Caladenia

Source: Wikipedia, the free encyclopedia.

Spider orchids
C. carnea growing in Tasmania
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Subtribe: Caladeniinae
Genus: Caladenia
R.Br., 1810
Species
Synonyms[1][2]
  • Petalochilus R.S.Rogers
  • Arachnorchis D.L.Jones & M.A.Clem.
  • Calonemorchis Szlach.
  • Drakonorchis (Hopper & A.P.Br.) D.L.Jones & M.A.Clem.
  • Jonesiopsis Szlach.
  • Phlebochilus (Benth.) Szlach.
  • Stegostyla D.L.Jones & M.A.Clem.
  • Caladeniastrum (Szlach.) Szlach.
  • Cyanicula Hopper & A.P.Br.

Caladenia, commonly known as spider orchids,

Orchidaceae. Spider orchids are terrestrial herbs with a single hairy leaf and a hairy stem. The labellum is fringed or toothed in most species and there are small projections called 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,

sympodial herbs with a few inconspicuous, fine roots and a tuber partly surrounded by a fibrous sheath. The tuber produces two "droppers" which become daughter tubers in the following year. There is a single hairy 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 simple, lacking lobes and serrations.[3][4][5]

The

capsule containing up to 500 seeds.[3][4][5]

C. flava growing near Bertram, W.A.

Taxonomy and naming

The first specimens of the genus were collected by

King George Sound in Western Australia in 1784. James Edward Smith formally described Arethusa catenata, now known as Caladenia catenata in 1805, from specimens collected in Sydney.[6][7]

The genus was first formally described by

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.[8][9]

The genus name (Caladenia) is derived from the Ancient Greek words kalos meaning "beautiful" and aden meaning "a gland" referring to the colourful labellum.[10]

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.[11] 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),[12] 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.[2]

Caladenia orchids are informally grouped into those with long narrow sepals and petals, such as the white spider orchid (C. longicauda) and the clubbed spider orchid (C. longiclavata), those with short sepals and petals which tend to hang near the stem, such as the zebra orchid (C. cairnsiana) and dwarf zebra orchid (C. pachychila) and a third group with short, spreading sepals and petals such as the cowslip orchid (C. flava) and fan orchid (C. nana).[3]

Distribution and habitat

Most caladenias are endemic to Australia. Eleven species, ten of which are endemic, occur in New Zealand with one also occurring in Australia. Caladenia catenata and C. carnea occur in New Caledonia, with the latter also found in Indonesia. There are about 136 species endemic to the south-west of Western Australia, 114 of which have been formally described and a further 18 hybrids which have been described and named.[13]

In Western Australia, caladenias are found in the south-west from north of Kalbarri on the west coast to the Nuytsland Nature Reserve on the coast of the Great Australian Bight. Their habitats range from cool, moist Karri forest, to swamplands near the coast and to almost arid mallee woodland.[3]

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, 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 pollinia. Many such orchids are only attractive to one species of insect. Sometimes hybrids between female-mimicking and food-attracting species occur as in the case of C. patersonii which has the odour of fermentation. C. patersonii attracts several insect species, and forms hybrids with insect-mimicking species including C. lobata and C. dilatata.[14][15]

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 C. multiclavia, it is the labellum that mimics the size, shape and presumably the scent of females.[3]

Use in horticulture

Caladenia have generally proven difficult to maintain and cultivate artificially.[16] Some enthusiasts have had limited success by cultivating the symbiotic fungus that the orchid requires and by careful use of fertiliser to keep the fungus and orchid in balance.[17] The 1889 book 'The Useful Native Plants of Australia' records that "These and other orchids have edible tubers."[18]

Gallery

See also

References

  1. ^ "Caladenia". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 25 June 2016.
  2. ^ a b "Caladenia". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew. Retrieved 15 April 2018.
  3. ^
    ISBN 9780646562322
    .
  4. ^
    Department of Biodiversity, Conservation and Attractions
    .
  5. ^ a b Bernhardt, Peter. "Genus Caladenia". Royal Botanic Gardens Sydney: plantnet. Retrieved 22 June 2016.
  6. ^ "Arethusa catenata". APNI. Retrieved 21 November 2018.
  7. PMID 25878091
    .
  8. ^ "Caladenia". APNI. Retrieved 21 November 2018.
  9. ^ Brown, Robert (1810). Prodromus Florae Novae Hollandiae. London. pp. 321–322. Retrieved 9 June 2016.
  10. ISBN 0849326753
    .
  11. PMID 19398445
    .
  12. ^ Lindley, John (1840). The Genera and Species of Orchidaceous Plants. Piccadilly, London: Ridgways. p. 421. Retrieved 23 June 2016.
  13. ^ Brockman, Garry; Brown, Andrew P. (2015). "New taxa of Caladenia (Orchidaceae) from south-west Western Australia". Nuytsia. 25: 45–123.
  14. doi:10.1071/BT9830383
    .
  15. ISBN 9054104864
    .
  16. ^ Coker, Julian. "Australian Native Orchids - An Overview". Orchid Societies Council of Victoria Inc. Archived from the original on 28 March 2016. Retrieved 23 June 2016.
  17. ^ "Caladenia". Pacific Bulb Society. Retrieved 23 June 2016.
  18. ^ J. H. Maiden (1889). The useful native plants of Australia : Including Tasmania. Turner and Henderson, Sydney.
  • New species in Orchid Research Newsletter No. 47 (January 2006) (Royal Botanical Gardens, Kew)

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Caladenia&oldid=1176891406"