Banksia violacea

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Violet banksia
Banksia violacea 3 email.jpg
Inflorescence of Banksia violacea
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Proteales
Family: Proteaceae
Genus: Banksia
Species:
B. violacea
Binomial name
Banksia violacea

Banksia violacea, commonly known as violet banksia, is a species of shrub or tree in the plant genus Banksia (family Proteaceae). 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. [2] 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.

Contents

First described in 1927 by the West Australian botanist Charles Gardner, the species was at one stage considered a variety of B. sphaerocarpa . Although there are no recognised subspecies or varieties, both lignotuberous and nonlignotuberous forms exist for Banksia violacea. Wasps, ants and flies have been recorded visiting flower spikes. Banksia violacea is classified as Not Threatened under the Wildlife Conservation Act of Western Australia. Regarded as of little value to floriculture, it is rarely cultivated.

Description

Typical shrubby habit Banksia violacea.jpg
Typical shrubby habit

Banksia violacea grows as a shrub up to 1.5 m (5 ft) tall, with narrow leaves 1–2 cm (0.4–0.8 in) long and about 0.15 cm (0.06 in) wide. [2] New growth occurs in summer, and flowering ranges from November to April with a peak in February, but can be irregular in timing. [3] Flowers arise from typical Banksia "flower spikes", and the inflorescences are made up of hundreds of pairs of flowers densely packed in a spiral around a woody axis. Roughly spherical with a diameter of 2–3 cm (0.8–1.2 in), the flower spikes arise from lateral stems lie partly within the foliage. Unusually for Banksia species, the inflorescences are often violet in colour, ranging anywhere from a dark violet-black through various combinations of violet and greenish-yellow in less pigmented blooms. Each flower consists of a tubular perianth made up of four fused tepals, and one long wiry style. The styles are hooked rather than straight, and are initially trapped inside the upper perianth parts, but break free at anthesis. The old flowers gradually fade to brown. The fruiting structure or follicle is a stout woody "cone", with a hairy appearance caused by the persistence of old withered flower parts. [4] These follicles are crowded around the globular spike (called an infructescence at this point) and are oval to rhomboid, although the crowding makes some irregularly shaped. They measure 1–2.5 cm (0.4–1 in) long, 0.6 cm (0.2 in) high and 0.8–2.2 cm (0.3–0.9 in) wide. They are quite flattened and lack a ridge along the valve line. When young, the follicles are greenish in colour and slightly sticky, and covered in fine white hairs, fading to tan or grey with age. They open with fire, releasing a winged wedge-shaped (cuneate) seed 2–2.5 cm (0.8–1 in) long. The mottled dark grey seed body is falcate (crescent-shaped) and measures 1.2–1.8 cm (0.5–0.7 in) long and 0.2–0.25 cm (0.1 in) wide, with a flattened dark brown wing 1.1–1.7 cm (0.4–0.5 in) wide. The woody separator has the same dimensions as the seed. [2]

The bright green cotyledon leaves of the seedlings are oblong to linear in shape and measure 1.5 cm (0.6 in) long by 0.3 cm (0.1 in) wide. The greenish red hypocotyl is hairy, as are the stems of young plants. The hairy seedling leaves are crowded and oppositely arranged. They measure 0.7–1.3 cm (0.2–0.5 in) in length and have recurved margins. Young plants often begin branching within their first year of life. [2]

Taxonomy

Inflorescence in early bud Banksia violacea bud cropped.jpg
Inflorescence in early bud

The type specimen of Banksia violacea was collected by the West Australian botanist Charles Gardner on 14 December 1926 in the vicinity of Lake Grace. The following year, he published a description of the species in Journal and Proceedings of the Royal Society of Western Australia . [5] He placed it in section Oncostylis of Bentham's taxonomic arrangement of Banksia, giving it the specific epithet violacea in reference to the violet flowers. Thus the full name of the species, with author citation, is Banksia violacea C.A.Gardner. [6] The species has been considered a variety of B. sphaerocarpa (Fox Banksia); [7] this view was published by William Blackall in his 1954 How to know Western Australian wildflowers . He considered B. violacea to be a variety of B. sphaerocarpa with violet flowers. [8] This description was an invalid publication, however, and a nomen nudum . In 1981 Alex George declared Banksia sphaerocarpa var. violacea Blackall a nomenclatural synonym of B. violacea. [2] [6]

In George's 1981 arrangement, B. violacea was placed in subgenus Banksia because its inflorescence is a typical Banksia "flower spike"; section Oncostylis because of its hooked styles; and series Abietinae because its inflorescence is roughly spherical. It was placed in taxonomic sequence between B. incana (Hoary Banksia) and B. meisneri (Meissner's Banksia). [2]

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. B. ser. Abietinae was found to be very nearly monophyletic and so it was retained. It further resolved into four subclades, so Thiele and Ladiges split it into four subseries. B. violacea appeared in the last of these: [9]

Young follicles are green, and slightly sticky at this stage. Banksia violacea 9 email.jpg
Young follicles are green, and slightly sticky at this stage.

