Dryandra sessilis
Encyclopedia
Banksia sessilis, commonly known as Parrot Bush, is a species
of shrub
or tree
in the plant
genus
Banksia
in the Proteaceae
family. It had been known as Dryandra sessilis until 2007, when the genus Dryandra
was sunk into Banksia. Widespread throughout southwest
Western Australia
, it is found on sandy soils over laterite
or limestone
, often as an understorey
plant in open forest, woodland or shrubland. Encountered as a shrub or small tree up to 6 m (20 ft) in height, it has prickly dark green leaves and dome-shaped cream-yellow flowerheads
. Flowering from winter through to late spring, it provides a key source of food—both the nectar and the insects it attracts—for honeyeater
s in the cooler months, and species diversity
is reduced in areas where there is little or no parrot bush occurring. Several species of honeyeater, some species of native bee, and the European Honey Bee
seek out and consume the nectar, while the Long-billed Black Cockatoo and Australian Ringneck
eat the seed. The life cycle of Banksia sessilis is adapted to regular bushfires. Killed by fire and regenerating by seed afterwards, each shrub generally produces many flowerheads and a massive amount of seed. It can recolonise disturbed areas, and may grow in thickets.
Banksia sessilis has a somewhat complicated taxonomic
history. It was collected from King George Sound
in 1801 and described by Robert Brown
in 1810 as Dryandra floribunda, a name by which it was known for many years. However, Joseph Knight had published the name Josephia sessilis in 1809, which had precedence due to its earlier date, and the specific name was formalised in 1924. Four varieties are recognised. It is a prickly plant with little apparent horticultural
potential, and none of the varieties are commonly seen in cultivation. A profuse producer of nectar, B. sessilis is valuable to the beekeeping
industry.
. In most varieties, new stems are covered in soft, fine hairs that are lost with maturity; but new stems of B. sessilis var. flabellifolia
are usually hairless. Leaves are blue-green or dark green. Their shape differs by variety: in var. cygnorum
and var. flabellifolia they are wedge-shaped, with teeth only near the apex; in var. cordata
they are wedge-shaped, but with teeth along the entire margin; and in var. sessilis
they are somewhat broader at the base, sometimes almost oblong in shape. Leaf size ranges from 2 to 6 cm (1–2.5 in) in length, and 0.8–4 cm (0.3–1.6 in) in width. They may be sessile (that is, growing directly from the stem without a petiole
) or on a petiole up to 0.5 cm (0.2 in) long.
The inflorescence
s are cream or yellow, and occur in domed heads
4 to 5 cm (1½–2 in) wide, situated at the end of a stem. Each head contains from 55 to 125 individual flowers, surrounded at the base by a whorl of short involucral bracts. As with most other Proteaceae
, individual flowers consist of a tubular perianth
made up of four united tepal
s, and one long wiry style. The style end is initially trapped inside the upper perianth parts, but breaks free at anthesis
. In B. sessilis the perianth is straight, 20 to 32 mm (0.8–1.3 in) long, and pale yellow. The style is slightly shorter, also straight, and cream-coloured. Thus in B. sessilis, unlike many other Banksia species, the release of the style at anthesis does not result in a showy flower colour change.
Flowering mostly takes place from July to November, although var. sessilis can start as early as May. After flowering, the flower parts wither and fall away, and up to four follicles develop in the receptable (the base of the flower head). Young follicles are covered in a fine fur, but this is lost as they mature. Mature follicles are ovoid in shape, and measure 1–1.5 cm (0.4–0.6 in) in length. Most follicles open as soon as they are ripe, revealing their contents: a woody seed separator
and up to two winged seeds.
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Specimens of B. sessilis were first collected by Scottish surgeon Archibald Menzies
during the visit of the Vancouver Expedition
to King George Sound
in September and October 1791. No firm location or collection date can be ascribed to Menzies' specimens, as their labels simply read "New Holland, King Georges Sound, Mr. Arch. Menzies", and Menzies' journal indicates that he collected over a wide area, visiting a different location every day from 29 September to 8 October. In addition to B. sessilis, Menzies collected plant material of B. pellaeifolia
, and seeds of at least four more Banksia species. This was therefore an important early collection for the genus, only seven species of which had previously been collected.
Menzies' seed specimens were sent to England
from Sydney
in 1793, but his plant material remained with him for the duration of the voyage, during which some material was lost. On his return to England in 1795, the surviving specimens were deposited into the herbarium
of Sir Joseph Banks
, where they lay undescribed for many years.
The next collection was made in December 1801, when King George Sound was visited by HMS Investigator under the command of Matthew Flinders
. On board were botanist Robert Brown
, botanical artist Ferdinand Bauer
, and gardener Peter Good
. All three men gathered material for Brown's specimen collection, including specimens of B. sessilis, although neither Brown's nor Good's diary can be used to assign a precise location or date for their discovery of the species. Good also made a separate seed collection, which included B. sessilis, and the species was drawn by Bauer. Like nearly all of his field drawings of Proteaceae, Bauer's original field sketch of B. sessilis was destroyed in a Hofburg fire
in 1945. A painting based on the drawing survives, however, at the Natural History Museum
in London
.
On returning to England in 1805, Brown began preparing an account of his Australian plant specimens. In September 1808, with Brown's account still far from finished, Swedish botanist Jonas Dryander asked him to prepare a separate paper on the Proteaceae
, so that he could use the genera erected by Brown in a new edition of Hortus Kewensis
. Brown immediately began a study of the Proteaceae, and in January 1809 he read to the Linnean Society of London
a monograph
on the family entitled On the Proteaceae of Jussieu. Among the eighteen new genera presented was one that Brown named Josephia in honour of Banks.
Brown's paper was approved for printing in May 1809, but did not appear in print until March the following year. In the meantime, Joseph Knight published On the cultivation of the plants belonging to the natural order of Proteeae
, which appeared to draw heavily on Brown's unpublished material, without permission, and in most cases without attribution. It contained the first publication of Brown's Josephia, for which two species were listed. The first, Josephia sessilis, was based on one of Menzies' specimens: "This species, discovered by Mr. A. Menzies on the West coast of New Holland, is not unlike some varieties of Ilex Aquifolium, and now in his Majesty's collection at Kew." The etymology
of the specific epithet was not explicitly stated, but it is universally accepted that it comes from the Latin
sessilis (sessile
, stalkless), in reference to the sessile leaves of this species. Blame for the alleged plagiarism
largely fell on Richard Salisbury, who had been present at Brown's readings and is thought to have provided much of the material for Knight's book. Salisbury was ostracized by the botanical community, which undertook to ignore his work as much as possible. By the time Brown's monograph appeared in print, Brown had exchanged the generic name Josephia for Dryandra, giving the name Dryandra floribunda to Knight's Josephia sessilis. As there were then no firm rules pertaining to priority
of publication, Brown's name was accepted, and remained the current name for over a century.
Another significant early collection was the apparent discovery of the species at the Swan River in 1827. In that year, the colonial botanist of New South Wales
Charles Fraser
visited the area as part of an exploring expedition under James Stirling
. Among the plants that Fraser found growing on the south side of the river entrance was "a beautiful species of Dryandra", which was probably this species.
Over the course of the 19th century, the principle of priority in naming gradually came to be accepted by botanists, as did the need for a mechanism by which names in current usage could be conserved
against archaic or obscure prior names. By the 1920s, Dryandra R.Br. was effectively conserved against Josephia Knight, although a mechanism for formal conservation was not put in place until 1933. Brown's specific name, however, was not conserved, and Karel Domin
overturned Dryandra floribunda R.Br. by transferring Knight's name into Dryandra as Dryandra sessilis (Knight) Domin in 1924. This name was current until 2007, when all Dryandra species were transferred into Banksia
by Austin Mast
and Kevin Thiele
. The full citation for the current name is thus Banksia sessilis (Knight) A.R.Mast & K.R.Thiele.
translated it as Many Flowered Dryandra. This name was also used when the plant was featured in Curtis's Botanical Magazine
in 1813. In Australia, the names Prickly Banksia and Shaving-brush Flower were offered up by Emily Pelloe
in 1921, the latter because "when in bud the flower very much resembles a shaving-brush". Shaving-brush flower was still in use as late as the 1950s. The name Holly-leaved Dryandra was used when the plant was featured as part of a series of articles in the Western Mail
of 1933–34, and this was taken up by William Blackall
in 1954, and was still in use as late as 1970. Meanwhile, Gardner used the name Parrot Bush in 1959, a name derived from the observation that the blooms attract parrots., by which the species was already "well-known to bee-keepers". This name was widely adopted, and since 1970 has been in almost exclusive usage.
The only indigenous names reported for the plant are Budjan and But-yak. These were published by Ian Abbott in his 1983 Aboriginal Names for Plant Species in South-western Australia, with Abbott suggesting that the latter name should be preferred, but with the orthography
"Pudjak". However, Abbott sources these names to George Fletcher Moore
's 1842 A Descriptive Vocabulary of the Language of the Aborigines
, which in fact attributes these names to the species Dryandra fraseri (now Banksia fraseri
). It is unclear whether Abbott has corrected Moore's error, or introduced an error of his own.
, published later that year. In 1830, however, he introduced the first taxonomic arrangement of Dryandra
, placing D. floribunda in section Dryandra verae along with most other species, because its follicles
contain a single seed separator. Dryandra verae was renamed Eudryandra by Carl Meissner
in 1845. Eleven years later Meissner published a new arrangement
, retaining D. floribunda in D. sect. Eudryandra, and further placing it in the unranked subgroup § Ilicinae, because of the similarity of its leaves to those of Ilex (Holly). In 1870, George Bentham
published a revised arrangement
in his Flora Australiensis
. Bentham retained section Eudryandra, but abandoned almost all of Meissner's unranked groups, including § Ilicinae. D. floribunda was instead placed in D. ser. Floribundae
along with four other species with small, mostly terminal flowers, left exposed by their having unusually short floral leaves.
