Banksia grossa
Encyclopedia
Banksia grossa, commonly known as Coarse Banksia is a species of shrub in the plant
family
Proteaceae
endemic to south west
Western Australia
. One of fourteen species of banksia with predominantly round or oval inflorescences of the series Abietinae
, it was described in 1981 as a distinct species by Alex George
. Found in sand among heath between Eneabba
and Badgingarra
in Western Australia
, it grows as a shrub to 1 m (3 ft) high with narrow leaves and oval brownish flower spikes composed of hundreds of individual flowers.
from 3 to 5 mm long. The margins are linear and inrolled, and the upper surface is sparsely hairy when young, but later hairless.
Flowers occur in a typical Banksia flower spike, an inflorescence
made up of hundreds of small individual flowers, or florets, densely packed around a cylindrical axis. In B. grossa is this 5 to 7 centimetres high. Flowers are rusty brown to golden brown, with dark red to purple styles that are not revealed until the flower fully opens.
Flowering occurs between March and September. It takes five to eight weeks for a flower to develop from bud to the end of flowering. About three weeks before the flowers open, they develop a strong musky smell. The opening of flowers, known as anthesis
, occurs sequentially, starting at the bottom of the inflorescence and sweeping through to the top over a period of around two weeks. At anthesis the flowers produce unusually large quantities of nectar; indeed some flowers produce so much that it drips to the ground. After flowering the old withered florets persist on the spike, giving it a hairy appearance. Up to 25 smooth, elliptical follicle
s develop in the spike, each containing up to two wide wedge-shaped winged seeds.
has expressed surprise that it was not collected by earlier visitors to the area, speculating that "perhaps they were diverted by its similarity to B. leptophylla
and B. sphaerocarpa
." George formally described the species in his 1981 monograph "The genus Banksia L.f. (Proteaceae)
", based on a specimen collected by him on the Brand Highway
, 76 km north of Regans Ford
, on 14 May 1969. He placed it in subgenus Banksia
because of its flower spike; section Oncostylis
because its styles are hooked; and the resurrected series Abietinae
, which he constrained to contain only round-fruited species. It was placed in phyletic order between B. micrantha
and B. leptophylla. The specific epithet is from the Latin
grossus ("coarse") and refers to the leaves, flowers and fruit, all of which George thought more coarse than other members of B. ser. Abietinae.
George's arrangement remained current until 1996, when Kevin Thiele
and Pauline Ladiges published an arrangement
informed by a cladistic
analysis of morphological
characteristics. They retained George's subgenera and many of his series, but discarded his sections. Banksia ser. Abietinae was found to be very nearly monophyletic
, and so retained. It further resolved into four subclades, so Thiele and Ladiges split it into four subseries. B. grossa appeared as the most basal member of the second of these:
This clade became the basis for the new subseries Sphaerocarpae
, which Thiele defined as containing those species with lignotubers, styles loosely curling around the infructescence (although this trait was reversed in micrantha), and "transversely aligned cells of the seed wing inner face". Other than B. grossa, these species also have shouldered follicles.
Questioning the emphasis on cladistics in Thiele and Ladiges' arrangement, George published a slightly modified version of his 1981 arrangement in his 1999 treatment of Banksia for the Flora of Australia
series of monographs. B. grossa' s placement was the same as in 1981, except that B. telmatiaea
was moved to set between it and B. leptophylla. The placement of B. sphaerocarpa in George's 1999 arrangement
may be summarised as follows:
Since 1998, Austin Mast
has been publishing results of ongoing cladistic analyses of DNA sequence
data for the subtribe Banksiinae. His analyses suggest a phylogeny that is very different to George's arrangement. B. grossa was inferred as sister to a polytomous clade consisting of B. leptophylla, B. telmatiaea, B. scabrella and B. lanata:
Early in 2007, Mast and Thiele initiated a rearrangement of Banksia by merging Dryandra
into it, and publishing B. subg. Spathulatae
for the taxa having spoon-shaped cotyledon
s. They foreshadowed publishing a full arrangement once DNA sampling of Dryandra was complete; in the meantime, if Mast and Thiele's nomenclatural changes are taken as an interim arrangement, then B. grossa is placed in B. subg. Spathulatae.
