Distribution:  World wide, except southern Africa with maximum diversity in the North temperate zone - 3 genera and 45 species in Texas.

Floral structure:

Significant features:  Like the Ulmaceae (Urticales) and Juglandaceae (Juglandales), the Fagaceae includes common and important elements of North temperate deciduous forests world wide, including Oak (Quercus) and Beech (Fagus), and Chestnut (Castanea) species.  Distinctive by their 'amentiferous' floral structures combined with alternate, simple leaves  and a distinctive fruiting structure.  The true fruit is a nut, but this is subtended by involucre of the pistillate flower which, in Quercus species, is connate and lignified to form the acorn cap.  Like taxa of the Juglandaceae, the mature seed contains a fully developed embryo which provides a high protein/oil food product for both wildlife (ecological importance) and humans (economic importance - European chestnut = Castanea sativa (the species epithet 'sativa' denotes cultivation).  Bark of the Cork Oak (Quercus suber - native to southern Europe) is used for cork, a unique biological (cellular) material that is difficult to replace by synthetics.  The American chestnut (Castanea dentata), an important element of eastern North American forests from both economic and ecological points of view, has followed a path similar to that described here for the American Elm (Ulmus americana) in that it has been decimated by an introduced, European fungus.
 
 

Quercus nigra - staminate inflorescence at anthesis

Quercus nigra - pistillate inflorescence at anthesis

Quercus nigra - pistillate flower past anthesis, maturing with involucre

Quercus nigra - pistillate flowers past anthesis, maturing with involucre
 

Quercus suber - overview from Kohler's Medicinal Plants

Castanea pumila - staminate catkins and mature pistillate inflorescences
 

More information on the Fagaceae