Banksia violacea
Encyclopedia
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 inflorescence
s. 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.
First described in 1927 by 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 lignotuber
ous 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.
", and the inflorescence
s 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 tepal
s, 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. 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.
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.
of Banksia violacea was collected by 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. 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. The species has been considered a variety of B. sphaerocarpa
(Fox Banksia); 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. 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.
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).
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:
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). 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:
Since 1998, 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 to George's arrangement, and somewhat different to 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). 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.
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 cotyledon
s. 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.
B. violacea occurs in southern regions of Western Australia, from Woodanilling
to Esperance
and as far north as Hyden
. This distribution includes areas of the Avon Wheatbelt
, Esperance Plains
and Mallee
biogeographic
regions. It favours white sand
y soils, often overlying laterite
, clay
or quartzite
. It usually grows among heath
and shrubland
s, associated with mallee
eucalypts and Banksia sphaerocarpa var. caesia
. Banksia violacea is classified as Not Threatened under the 1950 Wildlife Conservation Act of Western Australia
.
, Banksia violacea has proteoid root
s, 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. B. violacea is highly susceptible to Phytophthora cinnamomi
dieback.
Banksia violacea is one of a small number of Banksia species that has both lignotuber
ous 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, in the vicinity of Woodanilling
. 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.
Banksia flowerheads in general play host to a variety of birds, mammals and insects. However, only wasps, ants and flies were recorded visiting flower spikes during observations for The Banksia Atlas
in the mid 1980s.
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. Professor Margaret 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
. Seeds do not require any treatment, and take 19 to 50 days to germinate.
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
or tree in the plant genus Banksia
Banksia
Banksia is a genus of around 170 species in the plant family Proteaceae. These Australian wildflowers and popular garden plants are easily recognised by their characteristic flower spikes and fruiting "cones" and heads. When it comes to size, banksias range from prostrate woody shrubs to trees up...
(family Proteaceae
Proteaceae
Proteaceae is a family of flowering plants distributed in the Southern Hemisphere. The family comprises about 80 genera with about 1600 species. Together with the Platanaceae and Nelumbonaceae they make up the order Proteales. Well known genera include Protea, Banksia, Embothrium, Grevillea,...
). 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 inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
s. 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
Shrubland
Shrubland, scrubland, scrub or brush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity...
in southern regions of Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
from Esperance
Esperance, Western Australia
Esperance is a large town in the Goldfields-Esperance region of Western Australia, located on the Southern Ocean coastline approximately east-southeast of the state capital, Perth. The shire of Esperance is home to 9,536 people as of the 2006 census, its major industries are tourism, agriculture,...
in the east to Narrogin
Narrogin, Western Australia
Narrogin is a large town in the Wheatbelt region of Western Australia, southeast of Perth on the Great Southern Highway between Pingelly and Wagin...
in the west, growing exclusively in sandy soils.
First described in 1927 by West Australian botanist Charles Gardner
Charles Gardner
Charles Austin Gardner was a Western Australian botanist.Born in Lancaster, England on 6 January 1896, he emigrated to Western Australia with his family in 1909....
, the species was at one stage considered a variety of B. sphaerocarpa
Banksia sphaerocarpa
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 high shrub, and is usually smaller in the north of its range...
. Although there are no recognised subspecies or varieties, both lignotuber
Lignotuber
A lignotuber is a starchy swelling of the root crown possessed by some plants as a protection against destruction of the plant stem by fire. The crown contains buds from which new stems may sprout, and a sufficient store of nutrients to support a period of growth in the absence of...
ous 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
Wildlife Conservation Act 1950
The Wildlife Conservation Act 1950 is an act of the Western Australian Parliament that provides the statute relating to conservation and legal protection of flora and fauna....
. Regarded as of little value to floriculture
Floriculture
Floriculture, or flower farming, is a discipline of horticulture concerned with the cultivation of flowering and ornamental plants for gardens and for floristry, comprising the floral industry...
, it is rarely cultivated.
Description
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. New growth occurs in summer, and flowering ranges from November to April with a peak in February, but can be irregular in timing. Flowers arise from typical Banksia "flower spikesRaceme
A raceme is a type of inflorescence that is unbranched and indeterminate and bears pedicellate flowers — flowers having short floral stalks called pedicels — along the axis. In botany, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne...
