Caladenia

{{short description|Genus of orchids}} {{Use Australian English|date=July 2024}} {{Italic title}} {{automatic taxobox | name = Spider orchids | image = Pink fingers.jpg | image_caption = ''[[Caladenia carnea|C. carnea]]'' growing in [[Tasmania]] | display_parents = 3 | taxon = Caladenia | authority = [[Robert Brown (botanist, born 1773)|R.Br.]]<ref name="PoWO">{{cite web |title=''Caladenia'' |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:28913-1 |publisher=Plants of the World Online |access-date=23 October 2025}}</ref> | type_species = | type_species_authority = | subdivision_ranks = Species | subdivision = *[[List of Caladenia species|List of ''Caladenia'' species]] | synonyms_ref = <ref name="PoWO" /> | synonyms = {{Collapsible list| * ''Arachnorchis'' [[D.L.Jones]] & [[M.A.Clem.]] * ''Caladeniastrum'' ([[Szlach.]]) Szlach. * ''Calonema'' ([[Lindl.]]) [[Wittst.]] [[nom. illeg.]] * ''Calonemorchis'' Szlach. * ''Cyanicula'' [[Stephen Hopper|Hopper]] & [[Andrew Phillip Brown|A.P.Br.]] * ''Drakonorchis'' (Hopper & A.P.Br.) D.L.Jones & M.A.Clem. * ''Elythranthera'' ([[Endl.]]) [[A.S.George]] * ''Ericksonella'' Hopper & A.P.Br. * ''Glossodia'' R.Br. * ''Glycorchis'' D.L.Jones & M.A.Clem. * ''Jonesiopsis'' Szlach. * ''Pentisea'' (Lindl.) Szlach. * ''Petalochilus'' [[R.S.Rogers]] * ''Phlebochilus'' ([[Benth.]]) Szlach. * ''Stegostyla'' D.L.Jones & M.A.Clem. }} }}

'''''Caladenia''''', commonly known as '''spider orchids''',<ref name="Hoffman" /> is a [[genus]] of 350 [[species]] of [[plant]]s in the orchid [[Family (taxonomy)|family]], [[Orchidaceae]]. Spider orchids are [[Terrestrial plant|terrestrial]] [[Herbaceous plant|herbs]] with a single hairy leaf and a hairy stem. The [[labellum (botany)|labellum]] is fringed or toothed in most species and there are small projections called [[Labellum (botany)|calli]] on the labellum. The flowers have adaptations to attract particular species of insects for [[pollination]]. The genus is divided into three groups on the basis of flower shape, broadly, spider orchids, zebra orchids and cowslip orchids, although other common names are often used. Although they occur in other countries, most are Australian and 136 species occur in [[Western Australia]], making it the most species-rich orchid genus in that state.

== Description == Orchids in the genus ''Caladenia'' are terrestrial, [[Perennial plant|perennial]], [[deciduous]], [[sympodial]] herbs with a few inconspicuous, fine roots and a [[tuber]] partly surrounded by a fibrous [[Tunica (biology)|sheath]]. The tuber produces two "droppers" which become daughter tubers in the following year. There is a single hairy [[Convolute (botany)|convolute]] leaf at the base of the plant. Most species have an enlarged cell at the base of each hair. The leaf may be medium-sized to large, fleshy or leathery, lance-shaped to oblong, but is always [[Leaf#Divisions of the blade|simple]], lacking lobes and serrations.<ref name="Hoffman">{{cite book|last1=Hoffman|first1=Noel|last2=Brown|first2=Andrew|title=Orchids of South-West Australia.|date=2011|publisher=Noel Hoffman|location=Gooseberry Hill|isbn=9780646562322|page=25|edition=3rd}}</ref><ref name=FloraBase>{{FloraBase|name=''Caladenia''|id=21262}}</ref><ref name="RBGS">{{cite web|last1=Bernhardt|first1=Peter|title=Genus ''Caladenia''|url=http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=gn&name=Caladenia|publisher=Royal Botanic Gardens Sydney: plantnet|access-date=22 June 2016}}</ref>