Bentham's arrangement stood for over a hundred years, eventually replaced in 1996 by the arrangement of
Alex George
. Section Eudryandra was promoted to subgenus rank, but replaced by the autonym
D. subg. Dryandra
. D. sessilis, as this species was now called, was retained in D. ser. Floribundae, but alone, as the series was redefined as containing only those taxa that apparently lack floral bracts altogether. The placement of D. sessilis in George's arrangement, with 1999 and 2005 amendments, may be summarised as follows:
George's arrangement remained current until 2007, when Austin Mast
and Kevin Thiele
transferred Dryandra into Banksia. They also published B. subg. Spathulatae
for the Banksia taxa having spoon-shaped cotyledon
s, thus redefining B. subg. Banksia
as comprising those that do not. They were not ready, however, to tender an infrageneric arrangement encompassing Dryandra, so as an interim measure they transferred Dryandra into Banksia at series
rank. This minimised the nomenclatural disruption of the transfer, but also caused George's rich infrageneric arrangement to be set aside. Thus under the interim arrangements implemented by Mast and Thiele, B. sessilis is placed in B. subg. Banksia
, ser. Dryandra.
Banksia sessilis is endemic to the Southwest Botanical Province, a floristic province
renowned as a biodiversity hotspot
, located in the southwest corner of Western Australia. This area has a Mediterranean climate
, with wet winters and hot, dry summers. B. sessilis occurs throughout much of the province, ranging from Kalbarri in the north, south to Cape Leeuwin
, east along the south coast as far as Bremer Bay, and inland to Wongan Hills
and Kulin
. It thus spans a wide range of climates, occurring in all but the semi-arid areas well inland. It is also absent from the Karri forest
in the cool, wet, southwest corner of the province, but even there, B. sessilis var. cordata occurs along the coast.
The species tolerates a range of soils, requiring only that its soil be well-drained. Like most dryandras, it grows well in lateritic
soils and gravels, although this species is also found in deep sand, sand over laterite, and sand over limestone
. It also occurs in a range of vegetation
complexes, including coastal and kwongan
heath
, tall shrubland
, woodland
and open forest
. It is a common understorey
plant in drier areas of Jarrah forest
, and forms thicket
s on limestone soils of the Swan Coastal Plain
. Banksia sessilis sets a large amount of seed and is an aggressive coloniser of disturbed and open areas; for example, it has been recorded colonising gravel pit
s in the Darling Scarp
.
Nothing is known of the conditions that affect its distribution, as its biogeography
is as yet unstudied. An assessment of the potential impact of climate change
on this species found that its range is likely to contract by half in the face of severe change, but unlikely to change much under less severe scenarios.
. In one study, B. sessilis was found to be the main source of nectar for all six species studied, namely the Tawny-crowned Honeyeater
(Gliciphila melanops), White-cheeked Honeyeater
(Phylidonyris niger), Western Spinebill
(Acanthorhynchus superciliosus), Brown Honeyeater
(Lichmera indistincta), Brown-headed Honeyeater
(Melithreptus brevirostris), and Black Honeyeater
(Certhionyx niger). Moreover, B. sessilis played an important role in their distributions, with species that feed only on nectar occurring only where B. sessilis occurs, and remaining for longest at sites where B. sessilis is most abundant. Other honeyeaters that have been recorded feeding on B. sessilis include the Red Wattlebird
(Anthochaera carunculata), Western Wattlebird
(A. lunulata), and New Holland Honeyeater
(Phylidonyris novaehollandiae). Furthermore, a study of bird species diversity in wandoo
woodland around Bakers Hill
found that honeyeater species and numbers were much reduced in forest that lacked a Banksia sessilis understorey; the plant is a key source of nectar and insects during the winter months.
Banksia sessilis is also a source of food for the Australian Ringneck
(Barnardius zonarius), and the Long-billed Black Cockatoo (Calyptorhynchus baudinii), which tear open the follicles
and consume the seeds.
The introduced European Honey Bee
(Apis mellifera) has also been observed feeding on B. sessilis, as have seven species of native bee
, comprising four species of Hylaeus (including the Banksia Bee
H. alcyoneus), two of Leioproctus
, and a Lasioglossum
.
vector, as inflorescences from which honeyeaters are excluded generally do not set any fruit. Moreover, honeyeaters have been observed moving from tree to tree with significant loads of B. sessilis pollen on their foreheads, beaks and throats, having acquired it by brushing against pollen presenters while foraging for nectar; experiments have shown that some of this pollen may be subsequently deposited on stigmas during later foraging.
The flowers of B. sessilis have a number of adaptations that serve to encourage outcrossing
. Firstly, they are protandrous: a flower's pollen is released around 72 hours before it becomes itself receptive to pollen, by which time around half of its pollen has lost its viability. Secondly, the period of maximum nectar production closely matches the period during which the flower is sexually active, so honeyeaters are enticed to visit at the most opportune time for pollination. This has proven an effective strategy: almost all pollen is removed within two to three hours of presentation. In addition, honeyeaters tend to move between inflorescences on different plants, rather than between inflorescences on the same plant, at least in high density sites. These factors combine to make it fairly unusual for a flower to be fertilised by its own pollen. When self-fertilisation does occur, whether autogamous or geitonogamous, the resulting seed is almost always aborted, and the species ultimately achieves an outcrossing rate of nearly 100%, at least in high density sites. Limited data for low-density sites, where honeyeaters move from plant to plant less frequently, suggest more of a mixed-mating system.
The species is a prolific flowerer, and this, combined with the very high outcrossing rates, results in massive seed output. In one study, the average number of seeds produced per B. sessilis plant was 622, compared with an average of 2 for B. dallanneyi
. This exceptionally high fecundity
can be understood as an adaption to regular bushfire. Most Banksia species can be placed in one of two broad groups according to their response to fire: resprouter
s survive fire, resprouting from a lignotuber
or, more rarely, epicormic buds
protected by thick bark; reseeders are killed by fire, but populations are rapidly re-established through the recruitment of seedlings. B. sessilis is a reseeder, but it differs from many other reseeders in not being strongly serotinous: the vast majority of seeds are released spontaneously in autumn, even in the absence of fire. The degree of serotiny is a matter of some contradiction in the scientific literature: it has been treated as "serotinous", "weakly serotinous" and "non-serotinous". Regardless of the terminology used, the massive spontaneous seed output of B. sessilis is its primary survival strategy, and is so effective that the species has a reputation as an excellent coloniser. However, this strategy, together with its relatively long juvenile period, makes it vulnerable to overly frequent fire.
Seeds of B. sessilis are short-lived, and must germinate in the winter following their release, or they die. They are also very sensitive to heating, and thus killed by bushfire; in one study, just 30 seconds in boiling water reduced the germination rate from 85% to 22%, and not a single seed survived one minute of boiling.
Like most other Proteaceae
, B. sessilis has compound cluster roots, roots with dense clusters of short lateral rootlets that form a mat in the soil just below the leaf litter. These exude a range of carboxylates, including citrate
, malonate
and trans-aconitate, that act as acid phosphatase
, allowing the absorption of nutrients from nutrient-poor soils, such as the phosphorus
-deficient native soils of Australia
.
Phytophthora cinnamomi
, a soil-borne water mould
that causes root rot
; in fact it is so reliably susceptible that it is considered a good indicator species
for the presence of the disease. Most highly susceptible species quickly become locally extinct in infected areas, and in the absence of hosts the disease itself eventually dies out. However, B. sessilis, being an aggressive coloniser of disturbed and open ground, often colonises old disease sites. The new colonies are themselves infected, and thus P. cinnamomi survives at these sites indefinitely.
The application of phosphite
inhibits growth of P. cinnamomi in B. sessilis, but does not kill the pathogen. In one study, a foliar spray containing phosphite inhibited the growth of P. cinnamomi by over 90% in plants infected with B. sessilis two weeks after spraying, and by 66% in plants infected one year after spraying; yet most plants infected shortly before or after spraying were dead 100 days later, while nearly all plants infected seven months later spraying survived a further 100 days. Phosphite is not known to affect plant growth, but has been shown to reduce pollen fertility: one study recorded fertility reductions of up to 50%, and, in a separate experiment, fertility reductions that persisted for more than a year.
Infection of coastal stands of B. sessilis by the fungus Armillaria luteobubalina
has also been recorded. The apparent infection rate
of 0.31 is quite slow compared to the progress of other Armillaria species through pine
plantation
s.
, by Menzies in 1793 included seeds of B. sessilis, but if it did then it did not germinate. The species was successfully germinated, however, from Good's seed, which was sent from Sydney on 6 June 1802 and arrived at Kew the following year. According to Brown's notes it was flowering at Kew by May 1806, and in 1810 it was reported in the second edition of Hortus Kewensis as flowering "most part of the Year". In 1813 a flowering specimen from the nursery of Malcolm and Sweet was featured as Plate 1581 in Curtis's Botanical Magazine
.
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By the 1830s the species was in cultivation in continental Europe. It was recorded as being cultivated in the garden of Karl von Hügel in Vienna
, Austria
in 1831, and in 1833 it was listed amongst the rare plants that had been introduced into Belgium
. Along with several hundred other native Australian plants it was exhibited at plant shows held at Utrecht
and Haarlem
in the Netherlands
in the 1840s and 1850s. By this time, however, English gardeners had already begun to lose interest in the Proteaceae, and by the end of the 19th century European interest in the cultivation of Proteaceae was virtually non-existent.
In Australia, there was little interest in the cultivation of Australian plants until the mid-20th century, despite a long-standing appreciation of their beauty as wildflower
s. For example, in 1933 and 1934 The Western Mail
published a series of Edgar Dell
paintings of Western Australian wildflowers, including a painting of B. sessilis. These were subsequently republished in Charles Gardner
's 1935 West Australian Wild Flowers. One of the first published colour photographs of the species appeared in William Blackall
's 1954 How to know Western Australian wildflowers
, but this publication was restricted to plant identification. The species was discussed and illustrated in the 1959 Wildflowers of Western Australia, and in the 1973 Flowers and plants of Western Australia, but these books did not provide cultivation advice either.
