The family Fagaceae, or beech family, comprises about 900 species of both evergreen and deciduous trees and shrubs, which are characterized by alternate simple leaves with pinnate venation, unisexual flowers in the form of catkins, and fruit in the form of cup-like (cupule) nuts. Fagaceous leaves are often lobed and both petioles and stipules are generally present. Fruits lack endosperm and lie in a scaly or spiny husk that may or may not enclose the entire nut, which may consist of one to seven seeds. The best-known group of this family is the oaks, genus Quercus, the fruit of which is a non-valved nut (usually containing one seed) called an acorn. The husk of the acorn in most oaks only forms a cup in which the nut sits.
Several members of the Fagaceae have important economic uses. Many species of oak, chestnut, and beech (genera Quercus, Castanea, and Fagus respectively) are commonly used as timber for floors, furniture, cabinets, and wine barrels. Cork for stopping wine bottles and a myriad of other uses is made from the bark of cork oak, Quercus suber. Chestnuts, a tasty treat enjoyed by many in the winter, are the fruits from species of the genus Castanea. Numerous species from several genera are prominent ornamentals, and wood chips from the genus Fagus are often used in flavoring beers.
The Southern Hemisphere genus Nothofagus, commonly the southern beeches, was historically placed in the Fagaceae sister to the genus Fagus, but recent molecular evidence suggests otherwise. While Nothofagus shares a number of common characteristics with the Fagaceae, such as cupule fruit structure, it differs significantly in a number of ways including distinct stipule and pollen morphology as well as having a different number of chromosomes. The currently accepted view by systematic botanists is to place Nothofagus in its own family, Nothofagaceae.
Phylogeny and Phylogeography of North American Castanea Mill. (Fagaceae) Using cpDNA Suggests Gene Sharing in the Southern Appalachians (Castanea Mill., Fagaceae)
Jun 01, 2012; ABSTRACT North American Castanea consists of three morphologically variable species: Castanea dentata, Castanea pumila, and...