Editing Oak (section)

== Evolution ==

=== Fossil history ===

Potential records of ''Quercus'' have been reported from [[Late Cretaceous]] deposits in North America and East Asia. These are not considered definitive, as macrofossils older than the [[Paleogene]], and possibly from before the [[Eocene]] are mostly poorly preserved without critical features for certain identification. Amongst the oldest unequivocal records of ''Quercus'' are pollen from Austria, dating to the [[Paleocene]]-Eocene boundary, around 55 million years ago. The oldest records of ''Quercus'' in North America are from [[Oregon]], dating to the Middle Eocene, around 44 million years ago, with the oldest records in Asia from the Middle Eocene of Japan; both forms have affinities to the ''[[Cyclobalanopsis]]'' group.<ref>{{Citation |last1=Barrón |first1=Eduardo |title=The Fossil History of ''Quercus'' |date=2017 |work=Oaks Physiological Ecology. Exploring the Functional Diversity of Genus Quercus L. |volume=7 |pages=39–105 |editor-last=Gil-Pelegrín |editor-first=Eustaquio |place=Cham |publisher=Springer International Publishing |doi=10.1007/978-3-319-69099-5_3 |isbn=978-3-319-69098-8 |last2=Averyanova |first2=Anna |last3=Kvaček |first3=Zlatko |last4=Momohara |first4=Arata |last5=Pigg |first5=Kathleen B. |last6=Popova |first6=Svetlana |last7=Postigo-Mijarra |first7=José María |last8=Tiffney |first8=Bruce H. |last9=Utescher |first9=Torsten |display-authors=3 |series=Tree Physiology |hdl=10261/277765 |editor2-last=Peguero-Pina |editor2-first=José Javier |editor3-last=Sancho-Knapik |editor3-first=Domingo |hdl-access=free }}</ref>

<gallery class=center mode=nolines widths=200px heights=200px>
File:Quercus hispanica 20170317.jpg|''[[Quercus × hispanica]]'' leaf. [[Miocene]], [[Lleida]], Spain
File:Quercus hiholensis acorn UWBM 56470-3 Pigg & Wehr 2002 Plt2 fig16.png|''[[Quercus hiholensis]]'' acorn, [[Langhian]] age (Middle Miocene), Washington State, US (c. 15 mya)
File:Quercus kobatakei leaf (cropped).jpg|''Quercus kobatakei'' leaf. Early [[Oligocene]], Japan
File:Early Oligocene oak acorn from Bridge Creek Flora.jpg|Early Oligocene acorn, Oregon, US (33 mya)
</gallery>

=== External phylogeny ===

''Quercus'' forms part, or rather two parts, of the Quercoideae subfamily of the [[Fagaceae]], the beech family. Modern [[molecular phylogenetics]] suggests the following relationships:<ref name="Manos Cannon Oh 2008">{{cite journal | last1=Manos | first1=Paul S. | last2=Cannon | first2=Charles H. | last3=Oh | first3=Sang-Hun | title=Phylogenetic Relationships and Taxonomic Status Of the Paleoendemic Fagaceae Of Western North America: Recognition Of A New Genus, Notholithocarpus | journal=Madroño | publisher=California Botanical Society | volume=55 | issue=3 | year=2008 | issn=0024-9637 | doi=10.3120/0024-9637-55.3.181 | pages=181–190| s2cid=85671229 | url=https://www.biodiversitylibrary.org/part/168898 }}</ref><ref name="Xiang Wang Li 2014">{{cite journal | last1=Xiang | first1=Xiao-Guo | last2=Wang | first2=Wei | last3=Li | first3=Rui-Qi | last4=Lin | first4=Li | last5=Liu | first5=Yang | last6=Zhou | first6=Zhe-Kun | last7=Li | first7=Zhen-Yu | last8=Chen | first8=Zhi-Duan |display-authors=3 | title=Large-scale phylogenetic analyses reveal fagalean diversification promoted by the interplay of diaspores and environments in the Paleogene | journal=Perspectives in Plant Ecology, Evolution and Systematics | publisher=Elsevier BV | volume=16 | issue=3 | year=2014 | issn=1433-8319 | doi=10.1016/j.ppees.2014.03.001 | pages=101–110| bibcode=2014PPEES..16..101X }}</ref>