B. violacea

B. laricina

B. incana

B. tricuspis

B. pulchella

B. meisneri var. meisneri

B. meisneri var. ascendens

This clade became the basis of B. subseries Longistyles, which Thiele defined as containing those taxa with very long and slender styles, smoothly convex perianth limbs without a costal ridge, and thickened margins. In accordance with their cladogram, their arrangement placed B. violacea first in taxonomic sequence, followed by B. laricina (Rose-fruited Banksia). [9] However, Thiele and Ladiges' arrangement was not accepted by George, who, questioning the emphasis on cladistics, rejected most of their changes in his 1999 arrangement, restored B. series Abietinae to his broader 1981 definition, and abandoned all of Thiele and Ladiges' subseries. George commented that the species has no close relatives, being "loosely allied" to B. sphaerocarpa (Fox Banksia) and B. telmatiaea (Swamp Fox Banksia). Despite this, the sequence of the series was altered so that B. violacea fell between B. scabrella (Burma Road Banksia) and B. incana, and its placement in George's arrangement may be summarised as follows: [4]

Older follicles Banksia violacea 4 email.jpg
Older follicles
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. ser. Tricuspidae (1 species)
B. ser. Dryandroideae (1 species)
B. ser. Abietinae
B. sphaerocarpa (3 varieties)
B. micrantha
B. grossa
B. telmatiaea
B. leptophylla (2 varieties)
B. lanata
B. scabrella
B. violacea
B. incana
B. laricina
B. pulchella
B. meisneri (2 subspecies)
B. nutans (2 varieties)
B. subg. Isostylis (3 species)

Since 1998, an American botanist, 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 very greatly different from George's arrangement, and somewhat different from Thiele and Ladiges'. With respect to B. violacea, Mast's results agree with its placement near B. laricina and B. incana, placing it in a clade with these two species and B. sphaerocarpa var. dolichostyla (treated at species rank as B. dolichostyla). [10] However, Thiele's B. subseries Longistyles appears to be polyphyletic, as do both definitions of B. ser. Abietinae—that is, none form a natural grouping. [10] [11] [12]

Paler inflorescence and leaves Banksia violacea 12 cropped.jpg
Paler inflorescence and leaves

B. dolichostyla

B. violacea

B. laricina

B. incana

Early in 2007, Mast and Thiele initiated a rearrangement of Banksia by merging Dryandra into it, and publishing B. subgenus Spathulatae for the taxa having 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. violacea is placed in B. subgenus Spathulatae. [13]

Distribution and habitat

Distribution of B. violacea, shown on a map of Western Australia's biogeographic regions. Banksia violacea map.png
Distribution of B. violacea, shown on a map of Western Australia's biogeographic regions.

B. violacea occurs in southern regions of Western Australia, from Woodanilling to Esperance and as far north as Hyden. [3] [4] This distribution includes areas of the Avon Wheatbelt, Esperance Plains and Mallee biogeographic regions. [14] It favours white sandy soils, often overlying laterite, clay or quartzite. It usually grows among heath and shrublands, associated with mallee eucalypts and Banksia sphaerocarpa var. caesia. [2] Banksia violacea is classified as Not Threatened under the 1950 Wildlife Conservation Act of Western Australia. [14]

Ecology

Like most other Proteaceae, Banksia violacea has proteoid roots, roots with dense clusters of short lateral rootlets that form a mat in the soil just below the leaf litter. These enhance solubilisation of nutrients, thus allowing their uptake in low-nutrient soils such as the phosphorus-deficient soils of Australia. [15] B. violacea is highly susceptible to Phytophthora cinnamomi dieback. [16]

Banksia violacea is one of a small number of Banksia species that has both lignotuberous and non-lignotuberous populations. In both cases, plants are adapted to release their aerial seed bank following a bushfire, ensuring seedlings are established on clear and relatively fertile ground; however the possession of a lignotuber makes plants much less reliant on fire regime for population maintenance and regeneration, as maternal plants are not killed by bushfire, but resprout from below ground level. Lignotuberous plants generally occur among the north-eastern populations, [2] [17] in the vicinity of Woodanilling. [3] An investigation into the biogeography of these plants failed to find any vegetative, climatic or other environmental factors associated with the possession of a lignotuber. [18]

