Banksia verticillata

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Granite banksia
A New Holland honeyeater feeds on one of several cylindrical golden flower spikes partly hidden by foliage.
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Proteales
Family: Proteaceae
Genus: Banksia
Species:
B. verticillata
Binomial name
Banksia verticillata
Distribution of B. verticillata in Western Australia.

Banksia verticillata, commonly known as granite banksia or Albany banksia, is a species of

southwest of Western Australia and can reach up to 3 m (10 ft) in height. It can grow taller to 5 m (16 ft) in sheltered areas, and much smaller in more exposed areas. This species has elliptic green leaves and large, bright golden yellow inflorescences or flower spikes, appearing in summer and autumn. The New Holland honeyeater (Phylidonyris novaehollandiae) is the most prominent pollinator, although several other species of honeyeater
, as well as bees, visit the flower spikes.

A declared vulnerable species, it occurs in two disjunct populations on granite outcrops along the south coast of Western Australia, with the main population near Albany and a smaller population near Walpole, and is threatened by dieback (Phytophthora cinnamomi) and aerial canker (Zythiostroma). B. verticillata is killed by bushfire and new plants regenerate from seed afterwards. Populations take over a decade to produce seed and fire intervals of greater than twenty years are needed to allow the canopy seed bank to accumulate.

Description

Banksia verticillata grows as a spreading, bushy shrub with many branches up to 3 m (10 ft) high, but can reach 5 m (16 ft) high in sheltered locations.

elliptic in shape with entire (straight) recurved margins. They are initially hairy and become smooth with maturity, although their undersides remain covered with white hair.[2] The golden-yellow inflorescences appear in summer and autumn (January to April) and are 8–20 cm (3–8 in) high and 6.5 cm (2.6 in) wide. The smooth pistils are 3–3.5 cm long and hooked at the end.[4] Individual flowers open from the base of the flower spike, the wave of anthesis moving up the inflorescence. Occasionally, flowers on exposed parts may open early. It takes around 9.5 days for all flowers to open, and rates are similar during the day and night.[5] The inflorescences age to grey and the individual old flowers linger for some time before falling. Up to 100 small woody follicles may follow on old flower spikes. Measuring 1.1–1.5 cm wide, 3–4 mm wide, and jutting out 2–3 mm from the spike, they open after several years, releasing the seed.[4] Follicles more commonly appear in the middle third of the spike. The reasons for this are unknown, although timing of visits by pollinators or some anatomical factor may be relevant.[2]

Taxonomy

Discovery and naming

King George's Sound, view on the peninsula to the north of Peak Head, a field sketch executed by William Westall in December 1801. The sprawling shrub in the foreground has been tentatively identified as B. verticillata, which would make this sketch, together with another Westall sketch thought to depict B. verticillata, the earliest known drawings of the species.[6]

The earliest known botanical collection of B. verticillata was made by Scottish surgeon and naturalist

King George Sound in September and October 1791. As a result of this collection the species was introduced into cultivation in England,[7]
yet it did not result in formal publication of the species.

The next known collection was in December 1801, during the visit of

Admiralty.[6]

Brown formally described and named the species in his 1810

specific epithet, but it is accepted that the name derives from the Latin verticillatus ("whorled"), in reference to the whorled leaf arrangement.[16]

No

L.f., on the grounds that the name Banksia had previously been published in 1776 as Banksia J.R.Forst & G.Forst, referring to the genus now known as Pimelea. Kuntze proposed Sirmuellera as an alternative, referring to this species as Sirmuellera verticillata.[18] This application of the principle of priority was largely ignored by Kuntze's contemporaries,[19] and Banksia L.f. was formally conserved and Sirmuellera rejected in 1940.[20]

Infrageneric placement

Banksia verticillata flower spike

In

Stephan Endlicher in 1847, with B. verticillata remaining between the same two species as in Brown's sequence.[21] A more detailed arrangement was published by Carl Meissner in 1856. Eubanksia was demoted to sectional rank, and divided it into four series. B. verticillata was placed in series Salicinae because its leaves are more or less linear, and have white undersides.[22] Based as they were on leaf characters, Meissner's series were highly heterogeneous,[15] and George Bentham discarded them all in his 1870 revision of Banksia. B. verticillata was instead placed in a new section, Oncostylis, because of its hooked styles.[23]
This arrangement would stand for over a century.

