Oak

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

Famous quotes containing the word oak:

    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)

    When the red-cheeked, dancing girls, April and May, trip home to the wintry, misanthropic woods; even the barest, ruggedest, most thunder-cloven old oak will at least send forth some few green sprouts, to welcome such glad-hearted visitants.
    Herman Melville (1819–1891)

    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)