, and east almost to Coorow
. It grows in shallow sand over laterite
, in deep sand, and occasionally atop lateritic rises, on flat or gently undulating land, among kwongan
shrubland
.
inflorescences. No pollinators were recorded in The Banksia Atlas
survey.
Banksia grossa is one of five closely related Banksia species that have highly unusual flower nectar. Whereas other Banksia species produce nectar that is clear and watery, the nectar of these species is pale yellow initially, but gradually becomes darker and thicker, changing to a thick, olive-green mucilage within one to two days of secretion, and eventually becoming "an almost black, gelatinous lump adhering to the base of the flowers". It was first noted by Byron Lamont in 1980; he attributed it to cyanobacteria that feed off the nectar sugar
s. Noting that many of these cyanobacteria had heterocyst
s, he speculated that they aid the plant by fixing atmospheric nitrogen
, which is then washed off the flower heads by rain, and absorbed by the proteoid root mat. This purported symbiosis
was investigated by Barrett and Lamont in 1985, but no evidence of nitrogen fixing was found. Further investigation by Markey and Lamont in 1996 suggested that the discolouration is not caused by cyanobacteria or other microorganisms in the nectar, but is rather "a chemical phenomenon of plant origin". Their analyses indicated that the nectar had unusually high levels of sugar and free amino acid
s, but three of these species, including B. sphaerocarpa, have since been shown to have normal nectar sugar compositions.
Propagation is by seed. The seeds do not require any treatment prior to sowing, and take around 14 days to germinate. This is a slow-growing plant, taking 5 to 7 years to reach maturity and begin flowering.
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...
family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by 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,...
endemic to south west
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...
. One of fourteen species of banksia with predominantly round or oval inflorescences of the series Abietinae
Banksia ser. Abietinae
Banksia ser. Abietinae is avalid botanic name for a series of Banksia. First published by Carl Meissner in 1856, the name has had three circumscriptions.-According to Meissner:...
, it was described in 1981 as a distinct species by Alex George
Alex George
Alexander Segger George is a Western Australian botanist. He is the authority on the plant genera Banksia and Dryandra...
. Found in sand among heath between Eneabba
Eneabba, Western Australia
Eneabba is a town on the Brand Highway located 278 km north of Perth, Western Australia.The area is famous for its spectacular display of wildflowers in the spring. It is also home to the Iluka Resources mineral sands facility....
and Badgingarra
Badgingarra, Western Australia
Badgingarra is a small town located in the Wheatbelt region of Western Australia, about north of Perth in the Shire of Dandaragan.It lies on the Brand Highway adjacent to the Badgingarra National Park.-History:...
in 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 grows as a shrub to 1 m (3 ft) high with narrow leaves and oval brownish flower spikes composed of hundreds of individual flowers.
Description
Banksia grossa grows as a lignotuberous shrub up to a metre high. Young stems have a coating of woolly hairs, older stems flaky pale brown bark. The leaves are needle-like, being from 4 to 12 cm (1.6-4.6 in) long, and only 2 to 3 mm wide, on a petiolePetiole (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...
from 3 to 5 mm long. The margins are linear and inrolled, and the upper surface is sparsely hairy when young, but later hairless.
Flowers occur in a typical Banksia flower spike, an 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...
made up of hundreds of small individual flowers, or florets, densely packed around a cylindrical axis. In B. grossa is this 5 to 7 centimetres high. Flowers are rusty brown to golden brown, with dark red to purple styles that are not revealed until the flower fully opens.
Flowering occurs between March and September. It takes five to eight weeks for a flower to develop from bud to the end of flowering. About three weeks before the flowers open, they develop a strong musky smell. The opening of flowers, known as 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...
, occurs sequentially, starting at the bottom of the inflorescence and sweeping through to the top over a period of around two weeks. At anthesis the flowers produce unusually large quantities of nectar; indeed some flowers produce so much that it drips to the ground. After flowering the old withered florets persist on the spike, giving it a hairy appearance. Up to 25 smooth, elliptical follicle
Follicle (fruit)
In botany, a follicle is a dry unilocular many-seeded fruit formed from one carpel and dehiscing by the ventral suture in order to release seeds, such as in larkspur, magnolia, banksia, peony and milkweed....
s develop in the spike, each containing up to two wide wedge-shaped winged seeds.