For many years there was confusion between B. verticillata and B. littoralis (swamp banksia). Until 1984, the latter was circumscribed as encompassing what is now Banksia seminuda (river banksia), which has whorled leaves like B. verticillata. Thus it was easy to perceive B. verticillata as falling within the range of variation of this broadly defined species. The confusion was largely cleared up once B. seminuda was recognised as a distinct taxon.[24]

Alex George published a new taxonomic arrangement of Banksia in his landmark 1981 monograph The genus Banksia L.f. (Proteaceae). Endlicher's Eubanksia became B. subg. Banksia, and was divided into three sections, one of which was Oncostylis. Oncostylis was further divided into four series, with B. verticillata placed in series Spicigerae because its inflorescences are cylindrical.[4]

In 1996,

polyphyletic, but series Spicigerae was inferred to be monophyletic, and B. verticillata appeared in a succession of clades with the species previously identified as its closest relatives: first B. littoralis, then B. seminuda, then B. brownii, and finally B. occidentalis (red swamp banksia):[25]

This clade became the basis of Thiele and Ladiges'

opposite-decussate seedling leaves and adult leaves in true whorls."[25] This arrangement stood until 1999, when George largely reverted to his 1981 arrangement in his monograph for the Flora of Australia series. Under George's taxonomic arrangement of Banksia, B. verticillata's taxonomic placement may be summarised as follows:[4]

Banksia
B. subg. Banksia
B. sect. Banksia (9 series, 50 species, 9 subspecies, 3 varieties)
B. sect. Coccinea
(1 species)
B. sect. Oncostylis
B. ser. Spicigerae (7 species, 2 subspecies, 4 varieties)
B. spinulosa (4 varieties)
B. ericifolia (2 subspecies)
B. verticillata
B. seminuda
B. littoralis
B. occidentalis
B. brownii
B. ser. Tricuspidae
(1 species)
B. ser. Dryandroideae (1 species)
B. ser. Abietinae (13 species, 2 subspecies, 9 varieties)
B. subg. Isostylis (3 species)

More recent molecular research by Austin Mast and colleagues provide further support of B. verticillata's placement among its nearest relatives, but these do not appear to be closely related to the remaining members of B. ser. Spicigerae, but rather occur in a clade that is sister (next closest relative) to B. nutans:[26]

(B. seminuda is omitted because it was not sampled in the study, not because it occurs elsewhere in the cladogram.)

Distribution and habitat

Banksia verticillata is found in scattered populations in two disjunct segments: one clustered around

heath.[2]

Ecology

See also: Ecology of Banksia

The New Holland honeyeater (Phylidonyris novaehollandiae) is a major visitor and pollinator of Banksia verticillata. These birds can travel 15 m (50 ft) between inflorescences in a feeding session, and preferentially choose flower spikes with partly opened flowers. Other honeyeater species observed, the white-cheeked honeyeater (Phylidonyris nigra) and western spinebill (Acanthorhynchus superciliosus), visit this species to a much lesser extent.[2] The brown honeyeater (Lichmera indistincta) has also been recorded as a visitor.[28] Small mammals are not major pollinators, although bush rats (Rattus fuscipes) and house mice (Mus musculus) have been recorded. Honey bees (Apis mellifera) visit flower spikes but are not effective pollinators.[2][5]

B. verticillata is significantly threatened by at least three microorganisms. Several populations have reduced or vanished from dieback (Phytophthora cinnamomi), such as those at Two Peoples Bay Nature Reserve and Gull Rock National Park. The honey fungus Armillaria luteobubalina has killed plants in Torndirrup National Park, and aerial canker (Zythiostroma) has decimated populations at Waychinicup National Park east of Albany.[2]

B. verticillata plants are generally killed by fire and regenerate from seed. A

field study after a mild fire in Torndirrup National Park published in 1994 found that plants burnt by fire were ten times as likely to have seedlings come up under their crown as unburnt plants (with an average of 25.2 seedlings per burnt plant), and burnt spikes released double the number of seeds as unburnt spikes. Despite this, interfire recruitment (seedlings arising between fires) has also been recorded, and might be more common than in other Banksia species. Observations at several of the populations showed many plants produced their first seed anywhere from 13 to 17 years of age, leading to a recommendation of 20 years between fires to allow seed banks to accumulate.[2] If fire occurs too frequently, plants are burned before reaching maturity or before they have produced sufficient seed to ensure regeneration of the population. This may cause a population decline or even local extinction. Too long a time between fires also causes population decline, as more plants die of natural attrition without releasing their seed, resulting in seed wastage.[29]