{{clade
|label1=[[Fagaceae]]
|1={{clade
   |label1=Fagoideae
   |1=''[[beech|Fagus]]'' (beeches)
   |label2=Quercoideae
   |2={{clade
      |1=''[[Trigonobalanus]]'' (3 evergreen species)
      |2={{clade
         |1={{clade
            |1=''[[Lithocarpus]]'' (stone oaks)
            |2=''[[Chrysolepis]]'' (chinquapins)
            }}
         |2={{clade
            |1='''''Quercus''' [[pro parte]]''
            |2={{clade
               |1=''[[Notholithocarpus]]'' (tan oak)
               |2={{clade
                 |1='''''Quercus''' [[pro parte]]''
                 |2={{clade
                   |1=''[[Castanopsis]]'' (also called chinquapins)
                   |2=''[[chestnut|Castanea]]'' (chestnuts)
                   }}
                }}
             }}
          }}
       }}
   }}
}}
}}

=== Internal phylogeny ===

Molecular techniques for phylogenetic analysis show that the genus ''Quercus'' consisted of [[Old World]] and [[New World]] clades.<ref name=":0"/><ref>{{Cite journal |last1=Hipp |first1=Andrew L. |last2=Manos|first2=Paul S. |last3=González-Rodríguez|first3=Antonio |last4=Hahn |first4=Marlene |last5=Kaproth|first5=Matthew |last6=McVay|first6=John D.| last7=Avalos|first7=Susana Valencia |last8=Cavender-Bares|first8=Jeannine |author-link8=Jeannine Cavender-Bares |display-authors=3 |date=January 2018 |title=Sympatric parallel diversification of major oak clades in the Americas and the origins of Mexican species diversity |journal=New Phytologist |volume=217 |issue=1 |pages=439–452 |doi=10.1111/nph.14773|pmid=28921530 |doi-access=free |bibcode=2018NewPh.217..439H |hdl=10161/15608|hdl-access=free }}</ref><ref>{{Cite journal |last1=Hubert|first1=François |last2=Grimm|first2=Guido W. |last3=Jousselin|first3=Emmanuelle |last4=Berry |first4=Vincent |last5=Franc|first5=Alain |last6=Kremer|first6=Antoine |display-authors=3 |date=2014-10-02 |title=Multiple nuclear genes stabilize the phylogenetic backbone of the genus ''Quercus'' |journal=Systematics and Biodiversity |volume=12 |issue=4 |pages=405–423 |doi=10.1080/14772000.2014.941037 |bibcode=2014SyBio..12..405H |s2cid=85604759 |issn=1477-2000 |url=https://figshare.com/articles/dataset/Multiple_nuclear_genes_stabilize_the_phylogenetic_backbone_of_the_genus_i_Quercus_i_/1128657}}</ref> The entire [[genome]] of ''Quercus robur'' (the pedunculate oak) has been [[DNA sequencing|sequenced]],<ref>{{Cite journal |last1=Plomion |first1=Christophe |last2=Aury |first2=Jean-Marc |last3=Amselem |first3=Joëlle |last4=Alaeitabar |first4=Tina |last5=Barbe |first5=Valérie |last6=Belser |first6=Caroline |last7=Bergès |first7=Hélène |last8=Bodénès |first8=Catherine |last9=Boudet|first9=Nathalie |last10=Boury |first10=Christophe |last11=Canaguier |first11=Aurélie |display-authors=3 |date=January 2016 |title=Decoding the oak genome: public release of sequence data, assembly, annotation and publication strategies |journal=Molecular Ecology Resources |volume=16 |issue=1|pages=254–265 |doi=10.1111/1755-0998.12425 |pmid=25944057 |s2cid=42715997|doi-access=free |bibcode=2016MolER..16..254P }}</ref> revealing an array of [[mutation]]s that may underlie the evolution of longevity and [[Plant disease resistance|disease resistance]] in oaks.<ref>{{Cite journal |last1=Plomion |first1=Christophe |last2=Aury |first2=Jean-Marc |last3=Amselem |first3=Joëlle |last4=Leroy |first4=Thibault |last5=Murat |first5=Florent |last6=Duplessis |first6=Sébastien |last7=Faye |first7=Sébastien |last8=Francillonne |first8=Nicolas |last9=Labadie |first9=Karine |last10=Le Provost |first10=Grégoire |last11=Lesur |first11=Isabelle |date=July 2018 |title=Oak genome reveals facets of long lifespan |journal=Nature Plants |volume=4 |issue=7 |pages=440–452 |doi=10.1038/s41477-018-0172-3 |pmc=6086335 |pmid=29915331|bibcode=2018NatPl...4..440P }}</ref> In addition, hundreds of oak species have been compared (at [[RAD-seq]] loci), allowing a detailed phylogeny to be constructed. However, the high signal of [[introgressive hybridization]] (the transfer of genetic material by repeated backcrossing with hybrid offspring) in the genus has made it difficult to resolve an unambiguous, unitary history of oaks. The phylogeny from Hipp et al. 2019 is:<ref>{{Cite journal |last1=Hipp |first1=Andrew L. |last2=Manos |first2=Paul S. |last3=Hahn |first3=Marlene |last4=Avishai |first4=Michael |last5=Bodénès |first5=Cathérine |last6=Cavender-Bares |first6=Jeannine|last7=Crowl |first7=Andrew A. |last8=Deng |first8=Min |last9=Denk |first9=Thomas |last10=Fitz-Gibbon |first10=Sorel |last11=Gailing |first11=Oliver |display-authors=3 |date=2019-10-14 |title=Genomic landscape of the global oak phylogeny |journal=New Phytologist |volume=226 |issue=4 |pages=1198–1212 |doi=10.1111/nph.16162 |pmid=31609470 |doi-access=free}}</ref>