Taxonomy
The first known specimen collection of B. grossa was made by botanist Fred W. Humphreys in 1965. Alex GeorgeAlex George
Alexander Segger George is a Western Australian botanist. He is the authority on the plant genera Banksia and Dryandra...
has expressed surprise that it was not collected by earlier visitors to the area, speculating that "perhaps they were diverted by its similarity to B. leptophylla
Banksia leptophylla
The Slender-leaved Banksia is a species of shrub in the plant genus Banksia. It occurs along the west coast of Western Australia from Gingin to Kalbarri. Before Alex George's revision of 1981, it was labelled informally as B. sphaerocarpa var. pinifolia or var...
and B. sphaerocarpa
Banksia sphaerocarpa
Banksia sphaerocarpa, commonly known as the Fox Banksia or Round-fruit Banksia, is a species of shrub or tree in the plant genus Banksia . It is generally encountered as a 1–2 m high shrub, and is usually smaller in the north of its range...
." George formally described the species in his 1981 monograph "The genus Banksia L.f. (Proteaceae)
The genus Banksia L.f. (Proteaceae)
The genus Banksia L.f. is a 1981 monograph by Alex George on the taxonomy of the plant genus Banksia. Published by the Western Australian Herbarium as Nuytsia 3, it presented George's taxonomic arrangement of Banksia, the first major taxonomic revision of the genus since George Bentham published...
", based on a specimen collected by him on the Brand Highway
Brand Highway
Brand Highway is a 362 kilometre main highway linking the northern outskirts of Perth, the capital of Western Australia, to the port city of Geraldton in Western Australia's Mid West region. Together with North West Coastal Highway, it forms part of the Western Australian coastal link to the...
, 76 km north of Regans Ford
Regans Ford, Western Australia
Regans Ford is a small town located in the Wheatbelt region of Western Australia, about north of Perth in the Shire of Dandaragan.-History:...
, on 14 May 1969. He placed it in subgenus Banksia
Banksia subg. Banksia
Banksia subg. Banksia is a valid botanic name for a subgenus of Banksia. As an autonym, it necessarily contains the type species of Banksia, B. serrata . Within this constraint, however, there have been various circumscriptions.-Banksia verae:B. subg...
because of its flower spike; section Oncostylis
Banksia sect. Oncostylis
Banksia sect. Oncostylis is one of four sections of subgenus Banksia subg. Banksia. It contains those Banksia species with hooked pistils. All of the species in Oncostylis also exhibit a top-down sequence of flower anthesis, except for Banksia nutans which is bottom-up.Banksia sect...
because its styles are hooked; and the resurrected series Abietinae
Banksia ser. Abietinae
Banksia ser. Abietinae is avalid botanic name for a series of Banksia. First published by Carl Meissner in 1856, the name has had three circumscriptions.-According to Meissner:...
, which he constrained to contain only round-fruited species. It was placed in phyletic order between B. micrantha
Banksia micrantha
Banksia micrantha is a species of shrub in the plant genus Banksia. A small spreading bush with pale yellow flower spikes, it occurs between Eneabba and Cervantes in South west Western Australia...
and B. leptophylla. The specific epithet is 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...
grossus ("coarse") and refers to the leaves, flowers and fruit, all of which George thought more coarse than other members of B. ser. Abietinae.
George's arrangement remained current until 1996, when Kevin Thiele
Kevin Thiele
Kevin R. Thiele is curator of the Western Australian Herbarium. His research interests include the systematics of the plant families Proteaceae, Rhamnaceae and Violaceae, and the conservation ecology of grassy woodland ecosystems...
and Pauline Ladiges published an arrangement
Thiele and Ladiges' taxonomic arrangement of Banksia
Kevin Thiele and Pauline Ladiges' taxonomic arrangement of Banksia, published in 1996, was a novel taxonomic arrangement that was intended to align the taxonomy of Banksia more closely with the phylogeny that they had inferred from their cladistic analysis of the genus...
informed by a cladistic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
analysis of morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
characteristics. They retained George's subgenera and many of his series, but discarded his sections. Banksia ser. Abietinae was found to be very nearly monophyletic
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...