", and the inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
s are made up of hundreds of pairs of flowers densely packed in a spiral
Helix
A helix is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helixes are coil springs and the handrails of spiral staircases. A "filled-in" helix – for...
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
Violet (color)
As the name of a color, violet is synonymous with a bluish purple, when the word "purple" is used in the common English language sense of any color between blue and red, not including either blue or red...
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
Perianth
The term perianth has two similar but separate meanings in botany:* In flowering plants, the perianth are the outer, sterile whorls of a flower...
made up of four fused tepal
Tepal
Tepals are elements of the perianth, or outer part of a flower, which include the petals or sepals. The term tepal is more often applied specifically when all segments of the perianth are of similar shape and color, or undifferentiated, which is called perigone...
s, 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
Anthesis
Anthesis is the period during which a flower is fully open and functional. It may also refer to the onset of that period.The onset of anthesis is spectacular in some species. In Banksia species, for example, anthesis involves the extension of the style far beyond the upper perianth parts...
. The old flowers gradually fade to brown. The fruiting structure or follicle
Follicle (fruit)
In botany, a follicle is a dry unilocular many-seeded fruit formed from one carpel and dehiscing by the ventral suture in order to release seeds, such as in larkspur, magnolia, banksia, peony and milkweed....
is a stout woody "cone", with a hairy appearance caused by the persistence of old withered flower parts. 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.
The bright green cotyledon
Cotyledon
A cotyledon , is a significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of a seedling. The number of cotyledons present is one characteristic used by botanists to classify the flowering plants...
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
Hypocotyl
The hypocotyl is the stem of a germinating seedling, found below the cotyledons and above the radicle .-Dicots:...
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.
Taxonomy
The type specimenHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
of Banksia violacea was collected by West Australian botanist Charles Gardner
Charles Gardner
Charles Austin Gardner was a Western Australian botanist.Born in Lancaster, England on 6 January 1896, he emigrated to Western Australia with his family in 1909....
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. He placed it in section
Section (botany)
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...
Oncostylis
Banksia sect. Oncostylis
Banksia sect. Oncostylis is one of four sections of subgenus Banksia subg. Banksia. It contains those Banksia species with hooked pistils. All of the species in Oncostylis also exhibit a top-down sequence of flower anthesis, except for Banksia nutans which is bottom-up.Banksia sect...
of Bentham's taxonomic arrangement of Banksia
Bentham's taxonomic arrangement of Banksia
George Bentham's taxonomic arrangement of Banksia was published in 1870, in Volume 5 of Bentham's Flora Australiensis. A substantial improvement on the previous arrangement, it would stand for over a century. It was eventually replaced by Alex George's 1981 arrangement, published in his classic...
, 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. The species has been considered a variety of B. sphaerocarpa
Banksia sphaerocarpa
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 high shrub, and is usually smaller in the north of its range...
(Fox Banksia); this view was published by William Blackall
William Blackall
William E. Blackall was a Western Australia medical doctor who made a substantial contribution to that state's botany.Born in Folkestone, Kent, England, he emigrated to Perth in 1905. His occupation was in medicine, but he is now best known for his amateur botany...
in his 1954 How to know Western Australian wildflowers
How to know Western Australian wildflowers
How to know Western Australian wildflowers is a series of books that provide illustrated keys to the vascular flora of the southern half of Western Australia....
. He considered B. violacea to be a variety of B. sphaerocarpa with violet flowers. This description was an invalid publication, however, and a nomen nudum
Nomen nudum
The phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
. In 1981 Alex George
Alex George
Alexander Segger George is a Western Australian botanist. He is the authority on the plant genera Banksia and Dryandra...
declared Banksia sphaerocarpa var. violacea Blackall a nomenclatural synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
of B. violacea.