{{clade |style=font-size:95%; line-height:105%;
|label1='''''Quercus'''''
|sublabel1= 56 [[Mya (geology)|mya]]
|1={{clade
   |label1=[[Quercus subg. Cerris|subgenus ''Cerris'']]
   |sublabel1=[[Old World]]
   |1={{clade
      |1={{clade
       |label1=section ''Cyclobalanopsis''
       |sublabel1= 44 [[Mya (geology)|mya]]
       |1={{clade
         |1={{clade
            |1=CTB<!--Compound [[Trichome]] Base--> lineage <!--e.g. Quercus chungii--> [[File:Quercus rex leaf white background.jpg|60px]]
            |2=Cyclobalanoides <!--Q. corrugata-->
            }}
         |2={{clade
            |1=Glauca [[File:Quercus glauca MHNT.BOT.2010.4.2 (cropped).jpg|80px]]
            |2={{clade
               |1=Acuta [[File:Quercus acuta2 (cropped).jpg|70px]]
               |2=Semiserrata <!--e.g. Quercus macrocalyx-->
               }}
            }}
          }}
         }}
      |2={{clade
         |label1=section ''Cerris''
         |1={{clade
            |1=East Asian Cerris [[File:Quercus acutissima leaf white background.jpg|70px]]
            |2=West Eurasian Cerris [[File:Quercus cerris leaf illustrations.jpg|80px]]
            }}
         |label2=section ''Ilex''
         |2={{clade
            |1={{clade
               |1=Early-diverging Ilex [[File:Macedonian Oak Quercus trojana white background.jpg|60px]]
               |2=East Asian Ilex [[File:Quercus phillyreoides leaf white background.jpg|50px]]
               }}
            |2={{clade
               |1=Himalaya-Mediterranean [[File:Quercus ilex leaf illustration.jpg|50px]]
               |2=Himalayan subalpine [[File:Quercus semecarpifolia leaf.jpg|60px]]
               }}
            }}
         }}
      }}
   |label2=[[Quercus subg. Quercus|subgenus ''Quercus'']]
   |sublabel2=[[New World]]
   |2={{clade
      |1={{clade
       |label1=section ''Lobatae''
       |1={{clade
         |1=Agrifoliae [[File:Quercus agrifolia leaf.JPG|40px]]
         |2={{clade
            |1=Palustres [[File:Quercus palustris leaf (white background).jpg|60px]]
            |2={{clade
               |1={{clade
                  |1=Coccineae (Rubrae) [[File:Quercus rubra-(EU).jpg|35px]]
                  |2=Phellos (Laurifoliae) [[File:Leaf_of_Willow_Oak_Quercus_phellos_white_background.jpg|60px]]
                  }}
               |2={{clade
                  |1=Texas red oaks [[File:Quercus buckleyi leaf.jpg|50px]]
                  |2=Erythromexicana [[File:Quercus hypoleucoides leaf white background.jpg|40px]]
                  }}
               }}
            }}
         }}
        }}
      |2={{clade
         |1={{clade
            |label1=section ''Protobalanus'' 
            |1=[[File:Quercus palmeri leaf white background.jpg|50px]]
            |label2=section ''Ponticae'' 
            |2=[[File:Quercus pontica leaf (white background).jpg|55px]]
            |sublabel2=[[New World]], C. Asia
            }}
         |2={{clade
            |label1=section ''Virentes'' 
            |1=[[File:Quercus oleoides leaf white background.jpg|55px]]
            |label2=section ''Quercus''
            |sublabel2=[[New World]], Europe
            |2={{clade
				|1={{clade
				   |1=Dumosae [[File:Quercus dumosa leaf (white background).jpg|33px]]
				   |2={{clade
					  |1={{clade
						 |1=Prinoids [[File:Quercus prinoides leaf white background.jpg|40px]]
						 |2={{clade
						    |1=Albae [[File:Quercus montana leaf white background.jpg|38px]]
                            |2=Roburoids [[File:Quercus robur leaf.jpg|40px]]
							}}
						 }}
					  |2={{clade
						 |1=Stellatae [[File:Quercus stellata (EU).jpg|40px]]
						 |2={{clade
							|1=Texas white oaks [[File:Autumn White Oak Leaf.jpg|40px]]
							|2=Leucomexicana [[File:Quercus rugosa leaf white background.jpg|55px]]
							}}
						 }}
					  }}
				   }}
			    }}
            }}
         }}
      }}
   }}
}}

