The genus is native to the Old World, with the species concentrated around the equatorial regions - eastern and southeastern Asia including the Philippines with 10 species (9 of which are endemic), eastern Africa (including Madagascar), northern Australia, Polynesia, and Micronesia.[citation needed] Australia has 26 species, while the Indo-Chinese area has about 30.[citation needed] India has 9 species.[citation needed] The northernmost species (C. revoluta) is found at 31°N in southern Japan.[citation needed] The southernmost (C. megacarpa) is found at 26°S in southeast Queensland.[citation needed] Due to the occurrence of large number of Cycas species in China, Australia and India, those countries are considered as centres of Cycas diversity.[4][failed verification]
Evolution
Cycas sp.
Cycas is though to have split from all other living cycads at least 200 million years ago, possibly much earlier. Fossil seeds from the Middle Jurassic of England and British Columbia were suggested in a 2017 study to be more closely related to Cycas than other cycads, and were assigned to the same family, Cycadaceae.[5] However, a later study suggested that these seeds could not be assigned to the stem-group of Cycas with confidence due to lacking the double vascular system that characterises the seeds of all living cycads.[6] The earliest fossils assignable to Cycas are known from the Paleogene of East Asia, such as Cycas fushunensis from the Eocene of Northeast China, with East Asia likely representing the ancestral homeland of the genus.[7]
The plants are dioecious, and the family Cycadaceae is unique among the cycads in not forming seed cones on female plants, but rather a group of leaf-like structures called megasporophylls each with seeds on the lower margins, and pollen cones or strobilus on male individuals.
The caudex is cylindrical, surrounded by the persistent petiole bases. Most species form distinct branched or unbranched trunks but in some species the main trunk can be subterranean with the leaf crown appearing to arise directly from the ground. There are two types of leaves - foliage leaves and scaly leaves. The foliage leaves are pinnate (or more rarely bipinnate) and arranged spirally, with thick and hard keratinose.[clarification needed] They are not permanent and fall off leaving back leaf-bases. The leaflets are articulated, have midrib but lack secondary veins. The scaly leaves are persistent, brown in colour and protective in function. Megasporophylls are not gathered in cones. Pollination takes place by air.
A male cone of Cycas orixensis with unique forked microsporophylls
Cykas take about 10 years to reach sexual maturity, after years of exclusive vegetative growth, which occurs by bulbils arising at the base of the trunk.[citation needed]
Cycas species are threatened worldwide and almost all the species are listed in the IUCN Red List. Cycas beddomei is the only species of the genus Cycas listed in Appendix I of CITES. Cycas rumphii and Cycas pectinata have the most widespread distribution.
Phylogeny
Cycas media megasporophylls with nearly-mature seeds on a wild plant in north Queensland, Australia
^ abcHill, Ken; Leonie Stanberg; Dennis Stevenson. . Genus Cycas. Royal Botanic Gardens Sydney. Archived from the original on 2021-03-01. Retrieved 6 September 2013.
^Kramer, K.U.; Green, P.S., eds. (1990). Pteridophytes and Gymnosperms(PDF). The families and genera of vascular plants. Vol. 1. Assisted by E. Götz (illustrations). Berlin: Springer-Verlag. p. 370. ISBN978-3-540-51794-8.
^. World Checklist of Selected Plant Families. Board of Trustees of the Royal Botanic Gardens, Kew. Archived from the original on 13 April 2020. Retrieved 28 March 2023.
^Spencer, Alan R. T.; Garwood, Russell J.; Rees, Andrew R.; Raine, Robert J.; Rothwell, Gar W.; Hollingworth, Neville T. J.; Hilton, Jason (2017-08-28). "New insights into Mesozoic cycad evolution: an exploration of anatomically preserved Cycadaceae seeds from the Jurassic Oxford Clay biota". PeerJ. 5: e3723. doi:10.7717/peerj.3723. ISSN 2167-8359. PMC5578371. PMID 28875075.
