Banksia aculeata

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Banksia aculeata
Banksia aculeata.JPG
Status DECF P2.svg
Priority Two — Poorly Known Taxa (DEC)
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Proteales
Family: Proteaceae
Genus: Banksia
Species:
B. aculeata
Binomial name
Banksia aculeata

Banksia aculeata, commonly known as prickly banksia, is a species of plant of the family Proteaceae native to the Stirling Range in the southwest of Western Australia. A shrub up to 2 m (7 ft) tall, it has dense foliage and leaves with very prickly serrated margins. Its unusual pinkish, pendent (hanging) flower spikes, known as inflorescences, are generally hidden in the foliage and appear during the early summer. Although it was collected by the naturalist James Drummond in the 1840s, Banksia aculeata was not formally described until 1981, by Alex George in his monograph of the genus.

Contents

A rare plant, Banksia aculeata is found in gravelly soils in elevated areas. Native to a habitat burnt by periodic bushfires, it is killed by fire and regenerates from seed afterwards. In contrast to other Western Australian banksias, it appears to have some resistance to the soil-borne water mould Phytophthora cinnamomi .

Description

A bushy shrub, Banksia aculeata grows up to 2 m (7 ft) tall, with fissured grey bark on its trunk and branches. Unlike many other banksia species, it does not have a woody base, or lignotuber. The leaves range from 4–9 cm (1+123+12 in) long and 0.8–3 cm (141+14 in) wide, with sharply pointed rigid lobes on the margins. [2] Appearing in February and March, [3] the cylindrical flower spikes—known as inflorescences—range from 6–9 cm (2+143+12 in) long, growing at the ends of short leafy 2–3-year-old side branches. Hanging downward rather than growing upright like those of most other banksias, they are composed of a central woody spike or axis, from which many compact individual flowers arise perpendicularly. These floral units are made up of a smooth tubular perianth that envelops the flower's sexual organs. The perianth is 3.0–4.3 cm (1+141+34 in) long and pink at the base grading into cream. In late bud, the end of the perianth has a characteristic four-angled (squarish) appearance. It then splits at anthesis to reveal the smooth straight pistil, which is slightly shorter than its enveloping structure at 3.0–4.2 cm (1+141+34 in) long. [4] The fruiting cone, known as an infructescence, is a swollen woody spike in which up to 20 massive follicles are embedded; the withered flower parts persist on the spike, giving it a hairy appearance. [2] Oval in shape, the follicles are wrinkled in texture and covered with fine hair. They are 3.0–4.5 cm (1+141+34 in) long, 2.5–3.0 cm (1–1+14 in) high, and 2.0–2.5 cm (34–1 in) wide. [4]

The obovate (egg-shaped) seed is 4–5 cm (1+58–2 in) long and fairly flattened. It is composed of the wedge-shaped seed body (containing the embryonic plant), measuring 1.0–1.2 cm (3812 in) long by 1.5–1.8 cm (5834 in) wide, and a papery wing. One side, termed the outer surface, is grey and wrinkled and the other is black and sparkles slightly. The seeds are separated by a sturdy dark brown seed separator that is roughly the same shape as the seeds with a depression where the seed body sits adjacent to it in the follicle. Known as cotyledons, the first pair of leaves produced by seedlings are cuneate (wedge-shaped) and measure 1.1–1.2 cm (3812 in) long by 1.9 cm (34 in) wide. They are dull dark green, sometimes with a reddish tinge, and the margin of the wedge is convex. The auricle at the base of the cotyledon leaf is pointed and measures 0.3 cm (18 in) long. The hypocotyl is thick, smooth and dark red. The obovate to oblong seedling leaves are 4–9 cm (1+123+12 in) long by 2.0–2.5 cm (34–1 in) wide with serrated margins, v-shaped sinuses and sharp teeth. [4]

The related Banksia caleyi is similar in appearance but can be distinguished by its recurved (downward curving) leaf margins, and smaller follicles and perianths. Its flowers appear from October to December. [3]

