HOME

TheInfoList



OR:

''Cycas'' is a
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of plants belonging to a very ancient lineage, the
Cycadophyta Cycads are seed plants that typically have a stout and woody (ligneous) trunk (botany), trunk with a crown (botany), crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants o ...
, which are not closely related to palms, ferns, trees or any other modern group of plants. They are
evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...
perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...
s which achieved their maximum diversity in the
Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
and
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
periods, when they were distributed almost worldwide. At the end of the Cretaceous, when the non-avian dinosaurs became extinct, so did most of the cycas in the Northern Hemisphere. ''Cycas'' is the
type genus In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal f ...
and the only extant genus recognised in the
family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Cycadaceae. About 113
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
are accepted. ''Cycas circinalis'', a species endemic to India, was the first
cycad Cycads are seed plants that typically have a stout and woody (ligneous) trunk (botany), trunk with a crown (botany), crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants o ...
species to be described in western literature, and was the type of the generic name, ''Cycas''. The best-known ''Cycas'' species is '' Cycas revoluta''.


Range

The genus is
native Native may refer to: People * Jus soli, citizenship by right of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Native Americans (disambiguation) In arts and entert ...
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. Australia has 26 species, while the Indo-Chinese area has about 30. India has 9 species. The northernmost species (''C. revoluta'') is found at 31°N in southern Japan. The southernmost (''C. megacarpa'') is found at 26°S in southeast Queensland. Due to the occurrence of large number of ''Cycas'' species in China, Australia and India, those countries are considered as centres of ''Cycas'' diversity.Kew World Checklist of Selected Plant Families
/ref>


Evolution

''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, were assigned to the same family, Cycadaceae. However, a later study suggested that these seeds could not be assigned to the
stem-group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...
of ''Cycas'' with confidence due to lacking the double vascular system that characterises the seeds of all living cycads. The earliest
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
s assignable to ''Cycas'' are known from the
Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...
of East Asia, such as ''Cycas fushunensis'' from the
Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...
of
Northeast China Northeast China or Northeastern China () is a geographical region of China, which is often referred to as "Manchuria" or "Inner Manchuria" by surrounding countries and the West. It usually corresponds specifically to the three provinces east of t ...
, with East Asia likely representing the ancestral homeland of the genus.


Morphology

The plants are
dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...
, 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 A caudex (plural: caudices) of a plant is a stem, but the term is also used to mean a rootstock and particularly a basal stem structure from which new growth arises.pages 456 and 695 In the strict sense of the term, meaning a stem, "caudex" is m ...
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 Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and in ...
(or more rarely bipinnate) and arranged spirally, with thick and hard keratinose. 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.
Megasporophyll A sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls (whether they are microphylls or megaphylls) bear either megasporangia and thus are called megasporophylls, or mi ...
s are not gathered in cones.
Pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds ...
takes place by air.


Reproduction

The plant takes several years to grow, sexual reproduction takes place after 10 years of exclusive vegetative growth which occurs by bulbils arising at the base of the trunk.


Conservation status

''Cycas'' species are threatened worldwide and almost all the species are listed in IUCN Redlist. ''Cycas beddomei'' is the only species of the genus ''Cycas'' listed in Appendix I of CITES. ''
Cycas rumphii ''Cycas rumphii'', commonly known as queen sago or the queen sago palm, is a dioecious gymnosperm, a species of cycad in the genus ''Cycas'' native to Indonesia, New Guinea and Christmas Island. Although palm-like in appearance, it is not a palm ...
'' and '' Cycas pectinata'' have the most widespread distribution


