Banksia incana

Species of shrub in the family Proteaceae endemic to the south west of Western Australia
speciesbox
|name = Hoary banksia
|image = Banksia incana. jpg
|genus = Banksia
|parent = Banksia subg. Banksia
|species = incana
|authority = A. S. George
|synonyms ref =

Carl Meissner noted the hoary banksia as a distinct form of Banksia sphaerocarpa and in 1856 gave it the name Banksia sphaerocarpa var. glabrescens in de Candolle's Prodromus Systematis Naturalis Regni Vegetabilis. Alex George raised the variety to species status in his 1981 monograph "The genus Banksia L. f. (Proteaceae)", based on a specimen he collected outside the Moore River Native Settlement, on 2 February 1967. He placed it in subgenus Banksia because of its flower spike, in section Oncostylis because its styles are hooked and in the resurrected series Abietinae, which he constrained to contain only round fruited species. The specific epithet (incana) is from the Latin incanus ("hoary") and refers to the grey furry follicles. typically a mounded shrub with leaves usually long;
Banksia incana A. S. George var. incana typically an open shrub with leaves usually long.

Banksia incana grows in sand in heath, shrubland or woodland, often with B. attenuata and B. menziesii and occurs between the Arrowsmith River and Perth. Variety brachyphylla is found between Arrowsmith and Mogumber with disjunct populations near Gingin and Perth.

Banksia incana resprouts from its woody lignotuber after bushfire. Banksia incana is one of five closely related Banksia species that have highly unusual flower nectar. efn|The other four species are Banksia sphaerocarpa, B. grossa, B. leptophylla and B. telmatiaea. It was first noted by Byron Lamont in 1980; he attributed it to cyanobacteria that feed off the nectar sugars. Noting that many of these cyanobacteria had heterocysts, he speculated that they aid the plant by fixing atmospheric nitrogen, which is then washed off the flower heads by rain, and absorbed by the proteoid root mat. This purported symbiosis was investigated by Barrett and Lamont in 1985, but no evidence of nitrogen fixing was found. Further investigation by Markey and Lamont in 1996 suggested that the discolouration is not caused by cyanobacteria or other microorganisms in the nectar, but is rather "a chemical phenomenon of plant origin". Their analyses indicated that the nectar had unusually high levels of sugar and free amino acids, but three of these species, including B. sphaerocarpa, have since been shown to have normal nectar sugar compositions. The purpose of coloured nectar is unclear, especially as pollinators such as nocturnal mammals are not thought to forage by sight. However, nectar that becomes more obvious by appearance or smell as it ages might encourage pollinators to prioritise it over newer nectar. It is possible the colour change is unrelated to pollination.

Both varieties of B. incana are classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.