Grevillea Lanigera 'Mt Tamboritha'
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''Grevillea'' (), commonly known as spider flowers, is a genus of about 360 species of evergreen flowering plants in the family
Proteaceae The Proteaceae form a family (biology), family of flowering plants predominantly distributed in the Southern Hemisphere. The family comprises 83 genus, genera with about 1,660 known species. Australia and South Africa have the greatest concentr ...
. Plants in the genus ''Grevillea'' are shrubs, rarely trees, with the leaves arranged alternately along the branches, the flowers
zygomorphic Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts. Uncommonly, flowers may have no axis of symmetry at all, typically because their parts are spir ...
, arranged in
raceme A raceme () or racemoid is an unbranched, indeterminate growth, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are ...
s at the ends of branchlets, and the fruit a follicle that splits down one side only, releasing one or two seeds.


Description

Plants in the genus ''Grevillea'' are shrubs, rarely small trees with
simple Simple or SIMPLE may refer to: *Simplicity, the state or quality of being simple Arts and entertainment * ''Simple'' (album), by Andy Yorke, 2008, and its title track * "Simple" (Florida Georgia Line song), 2018 * "Simple", a song by John ...
or
compound Compound may refer to: Architecture and built environments * Compound (enclosure), a cluster of buildings having a shared purpose, usually inside a fence or wall ** Compound (fortification), a version of the above fortified with defensive struc ...
leaves arranged alternately along the branchlets. The flowers are zygomorphic and typically arranged in pairs along a sometimes branched
raceme A raceme () or racemoid is an unbranched, indeterminate growth, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are ...
at the ends of branchlets. The flowers are
bisexual Bisexuality is romantic attraction, sexual attraction, or sexual behavior toward both males and females. It may also be defined as the attraction to more than one gender, to people of both the same and different gender, or the attraction t ...
, usually with four
tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...
s in a single
whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). In nature File:Photograph and axial plane floral diagra ...
. There are four
stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...
s and the
gynoecium Gynoecium (; ; : gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl (botany), whorl of a flower; it consists ...
has a single
carpel Gynoecium (; ; : gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more ...
. The fruit is a thin-walled follicle that splits down only one side, releasing one or two seeds before the next growing season.


Taxonomy

The genus ''Grevillea'' was first formally described in 1809 by Joseph Knight from an unpublished manuscript by
Robert Brown Robert Brown may refer to: Robert Brown (born 1965), British Director, Animator and author Entertainers and artists * Washboard Sam or Robert Brown (1910–1966), American musician and singer * Robert W. Brown (1917–2009), American printmaker ...
. Knight gave the spelling ''Grevillia'', corrected by Brown in 1810 to ''Grevillea'' in ''
Transactions of the Linnean Society of London The Linnean Society of London is a learned society dedicated to the study and dissemination of information concerning natural history, evolution, and taxonomy. It possesses several important biological specimen, manuscript and literature collec ...
''. The genus was named in honour of
Charles Francis Greville Charles Francis Greville PC FRS FRSE FLS FSA (12 May 1749 – 23 April 1809) was a British antiquarian, collector and politician who sat in the House of Commons from 1774 to 1790. Early life Greville was the second son of Francis Greville ...
, an 18th-century patron of botany and co-founder of the
Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...
.


Species

There are over 380 species which are
endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to Australia. 15 other species are endemic to areas outside Australia. Ten of these are endemic to New Caledonia, while '' G. elbertii'' and '' G. papuana'' are endemic to Sulawesi and New Guinea respectively. Two other species, '' G. baileyana'' and '' G. glauca'', occur in both New Guinea and
Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...
.


Distribution and habitat

Grevilleas grow in most habitats, although few grow in alpine areas, in swamps or saline soils. Most species are
endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to Australia but four species grow in New Guinea, ('' G. papuana'' is endemic), ten are endemic to New Caledonia and one species ('' G. elbertii'') is endemic to
Sulawesi Sulawesi ( ), also known as Celebes ( ), is an island in Indonesia. One of the four Greater Sunda Islands, and the List of islands by area, world's 11th-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Min ...
in Indonesia.


