Editing Oak (section)

== Description ==

Oaks are [[hardwood]] ([[dicotyledon]]ous) trees, [[deciduous]] or [[evergreen]], with spirally arranged leaves, often with [[Dentate leaf|lobate margins]]; some have [[serrated leaves]] or [[Entire (botany)|entire leaves]] with smooth margins. Many deciduous species are [[marcescent]], not dropping dead leaves until spring. In spring, a single oak tree [[Monoecy|produces both]] male and female flowers. The [[staminate]] (male) flowers are arranged in [[catkin]]s, while the small [[pistillate]] (female) flowers<ref>{{cite web |last=Conrad |first=Jim |url=http://www.backyardnature.net/fl_bloak.htm |title=Oak Flowers |archive-url=https://web.archive.org/web/20131104064011/http://www.backyardnature.net/fl_bloak.htm |archive-date=4 November 2013 |website=Backyardnature.com |date=12 December 2011}}</ref> produce an [[acorn]] (a&nbsp;kind of [[Nut (fruit)|nut]]) contained in a [[Calybium and cupule|cupule]]. Each acorn usually contains one seed and takes 6–18 months to mature, depending on the species. The acorns and leaves contain [[tannic acid]],<ref>{{Cite book |last=Tull |first=Delena  |url=https://books.google.com/books?id=pnnHgcasN-cC&pg=PA102 |title=Edible and Useful Plants of Texas and the Southwest: A Practical Guide |date=1999 |publisher=University of Texas Press |isbn=978-0-2927-8164-1 |url-status=live |archive-url=https://web.archive.org/web/20170215071946/https://books.google.com/books?id=pnnHgcasN-cC&pg=PA102 |archive-date=15 February 2017}}</ref> which helps to guard against fungi and insects.<ref>{{Cite book |last=Hipp |first=Andrew |title=Oak Trees Inside and Out |publisher=Rosen Publishing |year=2004 |page=4}}</ref> There are some 500 extant species of oaks.<ref name=powo>{{cite web |title=''Quercus'' L. |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:325819-2 |website=Plants of the World Online |publisher=[[Royal Botanic Gardens, Kew]] |access-date=30 September 2020}}</ref>

Trees in the genus are often large and slow-growing; ''Q.&nbsp;alba'' can reach an age of 600 years, a diameter of {{convert|13|ft|m}} and a height of {{convert|145|ft|m}}.<ref name="Core">{{cite web |last1=Core |first1=Earl L. |title=Silvical Characteristics of the Five Upland Oaks |url=https://www.nrs.fs.usda.gov/pubs/other/oak_sym/oak_symposium_proceedings_019.pdf |publisher=United States Department of Agriculture |access-date=5 October 2023 |pages=19–22}}</ref> The [[Granit oak]] in Bulgaria, a ''Q.&nbsp;robur'' specimen, has an estimated age of 1,637 years, making it the oldest oak in Europe.<ref>{{cite web |last=Todorov |first=Radoslav |title=Знаете ли кои са най-старите живи организми? |url=https://chr.bg/zhivot/znaete-li-koi-sa-naj-starite-zhivi-organizmi/ |trans-title=Do you know which are the oldest living organisms? |website=Chronicle.B |access-date=5 October 2023 |language=Bulgarian |date=30 September 2018}}</ref> The Wi'aaSal tree, a [[live oak]] in the reservation of the [[Pechanga Band of Indians]], California, is at least 1,000 years old, and might be as much as 2,000 years old, which would make it the oldest oak in the US.<ref>{{cite web |title=The Largest Oak Trees in the World |url=https://hardwoodsgroup.com/the-largest-oak-trees-in-the-world/ |website=Hardwoods Group |date=27 July 2021 |access-date=5 October 2023}}</ref> Among the smallest oaks is ''[[Quercus acuta|Q.&nbsp;acuta]]'', the Japanese evergreen oak. It forms a bush or small tree to a height of some {{convert|30|ft|m}}.<ref>{{cite web |last1=Gilman |first1=Edward F. |last2=Watson |first2=Dennis G. |title=''Quercus acuta'': Japanese Evergreen Oak |url=https://edis.ifas.ufl.edu/publication/ST539 |publisher=IFAS |access-date=5 October 2023}}</ref>

<gallery mode="packed" heights="220px">
File:Brockwell Oak (9).jpg|''[[Quercus robur]]'' habit
File:Quercus lusitanica - Köhler–s Medizinal-Pflanzen-253.jpg|Illustration of ''[[Quercus lusitanica|Q.&nbsp;lusitanica]]'' showing [[staminate]] (left) and [[pistillate]] flowers (right)
File:2021-04-22 18 54 32 Male flowers (catkins) on a White Oak within a wooded area in the Franklin Farm section of Oak Hill, Fairfax County, Virginia.jpg|Catkins of ''[[Quercus alba|Q.&nbsp;alba]]'' containing the staminate or 'male' flowers
File:Летен дъб - цъфтеж, нови листа.JPG|New leaves and reddish pistillate or 'female' flowers of ''[[Quercus robur|Q.&nbsp;robur]]''
</gallery>