^Rothwell, Gar W.; Stockey, Ruth A.; Stevenson, Dennis W.; Zumajo-Cardona, Cecilia (2022-10-01). "Large Permineralized Seeds in the Jurassic of Haida Gwaii, Western Canada: Exploring the Mode and Tempo of Cycad Evolution". International Journal of Plant Sciences. 183 (8): 674–690. doi:10.1086/721710. ISSN 1058-5893. S2CID 251947260.
^Liu, Jian; Lindstrom, Anders J; Marler, Thomas E; Gong, Xun (2022-01-28). "Not that young: combining plastid phylogenomic, plate tectonic and fossil evidence indicates a Palaeogene diversification of Cycadaceae". Annals of Botany. 129 (2): 217–230. doi:10.1093/aob/mcab118. ISSN 0305-7364. PMC8796677. PMID 34520529.
^Stull, Gregory W.; Qu, Xiao-Jian; Parins-Fukuchi, Caroline; Yang, Ying-Ying; Yang, Jun-Bo; Yang, Zhi-Yun; Hu, Yi; Ma, Hong; Soltis, Pamela S.; Soltis, Douglas E.; Li, De-Zhu; Smith, Stephen A.; Yi, Ting-Shuang; et al. (2021). "Gene duplications and phylogenomic conflict underlie major pulses of phenotypic evolution in gymnosperms". Nature Plants. 7 (8): 1015–1025. bioRxiv10.1101/2021.03.13.435279. doi:10.1038/s41477-021-00964-4. PMID 34282286. S2CID 232282918.
Hill, K.D.; Stevenson, Dennis W.; Osborne, Roy (2004). "The World List of Cycads". The Botanical Review. 70 (2): 274–298. doi:10.1663/0006-8101(2004)070[0274:TWLOC]2.0.CO;2. S2CID 36921733.
Lindstrom, Anders J.; Hill, Ken D. (2007). "The genus Cycas (Cycadaceae) in India". Telopea. 11 (4): 463–488. doi:10.7751/telopea20075745.
Singh, R.; Radha, P.; Khuraijam, J.S. (2015). "A new species, a new combination and a new subsection of Cycas from Odisha, northern Eastern Ghats of India". Asian Journal of Conservation Biology. 4 (1): 3–14.
Singh, R.; Radha, P. (2006). "Cycas annaikalensis, A new species of Cycas from the Malabar Coast, Western Ghats, India". Brittonia. 58 (2): 119–123. doi:10.1663/0007-196x(2006)58[119:ansocf]2.0.co;2. S2CID 32241023.
Terrence Walters & Roy Osborne (eds.) (2004), Cycad Classification: Concepts and Recommendations, CABI publishing, ISBN0-85199-741-4
June 01, 2023
cycas, genus, cycad, only, genus, family, cycadaceae, about, species, accepted, which, native, asia, pacific, east, africa, madagascar, circinalis, species, endemic, india, first, cycad, species, described, western, literature, type, species, genus, verified, . Cycas is a genus of cycad and the only genus in the family Cycadaceae About 113 species are accepted which are native to the Asia Pacific East Africa and Madagascar 3 Cycas circinalis a species endemic to India was the first cycad species to be described in western literature and is the type species of the genus not verified in body The best known Cycas species is Cycas revoluta not verified in body CycasTemporal range Paleogene Recent PreꞒ Ꞓ O S D C P T J K Pg NA large cycas under developmentScientific classificationKingdom PlantaeClade TracheophytesClade GymnospermsDivision CycadophytaClass CycadopsidaOrder CycadalesSuborder CycadineaeFamily CycadaceaePers 2 Genus CycasL 1 Type speciesC circinalis 1 L 1 Synonyms 3 Dyerocycas Nakai Epicycas de Laub Todda pana Adans Contents 1 Range 2 Evolution 3 Morphology 4 Reproduction 5 Conservation status 6 Phylogeny 7 References 8 External linksRange EditSee also List of cycad species by country The genus is native to the Old World with the species concentrated around the equatorial regions eastern and southeastern Asia including the Philippines with 10 species 9 of which are endemic eastern Africa including Madagascar northern Australia Polynesia and Micronesia citation needed Australia has 26 species while the Indo Chinese area has about 30 citation needed India has 9 species citation needed The northernmost