Possibly the first published information on the cultivation of Dryandra appeared in the magazine Australian Plants in June and September 1961. D. sessilis was among the species treated, but as there was not yet any experimental data on cultivation, information was restricted to its aesthetic qualities and the soil in which it naturally occurs.
From its inception in 1962, the Kings Park and Botanic Garden undertook extensive research into the cultivation of native plants, resulting in two early publications that mentioned the cultivation potential of B. sessilis. In 1965, John Stanley Beard
published Descriptive catalogue of Western Australian plants, "a work of reference in which the horticultural characteristics of the plants concerned could be looked up by the staff", which described D. sessilis as an erect shrub with pale yellow flowers appearing from May to October, growing in sand and gravel. Five years later, Arthur Fairall published West Australian native plants in cultivation. This presented largely the same information as Beard's catalogue, adding only that the species flowers well in its third season.
. However, its size makes it unsuitable for smaller gardens, and if given an ideal situation it may produce a great many seedlings. It is propagated only from seed, as propagating it from cutting
s has proven virtually impossible. Germination takes about five or six weeks, and plants may take two years to flower.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of shrub
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
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
in the plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
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...
in the 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,...
family. It had been known as Dryandra sessilis until 2007, when the genus 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...
was sunk into Banksia. Widespread throughout southwest
Southwest Australia
Southwest Australia is a biodiversity hotspot that includes the Mediterranean forests, woodlands, and scrub ecoregions of Western Australia. The region has a wet-winter, dry-summer Mediterranean climate, one of five such regions in the world...
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...
, it is found on sandy soils over 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...
or limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
, often as an understorey
Understory
Understory is the term for the area of a forest which grows at the lowest height level below the forest canopy. Plants in the understory consist of a mixture of seedlings and saplings of canopy trees together with understory shrubs and herbs...
plant in open forest, woodland or shrubland. Encountered as a shrub or small tree up to 6 m (20 ft) in height, it has prickly dark green leaves and dome-shaped cream-yellow flowerheads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
. Flowering from winter through to late spring, it provides a key source of food—both the nectar and the insects it attracts—for honeyeater
Honeyeater
The honeyeaters are a large and diverse family of small to medium sized birds most common in Australia and New Guinea, but also found in New Zealand, the Pacific islands as far east as Samoa and Tonga, and the islands to the north and west of New Guinea known as Wallacea...
s in the cooler months, and species diversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
is reduced in areas where there is little or no parrot bush occurring. Several species of honeyeater, some species of native bee, and the European Honey Bee
European honey bee
The Western honey bee or European honey bee is a species of honey bee. The genus Apis is Latin for "bee", and mellifera comes from Latin melli- "honey" and ferre "to bear"—hence the scientific name means "honey-bearing bee"...
seek out and consume the nectar, while the Long-billed Black Cockatoo and Australian Ringneck
Australian Ringneck
The Australian Ringneck is a parrot native to Australia. Except for extreme tropical and highland areas, the species has adapted to all conditions...
eat the seed. The life cycle of Banksia sessilis is adapted to regular bushfires. Killed by fire and regenerating by seed afterwards, each shrub generally produces many flowerheads and a massive amount of seed. It can recolonise disturbed areas, and may grow in thickets.
Banksia sessilis has a somewhat complicated taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
history. It was collected from King George Sound
King George Sound
King George Sound is the name of a sound on the south coast of Western Australia. Located at , it is the site of the city of Albany.The sound covers an area of and varies in depth from to ....
in 1801 and described by Robert Brown
Robert Brown (botanist)
Robert Brown was a Scottish botanist and palaeobotanist who made important contributions to botany largely through his pioneering use of the microscope...
in 1810 as Dryandra floribunda, a name by which it was known for many years. However, Joseph Knight had published the name Josephia sessilis in 1809, which had precedence due to its earlier date, and the specific name was formalised in 1924. Four varieties are recognised. It is a prickly plant with little apparent horticultural
Horticulture
Horticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...
potential, and none of the varieties are commonly seen in cultivation. A profuse producer of nectar, B. sessilis is valuable to the beekeeping
Beekeeping
Beekeeping is the maintenance of honey bee colonies, commonly in hives, by humans. A beekeeper keeps bees in order to collect honey and other products of the hive , to pollinate crops, or to produce bees for sale to other beekeepers...
industry.
Description
Banksia sessilis grows as an upright shrub or small tree up to 6 m (20 ft) high, without a lignotuberLignotuber
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...
. In most varieties, new stems are covered in soft, fine hairs that are lost with maturity; but new stems of B. sessilis var. flabellifolia
Banksia sessilis var. flabellifolia
Banksia sessilis var. flabellifolia is a variety of Banksia sessilis .-Description:It grows as a shrub up to five metres high. Unlike other varieties of B. sessilis, it has hairless stems. The leaves are fan shaped, with a long, toothless lower margin, and a toothed end...
are usually hairless. Leaves are blue-green or dark green. Their shape differs by variety: in var. cygnorum
Banksia sessilis var. cygnorum
Banksia sessilis var. cygnorum is a variety of Banksia sessilis .-Description:It grows as a shrub up to five metres high, with a down of fine hairs on the stems. This variety is has the smallest leaves of any B. sessilis variety, being no more than three centimetres long, and less than two...
and var. flabellifolia they are wedge-shaped, with teeth only near the apex; in var. cordata
Banksia sessilis var. cordata
Banksia sessilis var. cordata is a variety of Banksia sessilis , with unusually large leaves and flower heads. It is a rare variety that is restricted to the extreme south-west corner of Western Australia.-Description:...
they are wedge-shaped, but with teeth along the entire margin; and in var. sessilis
Banksia sessilis var. sessilis
Banksia sessilis var. sessilis is the most populous and most widespread variety of Banksia sessilis .-Description:The leaves of this variety are larger than those of B. sessilis var. cygnorum but smaller than those of B. sessilis var. cordata. It differs from B. sessilis var...
they are somewhat broader at the base, sometimes almost oblong in shape. Leaf size ranges from 2 to 6 cm (1–2.5 in) in length, and 0.8–4 cm (0.3–1.6 in) in width. They may be sessile (that is, growing directly from the stem without a petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
) or on a petiole up to 0.5 cm (0.2 in) long.
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 cream or yellow, and occur in domed heads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....
4 to 5 cm (1½–2 in) wide, situated at the end of a stem. Each head contains from 55 to 125 individual flowers, surrounded at the base by a whorl of short involucral bracts. As with most other 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,...
, individual flowers consist 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 united 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 style end is initially trapped inside the upper perianth parts, but breaks 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...
. In B. sessilis the perianth is straight, 20 to 32 mm (0.8–1.3 in) long, and pale yellow. The style is slightly shorter, also straight, and cream-coloured. Thus in B. sessilis, unlike many other Banksia species, the release of the style at anthesis does not result in a showy flower colour change.
Flowering mostly takes place from July to November, although var. sessilis can start as early as May. After flowering, the flower parts wither and fall away, and up to four follicles develop in the receptable (the base of the flower head). Young follicles are covered in a fine fur, but this is lost as they mature. Mature follicles are ovoid in shape, and measure 1–1.5 cm (0.4–0.6 in) in length. Most follicles open as soon as they are ripe, revealing their contents: a woody seed separator
Seed separator
A seed separator is a structure found in the follicles of some Proteaceae. These follicles typically contain two seeds, with a seed separator between them...
and up to two winged seeds.
Discovery and naming
Archibald Menzies
Archibald Menzies was a Scottish surgeon, botanist and naturalist.- Life and career :Menzies was born at Easter Stix in the parish of Weem, in Perthshire. While working with his elder brother William at the Royal Botanic Gardens, he drew the attention of Dr John Hope, professor of botany at...
during the visit of the Vancouver Expedition
Vancouver Expedition
The Vancouver Expedition was a four-and-a-half-year voyage of exploration and diplomacy, commanded by Captain George Vancouver. The expedition circumnavigated the globe, touched five continents and changed the course of history for the indigenous nations and several European empires and their...
to King George Sound
King George Sound
King George Sound is the name of a sound on the south coast of Western Australia. Located at , it is the site of the city of Albany.The sound covers an area of and varies in depth from to ....
in September and October 1791. No firm location or collection date can be ascribed to Menzies' specimens, as their labels simply read "New Holland, King Georges Sound, Mr. Arch. Menzies", and Menzies' journal indicates that he collected over a wide area, visiting a different location every day from 29 September to 8 October. In addition to B. sessilis, Menzies collected plant material of B. pellaeifolia
Banksia pellaeifolia
Banksia pellaeifolia is a shrub endemic to Western Australia.It was known as Dryandra blechnifolia until 2007, when all Dryandra species were transferred to Banksia by Austin Mast and Kevin Thiele...
, and seeds of at least four more Banksia species. This was therefore an important early collection for the genus, only seven species of which had previously been collected.
Menzies' seed specimens were sent to England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
from Sydney
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...
in 1793, but his plant material remained with him for the duration of the voyage, during which some material was lost. On his return to England in 1795, the surviving specimens were deposited into the herbarium
Herbarium
In botany, a herbarium – sometimes known by the Anglicized term herbar – is a collection of preserved plant specimens. These specimens may be whole plants or plant parts: these will usually be in a dried form, mounted on a sheet, but depending upon the material may also be kept in...
of Sir Joseph Banks
Joseph Banks
Sir Joseph Banks, 1st Baronet, GCB, PRS was an English naturalist, botanist and patron of the natural sciences. He took part in Captain James Cook's first great voyage . Banks is credited with the introduction to the Western world of eucalyptus, acacia, mimosa and the genus named after him,...
, where they lay undescribed for many years.
The next collection was made in December 1801, when King George Sound was visited by HMS Investigator under the command of Matthew Flinders
Matthew Flinders
Captain Matthew Flinders RN was one of the most successful navigators and cartographers of his age. In a career that spanned just over twenty years, he sailed with Captain William Bligh, circumnavigated Australia and encouraged the use of that name for the continent, which had previously been...