=== Taxonomy ===

{{See also|List of Quercus species}}

==== Taxonomic history ====

The genus ''Quercus'' was [[circumscription (taxonomy)|circumscribed]] by [[Carl Linnaeus]] in the first edition of his 1753 ''[[Species Plantarum]]''.<ref>{{cite journal |last1=Pardo |first1=Francisco M. Vázquez |last2=Maqueda |first2=Soledad Ramos |last3=Pérez |first3=Esperanza Doncel |title=''Quercus ilex'' L. and ''Quercus rotundifolia'' Lam.: Two Different Species |journal=International Oaks |issue=13 |year=2002 |pages=9–14 |url=https://www.internationaloaksociety.org/sites/default/files//files/IO/IOS%20Journal%20%2313/International%20Oaks%20No.%2013%20-%20Quercus%20ilex%20L.%20and%20Quercus%20rotundifolia%20Lam.-%20Two%20Different%20Species%20-%20Franciso%20M.%20V%C3%A1zquez%20Pardo%2C%20Soledad%20Ramos%20Maqueda%2C%20Esperanza%20Doncel%20P%C3%A9rez.pdf}}</ref> He described 15 species within the new genus, providing type specimens for 10 of these, and giving names but no types for ''[[Quercus cerris|Q.&nbsp;cerris]]'', ''[[Quercus coccifera|Q.&nbsp;coccifera]]'', ''[[Quercus ilex|Q.&nbsp;ilex]]'', ''[[Quercus smilax|Q.&nbsp;smilax]]'', and ''[[Quercus suber|Q.&nbsp;suber]]''.<ref>{{cite journal |last1=Iamonico |first1=Duilio |last2=Peruzzi |first2=Lorenzo |title=Lectotypification of Linnaean Names in the Genus ''Quercus'' (Fagaceae) |journal=Taxon |volume=62 |issue=5 |year=2013 |pages=1041–1045 |doi=10.12705/625.5 |jstor=taxon.62.5.1041|bibcode=2013Taxon..62.1041I }}</ref> He chose ''[[Quercus robur|Q.&nbsp;robur]]'', the pedunculate oak, as the [[type species]] for the genus.<ref>{{cite journal |last1=Nixon |first1=Kevin C. |last2=Carpenter |first2=James M. |last3=Stevenson |first3=Dennis W. |title=The PhyloCode is fatally flawed, and the 'Linnaean' system can easily be fixed |journal=The Botanical Review |volume=69 |issue=1 |year=2003 |pages=111–120 |doi=10.1663/0006-8101(2003)069[0111:TPIFFA]2.0.CO;2 |s2cid=43477057 |url=http://lamarck.unl.edu/systematics/papers-pdf/BotRev691_111-120.pdf}}</ref>