species C revoluta is found at 31 N in southern Japan citation needed The southernmost C megacarpa is found at 26 S in southeast Queensland citation needed Due to the occurrence of large number of Cycas species in China Australia and India those countries are considered as centres of Cycas diversity 4 failed verification Evolution Edit Cycas sp Cycas is though to have split from all other living cycads at least 200 million years ago possibly much earlier Fossil seeds from the Middle Jurassic of England and British Columbia were suggested in a 2017 study to be more closely related to Cycas than other cycads and were assigned to the same family Cycadaceae 5 However a later study suggested that these seeds could not be assigned to the stem group of Cycas with confidence due to lacking the double vascular system that characterises the seeds of all living cycads 6 The earliest fossils assignable to Cycas are known from the Paleogene of East Asia such as Cycas fushunensis from the Eocene of Northeast China with East Asia likely representing the ancestral homeland of the genus 7 Morphology EditThis section does not cite any sources Please help improve this section by adding citations to reliable sources Unsourced material may be challenged and removed March 2023 Learn how and when to remove this template message Bark of Cycas rumphii The plants are dioecious and the family Cycadaceae is unique among the cycads in not forming seed cones on female plants but rather a group of leaf like structures called megasporophylls each with seeds on the lower margins and pollen cones or strobilus on male individuals The caudex is cylindrical surrounded by the persistent petiole bases Most species form distinct branched or unbranched trunks but in some species the main trunk can be subterranean with the leaf crown appearing to arise directly from the ground There are two types of leaves foliage leaves and scaly leaves The foliage leaves are pinnate or more rarely bipinnate and arranged spirally with thick and hard keratinose clarification needed They are not permanent and fall off leaving back leaf bases The leaflets are articulated have midrib but lack secondary veins The scaly leaves are persistent brown in colour and protective in function Megasporophylls are not gathered in cones Pollination takes place by air Reproduction EditThis section does not cite any sources Please help improve this section by adding citations to reliable sources Unsourced material may be challenged and removed March 2023 Learn how and when to remove this template message A male cone of Cycas circinalis A male cone of Cycas orixensis with unique forked microsporophylls Cykas take about 10 years to reach sexual maturity after years of exclusive vegetative growth which occurs by bulbils arising at the base of the trunk citation needed Conservation status EditThis section does not cite any sources Please help improve this section by adding citations to reliable sources Unsourced material may be challenged and removed March 2023 Learn how and when to remove this template message Cycas species are threatened worldwide and almost all the species are listed in the IUCN Red List Cycas beddomei is the only species of the genus Cycas listed in Appendix I of CITES Cycas rumphii and Cycas pectinata have the most widespread distribution Phylogeny Edit Cycas media megasporophylls with nearly mature seeds on a wild plant in north Queensland Australia Grove of Cycas media in north Queensland Cycas platyphylla in north Queensland with new flush of fronds during the rainy season still with glaucous bloom Phylogeny of Cycas 8 9 section C micholitzii