Taxonomy

Banksia aculeata was first collected by James Drummond on one of his three trips to the Stirling Range between 1843 and 1848, though he did not regard it as distinct from B. caleyi —this was only recognised over a century later by Alex George. George described B. aculeata in his 1981 monograph "The genus Banksia L.f. (Proteaceae)". For the type of the species, George selected a specimen he collected on Chester Pass Road in the Stirling Range east of Cranbrook on 20 March 1972. He gave it the specific epithet aculeata (Latin for "sharp"), in reference to the sharply pointed leaf lobes. [4]

George placed B. aculeata in B. subg. Banksia because its inflorescence is a typical Banksia flower spike; in B. sect. Banksia because of its straight styles; and B. ser. Tetragonae because of its pendulous inflorescences. He considered its closest relative to be B. caleyi, from which it differs in having narrower leaves with fewer, larger lobes; longer perianths, which grade from red to cream rather than from cream to red; shorter pistils; and also differences in the follicles, seeds and flowering time. [4]

In 1996, Kevin Thiele and Pauline Ladiges published the results of a cladistic analysis of morphological characters of Banksia. They retained George's subgenera and many of his series, but discarded his sections. George's B. ser. Tetragonae was found to be monophyletic, and therefore retained; and their analysis of the relationships within the series supported the placement of B. aculeata alongside B. caleyi. [5]

Flower spikes in early bud stage Banksia aculeata-1.JPG
Flower spikes in early bud stage

B. aculeata's placement in Thiele and Ladiges' arrangement may be summarised as follows: [5]

Banksia
B. subg. Isostylis (3 species)
B. elegans (incertae sedis)
B. subg. Banksia
B. ser. Tetragonae
B. elderiana
B. lemanniana
B. caleyi
B. aculeata

The arrangement of Thiele and Ladiges was not accepted by George and was discarded in his 1999 revision. Under George's 1999 arrangement, B. aculeata's placement was as follows: [2]

Banksia
B. subg. Banksia
B. sect. Banksia
B. ser. Salicinae (11 species, 7 subspecies)
B. ser. Grandes (2 species)
B. ser. Banksia (8 species)
B. ser. Crocinae (4 species)
B. ser. Prostratae (6 species, 3 varieties)
B. ser. Cyrtostylis (13 species)
B. ser. Tetragonae
B. lemanniana
B. caleyi
B. aculeata

Since 1998, Austin Mast has been publishing results of ongoing cladistic analyses of DNA sequence data for the subtribe Banksiinae. His analyses suggest a phylogeny that is rather different from previous taxonomic arrangements, but support the placement of B. aculeata alongside B. caleyi in a clade corresponding closely with B. ser. Tetragonae. [6] [7] [8] A 2013 molecular study by Marcel Cardillo and colleagues using chloroplast DNA and combining it with earlier results found that B. aculeata was sister to B. lemanniana and that B. caleyi was the next closest relative. [9]

Early in 2007 Mast and Thiele initiated a rearrangement by transferring Dryandra to Banksia, and publishing B. subg. Spathulatae for the species having spoon-shaped cotyledons; in this way they also redefined the autonym B. subg. Banksia. 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. aculeata is placed in B. subg. Banksia. [10]

Distribution and habitat

Distribution within Western Australia Banksia aculeata map.png
Distribution within Western Australia

B. aculeata is native to the foothills of the Stirling Range in the southwest of Western Australia, occurring at elevations between 250 and 500 m (825 and 1,650 ft), in shrubland in gravelly, clayish soils. [11] The annual rainfall is around 600 mm (24 in). [3] It is a fairly rare plant, with most populations consisting of fewer than 100 plants. [11] With fairly small populations and a narrow distribution, B. aculeata is considered rare, but is not currently classed as endangered because at least some populations are thought not to be under immediate threat. The Department of Environment and Conservation of the Western Australian State Government classes it as "Priority Two – Poorly Known" flora. [12]