The [[inflorescence]] is a [[raceme]] with from one to eight [[Resupination#Orchidaceae|resupinate]] [[flower]]s. The three [[sepal]]s and two [[petal]]s are free and similar in size and shape to each other. In some species, the sepals or petals or both have narrow tips with club-like ends. As is usual in orchids, one petal is highly modified as the central labellum. The labellum is divided into three parts, each of which usually has a fringed or dentate margin, while the central lobe has stalked or button-like [[Labellum (botany)|calli]] which are often in rows. The sexual parts of the flower are fused to the [[Column (botany)|column]], which has wing-like structures on its sides. Most species flower in early spring but some species, such as the winter spider orchid (''[[Caladenia drummondii|C. drummondii]]'') flower in other months. The fruit that follows flowering is a non-fleshy, [[Dehiscence (botany)|dehiscent]] [[Capsule (botany)|capsule]] containing up to 500 seeds.<ref name="Hoffman" /><ref name="FloraBase" /><ref name="RBGS" />

==Taxonomy and naming== The first specimens of the genus were collected by [[Joseph Banks]] in [[Sydney]] in 1777 and by [[Archibald Menzies]] in [[King George Sound]] in Western Australia in 1784. [[James Edward Smith (botanist)|James Edward Smith]] formally described ''Arethusa catenata'', now known as ''[[Caladenia catenata]]'' in 1805, from specimens collected in Sydney.<ref name=APNI1>{{cite web|title=''Arethusa catenata''|url= https://id.biodiversity.org.au/instance/apni/526102|publisher=APNI|access-date=21 November 2018}}</ref><ref name="AJB">{{cite journal|last1=Clements|first1=Mark A.|last2=Howard|first2=Christopher G.|last3=Miller|first3=Joseph T.|title=Caladenia revisited: Results of molecular phylogenetic analyses of Caladeniinae plastid and nuclear loci|journal=American Journal of Botany|date=13 April 2015|volume=102|issue=4|pages=581–597|doi=10.3732/ajb.1500021|pmid=25878091|doi-access=free}}</ref>

The genus was first formally described by [[Robert Brown (Scottish botanist from Montrose)|Robert Brown]] in 1810 in ''[[Prodromus Florae Novae Hollandiae]]''. At the same time he described 15 species of ''Caladenia'' but did not nominate a [[type species]]. Brown collected the specimens as a member of [[Matthew Flinders]]' mapping and exploration voyage that circumnavigated [[Australia]]. He spent just over three years on botanical research with assistants in Australia.<ref name=APNI>{{cite web|title=''Caladenia''|url= https://id.biodiversity.org.au/instance/apni/512077|publisher=APNI|access-date=21 November 2018}}</ref><ref name="Brown">{{cite book|last1=Brown|first1=Robert|title=Prodromus Florae Novae Hollandiae|date=1810|location=London|pages=321–322|url=https://www.biodiversitylibrary.org/item/21771#page/193/mode/1up|access-date=9 June 2016}}</ref>

The genus name (''Caladenia'') is derived from the [[Ancient Greek]] words ''kalos'' meaning "beautiful" and ''aden'' meaning "a gland" referring to the colourful labellum.<ref name="Quattrocchi">{{cite book|last1=Quattrocchi|first1=Umberto|title=CRC World Dictionary of Plant Names (Volume 1: A - C)|date=2000|publisher=CRC Press|location=Boca Raton, FL|isbn=0849326753|page=389}}</ref>