DyerStangerioides Pectinata C multipinnata Chen amp YangC pectinata Buchanan HamiltonC thouarsii Brown ex Gaudichaud Beaupre Panzhihuaenses section C revoluta Thunberg Sago palm C taitungensis Shen et al Asiorientalessection C tropophylla Hill amp LocC ferruginea WeiC curranii Schuster HillC debaoensis Zhong amp ChenC brachycantha Hill Nguyen amp LocC immersa CraibPanzhihuaenses Cycas C bifida Dyer HillC szechuanensis Cheng amp Fusection subsection C wadei MerrillWadeanaesubsection C hainanensis ChenC taiwaniana CarruthersC fairylakea WangTaiwanianosaeWadeanaesection subsection C circinalis L Indu C micronesica HillCycassubsection C pschannae Srivastava amp SinghC edentata de LaubenfelsC nitida Hill amp LindstromC rumphii MiquelRumphiaeCycassection C clivicola Hillsubsection C siamensis MiquelC vespertilio Lindstrom amp HillC riuminiana Porte ex RegelC bougainvilleana HillC celebica MiquelIndosinensessubsection C macrocarpa GriffithC nongnoochiae HillC elongata Leandri WangC tansachana Hill amp YangC lindstromii Yang Hill amp NguyenC condaoensis Hill amp YangC chamaoensis HillC media BrownLindstroemiaeIndosinensessection C diannanensis Guan amp TaoC cairnsiana von MuellerC petrae Lindstrom amp HillC megacarpa HillC calcicola MaconochieC armstrongii MiquelC balansae WarburgC segmentifida Wang amp DengC dolichophylla Hill Nguyen amp LocC simplicipinna Smitinand HillC guizhouensis Lan amp ZouC chevalieri LeandriC maconochiei Chirgwin amp HillC arenicola HillC schumanniana LauterbachC aculeata Hill amp NguyenC silvestris HillC basaltica GardnerC semota HillC orientis HillC canalis HillC hongheensis Yang amp Yang ex WangC conferta ChirgwinC angulata BrownC couttsiana HillC ophiolitica HillC tanqingii WangC platyphylla HillC indica Lindstrom amp Hill Cycas swamyi C annaikalensis Rita Singh amp RadhaC beddomei DyerC sphaerica RoxburghEndemicaeOther species Cycas aenigma Hill amp Lindstrom Cycas apoa Hill Cycas arnhemica Hill Cycas badensis Hill Cycas bglswamyi Pant ex Agrawal Akhtar amp R C Srivast Cycas brunnea Hill Cycas campestris Hill Cycas candida Hill Cycas cantafolia Jutta Chew amp Saw Cycas changjiangensis Liu Cycas chenii Gong amp Zhou Cycas collina Hill Nguyen amp Loc Cycas cupida Forster Cycas darshii Srivastava amp Jana Cycas desolata Forster Cycas dharmrajii Singh Cycas distans P I Forst amp B Gray Cycas divyadarshanii Khuraijam amp Rita Singh Cycas elephantipes Lindstrom amp Hill Cycas falcata Hill Cycas flabellata Agoo Madulid amp Callado Cycas fugax Hill Nguyen amp Loc Cycas furfuracea W Fitzg Cycas glauca Miquel Cycas hoabinhensis Loc amp Nguyen Cycas inermis Oudem Cycas javana Miquel de Laubenfels Cycas lacrimans Lindstrom amp Hill Cycas lane poolei Cycas laotica Nguyen amp Nguyen Cycas litoralis Hill Cycas mindanaensis Agoo Madulid amp Callado Cycas miquelii Warburg Cycas montana Lindstrom amp Hill Cycas nayagarhensis Rita Singh Radha amp Khuraijam Cycas nathorstii Schuster Cycas orixensis Haines Rita Singh amp Khuraijam Cycas pachypoda Hill Cycas panzhihuaensis Zhou amp Yang Cycas papuana von Mueller Cycas pranburiensis Yang et al Cycas pruinosa Maconochie Cycas sainathii Srivastava Cycas sancti lasallei Agoo amp Madulid Cycas saxatilis Hill amp Lindstrom Cycas scratchleyana von Mueller Cycas seemannii A Braun Cycas seshachalamensis Rao et al Cycas sexseminifera Wei Cycas shanyaensis Fu Cycas sundaica Miquel ex Lindstrom amp Hill Cycas terryana Forster Cycas tuckeri Hill Cycas xipholepis Hill Cycas yorkiana Hill Cycas yunnanensis Cheng Fu amp Cheng Cycas zambalensis Madulid amp Agoo Cycas zeylanica Schuster Lindstrom amp HillReferences Edit a b c Hill Ken Leonie Stanberg Dennis Stevenson