Banksia aquilonia

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Banksia aquilonia
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Proteales
Family: Proteaceae
Genus: Banksia
Species:
B. aquilonia
Binomial name
Banksia aquilonia
(A.S.George) A.S.George[1]
Synonyms[1]

Banksia integrifolia subsp. aquilonia (A.S.George) K.R.Thiele
 Banksia integrifolia var. aquilonia A.S.George

Bright green and brownish new growth and green follicles on spike in summer

Banksia aquilonia, commonly known as the northern banksia[2] and jingana,[3] is a tree in the family Proteaceae and is endemic to north Queensland on Australia's northeastern coastline. With an average height of 8 m (26 ft), it has narrow glossy green leaves up to 20 cm (7.9 in) long and 6 to 10 cm (2.4 to 3.9 in) high pale yellow flower spikes, known as inflorescences, appearing in autumn. As the spikes age, their flowers fall off and they develop up to 50 follicles, each of which contains two seeds.

Alex George described the plant in his 1981 monograph of the genus Banksia as a variety of Banksia integrifolia, but later reclassified it as a separate species. Genetic studies show it to be related to Banksia plagiocarpa, Banksia oblongifolia and Banksia robur. The species is found in wet sclerophyll forest and rainforest margins on sandy soils. Banksia aquilonia regenerates after bushfire by regrowing from epicormic buds under its bark. It is rarely cultivated.

Description

Banksia aquilonia grows as a tall shrub or small tree up to 8 m (26 ft) high,

styles. All old flower parts fall away as up to 50 oval follicles develop on the bare woody spike. The follicles measure 0.8–1.2 cm (0.3–0.5 in) long, 0.5–0.9 cm (0.20–0.35 in) high, and 0.4–0.5 cm (0.16–0.20 in) wide. Furry at first, they become smooth with age and open when ripe,[4] and their two half-oval valves split to release the one or two seeds they contain.[6] The obovate dark grey-brown to black seeds sandwich a woody separator. Measuring 1.4–1.6 cm (0.6–0.6 in) long, they are made up of a wedge-shaped seed body, 0.8–1 cm (0.3–0.4 in) long by 0.2–0.3 cm (0.08–0.1 in) wide.[4] The woody separator is the same shape as the seed, with an impression where the seed body lies next to it.[6] Seedlings have bright obovate green cotyledons around 1 cm (0.39 in) long.[7] Juvenile leaves are narrower, measuring 7–24 cm (2.8–9.4 in) long and 0.6–2.1 cm (0.2–0.8 in) wide, and often have serrate (toothed) margins.[6]

Although the inflorescences of Banksia aquilonia are similar to B. integrifolia, the leaves are marked in their differences—the midrib on the leaves' undersides is distinctively covered in short reddish-brown hairs and the leaves are spirally arranged on the branches rather than in whorls as in all B. integrifolia subspecies. It was these differences that George felt were distinctive enough for it to be separate it as a full species from B. integrifolia.[8] The overall habit of a Banksia aquilonia tree resembles that of B. integrifolia, though is generally smaller.[6] The southernmost populations of B. aquilonia are separated from the northernmost B. integrifolia occurrence by 200 km (120 mi),[9] hence location is helpful in identification.[6]

Variants

Field volunteers for The Banksia Atlas recorded plants with large adult and juvenile leaves up to 38 cm (15 in) long along the Tully to Mission Beach Road, and a population of smaller shrub-sized plants to 3 m (10 ft) high with small narrow leaves 13 cm (5.1 in) long and 0.4 cm (0.2 in) wide at Coronation Lookout in Wooroonooran National Park, plants with normal morphology occurring further down the mountain.[5]

Taxonomy

See also: Taxonomy of Banksia
The undersides of the leaves have prominent furry midribs.
Detail of trunk

Banksia aquilonia was first described by

paraphyletic by elevating this taxon to species rank, and they were equally unwilling to elevate all four varieties to species rank, since the others all had significant overlaps in distribution and morphology. Therefore, they simply promoted all four to subspecies rank.[11] This example has since been held up as an interesting case study on how the concept of species should be defined, as it presents the problem of "a monophyletic group comprising a paraphyletic basal group of incompletely differentiated geographic forms within which is nested at least one divergent, autapomorphic taxon that invites treatment as a species."[12]

George promoted it to species rank on the basis of its distinctive leaf arrangement and midrib in 1996.[8] Thus its full name with author citation is "Banksia aquilonia (A.S.George) A.S.George". It is placed in subgenus Banksia, section Banksia and series Salicinae. Its placement within Banksia may be summarised as follows:[4]

Genus Banksia
Subgenus Banksia
Section Banksia
Series Salicinae
Banksia dentata - Banksia aquilonia - Banksia integrifolia - Banksia plagiocarpa - Banksia oblongifolia - Banksia robur - Banksia conferta - Banksia paludosa - Banksia marginata - Banksia canei - Banksia saxicola
Series Grandes
Series Banksia
Series Crocinae
Series Prostratae
Series Cyrtostylis
Series Tetragonae
Series Bauerinae
Series Quercinae
Section Coccinea
Section Oncostylis
Subgenus Isostylis