A 2017 classification of ''Quercus'', based on multiple molecular phylogenetic studies, divided the genus into two [[subgenera]] and eight [[Section (botany)|sections]]:<ref name=DenkGrimManoDeng17>{{Citation |last1=Denk |first1=Thomas |last2=Grimm |first2=Guido W. |last3=Manos |first3=Paul S. |last4=Deng |first4=Min |last5=Hipp |first5=Andrew L. |display-authors=3 |title=Oaks Physiological Ecology. Exploring the Functional Diversity of Genus ''Quercus'' L |series=Tree Physiology |date=2017 |volume=7 |editor1-last=Gil-Pelegrín |editor1-first=Eustaquio |editor2-last=Peguero-Pina |editor2-first=José Javier |editor3-last=Sancho-Knapik |editor3-first=Domingo |contribution=An Updated Infrageneric Classification of the Oaks: Review of Previous Taxonomic Schemes and Synthesis of Evolutionary Patterns |pages=13–38 |publication-place=Cham. |publisher=Springer International Publishing |doi=10.1007/978-3-319-69099-5_2 |isbn=978-3-319-69099-5 |contribution-url=https://doi.org/10.1007/978-3-319-69099-5_2 |mode=cs1}}</ref>

*Subgenus ''Quercus'' – the New World clade (or high-latitude clade), mostly native to North America
**Section ''Lobatae'' <small>Loudon</small> – North American red oaks
**Section ''Protobalanus'' <small>(Trelease) O.Schwarz</small> – North American intermediate oaks
**Section ''Ponticae'' <small>Stef.</small> – with a [[disjunct distribution]] between western [[Eurasia]] and western North America
**Section ''Virentes'' <small>Loudon</small> – American southern live oaks
**Section ''Quercus'' – white oaks from North America and Eurasia
*Subgenus ''Cerris'' <small>Oerst.</small>  – the Old World clade (or mid-latitude clade), exclusively native to Eurasia
**Section ''Cyclobalanopsis'' <small>Oerst.</small> – cycle-cup oaks of East Asia
**Section ''Cerris'' <small>Dumort.</small> – cerris oaks of subtropical and temperate Eurasia and North Africa
**Section ''Ilex'' <small>Loudon</small> – ilex oaks of tropical and subtropical Eurasia and North Africa
<!--note --- these sections are clearly marked on the cladogram below-->

The subgenus division supports the evolutionary diversification of oaks among two distinct clades: the Old World clade (subgenus ''Cerris''), including oaks that diversified in Eurasia; and the New World clade (subgenus ''Quercus''), oaks that diversified mainly in the Americas.<ref name=":0">{{Cite journal |last1=Manos |first1=Paul S. |last2=Zhou |first2=Zhe-Kun |last3=Cannon |first3=Charles H. |year=2001 |title=Systematics of Fagaceae: Phylogenetic Tests of Reproductive Trait Evolution |journal=International Journal of Plant Sciences |volume=162 |issue=6 |pages=1361–1379 |doi=10.1086/322949 |jstor=10.1086/322949 |bibcode=2001IJPlS.162.1361M |s2cid=85925622}}</ref><ref name="Manos Hipp 2021">{{cite journal |last1=Manos |first1=Paul S. |last2=Hipp |first2=Andrew L. |title=An Updated Infrageneric Classification of the North American Oaks (''Quercus'' Subgenus ''Quercus''): Review of the Contribution of Phylogenomic Data to Biogeography and Species Diversity |journal=Forests |publisher=MDPI AG |volume=12 |issue=6 |date=2021-06-15 |issn=1999-4907 |doi=10.3390/f12060786 |page=786 |doi-access=free |bibcode=2021Fore...12..786M }}</ref>

