An oak is a tree or shrub in the genus Quercus ( /ˈkwɜrkəs/; Latin "oak tree"), of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus. The genus is native to the Northern Hemisphere, and includes deciduous and evergreen species extending from cool temperate to tropical latitudes in Asia and the Americas.

Oaks have spirally arranged leaves, with lobed margins in many species; some have serrated leaves or entire leaves with smooth margins. Many deciduous species are marcescent, not dropping dead leaves until spring. The flowers are catkins, produced in spring. The fruit is a nut called an acorn, borne in a cup-like structure known as a cupule; each acorn contains one seed (rarely two or three) and takes 6–18 months to mature, depending on species. The live oaks are distinguished for being evergreen, but are not actually a distinct group and instead are dispersed across the genus.

Read more about Oak:  Classification, Hybridization, Uses, Biodiversity and Ecology, Diseases and Pests, Toxicity, Historical Note On Linnaean Species

Other articles related to "oak":

University Of Rochester Arboretum
... The River Campus is located beside the Genesee River on a site previously owned by the Oak Hill Country Club ... had designed a "River Walk" of oak trees along the river and after the university purchased the site in 1923, his son Frederick Law Olmsted, Jr ... area between Elmwood Avenue and Intercampus Drive are 197 oak trees representing 15 species ...
Oak Processionary
... The Oak Processionary (Thaumetopoea processionea) is a moth whose caterpillars can be found in oak forests ...
1980–81 NFL Playoffs - Conference Championships - January 11, 1981 - AFC Championship: Oakland Raiders 34, San Diego Chargers 27
... Lepore TV announcers (NBC) Dick Enberg and Merlin Olsen Game information Scoring OAK - Chester 65 pass from Plunkett (Bahr kick) OAK 7-0 SD - Joiner 48 pass from Fouts (Benirschke ...
Oak Park Conservatory
... Oak Park Conservatory is a conservatory and botanical garden located at 615 Garfield Street in the Chicago suburb of Oak Park, Illinois, United States ... The Oak Park Conservatory was added to the U.S ...
Wye Oak
... The Wye Oak was the honorary state tree of Maryland, and the largest white oak tree in the United States ... of Wye Mills, Talbot County, Maryland, the Wye Oak was believed to be over 460 years old at the time of its destruction during a severe thunderstorm on June 6, 2002, and ... It is believed that the acorn that became the oak germinated around the year 1540 ...

Famous quotes containing the word oak:

    Yet poetry, though the last and finest result, is a natural fruit. As naturally as the oak bears an acorn, and the vine a gourd, man bears a poem, either spoken or done. It is the chief and most memorable success, for history is but a prose narrative of poetic deeds.
    Henry David Thoreau (1817–1862)

    Alas for America as I must so often say, the ungirt, the diffuse, the profuse, procumbent, one wide ground juniper, out of which no cedar, no oak will rear up a mast to the clouds! It all runs to leaves, to suckers, to tendrils, to miscellany. The air is loaded with poppy, with imbecility, with dispersion, & sloth.
    Ralph Waldo Emerson (1803–1882)

    I could lecture on dry oak leaves; I could, but who would hear me? If I were to try it on any large audience, I fear it would be no gain to them, and a positive loss to me. I should have behaved rudely toward my rustling friends.
    Henry David Thoreau (1817–1862)