. On board were botanist Robert Brown
Robert Brown (botanist)
Robert Brown was a Scottish botanist and palaeobotanist who made important contributions to botany largely through his pioneering use of the microscope...
, botanical artist Ferdinand Bauer
Ferdinand Bauer
Ferdinand Lucas Bauer was an Austrian botanical illustrator who travelled on Matthew Flinders' expedition to Australia.-Biography:...
, and gardener Peter Good
Peter Good
Peter Good was the gardener assistant to botanist Robert Brown on the voyage of HMS Investigator under Matthew Flinders, during which the coast of Australia was charted, and various plants collected.-Biography:...
. All three men gathered material for Brown's specimen collection, including specimens of B. sessilis, although neither Brown's nor Good's diary can be used to assign a precise location or date for their discovery of the species. Good also made a separate seed collection, which included B. sessilis, and the species was drawn by Bauer. Like nearly all of his field drawings of Proteaceae, Bauer's original field sketch of B. sessilis was destroyed in a Hofburg fire
Hofburg fire
The term "Hofburg fire"refers to any of several major fires that burned in the Hofburg of Vienna, Austria. The Hofburg area has been the documented seat of government since 1279....
in 1945. A painting based on the drawing survives, however, at the Natural History Museum
Natural History Museum
The Natural History Museum is one of three large museums on Exhibition Road, South Kensington, London, England . Its main frontage is on Cromwell Road...
in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
.
On returning to England in 1805, Brown began preparing an account of his Australian plant specimens. In September 1808, with Brown's account still far from finished, Swedish botanist Jonas Dryander asked him to prepare a separate paper on the 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,...
, so that he could use the genera erected by Brown in a new edition of Hortus Kewensis
Hortus Kewensis
Hortus Kewensis, or a Catalogue of the Plants Cultivated in the Royal Botanic Garden at Kew by William Aiton was a 1789 catalogue of all the plant species then in cultivation at the Royal Botanic Gardens, Kew, which constituted the vast majority of plant species in cultivation in all of England...
. Brown immediately began a study of the Proteaceae, and in January 1809 he read to the Linnean Society of London
Linnean Society of London
The Linnean Society of London is the world's premier society for the study and dissemination of taxonomy and natural history. It publishes a zoological journal, as well as botanical and biological journals...
a monograph
Monograph
A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...
on the family entitled On the Proteaceae of Jussieu. Among the eighteen new genera presented was one that Brown named Josephia in honour of Banks.
Brown's paper was approved for printing in May 1809, but did not appear in print until March the following year. In the meantime, Joseph Knight published On the cultivation of the plants belonging to the natural order of Proteeae
On the cultivation of the plants belonging to the natural order of Proteeae
On the cultivation of the plants belonging to the natural order of Proteeae is an 1809 paper on the Proteaceae family of flowering plants. Although nominally written by Joseph Knight as a paper on cultivation techniques, all but 13 pages consists of an unattributed taxonomic revision now known to...
, which appeared to draw heavily on Brown's unpublished material, without permission, and in most cases without attribution. It contained the first publication of Brown's Josephia, for which two species were listed. The first, Josephia sessilis, was based on one of Menzies' specimens: "This species, discovered by Mr. A. Menzies on the West coast of New Holland, is not unlike some varieties of Ilex Aquifolium, and now in his Majesty's collection at Kew." The etymology
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
of the specific epithet was not explicitly stated, but it is universally accepted that it comes from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
sessilis (sessile
Sessility (botany)
In botany, sessility is a characteristic of plants whose flowers or leaves are borne directly from the stem or peduncle, and thus lack a petiole or pedicel...
, stalkless), in reference to the sessile leaves of this species. Blame for the alleged plagiarism
Plagiarism
Plagiarism is defined in dictionaries as the "wrongful appropriation," "close imitation," or "purloining and publication" of another author's "language, thoughts, ideas, or expressions," and the representation of them as one's own original work, but the notion remains problematic with nebulous...
largely fell on Richard Salisbury, who had been present at Brown's readings and is thought to have provided much of the material for Knight's book. Salisbury was ostracized by the botanical community, which undertook to ignore his work as much as possible. By the time Brown's monograph appeared in print, Brown had exchanged the generic name Josephia for Dryandra, giving the name Dryandra floribunda to Knight's Josephia sessilis. As there were then no firm rules pertaining to priority
Priority (botany)
Priority is a fundamental principle of modern botanical nomenclature and zoological nomenclature. Essentially, it is the principle of recognising the first valid application of a name to a plant or animal...
of publication, Brown's name was accepted, and remained the current name for over a century.
Another significant early collection was the apparent discovery of the species at the Swan River in 1827. In that year, the colonial botanist of New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
Charles Fraser
Charles Fraser (botanist)
Charles Fraser or Frazer was Colonial Botanist of New South Wales from 1821 to 1831. He collected and catalogued numerous Australian plant species, and participated in a number of exploring expeditions...
visited the area as part of an exploring expedition under James Stirling
James Stirling (Australian governor)
Admiral Sir James Stirling RN was a British naval officer and colonial administrator. His enthusiasm and persistence persuaded the British Government to establish the Swan River Colony and he became the first Governor and Commander-in-Chief of Western Australia...
. Among the plants that Fraser found growing on the south side of the river entrance was "a beautiful species of Dryandra", which was probably this species.
Over the course of the 19th century, the principle of priority in naming gradually came to be accepted by botanists, as did the need for a mechanism by which names in current usage could be conserved
Conserved name
A conserved name or nomen conservandum is a scientific name that has specific nomenclatural protection. Nomen conservandum is a Latin term, meaning a "name which should be conserved"...
against archaic or obscure prior names. By the 1920s, Dryandra R.Br. was effectively conserved against Josephia Knight, although a mechanism for formal conservation was not put in place until 1933. Brown's specific name, however, was not conserved, and Karel Domin
Karel Domin
Karel Domin was a Czech botanist and politician.After gymnasium school studies in Příbram, he studied botany at the Charles University in Prague, and graduated in 1906. In 1916 he was named as professor of botany. Domin specialised in phytogeography, geobotany and plant taxonomy...
overturned Dryandra floribunda R.Br. by transferring Knight's name into Dryandra as Dryandra sessilis (Knight) Domin in 1924. This name was current until 2007, when all Dryandra species were transferred into 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...
by 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...
and 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...
. The full citation for the current name is thus Banksia sessilis (Knight) A.R.Mast & K.R.Thiele.
Common names
The first common names for this species were literal translations of the scientific names. When published as Josephia sessilis in 1809, it was given the common name Sessile Josephia. Brown did not offer a common name when he published Dryandra floribunda in 1810, but later that year the Hortus KewensisHortus Kewensis
Hortus Kewensis, or a Catalogue of the Plants Cultivated in the Royal Botanic Garden at Kew by William Aiton was a 1789 catalogue of all the plant species then in cultivation at the Royal Botanic Gardens, Kew, which constituted the vast majority of plant species in cultivation in all of England...
translated it as Many Flowered Dryandra. This name was also used when the plant was featured in Curtis's Botanical Magazine
Curtis's Botanical Magazine
The Botanical Magazine; or Flower-Garden Displayed, is an illustrated publication which began in 1787. The longest running botanical magazine, it is widely referred to by the subsequent name Curtis's Botanical Magazine....
in 1813. In Australia, the names Prickly Banksia and Shaving-brush Flower were offered up by Emily Pelloe
Emily Pelloe
Emily Harriet Pelloe was a botanical illustrator, and author of books, of the flowering plants of Western Australia...
in 1921, the latter because "when in bud the flower very much resembles a shaving-brush". Shaving-brush flower was still in use as late as the 1950s. The name Holly-leaved Dryandra was used when the plant was featured as part of a series of articles in the Western Mail
Western Mail (Western Australia)
The Western Mail, or Western Mail, was the name of two weekly newspapers published in Perth, Western Australia.-West Australian newspapers:...
of 1933–34, and this was taken up 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 1954, and was still in use as late as 1970. Meanwhile, Gardner used the name Parrot Bush in 1959, a name derived from the observation that the blooms attract parrots., by which the species was already "well-known to bee-keepers". This name was widely adopted, and since 1970 has been in almost exclusive usage.
The only indigenous names reported for the plant are Budjan and But-yak. These were published by Ian Abbott in his 1983 Aboriginal Names for Plant Species in South-western Australia, with Abbott suggesting that the latter name should be preferred, but with the orthography
Orthography
The orthography of a language specifies a standardized way of using a specific writing system to write the language. Where more than one writing system is used for a language, for example Kurdish, Uyghur, Serbian or Inuktitut, there can be more than one orthography...
"Pudjak". However, Abbott sources these names to George Fletcher Moore
George Fletcher Moore
George Fletcher Moore was a prominent early settler in colonial Western Australia, and "one [of] the key figures in early Western Australia's ruling elite"...
's 1842 A Descriptive Vocabulary of the Language of the Aborigines
A Descriptive Vocabulary of the Language of the Aborigines
A Descriptive Vocabulary of the Language in Common Use Amongst the Aborigines of Western Australia is a book by George Fletcher Moore. First published in 1842, it represents one of the earliest attempts to record the languages used by the Aboriginal peoples of Western Australia...
, which in fact attributes these names to the species Dryandra fraseri (now Banksia fraseri
Banksia fraseri
Banksia fraseri is a shrub endemic to Western Australia. It was known as Dryandra fraseri until 2007, when all Dryandra species were transferred to Banksia by Austin Mast and Kevin Thiele.-Description:...
). It is unclear whether Abbott has corrected Moore's error, or introduced an error of his own.
Infrageneric placement
Brown's 1810 monograph did not include an infrageneric classification of Dryandra, and neither did his ProdromusProdromus Florae Novae Hollandiae et Insulae Van Diemen
Prodromus Florae Novae Hollandiae et Insulae Van Diemen is an 1810 flora of Australia by botanist Robert Brown. Often referred to as Prodromus Flora Novae Hollandiae, or by its standard botanical abbreviation Prodr. Fl. Nov. Holland., it was the first attempt at a survey of the Australian flora...
