View source for Fagales

==Systematics==
Fagales include the following seven families, according to the [[APG III system]] of [[Taxonomy|classification]]:<ref name=APGIII2009/>

*[[Betulaceae]] – birch family (''[[Alnus]]'', ''[[Betula]]'', ''[[Carpinus]]'', ''[[Corylus]]'', ''[[Ostrya]]'', and ''[[Ostryopsis]]'')
*[[Casuarinaceae]] – she-oak family (''[[Allocasuarina]]'', ''[[Casuarina]]'', ''[[Ceuthostoma]]'', and ''[[Gymnostoma]]'')
*[[Fagaceae]] – beech family (''[[Castanea (genus)|Castanea]]'', ''[[Castanopsis]]'', ''[[Chrysolepis]]'', ''[[Beech|Fagus]]'', ''[[Lithocarpus]]'', ''[[Notholithocarpus]]'', ''[[Quercus]]'', and ''[[Trigonobalanus]]'')
*[[Juglandaceae]] – walnut family (''[[Alfaroa]]'', ''[[Carya]]'', ''[[Cyclocarya]]'', ''[[Engelhardia]]'', ''[[Juglans]]'', ''[[Oreomunnea]]'',  ''[[Platycarya]]'', ''[[Pterocarya]]'', and ''[[Rhoiptelea]]'')
*[[Myricaceae]] – bayberry family (''[[Canacomyrica]]'', ''[[Comptonia (plant)|Comptonia]]'', and ''[[Myrica]]'')
*[[Nothofagaceae]] – southern beech family (''[[Nothofagus]]'')
*[[Ticodendron|Ticodendraceae]] – ticodendron family (''[[Ticodendron]]'')

Modern [[molecular phylogenetics]] suggest the following relationships:<ref name=APGIII2009/>{{citation needed|reason=AGGII gives the content, but not a phylogenetic analysis |date=February 2023}}

{{Clade| style=line-height:75%;
|1={{clade
  |1=[[Cucurbitales]]&nbsp;([[Outgroup (cladistics)|outgroup]])
  |label2=Fagales
  |2={{clade
    |1=[[Nothofagaceae]]
    |2={{clade
      |1=[[Fagaceae]]
      |2={{clade
        |1={{clade
          |1=[[Myricaceae]]
          |2=[[Juglandaceae]]
           }}
        |2={{clade
          |1={{clade
            |1=[[Ticodendraceae]]
            |2=[[Betulaceae]]
             }}
          |2=[[Casuarinaceae]]
           }}
         }}
       }}
     }}
   }}
}}

The older [[Cronquist system]] only included four families (Betulaceae, Corylaceae, Fagaceae, Ticodendraceae; Corylaceae now being included within Betulaceae); this arrangement is followed by, for example, the World Checklist of selected plant families.<ref>{{cite web |title=Royal Botanic Gardens, Kew: Databases and Publications |url=http://www.kew.org/wcb/aboutfag.html |archive-url=https://web.archive.org/web/20040203105430/http://www.kew.org/wcb/aboutfag.html |url-status=dead |archive-date=3 February 2004 |access-date=16 October 2018}}</ref> The other families were split into three different orders, placed among the [[Hamamelidae]].  The Casuarinales comprised the single family Casuarinaceae, the Juglandales comprised the Juglandaceae and Rhoipteleaceae, and the Myricales comprised the remaining forms (plus ''[[Balanops]]'').  The change is due to studies suggesting the Myricales, so defined, are [[paraphyletic]] to the other two groups.