The Cycad Pages Genus Cycas Royal Botanic Gardens Sydney Archived from the original on 2021 03 01 Retrieved 6 September 2013 Kramer K U Green P S eds 1990 Pteridophytes and Gymnosperms PDF The families and genera of vascular plants Vol 1 Assisted by E Gotz illustrations Berlin Springer Verlag p 370 ISBN 978 3 540 51794 8 a b Cycas L Plants of the World Online Royal Botanic Gardens Kew Retrieved 28 March 2023 World Checklist of Selected Plant Families WCSP World Checklist of Selected Plant Families Board of Trustees of the Royal Botanic Gardens Kew Archived from the original on 13 April 2020 Retrieved 28 March 2023 Spencer Alan R T Garwood Russell J Rees Andrew R Raine Robert J Rothwell Gar W Hollingworth Neville T J Hilton Jason 2017 08 28 New insights into Mesozoic cycad evolution an exploration of anatomically preserved Cycadaceae seeds from the Jurassic Oxford Clay biota PeerJ 5 e3723 doi 10 7717 peerj 3723 ISSN 2167 8359 PMC 5578371 PMID 28875075 Rothwell Gar W Stockey Ruth A Stevenson Dennis W Zumajo Cardona Cecilia 2022 10 01 Large Permineralized Seeds in the Jurassic of Haida Gwaii Western Canada Exploring the Mode and Tempo of Cycad Evolution International Journal of Plant Sciences 183 8 674 690 doi 10 1086 721710 ISSN 1058 5893 S2CID 251947260 Liu Jian Lindstrom Anders J Marler Thomas E Gong Xun 2022 01 28 Not that young combining plastid phylogenomic plate tectonic and fossil evidence indicates a Palaeogene diversification of Cycadaceae Annals of Botany 129 2 217 230 doi 10 1093 aob mcab118 ISSN 0305 7364 PMC 8796677 PMID 34520529 Stull Gregory W Qu Xiao Jian Parins Fukuchi Caroline Yang Ying Ying Yang Jun Bo Yang Zhi Yun Hu Yi Ma Hong Soltis Pamela S Soltis Douglas E Li De Zhu Smith Stephen A Yi Ting Shuang et al 2021 Gene duplications and phylogenomic conflict underlie major pulses of phenotypic evolution in gymnosperms Nature Plants 7 8 1015 1025 bioRxiv 10 1101 2021 03 13 435279 doi 10 1038 s41477 021 00964 4 PMID 34282286 S2CID 232282918 Stull Gregory W et al 2021 main dated supermatrix tree T9 tre Figshare doi 10 6084 m9 figshare 14547354 v1 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help External links Edit Wikimedia Commons has media related to Cycas Wikispecies has information related to Cycas de Laubenfels D J Adema F 1998 A taxonomic revision of the genera Cycas and Epicycas Gen Nov Cycadaceae Blumea 43 351 400 Hill K D 1998 2004 The Cycad Pages Royal Botanic Gardens Sydney http plantnet rbgsyd nsw gov au PlantNet cycad index html Archived 2021 03 29 at the Wayback Machine Virtual Cycad Encyclopedia edited by the Palm amp Cycad Societies of Florida David J de Laubenfels Cycas Taxonomy Hill K D Stevenson Dennis W Osborne Roy 2004 The World List of Cycads The Botanical Review 70 2 274 298 doi 10 1663 0006 8101 2004 070 0274 TWLOC 2 0 CO 2 S2CID 36921733 Lindstrom Anders J Hill Ken D 2007 The genus Cycas Cycadaceae in India Telopea 11 4 463 488 doi 10 7751 telopea20075745 Singh R amp JS Khuraijam 2013 Cycads of India http www cycadsofindia in Singh R Radha P Khuraijam J S 2015 A new species a new combination and a new subsection of Cycas from Odisha northern Eastern Ghats of India Asian Journal of Conservation Biology 4 1 3 14 Singh R Radha P 2006 Cycas annaikalensis A new species ofCycasfrom the Malabar Coast Western Ghats India Brittonia 58 2 119 123 doi 10 1663 0007 196x 2006 58 119 ansocf 2 0 co 2 S2CID 32241023 Terrence Walters amp Roy Osborne eds 2004 Cycad Classification Concepts and Recommendations CABI publishing ISBN 0 85199 741 4 Retrieved from https en wikipedia org w index php title Cycas amp oldid 1156823012, wikipedia, wiki, book, books, library,