, published later that year. In 1830, however, he introduced the first taxonomic arrangement of Dryandra
Brown's taxonomic arrangement of Dryandra
Robert Brown's taxonomic arrangement of Dryandra was the first arrangement of what is now Banksia ser. Dryandra. His initial arrangement was published in 1810, and a further arrangement, including an infrageneric classification, followed in 1830...
, placing D. floribunda in section Dryandra verae along with most other species, because its follicles
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....
contain a single seed separator. Dryandra verae was renamed Eudryandra by Carl Meissner
Carl Meissner
Carl Daniel Friedrich Meissner was a Swiss botanist.Born in Bern, Switzerland on 1 November 1800, he was christened Meisner but later changed the spelling of his name to Meissner. For most of his 40 year career he was Professor of Botany at University of Basel...
in 1845. Eleven years later Meissner published a new arrangement
Meissner's taxonomic arrangement of Dryandra
Carl Meissner's taxonomic arrangement of Dryandra, now Banksia ser. Dryandra, was published in 1856 as part of his chapter on the Proteaceae in A. P. de Candolle's Prodromus systematis naturalis regni vegetabilis...
, retaining D. floribunda in D. sect. Eudryandra, and further placing it in the unranked subgroup § Ilicinae, because of the similarity of its leaves to those of Ilex (Holly). In 1870, George Bentham
George Bentham
George Bentham CMG FRS was an English botanist, characterized by Duane Isely as "the premier systematic botanist of the nineteenth century".- Formative years :...
published a revised arrangement
Bentham's taxonomic arrangement of Dryandra
George Bentham's taxonomic arrangement of Dryandra was published in 1870, in Volume 5 of Bentham's Flora Australiensis...
in his Flora Australiensis
Flora Australiensis
Flora Australiensis: a description of the plants of the Australian Territory, more commonly referred to as Flora Australiensis, and also known by its standard abbreviation Fl. Austral., is a seven-volume flora of Australia published between 1863 and 1878 by George Bentham, with the assistance of...
. Bentham retained section Eudryandra, but abandoned almost all of Meissner's unranked groups, including § Ilicinae. D. floribunda was instead placed in D. ser. Floribundae
Dryandra ser. Floribundae
Dryandra ser. Floribundae is an obsolete series within the former genus Dryandra . It was first published by George Bentham in 1870, and was given a new circumscription by Alex George in 1996, but was ultimately discarded in 2007 when Austin Mast and Kevin Thiele sunk Dryandra into...
along with four other species with small, mostly terminal flowers, left exposed by their having unusually short floral leaves.
Bentham's arrangement stood for over a hundred years, eventually replaced in 1996 by the arrangement of
George's taxonomic arrangement of Dryandra
Alex George's taxonomic arrangement of Dryandra was the first modern-day arrangement of that taxon. First published in Nuytsia in 1996, it superseded the arrangement of George Bentham, which had stood for over a hundred years; it would later form the basis for George's 1999 treatment of Dryandra...
Alex George
Alex George
Alexander Segger George is a Western Australian botanist. He is the authority on the plant genera Banksia and Dryandra...
. Section Eudryandra was promoted to subgenus rank, but replaced by the autonym
Autonym (botany)
In botanical nomenclature, autonyms are automatically created names, as regulated by the International Code of Botanical Nomenclature . Autonyms are cited without an author. Relevant provisions are in articles 6.8, 22.1-3 and 26.1-3....
D. subg. Dryandra
Dryandra subg. Dryandra
Dryandra subg. Dryandra is an obsolete series within the former genus Dryandra . It was first published at sectional rank as Dryandra verae in 1830, before being renamed Eudryandra in 1847, the replaced by the autonym at subgenus rank in 1996...
. D. sessilis, as this species was now called, was retained in D. ser. Floribundae, but alone, as the series was redefined as containing only those taxa that apparently lack floral bracts altogether. The placement of D. sessilis in George's arrangement, with 1999 and 2005 amendments, may be summarised as follows:
- Dryandra (now Banksia ser. Dryandra)
- D. subg. DryandraDryandra subg. DryandraDryandra subg. Dryandra is an obsolete series within the former genus Dryandra . It was first published at sectional rank as Dryandra verae in 1830, before being renamed Eudryandra in 1847, the replaced by the autonym at subgenus rank in 1996...
- D. ser. FloribundaeDryandra ser. FloribundaeDryandra ser. Floribundae is an obsolete series within the former genus Dryandra . It was first published by George Bentham in 1870, and was given a new circumscription by Alex George in 1996, but was ultimately discarded in 2007 when Austin Mast and Kevin Thiele sunk Dryandra into...
- D. sessilis (now B. sessilis)
- D. sessilis var. sessilis (now B. sessilis var. sessilisBanksia sessilis var. sessilisBanksia sessilis var. sessilis is the most populous and most widespread variety of Banksia sessilis .-Description:The leaves of this variety are larger than those of B. sessilis var. cygnorum but smaller than those of B. sessilis var. cordata. It differs from B. sessilis var...
) - D. sessilis var. flabellifolia (now B. sessilis var. flabellifoliaBanksia sessilis var. flabellifoliaBanksia sessilis var. flabellifolia is a variety of Banksia sessilis .-Description:It grows as a shrub up to five metres high. Unlike other varieties of B. sessilis, it has hairless stems. The leaves are fan shaped, with a long, toothless lower margin, and a toothed end...
) - D. sessilis var. cordata (now B. sessilis var. cordataBanksia sessilis var. cordataBanksia sessilis var. cordata is a variety of Banksia sessilis , with unusually large leaves and flower heads. It is a rare variety that is restricted to the extreme south-west corner of Western Australia.-Description:...
) - D. sessilis var. cygnorum (now B. sessilis var. cygnorumBanksia sessilis var. cygnorumBanksia sessilis var. cygnorum is a variety of Banksia sessilis .-Description:It grows as a shrub up to five metres high, with a down of fine hairs on the stems. This variety is has the smallest leaves of any B. sessilis variety, being no more than three centimetres long, and less than two...
)
- D. sessilis var. sessilis (now B. sessilis var. sessilis
- D. sessilis (now B. sessilis)
- D. ser. ArmataeDryandra ser. ArmataeDryandra ser. Armatae is an obsolete series within the former genus Dryandra . It was first published by George Bentham in 1870, and was given a new circumscription by Alex George in 1996, but was ultimately discarded in 2007 when Austin Mast and Kevin Thiele sunk Dryandra into Banksia.-According...
- D. ser. Marginatae
- D. ser. Folliculosae
- D. ser. Acrodontae
- D. ser. CapitellataeDryandra ser. CapitellataeDryandra ser. Capitellatae is an obsolete series within the former genus Dryandra . It was published by Alex George in 1996, but discarded in 2007 when Austin Mast and Kevin Thiele sank Dryandra into Banksia.-Publication:George published the series in his 1996 "New taxa and a new infrageneric...
- D. ser. IlicinaeDryandra ser. IlicinaeDryandra ser. Ilicinae is an obsolete series within the former genus Dryandra . It was first published by Carl Meissner in 1856, but was discarded by George Bentham in 1870...
- D. ser. Dryandra
- D. ser. Foliosae
- D. ser. Decurrentes
- D. ser. Tenuifoliae
- D. ser. Runcinatae
- D. ser. Triangulares
- D. ser. AphragmaDryandra ser. AphragmaDryandra ser. Aphragma is an obsolete series within the former genus Dryandra . It was first published at sectional rank by Robert Brown in 1830, and was retained at that rank until 1999, when Alex George demoted it to a series...
- D. ser. Ionthocarpae
- D. ser. Inusitatae
- D. ser. Subulatae
- D. ser. Gymnocephalae
- D. ser. PlumosaeDryandra ser. PlumosaeDryandra ser. Plumosae is an obsolete series within the former genus Dryandra . It was published by Alex George in 1996, but discarded in 2007 when Austin Mast and Kevin Thiele sank Dryandra into Banksia....
- D. ser. Concinnae
- D. ser. Obvallatae
- D. ser. Pectinatae
- D. ser. Acuminatae
- D. ser. NiveaeDryandra ser. NiveaeDryandra ser. Niveae is an obsolete series within the former genus Dryandra . It was first published by George Bentham in 1870, and was given a new circumscription by Alex George in 1996, but was ultimately discarded in 2007 when Austin Mast and Kevin Thiele sunk Dryandra into Banksia.-According to...
- D. ser. Floribundae
- D. subg. HemiclidiaDryandra subg. HemiclidiaDryandra subg. Hemiclidia is an obsolete plant taxon that encompassed material that is now included in Banksia. Published at genus rank as Hemiclidia by Robert Brown in 1830, it was set aside by George Bentham in 1870, but reinstated at subgenus rank by Alex George in 1996...
- D. subg. DiplophragmaDryandra subg. DiplophragmaDryandra subg. Diplophragma is an obsolete subgenus within the former genus Dryandra . It was first published by Robert Brown in 1830, but was discarded by George Bentham in 1870...
- D. subg. Dryandra
George's arrangement remained current until 2007, when 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...
and 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...
transferred Dryandra into Banksia. They also published B. subg. 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 Banksia 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, thus redefining B. subg. 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...
as comprising those that do not. They were not ready, however, to tender an infrageneric arrangement encompassing Dryandra, so as an interim measure they transferred Dryandra into Banksia at series
Series (botany)
Series is a low-level taxonomic rank below that of section but above that of species.In botany, a series is a subdivision of a genus...
rank. This minimised the nomenclatural disruption of the transfer, but also caused George's rich infrageneric arrangement to be set aside. Thus under the interim arrangements implemented by Mast and Thiele, B. sessilis is placed in B. subg. 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...
, ser. Dryandra.