Ecology

Like many plants in Australia's southwest, Banksia aculeata is adapted to an environment in which bushfire events are relatively frequent. Most Banksia species can be placed in one of two broad groups according to their response to fire: reseeders are killed by fire, but fire also triggers the release of their canopy seed bank, thus promoting recruitment of the next generation; resprouters survive fire, resprouting from a lignotuber or, more rarely, epicormic buds protected by thick bark. [13] B. aculeata is killed by fire because it possesses neither thick protective bark nor a lignotuber to reshoot from. It is serotinous—it accumulates a canopy seed bank that is released only in response to fire—so populations typically recover rapidly after a fire, but this strategy makes it dependent on a suitable fire regime. Plants take three to four years to reach flowering after a bushfire. [11]

Pollinators have not been observed, [11] and the flowering period is brief when compared with other banksias. However, the flowers appear when little else is in bloom, rendering it a valuable food source for animals. [4]

B. aculeata has been reported as susceptible to dieback from the soil-borne water mould Phytophthora cinnamomi , [14] but in a 2008 study this pathogen was found to have no direct impact on the species. As a result of this finding, together with the low percentage of populations infested or facing imminent infestation, the species was classed as having a very low extinction risk. [15]

Cultivation

Banksia aculeata grows slowly, generally taking five to six years to flower from seed, [3] though there is a report of it flowering in three years at Strathmerton in Victoria. [16] Regarding its potential as an ornamental plant, Alex George observes that the flowers are brightly coloured but have a short life and are obscured by the foliage, which is quite prickly. He nonetheless considers both the new foliage and the infructescence attractive. [17] This species can grow in a range of soil types so long as they provide good drainage. The nominal soil pH range is from 5.5 to 6.5. It prefers full sun, although it will grow in partly shaded situations, producing fewer flowers. It will tolerate light pruning. [3] [17]

Related Research Articles

<i>Banksia <span style="font-style:normal;">subg.</span> Banksia</i> Subgenus in the family Proteaceae

Banksia subg. Banksia is a valid botanic name for a subgenus of Banksia. As an autonym, it necessarily contains the type species of Banksia, B. serrata. Within this constraint, however, there have been various circumscriptions.

<i>Banksia petiolaris</i> Flowering plant of the family Proteaceae native to Western Australia

Banksia petiolaris is a rare species of flowering plant in the family Proteaceae native to Western Australia, where it is found in sandy soils in the south coastal regions from Munglinup east to Israelite Bay. It was first described by Victorian state botanist Ferdinand von Mueller in 1864, and no subspecies are recognised. B. petiolaris is one of several closely related species that will all grow as prostrate shrubs, with horizontal stems and thick, leathery upright leaves. Those of this species can be viable for up to 13 years—the longest-lived of any flowering plant recorded. It bears yellow cylindrical flower spikes, known as inflorescences, up to 16 cm high in spring. As the spikes age, they turn grey and develop up to 20 woody seed pods, known as follicles, each.

<i>Banksia sceptrum</i> Flowering shrub in the family Proteaceae from Western Australia

Banksia sceptrum, commonly known as the sceptre banksia, is a plant that grows in Western Australia near the central west coast from Geraldton north through Kalbarri to Hamelin Pool. It extends inland almost to Mullewa. First collected and grown by early settler James Drummond in Western Australia, it was described by Swiss botanist Carl Meissner in 1855.

<i>Banksia caleyi</i> Australian species of shrub, the red lantern banksia

Banksia caleyi, commonly known as Caley's banksia or red lantern banksia, is a species of woody shrub of the family Proteaceae native to Western Australia. It generally grows as a dense shrub up to 2 m (7 ft) tall, has serrated leaves and red, pendent (hanging) inflorescences which are generally hidden in the foliage. First described by Scottish naturalist Robert Brown in 1830, Banksia caleyi was named in honour of the English botanist George Caley. No subspecies are recognised. It is one of three or four related species with hanging inflorescences, which is an unusual feature within the genus.

