The Fagales are an order of flowering plants, including some of the best known trees. The order name is derived from genus Fagus, beeches. They belong among the rosid group of dicotyledons. The families and genera currently included are as follows:
- Betulaceae - birch family (Betula, Alnus, Carpinus, Corylus, Ostrya, Ostryopsis)
- Casuarinaceae - she-oak family (Casuarina, Gymnostoma, Ceuthostoma, Allocasuarina)
- Fagaceae - beech family (Fagus, Quercus, Castanea, Castanopsis, Chrysolepis, Formanodendron, Lithocarpus, Trigonobalanus, Colombobalanus)
- Juglandaceae - walnut family (Juglans, Pterocarya, Carya, Cyclocarya, Alfaroa, Engelhardia, Oreomunnea, Platycarya, Rhoiptelea)
- Myricaceae - bayberry family (Myrica, Canacomyrica, Comptonia)
- Nothofagaceae - southern beech family (Nothofagus - subgenera Fuscospora, Brassospora and Lophozonia)
- Ticodendraceae - ticodendron family (Ticodendron)
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 (see external link below). 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.
- Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III" (PDF). Botanical Journal of the Linnean Society 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x. Retrieved 2013–07–06.