Ecology


Pollination

Many animals rely on the
pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...
and
nectar Nectar is a viscous, sugar-rich liquid produced by Plant, plants in glands called nectaries, either within the flowers with which it attracts pollination, pollinating animals, or by extrafloral nectaries, which provide a nutrient source to an ...
from grevilleas as a source of food, in particular, insects and birds. Generally, the
insect-pollinated Entomophily or insect pollination is a form of pollination whereby pollen of plants, especially but not only of flowering plants, is distributed by insects. Flowers pollinated by insects typically advertise themselves with bright colours, somet ...
species tend to be white, whereas the bird-pollinated species are varying shades of red, pink and other bright hues. ;
Birds Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
Most species of grevillea appear well-adapted to pollination by birds. Many of these species produce brightly-coloured inflorescences and produce large quantities of nectar. The most prominent avian pollinators of grevilleas are the honeyeaters, in which almost all species which coexist with grevilleas have been observed feeding from and pollinating them. Parrots such as
lorikeets Loriini is a tribe of small to medium-sized arboreal parrots characterized by their specialized brush-tipped tongues for feeding on nectar of various blossoms and soft fruits, preferably berries. The species form a monophyletic group within the p ...
which have special adaptations for nectivory are also likely pollinators of grevilleas. ;
Insects Insects (from Latin ') are hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed ...
Insects such as
beetles Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...
,
flies Flies are insects of the Order (biology), order Diptera, the name being derived from the Ancient Greek, Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwin ...
and
bees Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamil ...
are important pollinators of many species of grevillea. The insect-pollinated species tend to have smaller, more fragrant flowers than bird-pollinated species as a way to attract their preferred pollinators, as insects are more drawn to fragrances than birds are. The flowers of these grevilleas are usually white or cream in colour (though may also be brightly coloured) and appear during the summer months to coincide with the population increase of many insects.
Scarab beetles The family Scarabaeidae, as currently defined, consists of over 35,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change. Several groups formerly tre ...
are attracted to the smell of nectar and species such as the white plume grevillea ('' G. leptobotrys'') appear to be mainly pollinated by these and other beetles.


As an invasive species

Some species of grevillea have become
naturalised Naturalization (or naturalisation) is the legal act or process by which a non-national of a country acquires the nationality of that country after birth. The definition of naturalization by the International Organization for Migration of the ...
outside of their native distribution, thus becoming invasive. The most notable of which being '' G. robusta'', also known as silky oak. Native to eastern
Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...
and far northern
New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...
, it has been introduced to other parts of Australia and around the world. It has become an environmental weed in other parts of Australia and has been introduced to numerous other countries including
New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...
,
French Polynesia French Polynesia ( ; ; ) is an overseas collectivity of France and its sole #Governance, overseas country. It comprises 121 geographically dispersed islands and atolls stretching over more than in the Pacific Ocean, South Pacific Ocean. The t ...
,
Zimbabwe file:Zimbabwe, relief map.jpg, upright=1.22, Zimbabwe, relief map Zimbabwe, officially the Republic of Zimbabwe, is a landlocked country in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Bots ...
,
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
and
Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
and
Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...
in the
United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
, where it is regarded as invasive. Other species such as '' G. banksii'' have also been introduced well outside of their native range as
ornamental plants Ornamental plants or ''garden plants'' are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars th ...
and may be regarded as invasive.


Conservation

The
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
currently has 331 species of grevillea on the
IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...
, with 119 or more than 35% being in a threatened category (Critically Endangered, Endangered or Vulnerable). 30 of those species are listed as
Critically Endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...
, meaning they face an extremely high risk of extinction in the wild. Some of these species include Caley's grevillea (''G. caleyi''), Woolly cluster grevillea (''G. eribotrya''), Foote's grevillea (''G.'' ''calliantha),'' Tumut grevillea (''G. wilkinsonii'') and in New Caledonia, Lanterne rouge d’Unia (''G. vuniana''). The Australian Government ''
Environment Protection and Biodiversity Conservation Act 1999 The ''Environment Protection and Biodiversity Conservation Act 1999'' (Cth) is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and cult ...
'' lists 45 species and 11 subspecies as being in a threatened category. The main threats to grevillea species include habitat clearing for roads, mining, housing, agriculture and grazing, altered fire regimes and competition with both invasive and native species.