Banksia flowerheads in general play host to a variety of birds, mammals and insects. [19] However, only wasps, ants and flies were recorded visiting flower spikes during observations for The Banksia Atlas in the mid-1980s. [3]

Cultivation

Banksia violacea is rarely cultivated. It is a slow-growing plant that tends to become untidy with age, and generally does not flower until four to five years after sprouting from seed. Flowers are an unusual colour, but occur within the bush where they grow within and are usually obscured by foliage. It tolerates light pruning not below the green foliage, except for the variant with a lignotuber, which may be pruned heavily. George recommends a sunny position in light, sandy soil. [17] Professor Margaret Bernard Sedgley of the Waite Institute suggests the species is of no value to floriculture, as the inflorescences are too small and obscured by the foliage, although she does add that the purple colour may be a worthwhile character to select for in plant breeding. [20] Seeds do not require any treatment, and take 19 to 50 days to germinate. [21]

See also

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.

Taxonomy of <i>Banksia</i> Classification of the plant genus Banksia

As with other flowering plants, the taxonomy of Banksia has traditionally been based on anatomical and morphological properties of the Banksia flower, fruiting structure and seed, along with secondary characteristics such as leaf structure and growth habit. Increasingly, molecular evidence from DNA is providing important new insights into relationships within the genus and between this and other genera in the Proteaceae.

<i>Banksia aculeata</i> Shrub of the family Proteaceae native to the southwest of Western Australia.

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.

<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 grossa</i> Shrub in the family Proteaceae endemic to Australia

Banksia grossa is a species of shrub in the family Proteaceae and is endemic to Southwest Australia. It is one of fourteen species of banksia of the series Abietinae, all of which bear predominantly cylindrical or oval inflorescences. Collected in 1965, it was first formally described in 1981 by Alex George. Its thick leaves and large seeds distinguish it from other members of the Abietinae, and are the basis of its species name.

<i>Banksia media</i> Shrub native to Western Australia

Banksia media, the southern plains banksia or golden stalk banksia, is a species of flowering plant in the family Proteaceae. An evergreen shrub, it occurs on the south coast of Western Australia between Albany and Israelite Bay, where it is a common plant. A many-branched bush with wedge-shaped serrated leaves and large golden-yellow flower spikes, known as inflorescences, it grows up to 10 metres (30 ft) high.

<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 scabrella</i> Species of woody shrub in the family Proteaceae from Western Australia

Banksia scabrella, commonly known as the Burma Road banksia, is a species of woody shrub in the genus Banksia. It is classified in the series Abietinae, a group of several species of shrubs with small round or oval inflorescences. It occurs in a number of isolated populations south of Geraldton, Western Australia, with the largest population being south and east of Mount Adams. Found on sandy soils in heathland or shrubland, it grows to 2 m (7 ft) high and 3 m (10 ft) across with fine needle-like leaves. Appearing in spring and summer, the inflorescences are round to oval in shape and tan to cream with purple styles. Banksia scabrella is killed by fire and regenerates by seed.

<i>Banksia sphaerocarpa</i> Shrub or tree in the family Proteaceae widely distributed across the southwest of Western Australia

Banksia sphaerocarpa, commonly known as the fox banksia or round-fruit banksia, is a species of shrub or tree in the plant genus Banksia. It is generally encountered as a 1–2 m (3.3–6.6 ft) high shrub, and is usually smaller in the north of its range. This species has narrow green leaves, and brownish, orange or yellow round flower spikes which may be seen from January to July. It is widely distributed across the southwest of Western Australia, growing exclusively in sandy soils. It is usually the dominant plant in scrubland or low woodland. It is pollinated by, and is a food source for, birds, mammals, and insects.

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

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

<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 spinulosa <span style="font-style:normal;">var.</span> collina</i> Variety of shrub in the family Proteaceae from the east coast of Australia

Banksia spinulosa var. collina is a shrub that grows along the east coast of Australia, in Queensland and New South Wales. Commonly known as Hill Banksia or Golden Candlesticks, it is a taxonomic variety of B. spinulosa. It is a popular garden plant widely sold in nurseries.

<i>Banksia spinulosa <span style="font-style:normal;">var.</span> spinulosa</i> Variety of shrub in the family Proteaceae from the east coast of Australia

Banksia spinulosa var. spinulosa is a shrub that grows along the east coast of Australia, in Queensland and New South Wales.