, and so retained. It further resolved into four subclades, so Thiele and Ladiges split it into four subseries. B. grossa appeared as the most basal member of the second of these:
This clade became the basis for the new subseries Sphaerocarpae
Banksia subser. Sphaerocarpae
Banksia subser. Sphaerocarpae is a valid botanic name for a subseries of Banksia. It was published by Kevin Thiele in 1996, but discarded by Alex George in 1999.-Cladistics:...
, which Thiele defined as containing those species with lignotubers, styles loosely curling around the infructescence (although this trait was reversed in micrantha), and "transversely aligned cells of the seed wing inner face". Other than B. grossa, these species also have shouldered follicles.
Questioning the emphasis on cladistics in Thiele and Ladiges' arrangement, George published a slightly modified version of his 1981 arrangement in his 1999 treatment of Banksia for the Flora of Australia
Flora of Australia (series)
The Flora of Australia is a 59 volume series describing the vascular plants, bryophytes and lichens present in Australia and its external territories...
series of monographs. B. grossa
Banksia telmatiaea
Banksia telmatiaea, commonly known as Swamp Fox Banksia or rarely Marsh Banksia, is a shrub that grows in marshes and swamps along the lower west coast of Australia. It grows as an upright bush up to 2 m tall, with narrow leaves and a pale brown flower spike, which can produce profuse...
was moved to set between it and B. leptophylla. The placement of B. sphaerocarpa in George's 1999 arrangement
George's taxonomic arrangement of Banksia
Alex George's taxonomic arrangement of Banksia was the first modern-day arrangement for that genus. First published in 1981 in the classic monograph The genus Banksia L.f. , it superseded the arrangement of George Bentham, which had stood for over a hundred years. It was overturned in 1996 by Kevin...
may be summarised as follows:
- BanksiaBanksiaBanksia is a genus of around 170 species in the plant family Proteaceae. These Australian wildflowers and popular garden plants are easily recognised by their characteristic flower spikes and fruiting "cones" and heads. When it comes to size, banksias range from prostrate woody shrubs to trees up...
- B. subg. BanksiaBanksia subg. BanksiaBanksia subg. Banksia is a valid botanic name for a subgenus of Banksia. As an autonym, it necessarily contains the type species of Banksia, B. serrata . Within this constraint, however, there have been various circumscriptions.-Banksia verae:B. subg...
- B. sect. BanksiaBanksia sect. BanksiaBanksia sect. Banksia is one of four sections of Banksia subgenus Banksia. It contains those species of subgenus Banksia with straight or sometimes curved but not hooked styles. These species all have cylindrical inflorescences and usually exhibit a bottom-up sequence of flower anthesis...
(9 series, 50 species, 9 subspecies, 3 varieties) - B. sect. Coccinea (1 species)
- B. sect. OncostylisBanksia sect. OncostylisBanksia sect. Oncostylis is one of four sections of subgenus Banksia subg. Banksia. It contains those Banksia species with hooked pistils. All of the species in Oncostylis also exhibit a top-down sequence of flower anthesis, except for Banksia nutans which is bottom-up.Banksia sect...
- B. ser. SpicigeraeBanksia ser. SpicigeraeBanksia ser. Spicigerae is a taxonomic series in the genus Banksia. It consists of the seven species in section Oncostylis that have cylindrical inflorescences. These range in form from small shrubs to tall trees. The leaves grow in either an alternate or whorled pattern, with various shape forms...
(7 species, 2 subspecies, 4 varieties) - B. ser. Tricuspidae (1 species)
- B. ser. DryandroideaeBanksia ser. DryandroideaeBanksia ser. Dryandroideae is a valid botanic name for a taxonomic series in the plant genus Banksia. First published by Carl Meissner in 1856, the name has had two circumscriptions. As presently circumscribed it is monotypic, containing only B. dryandroides.-According to Meissner:B. ser...
(1 species) - B. ser. AbietinaeBanksia ser. AbietinaeBanksia ser. Abietinae is avalid botanic name for a series of Banksia. First published by Carl Meissner in 1856, the name has had three circumscriptions.-According to Meissner:...