List of species

*'' Cycas aculeata'' *'' Cycas aenigma'' *''
Cycas angulata ''Cycas angulata'' is a species of cycad in the genus ''Cycas'', native to Australia in northeast Northern Territory (lower reaches of the Foelsche, Robinson and Wearyan Rivers near Borroloola) and northwest Queensland ( Bountiful Islands). I ...
'' *''
Cycas annaikalensis ''Cycas annaikalensis'' is a Critically Endangered species of cycad in the genus ''Cycas'', native to the state of Kerala in India, where it is endemic to the Annaikal Hills near Palakkad Palakkad (), formerly known as Palghat, historicall ...
'' *'' Cycas apoa'' *'' Cycas arenicola'' *''
Cycas armstrongii ''Cycas armstrongii'' is a species of cycad in the genus ''Cycas'', endemic to Northern Territory of Australia. It is found from the Finniss River in the west to the Arnhem Highway in the east, north of Pine Creek. It also occurs on the Tiwi I ...
'' *'' Cycas arnhemica'' *''
Cycas badensis ''Cycas badensis'' is a species of cycad in the genus ''Cycas'', native to Australia, in the extreme north of Queensland, where it is endemic on Badu Island in the Torres Strait Islands. The stems grow up to 8 m tall. The leaves are numerous, ...
'' *'' Cycas balansae'' *'' Cycas basaltica'' *''
Cycas beddomei ''Cycas beddomei'' is a species of cycad in the genus ''Cycas'', native to India, where it is confined to a small area of Andhra Pradesh state in the Tirumala Hills in scrubland and brush covered hills. Superficially similar to ''Cycas revolu ...
'' *'' Cycas bifida'' *'' Cycas bougainvilleana'' *'' Cycas brachycantha'' *'' Cycas brunnea'' *'' Cycas cairnsiana'' *'' Cycas calcicola'' *'' Cycas campestris'' *'' Cycas canalis'' *'' Cycas candida'' *'' Cycas cantafolia'' *'' Cycas chamaoensis'' *''
Cycas changjiangensis ''Cycas changjiangensis'' is a plant species in the cycad order, Cycadales. It is endemism, endemic to Hainan Island of southern China. It grows at elevations of . It is found only in a small area in Bawangling 霸王岭国家森林公园, Changj ...
'' *'' Cycas chenii'' *'' Cycas chevalieri'' *'' Cycas circinalis'' *'' Cycas clivicola'' *''
Cycas collina ''Cycas collina'' is a species of cycad. It is found in the Mai Sơn area of Sơn La Province, Vietnam and in Sipsongpanna, Yunnan, China. It may also exist in Laos and Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . N ...
'' *'' Cycas condaoensis'' *'' Cycas conferta'' *'' Cycas couttsiana'' *'' Cycas cupida'' *'' Cycas curranii'' *''
Cycas debaoensis ''Cycas debaoensis'' is a plant species endemic to the Guangxi region of China. It grows in sunny locations at elevations of 700–1000 m. It is closely related to '' Cycas multipinnata''. Description ''Cycas debaoensis'' has a trunk that shows ...
'' *'' Cycas desolata'' *'' Cycas diannanensis'' *'' Cycas distans'' P.I.Forst. & B.Gray *'' Cycas dolichophylla'' *'' Cycas edentata'' *''
Cycas elephantipes ''Cycas elephantipes'' is a species of cycad. It is found only on a few high sandstone mesas in Nong Bua Rawe District, Chaiyaphum Province, northeastern Thailand. It is morphologically similar to '' Cycas pachypoda'' from southern Vietnam ...
'' *''
Cycas elongata ''Cycas elongata'' is a species of cycad endemic to southern Vietnam. Distribution The four main subpopulations of ''Cycas elongata'' are found in: *northern Ninh Thuan Province *west of Cam Ranh in Khanh Hoa Province * Song Cau in Phu Yen P ...
'' *'' Cycas falcata'' *'' Cycas fairylakea'' *'' Cycas ferruginea'' *''
Cycas fugax ''Cycas fugax'' is a species of cycad endemic to Vietnam. It has only been recorded in the wild from Phu Tho Province, Vietnam, but may be reasonably common in cultivation in Hanoi Hanoi or Ha Noi ( or ; vi, Hà Nội ) is the capital and ...
'' *'' Cycas furfuracea'' *'' Cycas glauca'' *'' Cycas guizhouensis'' *'' Cycas hainanensis'' *''
Cycas hoabinhensis ''Cycas hoabinhensis'' is a species of cycad endemic to central Vietnam, where it is found in Hoa Binh, Ha Nam, Ha Tay, and Ninh Binh provinces. Conservation ''Cycas hoabinhensis'' is protected in Cuc Phuong National Park in Ninh Binh provi ...
'' *'' Cycas hongheensis'' *''
Cycas indica ''Cycas indica'' is a species of cycad endemic to India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous de ...
'' (=''Cycas swamyi'') *'' Cycas inermis'' *''
Cycas javana ''Cycas javana'' is a species of cycad in Indonesia. It is found primarily in Java, as well as southern Sumatra Sumatra is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, ...
'' *'' Cycas lacrimans'' *'' Cycas lane-poolei'' *''
Cycas lindstromii ''Cycas lindstromii'' is a species of cycad endemic to southern Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland S ...
'' *'' Cycas litoralis'' *''
Cycas maconochiei ''Cycas maconochiei'' is a species of cycad, endemic to Australia's Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian t ...
'' *'' Cycas macrocarpa'' *''
Cycas media ''Cycas media'' is a palm-like cone-bearing plant widespread in seasonally dry tropical sclerophyll woodlands close to the east coast of Queensland, with scattered occurrences also in northern Northern Territory and Western Australia, Australia. ...
'' *'' Cycas megacarpa'' *''
Cycas micholitzii ''Cycas micholitzii'' is a species of cycad in Vietnam and Laos. References

