Editing Cycad (section)

==Distribution==

{{See also|List of cycad species by country}}

The living cycads are found across much of the [[subtropical]] and [[tropical]] parts of the world, with a few in temperate regions such as in Australia.<ref name="Orchard1998">Orchard, A.E. & McCarthy, P.M. (eds.) (1998). Flora of Australia 48: 1–766. Australian Government Publishing Service, Canberra.</ref> The greatest diversity occurs in [[South America|South]] and [[Central America]].{{citation needed|date=July 2015}} They are also found in [[Mexico]], the [[Antilles]], southeastern [[United States of America|United States]], [[Australia]], [[Melanesia]], [[Micronesia]], [[Japan]], [[China]], [[Southeast Asia]], [[Bangladesh]], [[India]], [[Sri Lanka]], [[Madagascar]], and [[Southern Africa|southern]] and tropical [[Africa]], where at least 65 [[species]] occur. Some can survive in harsh [[desert]] or semi-desert [[climate]]s ([[xerophytic]]),<ref>{{cite report |title=National Recovery Plan for the MacDonnell Ranges Cycad ''Macrozamia macdonnellii'' |publisher=Department of Natural Resources, Environment, The Arts and Sport, Northern Territory |url=http://www.environment.gov.au/system/files/resources/c17de516-c635-4c67-b040-c9db4da380e4/files/macrozamia-macdonnellii.pdf |access-date=16 July 2015}}</ref> others in wet [[rain forest]] conditions,<ref>{{cite book |author1=Bermingham, E. |author2=Dick, C.W. |author3=Moritz, C. |year=2005 |title=Tropical Rainforests: Past, Present, and Future |publisher=University of Chicago Press |isbn=9780226044682 |url=https://books.google.com/books?id=Y3dXZyCCDpEC}}</ref> and some in both.<ref>{{citation |chapter-url=http://iucnredlist.org/details/42000/0 |title=The IUCN Red List of Threatened Species |chapter=''Macrozamia communis''}}</ref> Some can grow in [[sand]] or even on [[rock (geology)|rock]], some in oxygen-poor, swampy, [[bog]]-like soils rich in [[organic material]].{{Citation needed|date=April 2011}} Some are able to grow in full sun, some in full shade, and some in both.{{Citation needed|date=April 2011}} Some are [[Sodium chloride|salt]] tolerant ([[halophyte]]s).{{citation needed|date=July 2015}}

Species diversity of the extant cycads peaks at 17˚ 15"N and 28˚ 12"S, with a minor peak at the [[equator]]. There is therefore not a [[Latitudinal gradients in species diversity|latitudinal diversity gradient]] towards the equator but towards the [[Tropic of Cancer]] and the [[Tropic of Capricorn]]. However, the peak near the northern tropic is largely due to ''Cycas'' in Asia and ''Zamia'' in the New World, whereas the peak near the southern tropic is due to ''Cycas'' again, and also to the diverse genus ''Encephalartos'' in southern and central Africa, and ''Macrozamia'' in Australia. Thus, the distribution pattern of cycad species with latitude appears to be an artifact of the geographical isolation of the remaining cycad genera and their species, and perhaps because they are partly [[xerophytic]] rather than simply [[tropical]].{{citation needed|date=February 2025}}