<i>Banksia elderiana</i> Species of shrub in the family Proteaceae endemic to Western Australia

Banksia elderiana, commonly known as the swordfish banksia, is a species of shrub in the plant genus Banksia. It is a tangled, bushy shrub with stiff, serrated leaves and spikes of yellow flowers. It occurs in two disjunct areas in the Goldfields-Esperance region of Western Australia. One population extends over a large area from west of Kalgoorlie south to Ravensthorpe, with another population in the Great Victoria Desert north of the Queen Victoria Spring.

<i>Banksia lemanniana</i> Shrub of the family Proteaceae native to Western Australia

Banksia lemanniana, the yellow lantern banksia or Lemann's banksia, is a species of flowering plant in the family Proteaceae, native to Western Australia. It generally grows as an open woody shrub or small tree to 5 m (16 ft) high, with stiff serrated leaves and unusual hanging inflorescences. Flowering occurs over summer, the greenish buds developing into oval flower spikes before turning grey and developing the characteristic large woody follicles. It occurs within and just east of the Fitzgerald River National Park on the southern coast of the state. B. lemanniana is killed by bushfire and regenerates from seed.

<i>Banksia lindleyana</i> Species of shrub in the family Proteaceae from Western Australia

Banksia lindleyana, commonly known as the porcupine banksia, is a species of woody shrub in the genus Banksia of the family Proteaceae. It generally grows as a small shrub to 1 m (3 ft) high with long narrow serrated leaves, and bright yellow oval or round inflorescences. Flowering occurs in late summer, after which time the flower spikes age and turn to brown and then grey, and develop up to 70 follicles. It occurs in the vicinity of Kalbarri, Western Australia. Found on sandy soils, the plant serves as a pollinator for a variety of bird and animal species.

<i>Banksia nutans</i> Species of shrub in the family Proteaceae native to the south coast of Western Australia

Banksia nutans, commonly known as nodding banksia, is a species of shrub native to the south coast of Western Australia in the genus Banksia. Growing to a metre (3 ft) tall, it has pale blue-green fine-leaved foliage and unusual purple-brown inflorescences which hang upside down rather than grow upright like most other banksias.

<i>Banksia praemorsa</i> Species of shrub in the family Proteaceae native to Western Australia

Banksia praemorsa, commonly known as the cut-leaf banksia, is a species of shrub or tree in the plant genus Banksia. It occurs in a few isolated populations on the south coast of Western Australia between Albany and Cape Riche.

<i>Banksia telmatiaea</i> Australian shrub that grows in marshes and swamps

Banksia telmatiaea, commonly known as swamp fox banksia or rarely marsh banksia, is a shrub that grows in marshes and swamps along the lower west coast of Australia. It grows as an upright bush up to 2 metres tall, with narrow leaves and a pale brown flower spike, which can produce profuse quantities of nectar. First collected in the 1840s, it was not published as a separate species until 1981; as with several other similar species it was previously included in B. sphaerocarpa.

<i>Banksia violacea</i> Species of plant

Banksia violacea, commonly known as violet banksia, is a species of shrub or tree in the plant genus Banksia. It generally grows as a small shrub to 1.5 m (5 ft) high with fine narrow leaves, and is best known for its unusually coloured dark purple-violet inflorescences. The colour of the inflorescences, short leaves, and flattened follicles which are sticky when young, help identify this species from others in the field. It is found in low shrubland in southern regions of Western Australia from Esperance in the east to Narrogin in the west, growing exclusively in sandy soils.