Varieties
Four varieties are recognised:- B. sessilis var. sessilisBanksia sessilis var. sessilisBanksia sessilis var. sessilis is the most populous and most widespread variety of Banksia sessilis .-Description:The leaves of this variety are larger than those of B. sessilis var. cygnorum but smaller than those of B. sessilis var. cordata. It differs from B. sessilis var...
is an autonymAutonym (botany)In botanical nomenclature, autonyms are automatically created names, as regulated by the International Code of Botanical Nomenclature . Autonyms are cited without an author. Relevant provisions are in articles 6.8, 22.1-3 and 26.1-3....
that encompasses the type material of the species. This is the most widespread variety, occurring from Regans FordRegans Ford, Western AustraliaRegans Ford is a small town located in the Wheatbelt region of Western Australia, about north of Perth in the Shire of Dandaragan.-History:...
and MooraMoora, Western AustraliaMoora is a townsite located 177 km north of Perth in the Wheatbelt region of Western Australia. Moora was one of the original stations on the Midland railway line to Walkaway, and the townsite was gazetted in 1895...
in the north, south-east to AlbanyAlbany, Western AustraliaAlbany is a port city in the Great Southern region of Western Australia, some 418 km SE of Perth, the state capital. As of 2009, Albany's population was estimated at 33,600, making it the 6th-largest city in the state....
, and inland as far as Wongan HillsWongan Hills, Western AustraliaWongan Hills is a town in the Shire of Wongan-Ballidu, in the Wheatbelt region of Western Australia. The town is approximately 182 km north of the State capital Perth, at an altitude of 286 metres....
, PingellyPingelly, Western AustraliaPingelly is a town and shire located in the Wheatbelt region of Western Australia, from Perth via the Brookton Highway and Great Southern Highway. The town is also located on the Great Southern railway line...
and KulinKulin, Western AustraliaKulin is a town located in the Eastern Wheatbelt region of Western Australia, approximately 280 km from Perth. It is the main town in the Shire of Kulin.- History :...
. Its blue-green leaves are cuneate (wedge-shaped) or oblong, and are usually two to three centimetres long but may reach five. - B. sessilis var. cordataBanksia sessilis var. cordataBanksia sessilis var. cordata is a variety of Banksia sessilis , with unusually large leaves and flower heads. It is a rare variety that is restricted to the extreme south-west corner of Western Australia.-Description:...
was published as Dryandra floribunda var. cordata by Carl MeissnerCarl MeissnerCarl Daniel Friedrich Meissner was a Swiss botanist.Born in Bern, Switzerland on 1 November 1800, he was christened Meisner but later changed the spelling of his name to Meissner. For most of his 40 year career he was Professor of Botany at University of Basel...
in 1848. In 1870, George BenthamGeorge BenthamGeorge Bentham CMG FRS was an English botanist, characterized by Duane Isely as "the premier systematic botanist of the nineteenth century".- Formative years :...
published D. floribunda var. major, but this is now considered a taxonomic synonym of B. sessilis var. cordata. It has larger inflorescences than var. sessilis, as well as larger dark green rather than blue green leaves. It is found in the state's far southwest, between Capes LeeuwinCape LeeuwinCape Leeuwin is the most south-westerly mainland point of the Australian Continent, in the state of Western Australia.A few small islands and rocks, the St Alouarn Islands, extend further to the south. The nearest settlement, north of the cape, is Augusta. South-east of Cape Leeuwin, the coast...
and NaturalisteCape NaturalisteCape Naturaliste is a headland in the south western region of Western Australia at the western edge of the Geographe Bay. It is the northernmost point of the Leeuwin-Naturaliste Ridge which was named after the cape...
, and east to WalpoleWalpole, Western AustraliaWalpole is a town in Western Australia, 432 km SSE of Perth and 66 km west of Denmark.Walpole lies very close to the northern point of the 100-hectare Walpole Inlet, from which it takes its name....
, and grows on sandy soils over limestone. - B. sessilis var. cygnorumBanksia sessilis var. cygnorumBanksia sessilis var. cygnorum is a variety of Banksia sessilis .-Description:It grows as a shrub up to five metres high, with a down of fine hairs on the stems. This variety is has the smallest leaves of any B. sessilis variety, being no more than three centimetres long, and less than two...
has its roots in Michel GandogerMichel GandogerAbbott Jean Michel Gandoger , was a French botanist and mycologist.. Gandoger was born in Arnas, the son of a wealthy vineyard owner in the Beaujolais region. Although he took holy orders at the age of 26, he devoted his life to the study of botany, specializing in the genus Rosa...
's publication of two new species names in 1919. He published Dryandra cygnorum and Dryandra quinquedentata, but in 1996 both of these were found to refer to the same taxonTaxon|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
, which Alex GeorgeAlex GeorgeAlexander Segger George is a Western Australian botanist. He is the authority on the plant genera Banksia and Dryandra...
gave variety rank as Dryandra sessilis var. cygnorum. The term cygnorum is Latin for "swan" and relates to the Swan River, which runs past the suburb of MelvilleMelville, Western AustraliaMelville is a suburb of Perth, Western Australia located within the likewise named City of Melville....
where the type material was collected. It has smaller dark green leaves only 2–3 cm (0.8–1.2 in) long and 0.8–1.7 cm (0.3–0.6 in) wide, whose teeth are limited to the distal part of the leaf. The range is along the Western Australian coastline from DongaraDongara, Western AustraliaDongara is a town located 351 km north-northwest of Perth on the Brand Highway. The town is located at the mouth of the Irwin River. In recent years the area has been marketed as the 'Rock lobster capital of Australia'....
southwards past FremantleFremantle, Western AustraliaFremantle is a city in Western Australia, located at the mouth of the Swan River. Fremantle Harbour serves as the port of Perth, the state capital. Fremantle was the first area settled by the Swan River colonists in 1829...
, and east to Lake Indoon and Kings ParkKings Park, Western AustraliaKings Park is a park located on the western edge of Perth, Western Australia central business district. The park is a mixture of grassed parkland, botanical gardens and natural bushland on Mount Eliza with two thirds of the grounds conserved as native bushland. With panoramic views of the Swan...
. - B. sessilis var. flabellifoliaBanksia sessilis var. flabellifoliaBanksia sessilis var. flabellifolia is a variety of Banksia sessilis .-Description:It grows as a shrub up to five metres high. Unlike other varieties of B. sessilis, it has hairless stems. The leaves are fan shaped, with a long, toothless lower margin, and a toothed end...
was published by George in 1996, the type specimen having been collected northwest of NorthamptonNorthampton, Western AustraliaNorthampton is a town north of Geraldton, in the Mid West region of Western Australia. At the 2006 census, the town had a population of 813. It is historic, with an outstanding National Trust building. The town lies on the North West Coastal Highway. Formerly named Gwalla after the location's...
in 1993. The northernmost of the four varieties, it is found from KalbarriKalbarri, Western AustraliaKalbarri is a coastal town in the Mid West region located 592 km north of Perth, Western Australia. The town is found at the mouth of the Murchison River and has an elevation of...
south to GeraldtonGeraldton, Western AustraliaGeraldton is a city and port in Western Australia located north of Perth in the Mid West region. Geraldton has an estimated population at June 2010 of 36,958...
and Northampton. There are some scattered records further south towards Moora. Its specific name is derived from the LatinLatinLatin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
flabellum "fan" and folium "leaf". Its leaves are fan shaped, with a long, toothless lower margin, and a toothed end. Its stems are hairless, unlike the other varieties.
Distribution and habitat
Floristic province
A phytochorion, in phytogeography, is a geographic area with a relatively uniform composition of plant species. Adjacent phytochoria do not usually have a sharp boundary, but rather a soft one, a transitional area in which many species from both regions overlap...
renowned as a biodiversity hotspot
Biodiversity hotspot
A biodiversity hotspot is a biogeographic region with a significant reservoir of biodiversity that is under threat from humans.The concept of biodiversity hotspots was originated by Norman Myers in two articles in “The Environmentalist” , revised after thorough analysis by Myers and others in...
, located in the southwest corner of Western Australia. This area has a Mediterranean climate
Mediterranean climate
A Mediterranean climate is the climate typical of most of the lands in the Mediterranean Basin, and is a particular variety of subtropical climate...
, with wet winters and hot, dry summers. B. sessilis occurs throughout much of the province, ranging from Kalbarri in the north, south to Cape Leeuwin
Cape Leeuwin
Cape Leeuwin is the most south-westerly mainland point of the Australian Continent, in the state of Western Australia.A few small islands and rocks, the St Alouarn Islands, extend further to the south. The nearest settlement, north of the cape, is Augusta. South-east of Cape Leeuwin, the coast...
, east along the south coast as far as Bremer Bay, and inland to Wongan Hills
Wongan Hills, Western Australia
Wongan Hills is a town in the Shire of Wongan-Ballidu, in the Wheatbelt region of Western Australia. The town is approximately 182 km north of the State capital Perth, at an altitude of 286 metres....
and Kulin
Kulin, Western Australia
Kulin is a town located in the Eastern Wheatbelt region of Western Australia, approximately 280 km from Perth. It is the main town in the Shire of Kulin.- History :...
. It thus spans a wide range of climates, occurring in all but the semi-arid areas well inland. It is also absent from the Karri forest
Karri forest
Karri forest is tall open forest of Eucalyptus diversicolor , one of the tallest hardwoods in the world.It occurs only in the south-west corner of the Southwest Botanical Province of Western Australia, in the Warren biogeographic region...
in the cool, wet, southwest corner of the province, but even there, B. sessilis var. cordata occurs along the coast.
The species tolerates a range of soils, requiring only that its soil be well-drained. Like most dryandras, it grows well in lateritic
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...
soils and gravels, although this species is also found in deep sand, sand over laterite, and sand over limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
. It also occurs in a range of vegetation
Vegetation
Vegetation is a general term for the plant life of a region; it refers to the ground cover provided by plants. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics. It is broader...
complexes, including coastal and kwongan
Kwongan
Kwongan is a type of heathland found on the coastal plains of Western Australia. The name is derived from the language of the Noongar people. Kwongan comprises floristically-rich heath with dense thickets of sclerophyllous shrubs and isolated small trees...