Cycas, micholitzii Flora of Vietnam Flora of Laos {{cycad-stub ...
'' *''
Cycas micronesica ''Cycas micronesica'' is a species of cycad found on the island of Yap in Micronesia, the Marianas islands of Guam and Rota, and The Republic of Palau. It is commonly known as federico nut or ''fadang'' in Chamorro. The species, previously lu ...
'' *'' Cycas montana'' *''
Cycas multipinnata ''Cycas multipinnata'' (or ''Epicycas multipinnata'') is a species of cycad (faily Cycadaceae) in southwestern China and northern Vietnam. It is noteworthy for three things: First it is one of the tuberous species which some taxonomists segregate ...
'' *'' Cycas nathorstii'' *'' Cycas nayagarhensis'' *''
Cycas nitida ''Cycas nitida'' is a species of cycad endemic to the northern Philippines. It is found in littoral forests. Range ''Cycas nitida'' has been recorded in the following locations. *Babuyan Islands: Dalupiri *Luzon: Quezon Quezon, officially ...
'' *'' Cycas nongnoochiae'' *'' Cycas ophiolitica'' *'' Cycas orientis'' *'' Cycas orixensis'' *''
Cycas pachypoda ''Cycas pachypoda'' is a species of cycad endemic to Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast As ...
'' *''
Cycas panzhihuaensis ''Cycas panzhihuaensis'' is a rare and vulnerable species of cycad known in the wild only from Sichuan and Yunnan provinces in China. It can be seen at the South China Botanical Garden in Guangzhou and is also cultivated for horticulture, where ...
'' *''
Cycas papuana ''Cycas papuana'' is a species of cycad endemic to Papua New Guinea. It is found in Western Province, including the floodplains of the Fly River and near Daru to the west, and also extending to the Bensbach River The Bensbach River is a river i ...
'' *'' Cycas pectinata'' *'' Cycas petraea'' *''
Cycas platyphylla ''Cycas platyphylla'' is a cycad in the genus ''Cycas'', native to Queensland, Australia. The stems are erect or decumbent, growing to 1.5 m tall but most often less than a metre. The leaf, leaves are pinnate, keeled, 60–100 cm long. New ...
'' *'' Cycas pranburiensis'' *'' Cycas pruinosa'' *'' Cycas revoluta'' (Sago palm) *'' Cycas riuminiana'' *''
Cycas rumphii ''Cycas rumphii'', commonly known as queen sago or the queen sago palm, is a dioecious gymnosperm, a species of cycad in the genus ''Cycas'' native to Indonesia, New Guinea and Christmas Island. Although palm-like in appearance, it is not a palm ...
'' Miq. *'' Cycas sancti-lasallei'' *'' Cycas sainathii'' *'' Cycas saxatilis'' *''
Cycas schumanniana ''Cycas schumanniana'' is a species of cycad endemic to New Guinea. Range It is found in northern New Guinea along the foothills of the Bismarck Range, where it is found in the valleys of the Markham River, Ramu River, and Bulolo River watershed ...
'' *'' Cycas scratchleyana'' *''
Cycas seemannii ''Cycas seemannii'' is a species of cycad found in Fiji, Vanuatu (in Efate), Tonga, and New Caledonia.Whitelock, Loran M. 2002. ''The Cycads''. Portland: Timber Press. In Vanuatu, the cycad is known as namele and is an important symbol of tra ...
'' A.Braun *'' Cycas segmentifida'' *'' Cycas semota'' *'' Cycas sexseminifera'' *'' Cycas shanyaensis'' *'' Cycas siamensis'' *'' Cycas silvestris'' *'' Cycas simplicipinna'' *'' Cycas sphaerica'' *'' Cycas sundaica'' *'' Cycas szechuanensis'' *'' Cycas taitungensis'' *''
Cycas taiwaniana ''Cycas taiwaniana'' is a species of plant in the genus ''Cycas''. The species is native to Yunnan, Guangdong, Guangxi and Fujian in China. Although the specific name (botany), specific epithet, ''taiwaniana'', is derived from Taiwan, where the o ...
'' *'' Cycas tanqingii'' *''
Cycas tansachana ''Cycas tansachana'' is a species of cycad in Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , ...
'' *''
Cycas thouarsii ''Cycas thouarsii'', the Madagascar cycad, is an evergreen arborescent cycad in the genus ''Cycas''. It is named after a French botanist Louis-Marie Aubert du Petit-Thouars (1758—1831). Description The stem of this cycad resembles that of a p ...
'' *'' Cycas tropophylla'' *'' Cycas tuckeri'' *'' Cycas vespertilio'' *''
Cycas wadei ''Cycas wadei'' (Wade's pitogo) is a species of cycad endemic to Culion island, Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republ ...
'' *'' Cycas xipholepis'' *'' Cycas yorkiana'' *'' Cycas yunnanensis'' *'' Cycas zambalensis'' *'' Cycas zeylanica''


References


External links

* *Hill, K.D.(1998–2004) The Cycad Pages, Royal Botanic Gardens Sydney. http://plantnet.rbgsyd.nsw.gov.au/PlantNet/cycad/index.html
Virtual Cycad Encyclopedia
edited by the Palm & Cycad Societies of Florida *David, J. de Laubenfels
Cycas Taxonomy
* * *Singh, R & JS Khuraijam (2013-) Cycads of India. http://www.cycadsofindia.in/ * * *Terrence Walters & Roy Osborne (eds.) (2004), ''Cycad Classification: Concepts and Recommendations'', CABI publishing, {{Taxonbar, from=Q161073