Toxicity

Some commonly cultivated grevilleas including fuchsia grevillea, ( ''G. bipinnatifida'') '' G. banksii'' and related
cultivars A cultivar is a kind of cultivated plant that people have selected for desired traits and which retains those traits when propagated. Methods used to propagate cultivars include division, root and stem cuttings, offsets, grafting, tissue cult ...
and hybrids contain toxic
cyanide In chemistry, cyanide () is an inorganic chemical compound that contains a functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. Ionic cyanides contain the cyanide anion . This a ...
. The greatest concentration of cyanoglucosides is found in the flowers, immature leaves, immature seeds and seedlings. Species including '' G. banksii'' and the common cultivar ''Grevillea'' 'Robyn Gordon' are responsible for allergic
contact dermatitis Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes ...
as they contain pentadecylresorcinol (adipostatin A) and tridecylresorcinol, also known as grevillol. These compounds are chemically similar to
urushiol Urushiol is an oily mixture of organic compounds with Allergic contact dermatitis, allergenic properties found in plants of the Family (biology), family Anacardiaceae, especially ''Toxicodendron'' ''spp.'' (e.g., poison oak, Toxicodendron vernic ...
, a compound which causes skin rashes and is found in
poison ivy Poison ivy is a type of allergenic plant in the genus '' Toxicodendron'' native to Asia and North America. Formerly considered a single species, '' Toxicodendron radicans'', poison ivies are now generally treated as a complex of three separate s ...
and other members of the ''
Toxicodendron ''Toxicodendron'' is a genus of flowering plants in the sumac family, Anacardiaceae. It contains trees, shrubs and woody vines, including poison ivy, poison oak, and the lacquer tree. All members of the genus produce the skin-irritating oil ...
'' genus.


Uses


Use in horticulture

Many species of grevilleas are popular
garden plant Ornamental plants or ''garden plants'' are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars th ...
s, especially in Australia but also in other temperate and subtropical climates. Many grevilleas have a propensity to interbreed freely, and extensive hybridisation and selection of horticulturally desirable attributes has led to the commercial release of many named
cultivars A cultivar is a kind of cultivated plant that people have selected for desired traits and which retains those traits when propagated. Methods used to propagate cultivars include division, root and stem cuttings, offsets, grafting, tissue cult ...
. Among the best known is 'Robyn Gordon', a small shrub up to high and wide which can flower 12 months of the year in subtropical climates. The cultivar 'Canberra Gem' has gained the
Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...
's
Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...
. They can be grown from soft tip
cutting Cutting is the separation or opening of a physical object, into two or more portions, through the application of an acutely directed force. Implements commonly used for wikt:cut, cutting are the knife and saw, or in medicine and science the sca ...
s from December–March (in the Southern Hemisphere) or fresh
seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...
. Many harder-to-grow species can be grafted onto hardy rootstock such as ''
Grevillea robusta ''Grevillea robusta'', commonly known as the southern silky oak, silk oak or silky oak, silver oak or Australian silver oak, is a species of flowering plant in the family Proteaceae. Despite its common names, it is unrelated to true oaks, whic ...
''. There is an active Grevillea Study Group in the
Australian Native Plants Society The Australian Native Plants Society (Australia) (ANPSA) is a federation of seven state-based member organisations for people interested in Australia's native flora, both in aspects of conservation and in cultivation. A national conference is ...
for people interested in grevilleas, both for uses in horticulture and for conservation in the wild.