In George's 1981 arrangement, B. violacea was placed in subgenus Banksia
Banksia subg. Banksia
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.-Banksia verae:B. subg...
because its inflorescence is a typical Banksia "flower spike"; section Oncostylis
Banksia sect. Oncostylis
Banksia sect. Oncostylis is one of four sections of subgenus Banksia subg. Banksia. It contains those Banksia species with hooked pistils. All of the species in Oncostylis also exhibit a top-down sequence of flower anthesis, except for Banksia nutans which is bottom-up.Banksia sect...
because of its hooked styles; and series Abietinae
Banksia ser. Abietinae
Banksia ser. Abietinae is avalid botanic name for a series of Banksia. First published by Carl Meissner in 1856, the name has had three circumscriptions.-According to Meissner:...
because its inflorescence is roughly spherical. It was placed in taxonomic sequence
Taxonomic sequence
Taxonomic sequence is a sequence followed in listing of taxa which aids ease of use and roughly reflects the evolutionary relationships among the taxa...
between B. incana
Banksia incana
The Hoary Banksia is a species of small shrub in the plant genus Banksia. It occurs on sandplain heathland between Badgingarra and Eneabba in Western Australia, with outlying populations as far south as Perth. Seeds do not require any treatment, and take around 14 days to germinate....
(Hoary Banksia) and B. meisneri
Banksia meisneri
The Meisner's Banksia is a species of small shrub in the plant genus Banksia. It occurs in a number of isolated populations throughout southwest Western Australia. Seeds do not require any treatment, and take 28 to 39 days to germinate.-External links:...
(Meissner's Banksia).
In 1996, Kevin Thiele
Kevin Thiele
Kevin R. Thiele is curator of the Western Australian Herbarium. His research interests include the systematics of the plant families Proteaceae, Rhamnaceae and Violaceae, and the conservation ecology of grassy woodland ecosystems...
and Pauline Ladiges published the results of a cladistic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
analysis of morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
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
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...
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:
This clade became the basis of B. subseries Longistyles
Banksia subser. Longistyles
Banksia subser. Longistyles is avalid botanic name for a subseries of Banksia. It was published by Kevin Thiele in 1996, but discarded by Alex George in 1999.-Cladistics:...
, 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
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
, their arrangement placed B. violacea first in taxonomic sequence, followed by B. laricina
Banksia laricina
The Rose-Fruited Banksia is a species of shrub in the plant genus Banksia endemic to southwestern Western Australia. It derives its specific Latin name from larix or larch, which its foliage is said to resemble. The common name comes from the striking fruits which resemble wooden roses...
(Rose-fruited Banksia). 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
George's taxonomic arrangement of 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. , it superseded the arrangement of George Bentham, which had stood for over a hundred years. It was overturned in 1996 by Kevin...
, 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
Banksia sphaerocarpa
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 high shrub, and is usually smaller in the north of its range...
(Fox Banksia) and B. telmatiaea
Banksia telmatiaea
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 m tall, with narrow leaves and a pale brown flower spike, which can produce profuse...
(Swamp Fox Banksia). Despite this, the sequence of the series was altered so that B. violacea fell between B. scabrella
Banksia scabrella
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...
(Burma Road Banksia) and B. incana, and its placement in George's arrangement may be summarised as follows:
- BanksiaBanksiaBanksia is a genus of around 170 species in the plant family Proteaceae. These Australian wildflowers and popular garden plants are easily recognised by their characteristic flower spikes and fruiting "cones" and heads. When it comes to size, banksias range from prostrate woody shrubs to trees up...
- B. subg. BanksiaBanksia subg. BanksiaBanksia 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.-Banksia verae:B. subg...
- B. sect. BanksiaBanksia sect. BanksiaBanksia sect. Banksia is one of four sections of Banksia subgenus Banksia. It contains those species of subgenus Banksia with straight or sometimes curved but not hooked styles. These species all have cylindrical inflorescences and usually exhibit a bottom-up sequence of flower anthesis...
(9 series, 50 species, 9 subspecies, 3 varieties) - B. sect. Coccinea (1 species)
- B. sect. OncostylisBanksia sect. OncostylisBanksia sect. Oncostylis is one of four sections of subgenus Banksia subg. Banksia. It contains those Banksia species with hooked pistils. All of the species in Oncostylis also exhibit a top-down sequence of flower anthesis, except for Banksia nutans which is bottom-up.Banksia sect...
