An oak is a tree or shrub in the genus Quercus of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably Lithocarpus, as well as in those of unrelated species such as Grevillea robusta and the Casuarinaceae (she-oaks). The genus Quercus is native to the Northern Hemisphere, and includes deciduous and evergreen species extending from cool temperate to tropical latitudes in the Americas, Asia, Europe, and North Africa. North America has the largest number of oak species, with approximately 160 species in Mexico of which 109 are endemic and about 90 in the United States. The second greatest area of oak diversity is China, with approximately 100 species.
Quercus rubra, the northern red oak, is an oak tree in the red oak group. It is a native of North America, in the eastern and central United States and southeast and south-central Canada. It has been introduced to small areas in Western Europe, where it can frequently be seen cultivated in gardens and parks. It prefers good soil that is slightly acidic. Often simply called red oak, northern red oak is so named to distinguish it from southern red oak (Q. falcata), also known as the Spanish oak. Northern Red Oak is sometimes called champion oak.
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.
Quercus alba, the white oak, is one of the preeminent hardwoods of eastern and central North America. It is a long-lived oak, native to eastern and central North America and found from Minnesota, Ontario, Quebec, and southern Maine south as far as northern Florida and eastern Texas. Specimens have been documented to be over 450 years old.
Quercus marilandica, the blackjack oak, is a small oak, one of the red oak group Quercus sect. Lobatae. It is native to the eastern and central United States.
Quercus robur, the pedunculate oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native to most of Europe and western Asia, and is widely cultivated in other temperate regions. It grows on circumneutral soils in the lowlands and is notable for its value to natural ecosystems, supporting a very wide diversity of herbivorous insects and other pests, predators and pathogens.
Quercus ilex, the evergreen oak, holly oak or holm oak is a large evergreen oak native to the Mediterranean region. It is a member of the Ilex section of the genus, with acorns that mature in a single summer.
Quercus garryana is an oak tree species of the Pacific Northwest, with a range stretching from southern California to southwestern British Columbia. It is commonly known as the Oregon white oak or Oregon oak or, in Canada, the Garry oak. It grows from sea level to an altitude of 690 feet in the northern part of its range, and from 980 to 5,900 ft in the south of the range in California. The eponymous Nicholas Garry was deputy governor of the Hudson's Bay Company.
Quercus suber, commonly called the cork oak, is a medium-sized, evergreen oak tree in the section Quercus sect. Cerris. It is the primary source of cork for wine bottle stoppers and other uses, such as cork flooring and as the cores of cricket balls. It is native to southwest Europe and northwest Africa. In the Mediterranean basin the tree is an ancient species with fossil remnants dating back to the Tertiary period.
Quercus petraea, commonly known as the sessile oak, Cornish oak, Irish Oak or durmast oak, is a species of oak tree native to most of Europe and into Anatolia and Iran. The sessile oak is the national tree of Ireland, and an unofficial emblem in Wales and Cornwall.
Live oak or evergreen oak is any of a number of oaks in several different sections of the genus Quercus that share the characteristic of evergreen foliage. These oaks are not more closely related to each other than they are to other oaks.
The acorn, or oaknut, is the nut of the oaks and their close relatives. It usually contains one seed, enclosed in a tough, leathery shell, and borne in a cup-shaped cupule. Acorns are 1–6 cm long and 0.8–4 cm on the fat side. Acorns take between 5 and 24 months to mature; see the list of Quercus species for details of oak classification, in which acorn morphology and phenology are important factors.
Quercus falcata, also called southern red oak, spanish oak, bottomland red oak or three-lobed red oak is an oak. Native to the southeastern United States, it gets its name the "Spanish Oak" as these are the areas of early Spanish colonies, whilst "southern red oak" comes from both its range and leaf color during late summer and fall. The southern red oak is a deciduous angiosperm, so has leaves that die after each growing period and come back in the next period of growth.
The Nansei Islands subtropical evergreen forests is a terrestrial ecoregion of the Ryukyu Islands, also known as the Nansei Islands, in Japan. The Nansei Islands are an island arc that stretches southwest from Kyushu towards Taiwan. The larger islands are mostly high islands and the smaller ones mostly coral. The largest is Okinawa Island. The highest point is Mount Miyanoura on Yakushima Island at 1,936 metres.
Quercus coccifera, the kermes oak, is an oak bush in the Ilex section of the genus. It has many synonyms, including Quercus calliprinos. It is native to the Mediterranean region and Northern African Maghreb, south to north from Morocco to France and west to east from Portugal to Cyprus and Turkey, crossing Spain, Italy, Libya, Balkans, and Greece, including Crete. The Kermes Oak was historically important as the food plant of the Kermes scale insect, from which a red dye called crimson was obtained. The etymology of the specific name coccifera is related to the production of red cochineal (crimson) dye and derived from Latin coccum which was from Greek κόκκος, the kermes insect. The Latin -fera means 'bearer'.
Quercus lyrata, the overcup oak, is an oak in the white oak group. The common name, overcup oak, refers to its acorns that are mostly enclosed within the acorn cup. It is native to lowland wetlands in the eastern and south-central United States, in all the coastal states from New Jersey to Texas, inland as far as Oklahoma, Missouri, and Illinois. There are historical reports of it growing in Iowa, but the species appears to have been extirpated there. It is a slow-growing tree that often takes 25 to 30 years to mature. It has an estimated lifespan of 400 years.
Quercus ilicifolia, commonly known as bear oak or scrub oak, is a small shrubby oak native to the eastern United States and southeastern Canada. Its range extends in the United States from Maine to North Carolina, with reports of a few populations north of the international frontier in Ontario. The name ilicifolia means "holly-leaved."
Quercus rotundifolia, the holm oak or ballota oak, is an evergreen oak native to the western Mediterranean region, with the majority on the Iberian Peninsula and minor populations in Northwest Africa. The species was first described by Jean-Baptiste Lamarck in 1785. It is the typical species of the Iberian dehesa or montado, where its sweet-astringent acorns are a source of food for livestock, particularly the Iberian pig. Its acorns have been used for human nourishment since the Neolithic era. It is placed in section Ilex. It has previously been described in the same species as Quercus ilex.
Quercus subgenus Cerris is one of the two subgenera into which the genus Quercus was divided in a 2017 classification. It contains about 140 species divided among three sections. It may be called the Old World clade or the mid-latitude clade; all species are native to Eurasia and North Africa.