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...
, tall 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...
, woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...
and open forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...
. It is a common understorey
Understory
Understory is the term for the area of a forest which grows at the lowest height level below the forest canopy. Plants in the understory consist of a mixture of seedlings and saplings of canopy trees together with understory shrubs and herbs...
plant in drier areas of Jarrah forest
Jarrah forest
Jarrah forest is tall open forest in which the dominant overstory tree is Eucalyptus marginata . The ecosystem occurs only in the Southwest Botanical Province of Western Australia...
, and forms thicket
Thicket
A thicket is a very dense stand of trees or tall shrubs, often dominated by only one or a few species, to the exclusion of all others. They may be formed by species that shed large amounts of highly viable seeds that are able to germinate in the shelter of the maternal plants.In some conditions the...
s on limestone soils of the Swan Coastal Plain
Swan Coastal Plain
The Swan Coastal Plain in Western Australia is the geographic feature which contains the Swan River as it travels west to the Indian Ocean. The coastal plain continues well beyond the boundaries of the Swan River and its tributaries, as a geological and biological zone, one of Western Australia's...
. Banksia sessilis sets a large amount of seed and is an aggressive coloniser of disturbed and open areas; for example, it has been recorded colonising gravel pit
Gravel pit
Gravel pit is the term for an open cast working for extraction of gravel. Gravel pits often lie in river valleys where the water table is high, so they may fill naturally with water to form ponds or lakes. Old, abandoned gravel pits are normally used either as nature reserves, or as amenity areas...
s in the Darling Scarp
Darling Scarp
The Darling Scarp, also referred to as the Darling Range or Darling Ranges, is a low escarpment running north-south to the east of the Swan Coastal Plain and Perth, Western Australia...
.
Nothing is known of the conditions that affect its distribution, as its 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...
is as yet unstudied. An assessment of the potential impact of climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
on this species found that its range is likely to contract by half in the face of severe change, but unlikely to change much under less severe scenarios.
As food
The nectar of B. sessilis is an important component of the diet of a number of species of honeyeaterHoneyeater
The honeyeaters are a large and diverse family of small to medium sized birds most common in Australia and New Guinea, but also found in New Zealand, the Pacific islands as far east as Samoa and Tonga, and the islands to the north and west of New Guinea known as Wallacea...
. In one study, B. sessilis was found to be the main source of nectar for all six species studied, namely the Tawny-crowned Honeyeater
Tawny-crowned Honeyeater
The Tawny-crowned Honeyeater is a passerine bird native to eastern Australia.The Tawny-crowned Honeyeater was originally described by ornithologist John Latham in 1802 as Certhia melanops...
(Gliciphila melanops), White-cheeked Honeyeater
White-cheeked Honeyeater
The White-cheeked Honeyeater inhabits the east coast and the south-west corner of Australia. It has a large white patch on its cheek, a brown eye, and a yellow panel on its wing.- Description :...
(Phylidonyris niger), Western Spinebill
Western Spinebill
The Western Spinebill, Acanthorhynchus superciliosus, is a honeyeater found in the heath and woodland of south-western Western Australia. It ranges between long, and weighs around . It has a black head, gray back and wings, with a red band behind its neck and from its throat to its breast. There...
(Acanthorhynchus superciliosus), Brown Honeyeater
Brown Honeyeater
The Brown Honeyeater is a honeyeater, a group of birds found mainly in Australia and New Guinea which have highly developed brush-tipped tongues adapted for nectar feeding...
(Lichmera indistincta), Brown-headed Honeyeater
Brown-headed Honeyeater
The Brown-headed Honeyeater is a species of passerine bird in the Meliphagidae family.It is endemic to Australia. Its natural habitats are temperate forests and Mediterranean-type shrubby vegetation....
(Melithreptus brevirostris), and Black Honeyeater
Black Honeyeater
The Black Honeyeater is a species of bird in the family of honeyeaters, Meliphagidae, and the sole species in the genus Sugomel. The Black Honeyeater exhibits sexual dimorphism with the male being black and white while the female is a speckled grey-brown; immature birds look like the female...
(Certhionyx niger). Moreover, B. sessilis played an important role in their distributions, with species that feed only on nectar occurring only where B. sessilis occurs, and remaining for longest at sites where B. sessilis is most abundant. Other honeyeaters that have been recorded feeding on B. sessilis include the Red Wattlebird
Red Wattlebird
The Red Wattlebird , also known as Barkingbird or Gillbird, is a honeyeater; a group of birds found mainly in Australia and New Guinea which have highly developed brush-tipped tongues adapted for nectar feeding...
(Anthochaera carunculata), Western Wattlebird
Western Wattlebird
The Western Wattlebird is a honeyeater, a passerine bird in the family Meliphagidae. It was formerly lumped with the Little Wattlebird which it closely resembles. It is restricted to south-western Western Australia....
(A. lunulata), and New Holland Honeyeater
New Holland Honeyeater
The New Holland Honeyeater is a honeyeater species found throughout southern Australia. It was among the first birds to be scientifically described in Australia, and was initially named Certhia novaehollandiae...
(Phylidonyris novaehollandiae). Furthermore, a study of bird species diversity in wandoo
Eucalyptus wandoo
Eucalyptus wandoo is a medium-sized tree widely distributed in southwest Western Australia.-Description:It grows as a small to medium-sized tree up to 25 metres in height. It has smooth bark, often in mottled patches of white, light grey, light brown light yellow and pink...
woodland around Bakers Hill
Bakers Hill, Western Australia
Bakers Hill is a town east of Perth, Western Australia on the Great Eastern Highway. The town is located within the Shire of Northam, between Wundowie and Clackline. At the 2006 census, Bakers Hill had a population of 637.-History:...
found that honeyeater species and numbers were much reduced in forest that lacked a Banksia sessilis understorey; the plant is a key source of nectar and insects during the winter months.
Banksia sessilis is also a source of food for the Australian Ringneck
Australian Ringneck
The Australian Ringneck is a parrot native to Australia. Except for extreme tropical and highland areas, the species has adapted to all conditions...
(Barnardius zonarius), and the Long-billed Black Cockatoo (Calyptorhynchus baudinii), which tear open the follicles
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....
and consume the seeds.
The introduced European Honey Bee
European honey bee
The Western honey bee or European honey bee is a species of honey bee. The genus Apis is Latin for "bee", and mellifera comes from Latin melli- "honey" and ferre "to bear"—hence the scientific name means "honey-bearing bee"...
(Apis mellifera) has also been observed feeding on B. sessilis, as have seven species of native bee
Australian native bees
Australia has over 1,500 species of native bee. Bees can be distinguished from flies in that bees have four wings, where flies have only two. Bees collect pollen, from flowers, to feed their young...
, comprising four species of Hylaeus (including the Banksia Bee
Banksia bee
The Banksia bee is a bee species endemic to Australia where it is commonly found in the coastal heaths of eastern and southern Western Australia...
H. alcyoneus), two of Leioproctus
Leioproctus
Leioproctus is a genus in the plaster bee family Colletidae. Its members are primarily found in Australasia and temperate South America, and include the most common native bees in New Zealand...
, and a Lasioglossum
Lasioglossum
The sweat bee genus Lasioglossum is the largest of all bee genera, containing over seventeen hundred species in numerous subgenera worldwide. They are highly variable in size, coloration, and sculpture; among the more unusual variants, some are cleptoparasites, some are nocturnal, and some are...
.
Life cycle
Honeyeaters are clearly the most important pollinationPollination
Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
vector, as inflorescences from which honeyeaters are excluded generally do not set any fruit. Moreover, honeyeaters have been observed moving from tree to tree with significant loads of B. sessilis pollen on their foreheads, beaks and throats, having acquired it by brushing against pollen presenters while foraging for nectar; experiments have shown that some of this pollen may be subsequently deposited on stigmas during later foraging.
The flowers of B. sessilis have a number of adaptations that serve to encourage outcrossing
Outcrossing
Outcrossing is the practice of introducing unrelated genetic material into a breeding line. It increases genetic diversity, thus reducing the probability of all individuals being subject to disease or reducing genetic abnormalities...
. Firstly, they are protandrous: a flower's pollen is released around 72 hours before it becomes itself receptive to pollen, by which time around half of its pollen has lost its viability. Secondly, the period of maximum nectar production closely matches the period during which the flower is sexually active, so honeyeaters are enticed to visit at the most opportune time for pollination. This has proven an effective strategy: almost all pollen is removed within two to three hours of presentation. In addition, honeyeaters tend to move between inflorescences on different plants, rather than between inflorescences on the same plant, at least in high density sites. These factors combine to make it fairly unusual for a flower to be fertilised by its own pollen. When self-fertilisation does occur, whether autogamous or geitonogamous, the resulting seed is almost always aborted, and the species ultimately achieves an outcrossing rate of nearly 100%, at least in high density sites. Limited data for low-density sites, where honeyeaters move from plant to plant less frequently, suggest more of a mixed-mating system.
The species is a prolific flowerer, and this, combined with the very high outcrossing rates, results in massive seed output. In one study, the average number of seeds produced per B. sessilis plant was 622, compared with an average of 2 for B. dallanneyi
Banksia dallanneyi
Banksia dallanneyi, commonly known as Couch Honeypot, is a prostrate shrub endemic to Western Australia. It grows to a height and width of up to 0.5 m, although it is very common for many plants to be growing side by side; thus the clump may be several metres across.It was known as Dryandra...