<i>Banksia spinulosa <span style="font-style:normal;">var.</span> cunninghamii</i> Variety of shrub in the family Proteaceae from the east coast of Australia

Banksia spinulosa var. cunninghamii, sometimes given species rank as Banksia cunninghamii, is a shrub that grows along the east coast of Australia, in Victoria and New South Wales. It is a fast-growing non-lignotuberous shrub or small tree infrequently cultivated.

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

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

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

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

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

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

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

Banksia ser. Ochraceae is a valid botanic name for a taxonomic series within the plant genus Banksia. It was published by Kevin Thiele in 1996, but discarded by Alex George in 1999.

References

  1. ↑ "Banksia violacea". Australian Plant Name Index (APNI), IBIS database. Canberra, Australian Capital Territory: Centre for Plant Biodiversity Research, Australian Government. Retrieved 26 November 2012.
  2. 1 2 3 4 5 6 7 8 George, Alex S. (1981). "The Genus Banksia L.f. (Proteaceae)". Nuytsia . 3 (3): 239–473.
  3. 1 2 3 4 Taylor, Anne; Hopper, Stephen (1988). The Banksia Atlas (Australian Flora and Fauna Series Number 8). Canberra: Australian Government Publishing Service. ISBN   0-644-07124-9.[ page needed ]
  4. 1 2 3 George, Alex S. (1999). "Banksia". In Wilson, Annette (ed.). Flora of Australia. Vol. 17B. CSIRO Publishing / Australian Biological Resources Study. pp. 175–251. ISBN   0-643-06454-0.
  5. ↑ Gardner, Charles A. (1927). "Contributiones florae Australiae occidentalis VI" [Contributions to the flora of western Australia 6]. Journal and Proceedings of the Royal Society of Western Australia . 13: 61–68.
  6. 1 2 "Banksia violacea C.A.Gardner". Australian Plant Name Index (APNI), IBIS database. Centre for Plant Biodiversity Research, Australian Government. Retrieved June 26, 2010
  7. ↑ Holliday, Ivan; Watton, Geoffrey (1975). A Field Guide to Banksias. Adelaide: Rigby. p. 136. ISBN   0-85179-864-0.
  8. ↑ Blackall, William E. (1954). B. J. Grieve (ed.). How to know Western Australian wildflowers. Nedlands: University of Western Australia Press. ISBN   1-875560-29-7.[ page needed ]
  9. 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.
  10. 1 2 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): 1311–1323. doi: 10.3732/ajb.89.8.1311 . PMID   21665734.
  11. ↑ 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): 321–342. doi:10.1071/SB97026.
  12. ↑ 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. CSIRO Publishing / Australian Systematic Botany Society. 18 (1): 75–88. doi:10.1071/SB04015.
  13. ↑ Mast, Austin R.; Thiele, Kevin (2007). "The transfer of Dryandra R.Br. to Banksia L.f. (Proteaceae)". Australian Systematic Botany. 20 (1): 63–71. doi:10.1071/SB06016.
  14. 1 2 3 "Banksia violacea C.A.Gardner". FloraBase . Western Australian Government Department of Biodiversity, Conservation and Attractions. Retrieved June 26, 2010
  15. ↑ Lamont, Byron B. (1993). "Why are hairy root clusters so abundant in the most nutrient-impoverished soils of Australia?". Plant and Soil . 156 (1): 269–272. doi:10.1007/BF00025034. S2CID   32550881.
  16. ↑ "Part 2, Appendix 4: The responses of native Australian plant species to Phytophthora cinnamomi" (PDF). Management of Phytophthora cinnamomi for Biodiversity Conservation in Australia. Department of the Environment and Heritage, Australian Government. 2006. Archived from the original (PDF) on 5 March 2011. Retrieved 22 April 2009.
  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.[ page needed ]
  18. ↑ Lamont, Byron; 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.
  19. ↑ "Banksia L.f." FloraBase . Western Australian Government Department of Biodiversity, Conservation and Attractions. Retrieved June 24, 2010.
  20. ↑ Sedgley, Margaret (1998). "Banksia: New proteaceous cut flower crop" (PDF). Horticultural Reviews. 22: 1–25.
  21. ↑ Sweedman, Luke; Merritt, David, eds. (2006). Australian seeds: a guide to their collection, identification and biology . Collingwood, Victoria: CSIRO Publishing. p.  203. ISBN   0-643-09298-6.

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