<i>Banksia blechnifolia</i> Species of shrub in the family Proteaceae from Western Australia

Banksia blechnifolia is a species of flowering plant in the genus Banksia found in Western Australia. It was first described by Victorian state botanist Ferdinand von Mueller in 1864, and no subspecies are recognised. It gained its specific name as its leaves are reminiscent of a fern (Blechnum). B. blechnifolia is one of several closely related species that grow as prostrate shrubs, with horizontal stems and leathery, upright leaves. The red-brown flower spikes, known as inflorescences, are up to 20 centimetres (8 in) high and appear from September to November in the Australian spring. As the spikes age, each turns grey and develops as many as 25 woody seed pods, known as follicles.

<i>Banksia epica</i> Shrub found on the south coast of Western Australia

Banksia epica is a shrub that grows on the south coast of Western Australia. A spreading bush with wedge-shaped serrated leaves and large creamy-yellow flower spikes, it grows up to 3½ metres (11½ ft) high. It is known only from two isolated populations in the remote southeast of the state, near the western edge of the Great Australian Bight. Both populations occur among coastal heath on cliff-top dunes of siliceous sand.

<i>Banksia <span style="font-style:normal;">ser.</span> Quercinae</i> Taxonomic series in the family Proteaceae

Banksia ser. Quercinae is a valid botanic name for a series of Banksia. First published by Carl Meissner in 1856, the name has had three circumscriptions.

<i>Banksia <span style="font-style:normal;">ser.</span> Cyrtostylis</i> Taxonomic series in the genus Banksia

Banksia ser. Cyrtostylis is a taxonomic series within the plant genus Banksia. First published at sectional rank by George Bentham in 1870, it was demoted to a series by Alex George in 1981. The name has had three circumscriptions.

<i>Banksia <span style="font-style:normal;">ser.</span> Banksia</i> Autonymous series in the genus Banksia

Banksia ser. Banksia is a valid botanic name for a series of Banksia. As an autonym, it necessarily contains the type species of Banksia, B. serrata. Within this constraint, however, there have been various circumscriptions.

<i>Banksia acanthopoda</i> Species of shrub in Western Australia

Banksia acanthopoda is a species of shrub in the family Proteaceae. It grows as a small spreading shrub to 2 m high and has prickly leaves and yellow composite flower heads, called inflorescences, composed of 50 to 60 individual yellow flowers. Flowering takes place in the southern hemisphere winter. Endemic to Western Australia, it occurs only in a few populations in the vicinities of Woodanilling, Katanning and Darkan. Because of its rarity, it is classed as "Priority Two" conservation flora by Western Australia's Department of Environment and Conservation.

Banksia acuminata is a rare prostrate shrub endemic to south-west Western Australia. It was published in 1848 as Dryandra preissii, but transferred into Banksia as B. acuminata in 2007.

<span class="mw-page-title-main">George's taxonomic arrangement of Banksia</span> 1981 and 1996 arrangements of the Australian endemic plant genus Banksia

Alex George's taxonomic arrangement of Banksia was the first modern-day arrangement for that genus. First published in 1981 in the classic monograph The genus Banksia L.f. (Proteaceae), it superseded the arrangement of George Bentham, which had stood for over a hundred years. It was overturned in 1996 by Kevin Thiele and Pauline Ladiges, but restored by George in 1999. A recent publication by Austin Mast and Kevin Thiele suggests that it will soon be overturned again.

<i>Banksia <span style="font-style:normal;">subser.</span> Cratistylis</i> Subseries in the family Proteaceae

Banksia subser. Cratistylis is a valid botanic name for a subseries of Banksia. It was first published by Kevin Thiele in 1996 but discarded by Alex George in 1999.