- B. ser. SpicigeraeBanksia ser. SpicigeraeBanksia ser. Spicigerae is a taxonomic series in the genus Banksia. It consists of the seven species in section Oncostylis that have cylindrical inflorescences. These range in form from small shrubs to tall trees. The leaves grow in either an alternate or whorled pattern, with various shape forms...
(7 species, 2 subspecies, 4 varieties) - B. ser. Tricuspidae (1 species)
- B. ser. DryandroideaeBanksia ser. DryandroideaeBanksia ser. Dryandroideae is a valid botanic name for a taxonomic series in the plant genus Banksia. First published by Carl Meissner in 1856, the name has had two circumscriptions. As presently circumscribed it is monotypic, containing only B. dryandroides.-According to Meissner:B. ser...
(1 species) - B. ser. AbietinaeBanksia ser. AbietinaeBanksia ser. Abietinae is avalid botanic name for a series of Banksia. First published by Carl Meissner in 1856, the name has had three circumscriptions.-According to Meissner:...
- B. sphaerocarpaBanksia sphaerocarpaBanksia 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 high shrub, and is usually smaller in the north of its range...
(3 varieties) - B. micranthaBanksia micranthaBanksia micrantha is a species of shrub in the plant genus Banksia. A small spreading bush with pale yellow flower spikes, it occurs between Eneabba and Cervantes in South west Western Australia...
- B. grossaBanksia grossaBanksia grossa, commonly known as Coarse Banksia is a species of shrub in the plant family Proteaceae endemic to south west Western Australia. One of fourteen species of banksia with predominantly round or oval inflorescences of the series Abietinae, it was described in 1981 as a distinct species...
- B. telmatiaeaBanksia telmatiaeaBanksia 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 m tall, with narrow leaves and a pale brown flower spike, which can produce profuse...
- B. leptophyllaBanksia leptophyllaThe Slender-leaved Banksia is a species of shrub in the plant genus Banksia. It occurs along the west coast of Western Australia from Gingin to Kalbarri. Before Alex George's revision of 1981, it was labelled informally as B. sphaerocarpa var. pinifolia or var...
(2 varieties) - B. lanataBanksia lanataThe Coomallo Banksia is a species of shrub in the plant genus Banksia. It occurs within a range of less than 100 square kilometres between Eneabba and Mount Lesueur, Western Australia. It has roughly spherical inflorescences with flowers of cream to orange-brown colour. The leaves are linear and...
- B. scabrellaBanksia scabrellaBanksia 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...
- B. violacea
- B. incanaBanksia incanaThe Hoary Banksia is a species of small shrub in the plant genus Banksia. It occurs on sandplain heathland between Badgingarra and Eneabba in Western Australia, with outlying populations as far south as Perth. Seeds do not require any treatment, and take around 14 days to germinate....
- B. laricinaBanksia laricinaThe Rose-Fruited Banksia is a species of shrub in the plant genus Banksia endemic to southwestern Western Australia. It derives its specific Latin name from larix or larch, which its foliage is said to resemble. The common name comes from the striking fruits which resemble wooden roses...
- B. pulchellaBanksia pulchellaThe Teasel Banksia is a species of small shrub in the plant genus Banksia. It occurs on the south coast of Western Australia from Fitzgerald River National Park east to Israelite Bay....
- B. meisneriBanksia meisneriThe Meisner's Banksia is a species of small shrub in the plant genus Banksia. It occurs in a number of isolated populations throughout southwest Western Australia. Seeds do not require any treatment, and take 28 to 39 days to germinate.-External links:...
(2 subspecies) - B. nutansBanksia nutansBanksia nutans, commonly known as Nodding Banksia, is a species of shrub native to the south coast of Western Australia in the genus Banksia...
(2 varieties)
- B. sphaerocarpa
- B. ser. Spicigerae
- B. sect. Banksia
- B. subg. IsostylisBanksia subg. IsostylisBanksia subg. Isostylis is a subgenus of Banksia. It contains three closely related species, all of which occur only in Southwest Western Australia. Members of subgenus Isostylis have dome-shaped flower heads that are superficially similar to those of B. ser...