. This exceptionally high fecundity
Fecundity
Fecundity, derived from the word fecund, generally refers to the ability to reproduce. In demography, fecundity is the potential reproductive capacity of an individual or population. In biology, the definition is more equivalent to fertility, or the actual reproductive rate of an organism or...
can be understood as an adaption to regular bushfire. Most Banksia species can be placed in one of two broad groups according to their response to fire: resprouter
Resprouter
Resprouters are plant species that are able to survive fire by the activation of dormant vegetative buds to produce regrowth.Plants may resprout by means of lignotubers at the base or epicormic buds on the trunk or major branches....
s survive fire, resprouting from a 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...
or, more rarely, epicormic buds
Epicormic shoot
An epicormic shoot is a shoot growing from an epicormic bud which lies underneath the bark of a trunk, stem, or branch of a plant.-Epicormic buds:...
protected by thick bark; reseeders are killed by fire, but populations are rapidly re-established through the recruitment of seedlings. B. sessilis is a reseeder, but it differs from many other reseeders in not being strongly serotinous: the vast majority of seeds are released spontaneously in autumn, even in the absence of fire. The degree of serotiny is a matter of some contradiction in the scientific literature: it has been treated as "serotinous", "weakly serotinous" and "non-serotinous". Regardless of the terminology used, the massive spontaneous seed output of B. sessilis is its primary survival strategy, and is so effective that the species has a reputation as an excellent coloniser. However, this strategy, together with its relatively long juvenile period, makes it vulnerable to overly frequent fire.
Seeds of B. sessilis are short-lived, and must germinate in the winter following their release, or they die. They are also very sensitive to heating, and thus killed by bushfire; in one study, just 30 seconds in boiling water reduced the germination rate from 85% to 22%, and not a single seed survived one minute of boiling.
Like most other 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,...
, B. sessilis has compound cluster roots, roots with dense clusters of short lateral rootlets that form a mat in the soil just below the leaf litter. These exude a range of carboxylates, including citrate
Citrate
A citrate can refer either to the conjugate base of citric acid, , or to the esters of citric acid. An example of the former, a salt is trisodium citrate; an ester is triethyl citrate.-Other citric acid ions:...
, malonate
Malonate
The malonate or propanedioate ion is CH222− . Malonate compounds include salts and esters of malonic acid, such as*diethyl malonate, 2,*dimethyl malonate, 2,...
and trans-aconitate, that act as acid phosphatase
Acid phosphatase
Acid phosphatase is a phosphatase, a type of enzyme, used to free attached phosphate groups from other molecules during digestion. It is basically a phosphomonoesterase...
, allowing the absorption of nutrients from nutrient-poor 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 native soils of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
Disease
Banksia sessilis is highly susceptible to dieback caused by the introduced plant pathogenPathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
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...
, a soil-borne water mould
Water mould
Oömycota or oömycetes form a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms . They are filamentous, microscopic, absorptive organisms that reproduce both sexually and asexually...
that causes root rot
Root rot
Root rot is a condition found in both indoor and outdoor plants, although more common in indoor plants with poor drainage. As the name states, the roots of the plant rot. Usually, this is a result of overwatering. In houseplants, it is a very common problem, and is slightly less common in outdoor...
; in fact it is so reliably susceptible that it is considered a good indicator species
Indicator species
An indicator species is any biological species that defines a trait or characteristic of the environment. For example, a species may delineate an ecoregion or indicate an environmental condition such as a disease outbreak, pollution, species competition or climate change...
for the presence of the disease. Most highly susceptible species quickly become locally extinct in infected areas, and in the absence of hosts the disease itself eventually dies out. However, B. sessilis, being an aggressive coloniser of disturbed and open ground, often colonises old disease sites. The new colonies are themselves infected, and thus P. cinnamomi survives at these sites indefinitely.
The application of phosphite
Phosphite
A phosphite is a salt of phosphorous acid. The phosphite ion is a polyatomic ion with a phosphorus central atom where phosphorus has an oxidation state of +3...
inhibits growth of P. cinnamomi in B. sessilis, but does not kill the pathogen. In one study, a foliar spray containing phosphite inhibited the growth of P. cinnamomi by over 90% in plants infected with B. sessilis two weeks after spraying, and by 66% in plants infected one year after spraying; yet most plants infected shortly before or after spraying were dead 100 days later, while nearly all plants infected seven months later spraying survived a further 100 days. Phosphite is not known to affect plant growth, but has been shown to reduce pollen fertility: one study recorded fertility reductions of up to 50%, and, in a separate experiment, fertility reductions that persisted for more than a year.
Infection of coastal stands of B. sessilis by the fungus Armillaria luteobubalina
Armillaria luteobubalina
Armillaria luteobubalina, commonly known as the Australian honey fungus, is a species of mushroom in the family Physalacriaceae. Widely distributed in southern Australia, the fungus is responsible for a disease known as Armillaria root rot, a primary cause of Eucalyptus tree death and forest dieback...
has also been recorded. The apparent infection rate
Apparent infection rate
Apparent infection rate is an estimate of the rate of progress of a disease, based on proportional measures of the extent of infection at different times.Firstly, a proportional measure of the extent of infection is chosen as the disease extent metric...
of 0.31 is quite slow compared to the progress of other Armillaria species through pine
Pine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
plantation
Plantation
A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...
s.
History
It is not known whether the seed collection sent to the Royal Botanic Gardens, KewRoyal Botanic Gardens, Kew
The Royal Botanic Gardens, Kew, usually referred to as Kew Gardens, is 121 hectares of gardens and botanical glasshouses between Richmond and Kew in southwest London, England. "The Royal Botanic Gardens, Kew" and the brand name "Kew" are also used as umbrella terms for the institution that runs...
, by Menzies in 1793 included seeds of B. sessilis, but if it did then it did not germinate. The species was successfully germinated, however, from Good's seed, which was sent from Sydney on 6 June 1802 and arrived at Kew the following year. According to Brown's notes it was flowering at Kew by May 1806, and in 1810 it was reported in the second edition of Hortus Kewensis as flowering "most part of the Year". In 1813 a flowering specimen from the nursery of Malcolm and Sweet was featured as Plate 1581 in Curtis's Botanical Magazine
Curtis's Botanical Magazine
The Botanical Magazine; or Flower-Garden Displayed, is an illustrated publication which began in 1787. The longest running botanical magazine, it is widely referred to by the subsequent name Curtis's Botanical Magazine....
.
Vienna
Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...
, Austria
Austria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...
in 1831, and in 1833 it was listed amongst the rare plants that had been introduced into Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
. Along with several hundred other native Australian plants it was exhibited at plant shows held at Utrecht
Utrecht (city)
Utrecht city and municipality is the capital and most populous city of the Dutch province of Utrecht. It is located in the eastern corner of the Randstad conurbation, and is the fourth largest city of the Netherlands with a population of 312,634 on 1 Jan 2011.Utrecht's ancient city centre features...
and Haarlem
Haarlem
Haarlem is a municipality and a city in the Netherlands. It is the capital of the province of North Holland, the northern half of Holland, which at one time was the most powerful of the seven provinces of the Dutch Republic...
in the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
in the 1840s and 1850s. By this time, however, English gardeners had already begun to lose interest in the Proteaceae, and by the end of the 19th century European interest in the cultivation of Proteaceae was virtually non-existent.
In Australia, there was little interest in the cultivation of Australian plants until the mid-20th century, despite a long-standing appreciation of their beauty as wildflower
Wildflower
A wildflower is a flower that grows wild, meaning it was not intentionally seeded or planted. Yet "wildflower" meadows of a few mixed species are sold in seed packets. The term "wildflower" has been made vague by commercial seedsmen who are interested in selling more flowers or seeds more...
s. For example, in 1933 and 1934 The Western Mail
Western Mail (Western Australia)
The Western Mail, or Western Mail, was the name of two weekly newspapers published in Perth, Western Australia.-West Australian newspapers:...
published a series of Edgar Dell
Edgar Dell
Edgar Dell was a Western Australian painter best known for his watercolour paintings of that state's wildflowers....
paintings of Western Australian wildflowers, including a painting of B. sessilis. These were subsequently republished in 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....
's 1935 West Australian Wild Flowers. One of the first published colour photographs of the species appeared in 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...
's 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....
, but this publication was restricted to plant identification. The species was discussed and illustrated in the 1959 Wildflowers of Western Australia, and in the 1973 Flowers and plants of Western Australia, but these books did not provide cultivation advice either.
Possibly the first published information on the cultivation of Dryandra appeared in the magazine Australian Plants in June and September 1961. D. sessilis was among the species treated, but as there was not yet any experimental data on cultivation, information was restricted to its aesthetic qualities and the soil in which it naturally occurs.
From its inception in 1962, the Kings Park and Botanic Garden undertook extensive research into the cultivation of native plants, resulting in two early publications that mentioned the cultivation potential of B. sessilis. In 1965, John Stanley Beard
John Stanley Beard
John Stanley Beard was a British-born forester and ecologist who resided in Australia. While working with the Forestry Division in Trinidad and Tobago during the 1940s, Beard developed a system of forest classification for Tropical America and described the forests of Trinidad, Tobago, and the...
published Descriptive catalogue of Western Australian plants, "a work of reference in which the horticultural characteristics of the plants concerned could be looked up by the staff", which described D. sessilis as an erect shrub with pale yellow flowers appearing from May to October, growing in sand and gravel. Five years later, Arthur Fairall published West Australian native plants in cultivation. This presented largely the same information as Beard's catalogue, adding only that the species flowers well in its third season.
Current knowledge
According to current knowledge, B. sessilis as an extremely hardy plant that grows in a range of soils and aspects, so long as it is given good drainage, and tolerates both drought and moderate frost. Unlike many dryandras, it grows well on limestone (alkaline) soils. It flowers very heavily and is an excellent producer of honey. It attracts birds, and is also popular with beekeepersBeekeeping
Beekeeping is the maintenance of honey bee colonies, commonly in hives, by humans. A beekeeper keeps bees in order to collect honey and other products of the hive , to pollinate crops, or to produce bees for sale to other beekeepers...
. However, its size makes it unsuitable for smaller gardens, and if given an ideal situation it may produce a great many seedlings. It is propagated only from seed, as propagating it from cutting
Cutting
Cutting is the separation of a physical object, or a portion of a physical object, into two portions, through the application of an acutely directed force. An implement commonly used for cutting is the knife or in medical cases the scalpel...
s has proven virtually impossible. Germination takes about five or six weeks, and plants may take two years to flower.