Traditional Aboriginal use

In Australia, many
Aboriginal peoples There is no generally accepted definition of Indigenous peoples, although in the 21st century the focus has been on self-identification, cultural difference from other groups in a state, a special relationship with their traditional territ ...
utilise grevilleas for a wide variety of uses, including food, medicine, tools and ceremonial purposes. Seeds from some species are used as food, such as from the prickly plume grevillea ('' G. annulifera'') of
Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...
and rock grevillea or djamudu ('' G. heliosperma'') by the
Bardi people The Bardi people, also spelt Baada or Baardi and other variations, are an Aboriginal Australian people, living north of Broome, Western Australia, Broome and inhabiting parts of the Dampier Peninsula in the Kimberley (Western Australia), Kimber ...
of the
Northern Territory The Northern Territory (abbreviated as NT; known formally as the Northern Territory of Australia and informally as the Territory) is an states and territories of Australia, Australian internal territory in the central and central-northern regi ...
. The most common and widespread use of grevillea as food among Aboriginal Australians is consuming the
nectar Nectar is a viscous, sugar-rich liquid produced by Plant, plants in glands called nectaries, either within the flowers with which it attracts pollination, pollinating animals, or by extrafloral nectaries, which provide a nutrient source to an ...
. Although some grevillea flowers contain toxic compounds, some species such as '' G. eriostachya, G. juncifolia'' and '' G. pteridifolia'' of northern and western Australia and '' G. lanigera'' of south-eastern Australia are used. Flowers are either directly chewed and sucked or entire inflorescences are soaked in water to create a sweet, sugary drink.


Colonial furniture

A grevillea
wood veneer Veneer refers to thin slices of wood and sometimes bark that typically are glued onto core panels (typically, wood, particle board or medium-density fiberboard) to produce flat panels such as doors, tops and panels for cabinets, parquet fl ...
was used on a
Pembroke table A table is a piece of furniture with a raised flat top and is supported most commonly by 1 to 4 legs (although some can have more). It is used as a surface for working at, eating from or on which to place things. Some common types of tables ar ...
, a small table with two drawers and folding sides, made in the 1790s for Commissioner of the Royal Navy, Sir
Andrew Snape Hamond Captain Sir Andrew Snape Hamond, 1st Baronet (17 December 1738 – 12 September 1828) was a British naval officer and Lieutenant Governor of Nova Scotia from 1781 to 1782 and Comptroller of the Navy from 1794 to 1828. Career Born in Blackhea ...
. The timber from which the veneer was made, referred to as 'beef wood', was sent from
Port Jackson Port Jackson, commonly known as Sydney Harbour, is a natural harbour on the east coast of Australia, around which Sydney was built. It consists of the waters of Sydney Harbour, Middle Harbour, North Harbour and the Lane Cove and Parramatta ...
by Surgeon-General John White, who arrived in the new penal colony of Australia with the
First Fleet The First Fleet were eleven British ships which transported a group of settlers to mainland Australia, marking the beginning of the History of Australia (1788–1850), European colonisation of Australia. It consisted of two Royal Navy vessel ...
. This table is in the collection of the
National Museum of Australia The National Museum of Australia (NMA), in the national capital Canberra, preserves and interprets Australia's social history, exploring the key issues, people and events that have shaped the nation. It was formally established by the ''Nation ...
in
Canberra Canberra ( ; ) is the capital city of Australia. Founded following the Federation of Australia, federation of the colonies of Australia as the seat of government for the new nation, it is Australia's list of cities in Australia, largest in ...
.


Gallery

File:Grevillea calliantha.jpg, '' G. calliantha'' File:Grevillea rivularis.jpg, '' G. rivularis'' File:Grevillea wilkinsonii.jpg, ''G. wilkinsonii'' File:Grevillea candelabroides mingenew email.jpg, '' G. candelabroides'' File:Grevillea dielsiana.jpg, '' G. dielsiana'' File:Grevillea eriobotrya.jpg, '' G. eriobotrya'' File:Grevillea wickhamii aprica grafted email.jpg, ''G. wickhamii'' subsp. ''aprica''


References


External links


ANPSA.org: Grevillea website
— ''by ASGAP−Australian Native Plants Society''.
Grevilleapark.org: Illawarra Grevillea Park website
* PlantListbr>search for Grevillea
Retrieved 20190318. {{Authority control Proteaceae genera Taxa named by Robert Brown (botanist, born 1773) Proteales of Australia Flora of the Australasian realm