(3 species)
- B. subg. Banksia
Since 1998, American botanist Austin Mast
Austin Mast
Austin R. Mast is a research botanist. Born in 1972, he obtained a Ph.D. from the University of Wisconsin–Madison in 2000. He is currently an associate professor within the Department of Biological Science at Florida State University , and has been director of FSU's since August 2003.One of his...
has been publishing results of ongoing cladistic analyses of DNA sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
data for the subtribe Banksiinae. His analyses suggest a phylogeny that is very greatly different to George's arrangement, and somewhat different to 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
Banksia sphaerocarpa var. dolichostyla
Banksia sphaerocarpa var. dolichostyla, commonly known as Ironcap Banksia, is a plant which is either considered a variety of Banksia sphaerocarpa, or as a species in its own right. It is native to the Southwest Botanical Province of Western Australia...
(treated at species rank as B. dolichostyla). However, Thiele's B. subseries Longistyles appears to be polyphyletic
Polyphyly
A polyphyletic group is one whose members' last common ancestor is not a member of the group.For example, the group consisting of warm-blooded animals is polyphyletic, because it contains both mammals and birds, but the most recent common ancestor of mammals and birds was cold-blooded...
, as do both definitions of B. ser. Abietinae—that is, none form a natural grouping.
Early in 2007, Mast and Thiele initiated a rearrangement of Banksia by merging Dryandra
Dryandra
Banksia ser. Dryandra is a series of 94 species of shrub to small tree in the plant genus Banksia. It was considered a separate genus named Dryandra until early 2007, when it was merged into Banksia on the basis of extensive molecular and morphological evidence that Banksia was paraphyletic with...
into it, and publishing B. subgenus Spathulatae
Banksia subg. Spathulatae
Banksia subg. Spathulatae is a valid botanic name for a subgenus of Banksia. It was published in 2007 by Austin Mast and Kevin Thiele, and defined as containing all those Banksia species having spathulate cotyledons...
for the taxa having spoon-shaped cotyledon
Cotyledon
A cotyledon , is a significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of a seedling. The number of cotyledons present is one characteristic used by botanists to classify the flowering plants...
s. 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.
Distribution and habitat
Woodanilling, Western Australia
Woodanilling is a small town in the Great Southern region of Western Australia, 254 km south of Perth on the Great Southern Highway, 24 km from Katanning and 30 km from Wagin....
to Esperance
Esperance, Western Australia
Esperance is a large town in the Goldfields-Esperance region of Western Australia, located on the Southern Ocean coastline approximately east-southeast of the state capital, Perth. The shire of Esperance is home to 9,536 people as of the 2006 census, its major industries are tourism, agriculture,...
and as far north as Hyden
Hyden, Western Australia
The town of Hyden is located 339 km east of Perth, Western Australia in the Shire of Kondinin. Hyden is home to Wave Rock and Mulka's Cave, both popular local tourist attractions....
. This distribution includes areas of the Avon Wheatbelt
Avon Wheatbelt
Avon Wheatbelt is an Interim Biogeographic Regionalisation for Australia region in Western Australia and part of the larger Southwest Australia savanna ecoregion.-Further reading:...
, Esperance Plains
Esperance Plains
Esperance Plains, also known as Eyre Botanical District, is a biogeographic region in southern Western Australia. Located on the south coast between the Avon Wheatbelt and Hampton regions, and bordered to the north by the Mallee region, it is a plain punctuated by granite and quartz outcrops and...
and Mallee
Mallee (biogeographic region)
Mallee, also known as Roe Botanical District, is a biogeographic region in southern Western Australia. Located between the Esperance Plains, Avon Wheatbelt and Coolgardie regions, it has a low, gently undulating topography, a semi-arid mediterranean climate, and extensive Eucalyptus mallee...
biogeographic
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
regions. It favours white sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
y soils, often overlying laterite
Laterite
Laterites are soil types rich in iron and aluminium, formed in hot and wet tropical areas. Nearly all laterites are rusty-red because of iron oxides. They develop by intensive and long-lasting weathering of the underlying parent rock...
, clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
or quartzite
Quartzite
Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...
