The Fagaceae (/fəˈɡeɪsi.iː,-ˌaɪ/; from Latinfagus 'beech tree') are a family of flowering plants that includes beeches, chestnuts and oaks, and comprises eight genera with about 927 species.[2] Fagaceae in temperate regions are mostly deciduous, whereas in the tropics, many species occur as evergreen trees and shrubs. They 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. Their leaves are often lobed, and both petioles and stipules are generally present. Their 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. In the oaks, genus Quercus, the fruit 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. Other members of the family have fully enclosed nuts. Fagaceae is one of the most ecologically important woody plant families in the Northern Hemisphere, as oaks form the backbone of temperate forest in North America, Europe, and Asia, and are one of the most significant sources of wildlife food.
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. Wood chips from the genus Fagus are often used in flavoring beers. Nuts of some species in the Asian tropical genera Castanopsis and Lithocarpus are edible and often used as ornamentals.
The Fagaceae are often divided into five or six subfamilies and are generally accepted to include 8 (to 10) genera (listed below). Monophyly of the Fagaceae is strongly supported by both morphological (especially fruit morphology) and molecular data.[3]
The Southern Hemisphere genus Nothofagus, commonly the southern beeches, was historically placed in the Fagaceae sister to the genus Fagus,[4] 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.[5] The currently accepted view by systematic botanists is to place Nothofagus in its own family, Nothofagaceae.[3]
FagusL.—beeches; about 10 to 13 species, north temperate east Asia, southwest Asia, Europe, eastern North America
The genus Nothofagus (southern beeches: from the Southern Hemisphere), formerly included in the Fagaceae, is now treated in the separate monotypic family Nothofagaceae.[6]
Trigonobalanus Forman 1962—three species, tropical southeast Asia, Northern South America (Colombia) (three species of Colombobalanus and Formanodendron are included)
The Quercus subgenus Cyclobalanopsis is treated as a distinct genus by the Flora of China, but as a section or subgenus by most taxonomists.
^ abJudd, Walter S.; Campbell, Christopher S.; Kellogg, Elizabeth A.; Stevens, Peter F.; Donoghue, Michael J. (2008). Plant Systematics: A Phylogenetic Approach (3rd ed.). Sinauer. ISBN978-0-87893-407-2.
^Manos PS, Stanford AM (2001). "The historical biogeography of Fagaceae: Tracking the tertiary history of temperate and subtropical forests of the Northern Hemisphere". International Journal of Plant Sciences. 162 (Suppl. 6): S77–S93. doi:10.1086/323280. S2CID84936653.
^Xiang X-G, Wang W, Li R-Q, Lin L, Liu Y, Zhou Z-K, Li Z-Y, Chen Z-D (2014). "Large-scale phylogenetic analyses reveal fagalean diversification promoted by the interplay of diaspores and environments in the Paleogene". Perspectives in Plant Ecology, Evolution and Systematics. 16 (3): 101–110. Bibcode:2014PPEES..16..101X. doi:10.1016/j.ppees.2014.03.001.
