Banksia densa

Banksia densa is a species of column-like shrub that is endemic to Western Australia. It has deeply serrated to pinnatifid leaves, creamy yellow flowers in heads of up to seventy-five, and hairy follicles.

Banksia densa

Priority Two — Poorly Known Taxa (DEC)
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Proteales
Family: Proteaceae
Genus: Banksia
Subgenus: Banksia subg. Banksia
Series: Banksia ser. Dryandra
Species:
B. densa
Binomial name
Banksia densa
Synonyms[1]

Description

Banksia densa is a shrub, usually with a column-like form that typically grows to a height of 2.5 m (8 ft 2 in) but does not form a lignotuber. It has linear, pinnatifid leaves that are 50–150 mm (2.0–5.9 in) long and 8–15 mm (0.31–0.59 in) wide on a petiole up to 10 mm (0.39 in) long. There are between eight and thirteen sharply pointed linear to triangular lobes up to 9 mm (0.35 in) long on each side of the leaves and the lower surface is covered with woolly white hairs. The flowers are arranged in heads of between forty and seventy-five with rusty-hairy or velvety, linear involucral bracts up to 15 mm (0.59 in) long at the base of the head. The flowers have a creamy yellow, hairy perianth 15–18 mm (0.59–0.71 in) or 21–25 mm (0.83–0.98 in) long, depending on subspecies, and a mostly glabrous pistil 16–26 mm (0.63–1.02 in) long or 25–30 mm (0.98–1.18 in) long. Flowering occurs from May to October and the fruit is a hairy, egg-shaped to elliptical follicle 9–13 mm (0.35–0.51 in) long.[2][3][4]

Taxonomy and naming

This species was first formally described in 1870 by George Bentham who gave it the name Dryandra conferta and published the description in Flora Australiensis.[5][6] The specific epithet (conferta) is from a Latin word meaning "crowded".[7]

In 1996, Alex George described two varieties:[4]

  • Dryandra conferta var. conferta with a perianth 21–25 mm (0.83–0.98 in) long and a pistil 25–30 mm (0.98–1.18 in) long and flowers with a mouse-like or honey-like scent;
  • Dryandra conferta var. parva with a perianth 15–18 mm (0.59–0.71 in) long and a pistil 16–26 mm (0.63–1.02 in) long.

In 2007, Austin Mast and Kevin Thiele transferred all Dryandra species to Banksia. As there was already a species named Banksia conferta, Mast and Thiele changed the specific epithet to "densa".[8][9]

The changed names of the varieties are as follows and are accepted at the Australian Plant Census:

Distribution and habitat

Banksia densa is widespread in inland parts of the south-west of Western Australia, growing in kwongan, woodland and shrubland between Miling, Cadoux the Porongorups, Bodallin and Mount Holland. Variety parva has a more southerly distribution than var. densa.[4][3]

Ecology

An assessment of the potential impact of climate change on this species found that its range is likely to contract by between 50% and 80% by 2080, depending on the severity of the change.[12]

Conservation status

This banksia is classified as "Priority Two" by the Western Australian Government Department of Parks and Wildlife[2] meaning that it is poorly known and from only one or a few locations.[13]

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References
  1. "Banksia densa". Australian Plant Census. Retrieved 22 April 2020.
  2. "Banksia densa". FloraBase. Western Australian Government Department of Parks and Wildlife.
  3. George, Alex S. (1999). Flora of Australia (PDF). 17B. Canberra: Australian Biological Resources Study, Canberra. pp. 344–346. Retrieved 22 April 2020.
  4. George, Alex S. (1996). "New taxa and a new infrageneric classification in Dryandra R.Br". Nuytsia. 10 (3): 387–388.
  5. "Dryandra conferta". APNI. Retrieved 22 April 2020.
  6. Bentham, George; von Mueller, Ferdinand (1870). Flora Australiensis (Volume 5). London: Lovell Reeve & Co/. p. 578. Retrieved 22 April 2020.
  7. Francis Aubie Sharr (2019). Western Australian Plant Names and their Meanings. Kardinya, Western Australia: Four Gables Press. p. 168. ISBN 9780958034180.
  8. "Banksia densa". APNI. Retrieved 22 April 2020.
  9. Mast, Austin R.; Thiele, Kevin (2013). "The transfer of Dryandra R.Br. to Banksia L.f. (Proteaceae)". Australian Systematic Botany. 20 (1): 63–71. doi:10.1071/SB06016.
  10. "Banksia densa var. densa". Australian Plant Census. Retrieved 22 April 2020.
  11. "Banksia densa var. parva". Australian Plant Census. Retrieved 22 April 2020.
  12. Fitzpatrick, Matthew C.; Gove, Aaron D.; Sanders, Nathan J.; Dunn, Robert R. (2008). "Climate change, plant migration, and range collapse in a global biodiversity hotspot: the Banksia (Proteaceae) of Western Australia". Global Change Biology. 14 (6): 1–16. doi:10.1111/j.1365-2486.2008.01559.x.
  13. "Conservation codes for Western Australian Flora and Fauna" (PDF). Government of Western Australia Department of Parks and Wildlife. Retrieved 22 April 2020.
  • Cavanagh, Tony; Pieroni, Margaret (2006). The Dryandras. Melbourne: Australian Plants Society (SGAP Victoria); Perth: Wildflower Society of Western Australia. ISBN 1-876473-54-1.
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