The family Fagaceae, includes beeches and oaks, and comprises about 600 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 other uses is made from the bark of cork oak, Quercus suber.Chestnuts 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 Fagaceae are often divided into five or six subfamilies and are generally accepted to include 9 or 10 genera (listed below). Monophyly of the Fagaceae is strongly supported by both morphological (especially fruit morphology) and molecular data.
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.
^ abJudd, Walter S., Christopher S. Campbell, Elizabeth A. Kellogg, Peter F. Stevens, Michael J. Donoghue. Plant Systematics: A Phylogenetic Approach Third Edition. Sinauer Associates, inc. Sunderland, MA 2008.
^Cronquist, Arthur. An Integrated System of Classification of Flowering Plants. Columbia University Press: New York, NY 1981.
^Takhtajan, Armen. Diversity and Classification of Flowering Plants. Columbia University Press, New York 1997.
^Manos, PS., AM Stanford. 2001b The historical biogeography of Fagaceae: Tracking the tertiary history of temperate and subtropical forests of the Northern Hemisphere. International Journal of Plant Sciences 162: S77-S93 Suppl. 6.
Monoecious trees and shrubs. Stipules present, caducous. Leaves alternate, simple. Flowers of both sexes with perianth segments. Male flowers in catkins or pendent tassel-like heads; perianth 4-6-lobed; stamens usually twice as many as perianth lobes. Female flowers in groups of 1 or 3, in spikes or at the base of the male inflorescence; each group surrounded at the base by an involucre of scales; perianth 4-6-lobed; ovary 3- or 6-locular; ovules 2 per loculus; styles 3 or 6. Fruit a 1-seeded nut, in clusters of 1-3, enclosed by an accrescent spiny or scaly cupule.
Barcode of Life Data Systems (BOLD) Stats Specimen Records:1943 Specimens with Sequences:2431 Specimens with Barcodes:1329 Species:227 Species With Barcodes:207 Public Records:1418 Public Species:169 Public BINs:0