desert areas. The most diversity in the genus occurs in the south of Western Australia where over 80% of the species occur.

Discovery

Archaeological evidence suggests that banksias or Banksia-like plants have existed for over 40 million years. The first humans to discover and make use of Banksia plants were the Australian aborigines who used the nectar from the flowers as part of their diet.

The first Europeans to observe banksias were probably Dutch explorers who made several landfalls along the West Australian coast during the 17th and early 18th centuries. No botanical collections were made, however, until the discovery of the east coast of Australia by Captain James Cook in the Endeavour in April 1770. Accompanying Cook were botanists Joseph Banks and Daniel Solander who collected many new species at Botany Bay including four which would later be included in a new genus, Banksia, named in honour of Joseph Banks' contribution to botany. The four species collected were B.serrata, B.ericifolia, B.integrifolia and B.robur. Later, on the same voyage, Banks and Solander collected a fifth species (B.dentata) on the north Queensland coast.

Characteristics

Banksia flowers are quite small but they occur in dense clusters which, in some species, can number several thousand individuals. Banksias are classified into two broad groups; sub-genus Isostylis and sub-genus Banksia. The former consists of only three species, all native to Western Australia, and is recognised by having flowers in cone-shaped clusters. This group is similar in many ways to the related genus Dryandra. The sub-genus Banksia has its flowers arranged in the more or less cylindrical spike familiar to most Australians.

The relationship between Banksia and Dryandra is so close that some botanists believe that the two genera should be combined. This view appears to be gaining wider acceptance and it is possible that Dryandra will be subsumed into Banksia in the future, which would more than double the number of Banksia species.

Banksia flowers are followed by large, woody seed "cones" in which the seeds are contained within closed follicles, two seeds per follicle. In the majority of species these follicles remain tightly closed unless stimulated to open by heat, such as following a bushfire but, with a few species, the seed is released annually. The seeds themselves have a papery wing which allows them to be distributed by wind.

The seed follicles on this cone of Banksia oblongifolia have opened following a fire to release the seeds. Click the thumbnail image or plant name for a higher resolution image [48k].

Most banksias are medium shrubs but some are prostrate and a few can become large trees. Those species native to areas where fires occur at regular intervals often have a "lignotuber", a woody swelling at or below ground level from which regeneration of the plant can occur if the above ground stems are destroyed. Other species are killed in fire, with seedlings sprouting in their place.