List of Quercus species#Section Ilex

{{Short description|Oaks and related plants}}

{{See also|Wikispecies:Quercus}}

The genus Quercus contains about 500 known species, plus about 180 hybrids between them.{{r|powo}} The genus, as is the case with many large genera, is divided into subgenera and sections. Traditionally, the genus Quercus was divided into the two subgenera Cyclobalanopsis, the ring-cupped oaks, and Quercus, which included all the other sections. However, a comprehensive revision in 2017 identified different relationships. Now the genus is commonly divided into a subgenus Quercus and a subgenus Cerris, with Cyclobalanopsis included in the latter. The sections of subgenus Quercus are mostly native to the New World, with the notable exception of the white oaks of sect. Quercus and the endemic Quercus pontica. In contrast, the sections of the subgenus Cerris are exclusively native to the Old World.

Unless otherwise indicated, the lists which follow contain all the species accepted by Plants of the World Online {{As of|2023|February|lc=yes}}, plus selected hybrids that are also accepted,{{r|powo}} with placement into sections based on a list produced by Denk et al. for their 2017 classification of the genus.

Legend

Species with evergreen foliage ("live oaks") are tagged '#'. Species in the genus have been recategorized between deciduous and evergreen on numerous occasions, although this does not necessarily mean that species in the two groups are closely related.

Subgenus ''Quercus''

= Section ''Quercus'' =

{{See also|Quercus subg. Quercus#Section Quercus|l1=Quercus subg. Quercus § Section Quercus}}

Section Mesobalanus was included in section Quercus in the 2017 classification used here. Other synonyms include Q. sect. Albae and Q. sect. Macrocarpae. The section comprises the white oaks from Europe, Asia, north Africa, Central and North America. Styles short; acorns mature in 6 months, sweet or slightly bitter, inside of acorn shell hairless.{{citation needed|date=February 2023}}

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file:Quercus hiholensis acorn UWBM 56470-3 Pigg & Wehr 2002 Plt2 fig16.png acorn in matrix]]

= Section ''Ponticae'' =

{{See also|Quercus subg. Quercus#Section Ponticae|l1=Quercus subg. Quercus § Section Ponticae}}

Species are native to Western Asia and Western North America. They produce catkins up to 10cm long; the acorns mature annually.

= Section ''Protobalanus'' =

{{See also|Quercus subg. Quercus#Section Protobalanus|l1=Quercus subg. Quercus § Section Protobalanus}}

The intermediate oaks. Southwest USA and northwest Mexico. Styles short, acorns mature in 18 months, very bitter, inside of acorn shell woolly.{{citation needed|date=March 2023}}

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= Section ''Lobatae'' =

{{See also|Quercus subg. Quercus#Section Lobatae|l1=Quercus subg. Quercus § Section Lobatae}}

The red oaks (synonym sect. Erythrobalanus), native to North, Central and South America. Styles long, acorns mature in 18 months (in most species),Kershner, Bruce, and Craig Tufts. National Wildlife Federation Field Guide to Trees of North America. New York: Sterling Pub., 2008. Print. very bitter, inside of acorn shell woolly.{{citation needed|date=March 2023}}

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= Section ''Virentes'' =

{{See also|Quercus subg. Quercus#Section Virentes|l1=Quercus subg. Quercus § Section Virentes}}

Section Virentes has also been treated at lower ranks. Species are native south-eastern Northern America, Mexico, the West Indies (Cuba), and Central America. A 2017 classification included seven species:

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Subgenus ''Cerris''

= Section ''Cerris'' =

{{See also|Quercus subg. Cerris#Section Cerris|l1=Quercus subg. Cerris § Section Cerris}}

Species are native to Europe, north Africa and Asia. Styles long; acorns mature in 18 months, very bitter, inside of acorn shell hairless or slightly hairy.{{citation needed|date=March 2023}}

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= Section ''Ilex'' =

{{See also|Quercus subg. Cerris#Section Ilex|l1=Quercus subg. Cerris § Section Ilex}}

Species in section Ilex are native to Eurasia and northern Africa. Styles medium-long; acorns mature in 12–24 months, appearing hairy on the inside. Evergreen leaves, with bristle-like extensions on the teeth. (Sister group to sect. Cerris and sometimes included in it.){{citation needed|date=February 2023}}

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= Section ''Cyclobalanopsis'' =

{{See also|Quercus subg. Cerris#Section Cyclobalanopsis|l1=Quercus subg. Cerris § Section Cyclobalanopsis}}

File:Quercus lamellosa.jpg

The ring-cupped oaks (synonym genus Cyclobalanopsis), native to eastern and southeastern tropical Asia. They have corns 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.{{citation needed|date=March 2023}} About 90 species.

; Species

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Section uncertain

Intersectional hybrids

References

{{reflist|refs=

{{Citation |last1=Backs |first1=J.R. |last2=Ashley |first2=M.V. |date=2021 |title=Quercus Conservation Genetics and Genomics: Past, Present, and Future |journal=Forests |volume=12 |issue=7 |page=882 |doi=10.3390/f12070882 |name-list-style=amp |mode=cs1|doi-access=free |bibcode=2021Fore...12..882B }}

{{Citation |last1=Carrero |first1=Christina |last2=Jerome |first2=Diana |last3=Beckman |first3=Emily |last4=Byrne |first4=Amy |last5=Coombes |first5=Allen J. |last6=Deng |first6=Min |last7=González Rodríguez |first7=Antonio |last8=Sam |first8=Hoang Van |last9=Khoo |first9=Eyen |last10=Nguyen |first10=Ngoc |last11=Robiansyah |first11=Iyan |last12=Rodríguez Correa |first12=Hernando |last13=Sang |first13=Julia |last14=Song |first14=Yi-Gang |last15=Strijk |first15=Joeri |last16=Sugau |first16=John |last17=Sun |first17=Weibang |last18=Valencia-Ávalos |first18=Susana |last19=Westwood |first19=Murphy |date=2020 |title=The Red List of Oaks 2020 |publication-place=Lisle, IL |publisher=The Morton Arboretum |url=https://static1.squarespace.com/static/557dec57e4b0c3993deb6044/t/60ba66607de08b6cc5e42d00/1622828642301/RedListOaks2020.pdf |access-date=2023-02-24 |name-list-style=amp |mode=cs1}}

{{Citation |last1=Denk |first1=Thomas |last2=Grimm |first2=Guido W. |last3=Manos |first3=Paul S. |last4=Deng |first4=Min |last5=Hipp |first5=Andrew L. |date=2017 |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 |title=Oaks Physiological Ecology. Exploring the Functional Diversity of Genus Quercus L. |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 |name-list-style=amp |mode=cs1}}

{{Citation |last1=Denk |first1=Thomas |last2=Grimm |first2=Guido W. |last3=Manos |first3=Paul S. |last4=Deng |first4=Min |last5=Hipp |first5=Andrew L. |date=2017-11-02 |title=Appendix 2.1: An updated infrageneric classification of the oaks |website=figshare |doi=10.6084/m9.figshare.5547622.v1 |url=https://figshare.com/articles/dataset/Appendix_2_1_________An_updated_infrageneric_classification_of_the_oaks/5547622/1 |access-date=2023-02-17 |format=xls |name-list-style=amp |mode=cs1}}

{{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=2023-02-17}}

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