- B. sphaerocarpaBanksia sphaerocarpaBanksia sphaerocarpa, commonly known as the Fox Banksia or Round-fruit Banksia, is a species of shrub or tree in the plant genus Banksia . It is generally encountered as a 1–2 m high shrub, and is usually smaller in the north of its range...
(5 varieties) - B. micranthaBanksia micranthaBanksia micrantha is a species of shrub in the plant genus Banksia. A small spreading bush with pale yellow flower spikes, it occurs between Eneabba and Cervantes in South west Western Australia...
- B. grossa
- B. telmatiaeaBanksia telmatiaeaBanksia telmatiaea, commonly known as Swamp Fox Banksia or rarely Marsh Banksia, is a shrub that grows in marshes and swamps along the lower west coast of Australia. It grows as an upright bush up to 2 m tall, with narrow leaves and a pale brown flower spike, which can produce profuse...
- B. leptophyllaBanksia leptophyllaThe Slender-leaved Banksia is a species of shrub in the plant genus Banksia. It occurs along the west coast of Western Australia from Gingin to Kalbarri. Before Alex George's revision of 1981, it was labelled informally as B. sphaerocarpa var. pinifolia or var...
(2 varieties) - B. lanataBanksia lanataThe Coomallo Banksia is a species of shrub in the plant genus Banksia. It occurs within a range of less than 100 square kilometres between Eneabba and Mount Lesueur, Western Australia. It has roughly spherical inflorescences with flowers of cream to orange-brown colour. The leaves are linear and...
- B. scabrellaBanksia scabrellaBanksia scabrella, commonly known as the Burma Road Banksia, is a species of woody shrub in the genus Banksia. It is classified in the series Abietinae, a group of several species of shrubs with small round or oval inflorescences...
- B. violaceaBanksia violaceaBanksia violacea, commonly known as Violet Banksia, is a species of shrub or tree in the plant genus Banksia . It generally grows as a small shrub to 1.5 m high with fine narrow leaves, and is best known for its unusually coloured dark purple-violet inflorescences...
- B. incanaBanksia incanaThe Hoary Banksia is a species of small shrub in the plant genus Banksia. It occurs on sandplain heathland between Badgingarra and Eneabba in Western Australia, with outlying populations as far south as Perth. Seeds do not require any treatment, and take around 14 days to germinate....
- B. laricinaBanksia laricinaThe Rose-Fruited Banksia is a species of shrub in the plant genus Banksia endemic to southwestern Western Australia. It derives its specific Latin name from larix or larch, which its foliage is said to resemble. The common name comes from the striking fruits which resemble wooden roses...
- B. pulchellaBanksia pulchellaThe Teasel Banksia is a species of small shrub in the plant genus Banksia. It occurs on the south coast of Western Australia from Fitzgerald River National Park east to Israelite Bay....
- B. meisneriBanksia meisneriThe Meisner's Banksia is a species of small shrub in the plant genus Banksia. It occurs in a number of isolated populations throughout southwest Western Australia. Seeds do not require any treatment, and take 28 to 39 days to germinate.-External links:...
(2 subspecies) - B. nutansBanksia nutansBanksia nutans, commonly known as Nodding Banksia, is a species of shrub native to the south coast of Western Australia in the genus Banksia...
(2 varieties)
- B. sphaerocarpa
- B. ser. Spicigerae
- B. sect. Banksia
- B. subg. IsostylisBanksia subg. IsostylisBanksia subg. Isostylis is a subgenus of Banksia. It contains three closely related species, all of which occur only in Southwest Western Australia. Members of subgenus Isostylis have dome-shaped flower heads that are superficially similar to those of B. ser...
