An oak is a hardwood tree or shrub in the genus Quercus of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne in a cup. The genus is widely distributed in the Northern Hemisphere; it includes some 500 species, both deciduous and evergreen. Fossil oaks date back to the Middle Eocene. Molecular phylogeny shows that the genus is divided into Old World and New World clades, but many oak species hybridise freely, making the genus's history difficult to resolve.
Quercus montana, the chestnut oak, is a species of oak in the white oak group, Quercus sect. Quercus. It is native to the eastern United States, where it is one of the most important ridgetop trees from southern Maine southwest to central Mississippi, with an outlying northwestern population in southern Michigan. It is also sometimes called rock oak because of its presence in montane and other rocky habitats.
The Fagaceae are a family of flowering plants that includes beeches, chestnuts and oaks, and comprises eight genera with about 927 species. 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 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.
Quercus muehlenbergii, the chinquapinoak, is a deciduous species of tree in the white oak group. The species was often called Quercus acuminata in older literature. Quercus muehlenbergii is native to eastern and central North America. It ranges from Vermont to Minnesota, south to the Florida panhandle, and west to New Mexico in the United States. In Canada it is only found in southern Ontario, and in Mexico it ranges from Coahuila south to Hidalgo.
Quercus michauxii, the swamp chestnut oak, is a species of oak in the white oak section Quercus section Quercus in the beech family. It is native to bottomlands and wetlands in the southeastern and midwestern United States, in coastal states from New Jersey to Texas, inland primarily in the Mississippi–Ohio Valley as far as Oklahoma, Missouri, Illinois, and Indiana.
Quercus coccinea, the scarlet oak, is a deciduous tree in the red oak section Lobatae of the genus Quercus, in the family Fagaceae.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1926.
Acer browni is an extinct maple species in the family Sapindaceae described from a series of isolated fossil leaves and samaras. The species is known from the early to middle Miocene sediments exposed in Western Oregon, Washington state, USA and Northern Graham Island, Haida Gwaii, Canada. It is one of several extinct species placed in the living section Parviflora.
Acer smileyi is an extinct maple species in the family Sapindaceae described from a series of isolated fossil leaves and samaras. The species is known from the late Oligocene to middle Miocene sediments exposed in the states of Alaska, Idaho, Nevada, and Oregon, USA. It is one of several extinct species placed in the living section Parviflora.
Quercus sagrana, also spelt Quercus sagraeana, the Cuban oak, is a medium-sized evergreen tree native to western Cuba in the Cuban pine forests ecoregion. It is the only oak native to the Caribbean.
Rhus malloryi is an extinct species of flowering plant in the sumac family Anacardiaceae. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States. The species was first described from a series of isolated fossil leaves in shale. R. malloryi is one of four sumac species to be described from the Klondike Mountain Formation, and forms a hybrid complex with the other three species.
Acer chaneyi is an extinct maple species in the family Sapindaceae described from a number of fossil leaves and samaras. The species is known from Oligocene to Miocene sediments exposed in Alaska, Idaho, Nevada, Oregon and Washington in the U.S. It is one of several extinct species belonging to the living section Rubra.
Quercus coffeicolor is a species of oak. It is native to Nayarit, Sinaloa, and Jalisco in western Mexico.
Acer whitebirdense is an extinct maple species in the family Sapindaceae described from a number of fossil leaves and samaras. The species is known from Miocene sediments exposed in Idaho, Oregon and Washington in the United States. It is one of several extinct species belonging to the living section Rubra.
Acer taggarti is an extinct maple species in the family Sapindaceae described from a number of fossil leaves and samaras. The species is known from Miocene sediments exposed in central Oregon, US. It is one of several extinct species belonging to the living section Rubra.
Quercus hiholensis is an extinct species of oak in the Fagaceae genus Quercus. The species is known from Middle Miocene fossils found in Central Washington.
Acer eonegundo is an extinct maple species in the family Sapindaceae described from a single partial fossil leaf. The species is known from Eocene sediments exposed in the US state of Nevada. It is placed into the living Acer section Negundo.
Quercus subgenus Quercus is one of the two subgenera into which the genus Quercus was divided in a 2017 classification. It contains about 190 species divided among five sections. It may be called the New World clade or the high-latitude clade; most species are native to the Americas, the others being found in Eurasia and northernmost North Africa.