. It usually grows among heath
Heath (habitat)
A heath or heathland is a dwarf-shrub habitat found on mainly low quality acidic soils, characterised by open, low growing woody vegetation, often dominated by plants of the Ericaceae. There are some clear differences between heath and moorland...
and shrubland
Shrubland
Shrubland, scrubland, scrub or brush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity...
s, associated with mallee
Mallee (habit)
Mallee is the growth habit of certain eucalypt species that grow with multiple stems springing from an underground lignotuber, usually to a height of no more than ten metres...
eucalypts and Banksia sphaerocarpa var. caesia
Banksia sphaerocarpa var. caesia
Banksia sphaerocarpa var. caesia is a variety of Banksia sphaerocarpa. It is native to the Southwest Botanical Province of Western Australia....
. Banksia violacea is classified as Not Threatened under the 1950 Wildlife Conservation Act of Western Australia
Wildlife Conservation Act 1950
The Wildlife Conservation Act 1950 is an act of the Western Australian Parliament that provides the statute relating to conservation and legal protection of flora and fauna....
.
Ecology
Like most other ProteaceaeProteaceae
Proteaceae is a family of flowering plants distributed in the Southern Hemisphere. The family comprises about 80 genera with about 1600 species. Together with the Platanaceae and Nelumbonaceae they make up the order Proteales. Well known genera include Protea, Banksia, Embothrium, Grevillea,...
, Banksia violacea has proteoid root
Proteoid root
Proteoid roots, also known as cluster roots, are plant roots that form clusters of closely spaced short lateral rootlets. They may form a two to five centimetre thick mat just beneath the leaf litter. They enhance nutrient uptake, possibly by chemically modifying the soil environment to improve...
s, 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
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
-deficient soils of Australia. B. violacea is highly susceptible to Phytophthora cinnamomi
Phytophthora cinnamomi
Phytophthora cinnamomi is a soil-borne water mould that produces an infection which causes a condition in plants called root rot or dieback. The plant pathogen is one of the world's most invasive species and is present in over 70 countries from around the world.- Life cycle and effects on plants :P...
dieback.
Banksia violacea is one of a small number of Banksia species that has both lignotuber
Lignotuber
A lignotuber is a starchy swelling of the root crown possessed by some plants as a protection against destruction of the plant stem by fire. The crown contains buds from which new stems may sprout, and a sufficient store of nutrients to support a period of growth in the absence of...
ous and non-lignotuberous populations. In both cases, plants are adapted to release their aerial seed bank following a bushfire
Bushfires in Australia
Bushfires in Australia are frequently occurring events during the hotter months of the year due to Australia's mostly hot, dry climate. Large areas of land are ravaged every year by bushfires, which also cause property damage and loss of life....
, 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, in the vicinity of Woodanilling
Woodanilling, Western Australia
Woodanilling is a small town in the Great Southern region of Western Australia, 254 km south of Perth on the Great Southern Highway, 24 km from Katanning and 30 km from Wagin....
. An investigation into the biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
of these plants failed to find any vegetative, climatic or other environmental factors associated with the possession of a lignotuber.
Banksia flowerheads in general play host to a variety of birds, mammals and insects. However, only wasps, ants and flies were recorded visiting flower spikes during observations for The Banksia Atlas
The Banksia Atlas
The Banksia Atlas is an atlas that documents the ranges, habitats and growth forms of various species and other subgeneric taxa of Banksia, an iconic Australian wildflower genus...
in the mid 1980s.
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 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 pruningPruning
Pruning is a horticultural practice involving the selective removal of parts of a plant, such as branches, buds, or roots. Reasons to prune plants include deadwood removal, shaping , improving or maintaining health, reducing risk from falling branches, preparing nursery specimens for...
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. Professor Margaret Sedgley of the Waite Institute suggests the species is of no value to floriculture
Floriculture
Floriculture, or flower farming, is a discipline of horticulture concerned with the cultivation of flowering and ornamental plants for gardens and for floristry, comprising the floral industry...
, 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
Plant breeding
Plant breeding is the art and science of changing the genetics of plants in order to produce desired characteristics. Plant breeding can be accomplished through many different techniques ranging from simply selecting plants with desirable characteristics for propagation, to more complex molecular...
. Seeds do not require any treatment, and take 19 to 50 days to germinate.