There has been disagreement between taxonomists as to which orchids belong in the genus ''Caladenia'' and which do not, and about classification within the genus.<ref name="Annals">{{cite journal|last1=Hopper|first1=Stephen D.|title=Taxonomic turmoil down-under: recent developments in Australian orchid systematics|journal=Annals of Botany|date=26 April 2009|volume=104|issue=3|pages=447–455|doi=10.1093/aob/mcp090|pmid=19398445|pmc=2720664}}</ref> Recent studies of the [[molecular phylogenetics]] of the group suggest that [[John Lindley]]’s 1840 description of ''Caladenia'' (in ''The Genera and Species of Orchidaceous Plants''),<ref name="Lindl.">{{cite book|last1=Lindley|first1=John|title=The Genera and Species of Orchidaceous Plants|date=1840|publisher=Ridgways|location=Piccadilly, London|page=421|url=https://www.biodiversitylibrary.org/item/9889#page/433/mode/1up|access-date=23 June 2016}}</ref> but including ''[[Glossodia]]'' and ''[[Elythranthera]]'', as being the most accurate reflection of the subtribe ''[[Caladeniinae]]''. Those orchids previously included in the genera ''Glossodia'', ''Elythranthera'' and ''Cyanicula'' have been transferred to ''Caladenia''.<ref name="PoWO" />

Caladenia orchids are informally grouped into those with long narrow sepals and petals, such as the white spider orchid (''[[Caladenia longicauda|C. longicauda]]'') and the clubbed spider orchid (''[[Caladenia longiclavata|C. longiclavata]]''), those with short sepals and petals which tend to hang near the stem, such as the zebra orchid (''[[Caladenia cairnsiana|C. cairnsiana]]'') and dwarf zebra orchid (''[[Caladenia pachychila|C. pachychila]]'') and a third group with short, spreading sepals and petals such as the cowslip orchid ([[Caladenia flava|''C. flava'']]) and fan orchid ([[Caladenia nana subsp. nana|''C. nana'']]).<ref name="Hoffman" />

==Distribution and habitat== Most caladenias are [[Endemism|endemic]] to Australia. Eleven species, ten of which are endemic, occur in [[New Zealand]] with one also occurring in Australia. ''[[Caladenia catenata]]'' and ''[[Caladenia carnea|C. carnea]]'' occur in [[New Caledonia]], with the latter also found in [[Indonesia]]. There are about 136 species endemic to the [[Southwest Australia|south-west]] of Western Australia, 114 of which have been formally described and a further 18 hybrids which have been described and named.<ref name="Brockman">{{cite journal|last1=Brockman|first1=Garry|last2=Brown|first2=Andrew P.|title=New taxa of ''Caladenia'' (Orchidaceae) from south-west Western Australia|journal=Nuytsia|date=2015|volume=25|pages=45–123|doi=10.58828/nuy00724 }}</ref>

In Western Australia, caladenias are found in the [[Southwest Australia|south-west]] from north of [[Kalbarri, Western Australia|Kalbarri]] on the west coast to the [[Nuytsland Nature Reserve]] on the coast of the [[Great Australian Bight]]. Their habitats range from cool, moist [[Eucalyptus diversicolor|karri]] forest, to [[swamp]]lands near the coast and to almost arid [[Mallee (habit)|mallee]] [[woodland]].<ref name="Hoffman" />

==Ecology== Orchids in the genus ''Caladenia'' are pollinated by insects, usually bees or wasps. Some species appear to attract male wasps by having the scent, shape and colouration of flightless female wasps. For example, ''[[Caladenia lobata|C. lobata]]'' attracts male ''[[Thynnoides bidens]]'' wasps. As the wasps lands on the flower, the labellum is pulled down by the insect's weight. As it moves up the labellum, that organ tips the insect against the column where the wasp contacts the sexual parts and either picks up or deposits [[Pollinium|pollinia]]. Many such orchids are only attractive to one species of insect. Sometimes [[Hybrid (biology)|hybrids]] between female-mimicking and food-attracting species occur as in the case of ''[[Caladenia patersonii|C. patersonii]]'' which has the odour of fermentation. ''C. patersonii'' attracts several insect species, and forms hybrids with insect-mimicking species including ''[[Caladenia lobata|C. lobata]]'' and ''[[Caladenia dilatata|C. dilatata]]''.<ref name="CSIRO">{{cite journal|last1=Stoutamire|first1=Warren P.|title=Wasp-Pollinated Species of (Orchidaceae) in South-Western Australia|journal=Australian Journal of Botany|date=1983|volume=31|issue=4|pages=383–394|doi=10.1071/BT9830383}}</ref><ref name="Cingel">{{cite book|last1=van der Cingel|first1=Nelis A.|title=An Atlas of Orchid Pollination : America, Africa, Asia and Australia|date=2000|publisher=Balkema|location=Rotterdam|isbn=9054104864|pages=196–200}}</ref>