References

  1. "Banksia aculeata". Australian Plant Census. Retrieved 26 March 2020.
  2. 1 2 3 George, Alex S. (1999). "Banksia". In Wilson, Annette (ed.). Flora of Australia. Vol. 17B. Collingwood, Victoria: CSIRO Publishing on behalf of the Australian Biological Resources Study. pp. 175–251. ISBN   0-643-06454-0.
  3. 1 2 3 4 5 Collins, Kevin; Collins, Kathy; George, Alex S. (2008). Banksias. Melbourne, Victoria: Bloomings Books Pty Ltd. ISBN   978-1-876473-68-6.
  4. 1 2 3 4 5 6 George, Alex S. (1981). "The Genus Banksia L.f. (Proteaceae)". Nuytsia . 3 (3): 239–473 [386–89]. doi:10.58828/nuy00060. ISSN   0085-4417. S2CID   196677407.
  5. 1 2 Thiele, Kevin; Ladiges, Pauline Y. (1996). "A Cladistic Analysis of Banksia (Proteaceae)". Australian Systematic Botany . 9 (5): 661–733. doi:10.1071/SB9960661.
  6. Mast, Austin R. (1998). "Molecular Systematics of Subtribe Banksiinae (Banksia and Dryandra; Proteaceae) Based on cpDNA and nrDNA Sequence Data: Implications for Taxonomy and Biogeography". Australian Systematic Botany. 11 (4): 321–42. doi:10.1071/SB97026.
  7. Mast, Austin R.; Givnish, Thomas J. (2002). "Historical Biogeography and the Origin of Stomatal Distributions in Banksia and Dryandra (Proteaceae) Based on Their cpDNA Phylogeny". American Journal of Botany . 89 (8): 1311–23. doi: 10.3732/ajb.89.8.1311 . PMID   21665734.
  8. Mast, Austin R.; Jones, Eric H.; Havery, Shawn P. (2005). "An Assessment of Old and New DNA Sequence Evidence for the Paraphyly of Banksia with Respect to Dryandra (Proteaceae)". Australian Systematic Botany. 18 (1): 75–88. doi:10.1071/SB04015.
  9. Cardillo, Marcel; Pratt, Renae (2013). "Evolution of a Hotspot Genus: Geographic Variation in Speciation and Extinction Rates in Banksia (Proteaceae)". BMC Evolutionary Biology. 13 (1): 155. Bibcode:2013BMCEE..13..155C. doi: 10.1186/1471-2148-13-155 . PMC   3751403 . PMID   23957450.
  10. Mast, Austin R.; Thiele, Kevin (2007). "The Transfer of Dryandra R.Br. to Banksia L.f. (Proteaceae)". Australian Systematic Botany . 20: 63–71. doi:10.1071/SB06016.
  11. 1 2 3 4 Taylor, Anne; Hopper, Stephen (1988). The Banksia Atlas (Australian Flora and Fauna Series Number 8). Canberra, Australian Capital Territory: Australian Government Publishing Service. pp. 48–49. ISBN   0-644-07124-9.
  12. "Banksia aculeata A.S.George". FloraBase . Western Australian Government Department of Biodiversity, Conservation and Attractions.
  13. Lamont, Byron B.; Markey, Adrienne (1995). "Biogeography of Fire-killed and Resprouting Banksia Species in South-western Australia". Australian Journal of Botany. 43 (3): 283–303. doi:10.1071/BT9950283.
  14. Shearer, B.L.; Crane, C.E.; Cochrane, J.A. (2013). "Variation in Susceptibility of Banksia (including Dryandra) to Phytophthora cinnamomi". Australasian Plant Pathology. 42 (3): 351–61. Bibcode:2013AuPP...42..351S. doi:10.1007/s13313-012-0189-4. S2CID   11713920.
  15. Barrett, Sarah; Shearer, B. L.; Crane, C. E.; Cochrane, A. (2008). "An Extinction-risk Assessment Tool for Flora Threatened by Phytophthora cinnamomi". Australian Journal of Botany. 56 (6): 477–86. doi:10.1071/BT07213. S2CID   85118645.
  16. Kennedy, Paul (2003). "Growing Banksias in Northern Victoria". Australian Plants Online. Retrieved 27 November 2016.
  17. 1 2 George, Alex S. (1987). The Banksia Book (Second Edition). Kenthurst, New South Wales: Kangaroo Press (in association with the Society for Growing Australian Plants). ISBN   0-86417-006-8.

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