Conservation

Banksia verticillata growing in a garden in Albany

Banksia verticillata has been declared vulnerable under the federal

foliar spraying of phosphite adversely affects root and shoot growth.[34]

Cultivation

Banksia verticillata is seldom seen in

germinate.[37]

References

  1. ^ a b Banksia verticillata — Granite Banksia, Albany Banksia, River Banksia, Species Profile and Threats Database, Department of the Environment and Heritage, Australia.
  2. ^ a b c d e f g h i j k l Kelly, Anne E.; Coates, David (1995). Population dynamics, reproductive biology and conservation of Banksia brownii and Banksia verticillata. ANCA ESP Project No. 352. Como, Western Australia: Department of Environment and Conservation, Government of Western Australia.
  3. ^ Atkins, K. J. (1998). Conservation Statements for threatened flora within the regional forest agreement region for Western Australia. Como, Western Australia: Department of Environment and Conservation, Government of Western Australia. pp. 1–95.
  4. ^
    ISBN 0-643-06454-0
    .
  5. ^ a b Rees, R.G.; Collins, B.G. (1994). Reproductive biology and pollen vectors of the rare and endangered Banksia verticillata R.Br. pp. 1–35. School of Environmental Biology. Curtin University of Technology, Perth.
  6. ^
    ISBN 1-920843-20-5
    .
  7. ISBN 1-4446-8481-7
    . The individual here given, remarkable for its verticillate entire leaves, of a pure white on the under side, was discovered by Mr Menzies in New Holland, and brought by him to our gardens in 1794.
  8. ^ "Banksia verticillata". Robert Brown's Australian Botanical Specimens, 1801–1805 at the BM. Western Australian Herbarium, Department of Environment and Conservation, Government of Western Australia. Retrieved 19 December 2009.
  9. doi:10.1111/1467-8748.00380
    .
  10. ISBN 0-642-56817-0.{{cite book}}: CS1 maint: others (link
    )
  11. ISSN 0068-2306. {{cite book}}: |journal= ignored (help
    )
  12. ISBN 0-85091-346-2
    .
  13. S2CID 140671788
    .
  14. ^
    doi:10.1111/j.1096-3642.1810.tb00013.x
    .
  15. ^
    ISSN 0085-4417
    .
  16. ISBN 978-1-876473-58-7
    .
  17. ^ "Banksia verticillata R.Br". Australian Plant Name Index (APNI), IBIS database. Centre for Plant Biodiversity Research, Australian Government.
  18. ^ Kuntze, Otto (1891). Revisio generum plantarum. Vol. 2. Leipzig: Arthur Felix. pp. 581–582.
  19. JSTOR 4107078
    .
  20. JSTOR 4111642
    .
  21. ^ Endlicher, Stephan (1847). "Pars II. CXIII". Genera Plantarum Secundum Ordines Naturales Disposita: Supplement IV (in Latin). pp. 88–89. Retrieved 8 September 2010.
  22. Prodromus systematis naturalis regni vegetabilis
    . Vol. 14. Paris: Sumptibus Sociorum Treuttel et Wurtz.
  23. ^ Bentham, George (1870). "Banksia". Flora Australiensis. Vol. 5. London: L. Reeve & Co. pp. 541–62.
  24. ISBN 0-85179-864-0
    .
  25. ^
    doi:10.1071/SB9960661
    .
  26. PMID 21665734
    .
  27. ISBN 0-644-07124-9
    . pp. 240–41
  28. ISBN 0-643-05006-X
    .
  29. ISBN 0-949324-66-3
    .
  30. Department of Biodiversity, Conservation and Attractions
    .
  31. ^ a b "Approved Conservation Advice for Banksia verticillata (Granite Banksia)" (PDF). Department of the Environment, Water, Heritage and the Arts website. Canberra, ACT: Department of the Environment, Water, Heritage and the Arts, Australian Government. 26 March 2008. Retrieved 14 September 2010.
  32. ISSN 0815-4465
    .
  33. S2CID 7742365
    .
  34. doi:10.1071/BT01018
    .
  35. ISBN 0-85091-143-5
    .
  36. ISSN 0728-2893
    .
  37. ISBN 0-643-09298-6
    .

External links

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