In some caladenias, the sepal and petals (apart from the labellum) are narrow with expanded tips called "clubs". These are thought to be the source of sexual attractants for those species that mimic female wasps. Most such species do not have a scent detectable by humans but are attractive to male Thynnid wasps. For some species, such as ''[[Caladenia multiclavia|C. multiclavia]]'', it is the labellum that mimics the size, shape and presumably the scent of females.<ref name="Hoffman" />

==Use in horticulture== ''Caladenia'' have generally proven difficult to maintain and cultivate artificially.<ref name="Coker">{{cite web|last1=Coker|first1=Julian|title=Australian Native Orchids - An Overview|url=http://www.oscov.asn.au/articles3/austnat.htm|publisher=Orchid Societies Council of Victoria Inc.|access-date=23 June 2016|archive-url=https://web.archive.org/web/20160328051547/http://@oscov.asn.au/articles3/austnat.htm|archive-date=28 March 2016|url-status=dead}}</ref> Some enthusiasts have had limited success by cultivating the [[Symbiosis|symbiotic]] fungus that the orchid requires and by careful use of fertiliser to keep the fungus and orchid in balance.<ref name="PBS">{{cite web|title=''Caladenia''|url=http://pacificbulbsociety.org/pbswiki/index.php/Caladenia|publisher=Pacific Bulb Society|access-date=23 June 2016}}</ref> The 1889 book 'The Useful Native Plants of Australia' records that "These and other orchids have edible tubers."<ref name="MAIDEN">{{cite book |last=Maiden |first=J. H. |title=The Useful Native Plants of Australia, (Including Tasmania) |date=1889 |publisher=The Technological Museum of New South Wales |location=Sydney |page=11 |access-date=20 December 2025 |url=https://www.biodiversitylibrary.org/page/12453191 }}</ref>

===Gallery=== <gallery> Image:Caladenia Crebra.jpg|Arrowsmith spider orchid (''[[Caladenia crebra|C. crebra]]'') Image:Kwinana gnangarra 300815-105.jpg|Clubbed spider orchid (''[[Caladenia longicauda|C. longicauda]]'') budding Image:Caladenia chlorostyla LC277.jpg|White fingers (''[[Caladenia chlorostyla|C. chlorostyla]]''), from [[New Zealand]] Image:Caladenia.PlateI.jpg|Several Caladenia species from [[Emily Pelloe|Pelloe]]'s ''West Australia Orchids'' Image:Caladenia atrovespa (5090971253).jpg|''[[Caladenia atrovespa|C. atrovespa]]'' growing near [[Canberra]] Image:Kwinana gnangarra 300815-100.jpg|Dancing spider (''[[Caladenia discoidea|C. discoidea]]'') growing near [[Perth]] Image:Caladenia lobata.JPG|Butterfly orchid (''[[Caladenia lobata|C. lobata]]'') near [[Mount Barker, Western Australia|Mount Barker]] Image:Caladenia venusta.JPG|Large white spider orchid (''[[Caladenia venusta|C. venusta]]'') </gallery>

==See also== * [[List of Caladenia species|List of ''Caladenia'' species]]

== References == {{Reflist}} * New species in ''Orchid Research Newsletter'' No. 47 (January 2006) (Royal Botanical Gardens, Kew)

== External links == * {{Commons-inline}} * [http://members.iinet.net.au/%7Eemntee/Caladenia3.htm Gallery of images] - Orchid Society of Western Australia

[[Category:Caladenia| ]] [[Category:Diurideae genera]] [[Category:Orchids of Australia]] [[Category:Taxa named by Robert Brown (botanist, born 1773)]]