(3 species)
- B. subg. Banksia
Since 1998, Austin Mast
Austin Mast
Austin R. Mast is a research botanist. Born in 1972, he obtained a Ph.D. from the University of Wisconsin–Madison in 2000. He is currently an associate professor within the Department of Biological Science at Florida State University , and has been director of FSU's since August 2003.One of his...
has been publishing results of ongoing cladistic analyses of DNA sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
data for the subtribe Banksiinae. His analyses suggest a phylogeny that is very different to George's arrangement. B. grossa was inferred as sister to a polytomous clade consisting of B. leptophylla, B. telmatiaea, B. scabrella and B. lanata:
Early in 2007, Mast and Thiele initiated a rearrangement of Banksia by merging Dryandra
Dryandra
Banksia ser. Dryandra is a series of 94 species of shrub to small tree in the plant genus Banksia. It was considered a separate genus named Dryandra until early 2007, when it was merged into Banksia on the basis of extensive molecular and morphological evidence that Banksia was paraphyletic with...
into it, and publishing B. 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 taxa having spoon-shaped cotyledon
Cotyledon
A cotyledon , is a significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of a seedling. The number of cotyledons present is one characteristic used by botanists to classify the flowering plants...
s. They foreshadowed publishing a full arrangement once DNA sampling of Dryandra was complete; in the meantime, if Mast and Thiele's nomenclatural changes are taken as an interim arrangement, then B. grossa is placed in B. subg. Spathulatae.
Distribution and habitat
Banksia grossa mainly occurs from west of Yandanooka in the north, south to Badgingarra National ParkBadgingarra National Park
Badgingarra National Park is a national park in Western Australia , 190 km north of Perth off the Brand Highway adjacent to the town of Badgingarra, Western Australia....
, and east almost to Coorow
Coorow, Western Australia
Coorow is a town in the Mid West region of Western Australia, north of Perth.The townsite of Coorow was gazetted in 1893, and the name is derived from the Aboriginal name of a nearby spring, first recorded in 1872...
. It grows in shallow sand 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...
, in deep sand, and occasionally atop lateritic rises, on flat or gently undulating land, among 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...
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...
.
Ecology
The inflorescences are highly attractive to insects. Large numbers of ladybirds have been reported drinking the nectar of this species, while ignoring nearby Banksia attenuataBanksia attenuata
Banksia attenuata, commonly known as the candlestick banksia or slender banksia, is a species of plant in the proteaceae family. Commonly a tree, it reaches 10 m high, but is often a shrub in dryer areas 0.4 to 2 m high...
inflorescences. No pollinators were recorded in The Banksia Atlas
The Banksia Atlas
The Banksia Atlas is an atlas that documents the ranges, habitats and growth forms of various species and other subgeneric taxa of Banksia, an iconic Australian wildflower genus...
survey.
Banksia grossa is one of five closely related Banksia species that have highly unusual flower nectar. Whereas other Banksia species produce nectar that is clear and watery, the nectar of these species is pale yellow initially, but gradually becomes darker and thicker, changing to a thick, olive-green mucilage within one to two days of secretion, and eventually becoming "an almost black, gelatinous lump adhering to the base of the flowers". It was first noted by Byron Lamont in 1980; he attributed it to cyanobacteria that feed off the nectar sugar
Sugar
Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...
s. Noting that many of these cyanobacteria had heterocyst
Heterocyst
Heterocysts are specialized nitrogen-fixing cells formed by some filamentous cyanobacteria, such as Nostoc punctiforme, Cylindrospermum stagnale and Anabaena sphaerica, during nitrogen starvation. They fix nitrogen from dinitrogen in the air using the enzyme nitrogenase, in order to provide the...
s, he speculated that they aid the plant by fixing atmospheric nitrogen
Nitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...
, which is then washed off the flower heads by rain, and absorbed by the proteoid root mat. This purported symbiosis
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...
was investigated by Barrett and Lamont in 1985, but no evidence of nitrogen fixing was found. Further investigation by Markey and Lamont in 1996 suggested that the discolouration is not caused by cyanobacteria or other microorganisms in the nectar, but is rather "a chemical phenomenon of plant origin". Their analyses indicated that the nectar had unusually high levels of sugar and free amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
s, but three of these species, including B. sphaerocarpa, have since been shown to have normal nectar sugar compositions.
Cultivation
Banksia grossa is cultivated for its attractive needle-like leaves and rusty-brown flower spikes, both of which can be quite variable in colour. This species favours well-drained sandy or loamy acidic soils, with a sunny aspect. Once established it tolerates dry spells. It can be pruned heavily as it resprouts from its lignotuber.Propagation is by seed. The seeds do not require any treatment prior to sowing, and take around 14 days to germinate. This is a slow-growing plant, taking 5 to 7 years to reach maturity and begin flowering.