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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. Fagaceae are one of the most ecologically important woody plant families in the Northern Hemisphere, as oaks form the backbone of temperate forests in North America, Europe, and Asia and one of the most significant sources of wildlife fodder. A characteristic of Fagaceae is their tendency to easily cross-pollinate with members of their same genus/section. In particular, oaks of the same section cross so easily that it is unclear how they manage to stay morphologically distinct. 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. ==Classification== 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.〔Judd, 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.〕 The Southern Hemisphere genus ''Nothofagus,'' commonly the southern beeches, was historically placed in the Fagaceae sister to the genus ''Fagus'',〔Cronquist, Arthur. ''An Integrated System of Classification of Flowering Plants''. Columbia University Press: New York, NY 1981.〕 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.〔Takhtajan, Armen. ''Diversity and Classification of Flowering Plants''. Columbia University Press, New York 1997.〕 The currently accepted view by systematic botanists is to place ''Nothofagus'' in its own family, Nothofagaceae.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Fagaceae」の詳細全文を読む スポンサード リンク
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