==== Subgenus ''Quercus'' ====

{{main|Quercus subg. Quercus|l1=''Quercus'' subg. ''Quercus''}}

* Sect. ''Lobatae'' ([[Synonym (taxonomy)|synonym]] ''Erythrobalanus''), the [[Erythrobalanus|red oaks]] of North America, [[Central America]] and northern [[South America]]. [[Style (botany)|Style]]s are long; the acorns mature in 18 months and taste very bitter. The inside of the acorn shell appears woolly. The actual nut is encased in a thin, clinging, papery skin. The leaves typically have sharp lobe tips, with spiny bristles at the lobe.<ref name=DenkGrimManoDeng17/>
* Sect. ''Protobalanus'', the [[Protobalanus|canyon live oak and its relatives]], in the southwestern [[United States]] and northwest [[Mexico]]. Styles are short; the acorns mature in 18 months and taste very bitter. The inside of the acorn shell appears woolly. The leaves typically have sharp lobe tips, with bristles at the lobe tip.<ref name=DenkGrimManoDeng17/>
* Sect. ''Ponticae,'' a disjunct including just two species. Styles are short, and the acorns mature in 12 months. The leaves have large [[stipule]]s, high secondary veins, and are highly toothed.<ref name=DenkGrimManoDeng17/>
* Sect. ''Virentes,'' the southern live oaks of the Americas. Styles are short, and the acorns mature in 12 months. The leaves are evergreen or subevergreen.<ref name=DenkGrimManoDeng17/>
* Sect. ''Quercus'' (synonyms ''Lepidobalanus'' and ''Leucobalanus''), the [[Lepidobalanus|white oaks]] of [[Europe]], [[Asia]] and North America. Trees or shrubs that produce nuts, specifically acorns, as fruits. Acorns mature in one year for annual trees and two years for biannual trees. Acorn is encapsulated by a spiny cupule as characterized by the family Fagaceae. Flowers in the ''Quercus'' genera produce one flower per node, with three or six styles, as well as three or six [[Ovary (botany)|ovaries]], respectively. The leaves mostly lack a bristle on their lobe tips, which are usually rounded. The type species is ''[[Quercus robur]]''.<ref name=DenkGrimManoDeng17/><ref>{{Cite book |last=Hitchcock |first=C. Leo |url=https://www.worldcat.org/oclc/1027726223 |title=Flora of the Pacific Northwest : an illustrated manual |publisher=University of Washington Press |others=Arthur Cronquist, David Giblin, Ben Legler, Peter F. Zika, Richard G. Olmstead |year=2018 |isbn=978-0-295-74289-2 |edition=Second |location=Seattle |pages=221 |oclc=1027726223}}</ref>

==== Subgenus ''Cerris'' ====

{{main|Quercus subg. Cerris|l1=''Quercus'' subg. ''Cerris''}}

The type species is ''Quercus cerris''.
* Sect. ''[[List of Quercus species#Section Cyclobalanopsis|Cyclobalanopsis]]'', the [[List of Quercus species#Section Cyclobalanopsis|ring-cupped oaks]] of eastern and southeastern Asia. These are evergreen trees growing {{convert|10|–|40|m|ft|0|abbr=off}} tall. They are distinct from subgenus ''Quercus'' in that they have acorns with distinctive cups bearing concrescent rings of scales; they commonly also have densely clustered acorns, though this does not apply to all of the species. Species of ''Cyclobalanopsis'' are common in the evergreen subtropical [[laurel forest]]s, which extend from southern Japan, southern Korea, and Taiwan across southern China and northern Indochina to the eastern Himalayas, in association with trees of the genus ''[[Castanopsis]]'' and the laurel family ([[Lauraceae]]).<ref name=DenkGrimManoDeng17/>
* Sect. ''Cerris'', the [[Cerris|Turkey oak and its relatives]] of Europe and Asia. Styles are long; acorns mature in 18 months and taste very bitter. The inside of the acorn's shell is hairless. Its leaves typically have sharp lobe tips, with bristles at the lobe tip.<ref name=DenkGrimManoDeng17/>
* Sect. ''[[List of Quercus species#Section Ilex|Ilex]]'', the Ilex oak and its relatives of Eurasia and northern [[Africa]]. Styles are medium-long; acorns mature in 12–24 months, appearing hairy on the inside. The leaves are evergreen, with bristle-like extensions on the teeth.<ref name=DenkGrimManoDeng17/>