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Unlike in other extant gymnosperms the soft and highly [[Ground tissue#Parenchyma|parenchymatous]] wood in cycads is poorly lignified,<ref>{{Cite journal|last1=Fisher|first1=Jack B.|last2=Lindström|first2=Anders|last3=Marler|first3=Thomas E.|date=2009-06-01|title=Tissue Responses and Solution Movement After Stem Wounding in Six Cycas Species|url=https://journals.ashs.org/hortsci/view/journals/hortsci/44/3/article-p848.xml|journal=HortScience|language=en-US|volume=44|issue=3|pages=848–851|doi=10.21273/HORTSCI.44.3.848|s2cid=83644706 |issn=0018-5345|doi-access=free}}</ref> and their main structural support comes from an armor of sclerenchymatous leaf bases covering the stem,<ref>{{Cite book|last1=Bell|first1=Peter R.|url=https://books.google.com/books?id=HYkTvGq_RccC&q=armor%2520sclerenchymatous%2520leaf%2520bases&pg=PA247|title=Green Plants: Their Origin and Diversity|last2=Bell|first2=Peter R.|last3=Hemsley|first3=Alan R.|date=2000|publisher=Cambridge University Press|isbn=978-0-521-64673-4|page=247}}</ref> with the exception of species with underground stems.<ref>{{Cite book|last1=Cleal|first1=Christopher J.|url=https://books.google.com/books?id=KDGdDwAAQBAJ&q=%2522exclusively%2520underground%2C%2520like%2520a%2520tuber%2520%28e.g.%2520some%2520Zamia%2520species%29%2522&pg=PA179|title=Introduction to Plant Fossils|last2=Thomas|first2=Barry A.|date=2019|publisher=Cambridge University Press|isbn=978-1-108-48344-5|page=179}}</ref> There are no [[Herbaceous plant|herbaceous]] gymnosperms and compared to angiosperms they occupy fewer [[ecological niche]]s, but have evolved both parasites (''[[Parasitaxus]]''), [[epiphyte]]s (''[[Zamia pseudoparasitica]]'') and [[rheophyte]]s (''[[Retrophyllum minus]]'').<ref>{{Cite journal|last=Mill|first=R. R.|title=A Monographic Revision of Retrophyllum (Podocarpaceae) |date=2016-06-22|journal=Edinburgh Journal of Botany|language=en|volume=73|issue=2|pages=171–261|doi=10.1017/S0960428616000081|issn=1474-0036|doi-access=free}}</ref>
[[Conifer]]s are by far the most abundant extant group of gymnosperms with six to eight families, with a total of 65–70 genera and 600–630 species (696 accepted names).<ref name="Catalogue">{{Cite web|url=http://www.catalogueoflife.org/show_database_details.php?database_name=Conifer+Database|archive-url=https://web.archive.org/web/20090115190412/http://www.catalogueoflife.org/show_database_details.php?database_name=Conifer+Database|url-status=dead|work=Catalogue of Life: 2008 Annual checklist |title= Conifer database|editor= A. Farjon | date=2006|archive-date=January 15, 2009}}</ref> Most conifers are [[evergreen]]s.<ref>Campbell, Reece, "Phylum Coniferophyta."Biology. 7th. 2005. Print. P.595</ref> The [[leaf|leaves]] of many conifers are long, thin and needle-like, while other species, including most [[Cupressaceae]] and some [[Podocarpaceae]], have flat, triangular scale-like leaves. ''[[Agathis]]'' in Araucariaceae and ''[[Nageia]]'' in Podocarpaceae have broad, flat strap-shaped leaves.{{cn}}
[[Cycad]]s are the next most abundant group of gymnosperms, with two or three families, 11 genera, and approximately 338 species. A majority of cycads are native to tropical climates and are most abundantly found in regions near the equator. The other extant groups are the 95–100 species of [[Gnetum|Gnetale]]s and one species of ''[[Ginkgo]]''.<ref name="Raven-2013" />
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