Despite initially assigning Banksia aquilonia to be variety of B. integrifolia, George noted that it had affinities with the then newly described species Banksia plagiocarpa, with which it co-occurs on and near Hinchinbrook Island in north Queensland.[6]

Since 1998, American botanist

DNA sequence data for Banksia and Dryandra. Their analyses suggest a phylogeny that differs greatly from George's taxonomic arrangement. Banksia aquilonia formed a clade with B. plagiocarpa, B. oblongifolia and B. robur, rather than B. integrifolia.[13][14][15] Early in 2007, Mast and Thiele rearranged the genus Banksia by merging Dryandra into it, and published B. subg. Spathulatae for the taxa having spoon-shaped cotyledons; thus B. subg. Banksia was redefined as encompassing taxa lacking spoon-shaped cotyledons. They foreshadowed publishing a full arrangement once DNA sampling of Dryandra was complete; in the meantime, if Mast and Thiele's nomenclatural changes are taken as an interim arrangement, then B. aquilonia is placed in B. subg. Spathulatae.[16]

Common names include northern banksia, white banksia, honeysuckle or white bottlebrush.[7] A local aboriginal name is jingana, in the Jirrbal and Girramay languages.[3]

Distribution and habitat

Range of Banksia aquilonia

Banksia aquilonia occurs in coastal areas of northern

understorey species such as coin spot wattle (Acacia cincinnata) and yellow wattle (A. flavescens). Much of its lowland habitat in the Wet Tropics has been degraded or fragmented.[18] Although the range overlaps with B. dentata, the two species are not known to occur together.[6]

Ecology

See also: Ecology of Banksia

Banksia aquilonia regenerates after bushfire by regrowing from epicormic buds under its bark.[19] Regeneration from root suckers has also been recorded.[20] Unlike many banksia species which release their seed after bushfires, Banksia aquilonia sets seed when the follicles mature.[21]

Banksia inflorescences are energy-rich sources of food, and B. aquilonia nectar is a likely food item of the endangered mahogany glider (Petaurus gracilis),[22] as well as many other mammals and birds.[21] Avian species observed visiting the flower spikes include the bridled honeyeater, white-cheeked honeyeater, eastern spinebill and rainbow lorikeet.[5]

Cultivation

Banksia aquilonia adapts readily to cultivation in humid or temperate climates,[17] but is rarely cultivated.[7] A fast-growing plant,[7] it can grow in acidic soils from pH 3.5 to 6.5. Propagation is generally by seed, and plants flower at four to six years of age. Vegetative propagation is possible from semi-hardened cuttings of pencil thickness.[17] The flower spikes attract birds to the garden.[7] It can also be grown in a pot, with its branches heavily pruned to keep foliage dense.[23]

References

  1. ^ a b "Banksia aquilonia". Australian Plant Census. Retrieved 26 March 2020.
  2. ^ Cotter, Zachariah. "Banksia aquilonia - northern banksia". Australian National Botanic Gardens. Retrieved 26 March 2020.
  3. ^
    ISSN 1444-285X
    .
  4. ^
    ISBN 0-643-06454-0
    .
  5. ^
    ISBN 0-644-07124-9
    .
  6. ^
    ISSN 0085-4417
    .
  7. ^
    Commonwealth Scientific and Industrial Research Organisation
    (CSIRO). Retrieved 3 March 2021.
  8. ^ a b George, A. S. (1996). "Notes on Banksia L. f". Nuytsia. 11 (1): 21–24.
  9. doi:10.1071/SB9940393
    .
  10. ISBN 0-207-17277-3
    .
  11. doi:10.1071/SB9960661
    .
  12. ISSN 0312-9764
    .
  13. PMID 21665734
    .
  14. doi:10.1071/SB97026
    .
  15. doi:10.1071/SB04015
    .
  16. doi:10.1071/SB06016
    .
  17. ^
    ISBN 978-1-876473-68-6
    .
  18. ISSN 0727-9620
    .
  19. ISBN 0-86417-818-2
    .
  20. doi:10.1071/BT99020
    .
  21. ^ a b Wet Tropics Management Authority (September 2001). "No. 69" (PDF). Tropical Topics: An Interpretive Newsletter for the Tourism Industry. Cairns, Queensland: Environmental Protection Agency, Queensland Parks and Wildlife Service. Retrieved 11 November 2012.
  22. doi:10.1017/S0952836901000012
    .
  23. ^ Radke, Peter (August 2003). "Growing Banksias in Tropical North Queensland". Yuruga Native Plant Nursery. Walkamin, Queensland: Yuruga Nursery Pty Ltd. Archived from the original on 19 April 2013. Retrieved 10 November 2012.

External links

Wikispecies has information related to Banksia aquilonia.

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