Quercus Section Protobalanus

The genus ''Quercus'' contains about 500 known species, plus about 180 hybrids between them. 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 , plus selected hybrids that are also accepted, 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''

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.

*''Quercus aculcingensis'' Trel. – Mexico
*'' Quercus ajoensis'' C.H.Mull. – Ajo Mountain shrub oak, Blue shrub oak – Arizona, New Mexico, Baja California
*''Quercus alba'' L. – white oak – eastern and central North America
*''Quercus aliena'' Blume – Oriental white oak – eastern Asia
*''Quercus alpescens'' Trel. – Mexico
*''Quercus ariifolia'' Trel. – Mexico (Sierra Madre Oriental)
*''Quercus arizonica'' Sarg. – Arizona white oak – # southwestern U.S., northwestern Mexico
*''Quercus austrina'' Small – bluff oak – southeastern North America
* ''Quercus'' × ''basaseachicensis'' C.H.Mull. – Mexico ( Chihuahua, Durango)
* ''Quercus'' × ''bebbiana'' C.K.Schneid. — Bebb's oak — northeastern North America
*''Quercus berberidifolia'' Liebm. – California scrub oak – # California
*''Quercus bicolor'' Willd. – swamp white oak – eastern and midwestern North America
* ''Quercus'' × ''bimundorum'' E.J.Palmer - two worlds oak - U.S.
*'' Quercus boyntonii'' Beadle – Boynton's post oak – south central North America
*''Quercus canariensis'' Willd. – Mirbeck's oak or Algerian oak – # North Africa & Spain
*'' Quercus carmenensis'' C.H.Mull. – Carmen oak – Coahuila and Texas
* ''Quercus'' × ''cerrioides'' Willk. & Costa – east Spain
*''Quercus chapmanii'' Sarg. – Chapman oak – # southeastern U.S.
*''Quercus chartacea'' Trel. – Southern Mexico
*'' Quercus chihuahuensis'' Trel. – Chihuahua oak – northern Mexico and Texas
*''Quercus congesta'' C.Presl – Italy
*''Quercus convallata'' Trel. – Mexico
*'' Quercus copeyensis'' C.H.Mull. – # Costa Rica, Panama
*''Quercus cornelius-mulleri'' Nixon & K.P.Steele – Muller oak – # southwestern North America
*''Quercus corrugata'' Hook. – Mexico, Central America
*''Quercus dalechampii'' Ten. – southeastern Europe
*''Quercus deliquescens'' C.H.Mull. – Mexico
*''Quercus dentata'' Thunb. – daimyo oak – eastern Asia
*''Quercus depressipes'' Trel. – Davis Mountain oak – northern Mexico and Texas
*'' Quercus deserticola'' Trel. – # Mexico
*'' Quercus diversifolia'' Née – Mexico
*''Quercus douglasii'' Hook. & Arn. – blue oak – California
*'' Quercus dumosa'' Nutt. – coastal scrub oak – # southern California, Baja California, Arizona
*''Quercus durata'' Jeps. – leather oak – # California
*'' Quercus edwardsiae'' C.H.Mull. – Mexico
*''Quercus engelmannii'' Greene – Engelmann oak – # southern California, Baja California
*''Quercus estremadurensis'' O.Schwarz – Portugal, Spain, Morocco
*'' Quercus fabrei'' Hance – Faber's oak – central to southern China
*''Quercus faginea'' Lam. – Portuguese oak – # southwestern Europe
*''Quercus frainetto'' Ten. — Hungarian oak — southeastern Europe
*'' Quercus frutex'' Trel. – Mexico
*†'' Quercus furuhjelmi'' — Eocene to Miocene - Alaska, Kazakhstan
*''Quercus gambelii'' Nutt. – Gambel oak – southwestern North America
*''Quercus garryana'' Douglas ex Hook. – Oregon white oak or Garry oak – western North America
*'' Quercus germana'' Schltdl. & Cham. – Mexico
*'' Quercus glabrescens'' Benth. – Mexico
*'' Quercus glaucescens'' Bonpl. – encino blanco – Mexico
*'' Quercus glaucoides'' M.Martens & Galeotti – # Mexico
*''Quercus greggii'' (A.DC.) Trel. – # Mexico
*'' Quercus griffithii'' Hook.f. & Thomson ex Miq. – southeast Asia
*''Quercus grisea'' Liebm. – gray oak – # southwestern North America
*''Quercus hartwissiana'' Steven – Strandzha oak – southeastern Bulgaria, northern Turkey, western Georgia, southwestern Russia
*''Quercus havardii'' Rydb. – Havard oak, shinnery oak, shin oak – south central North America
*†''Quercus hiholensis'' — Miocene — # Washington State
*'' Quercus hinckleyi'' C.H.Mull. – Hinckley oak – # Texas, northwestern Mexico
*''Quercus ichnusae'' Mossa, Bacch. & Brullo – Sardinia
*''Quercus infectoria'' G.Olivier – Aleppo oak, Cyprus oak – southern Europe, southwestern Asia
*'' Quercus insignis'' M.Martens & Galeotti – Mexico, Belize, Costa Rica, Guatemala, Panama
*'' Quercus intricata'' Trel. – Coahuila scrub oak – # two isolated localities in west Texas, northern Mexico
*''Quercus invaginata'' Trel. – Mexico
*''Quercus john-tuckeri'' Nixon & C.H.Mull. – Tucker's oak – California
*''Quercus juergensenii'' Liebm. – Mexico
*''Quercus kotschyana