Genus (Plantae): Quercus

An oak is a tree or shrub in the genus Quercus (/ˈkwɜːrkəs/; Latin "oak tree") 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 (stone oaks), as well as in those of unrelated species such as Grevillea robusta (silky oaks) 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 contains the largest number of oak species, with approximately 90 occurring in the United States, while Mexico has 160 species of which 109 are endemic. The second greatest center of oak diversity is China, which contains approximately 100 species.

Oaks have spirally arranged leaves, with lobate 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. In spring, a single oak tree produces both male flowers (in the form of catkins) and small female flowers, meaning that the trees are monoecious. The fruit is a nut called an acorn or oak nut 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 their species. The acorns and leaves contain tannic acid, which helps to guard from fungi and insects. The live oaks are distinguished for being evergreen, but are not actually a distinct group and instead are dispersed across the genus.

Famous Oak Trees

• The Emancipation Oak is designated one of the 10 Great Trees of the World by the National Geographic Society and is part of the National Historic Landmark district of Hampton University in Virginia.
• The Ivenack Oak which is one of the largest trees in Europe is located in Mecklenburg-Vorpommern, Germany, and is approximately 800 years old.
• The Bowthorpe Oak, located in Bourne, Lincolnshire, is thought to be 1,000 years old. It was featured in the Guinness Book of World Records and was filmed for a TV documentary for its astonishing longevity.
• The Minchenden (or Chandos) Oak, in Southgate, London, is said to be the largest oak tree in England (already 8.2 m or 27 ft in girth in the nineteenth century), and is perhaps 800 years old.
• The Seven Sisters Oak is the largest certified southern live oak tree. Located in Mandeville, Louisiana, it is estimated to be up to 1,500 years old with a trunk that measures 11.6 m (38 ft).
• The Major Oak is an 800- to 1000-year-old tree located in Sherwood Forest, Nottinghamshire. According to folklore, it was used by Robin Hood for shelter.
• Friendship Oak is a 500-year-old southern live oak located in Long Beach, Mississippi.
• The Crouch Oak is believed to have originated in the 11th Century and is located in Addlestone, Surrey. It is an important symbol of the town with many local businesses adopting its name. It used to mark the boundary of Windsor Great Park. Legend says that Queen Elizabeth I stopped by it and had a picnic.
• The Angel Oak is a southern live oak located in Angel Oak Park on John's Island near Charleston, South Carolina. The Angel Oak is estimated to be in excess of 400–500 years old, stands 20.3 m (66+1⁄2 ft) tall, and measures 8.5 m (28 ft) in circumference.
• The Kaiser's Oak, located at the village of Gommecourt in Artois, France, named in honor of Kaiser Wilhelm II, symbolically marked from late 1914 to April 1917 the furthest point in the West of the German Imperial Army during World War I.
• The Wye Oak Maryland was the United States' largest white oak tree before it blew down in a storm in 2002, at an estimated age of 460 years.
• The Bland Oak in Sydney ,Australia, planted in the 1840s, was the largest tree in Australia until it was split in a storm early on New Year Day 1941.
• The Treaty Oak in Austin, Texas, is a Texas live oak, and the last surviving member of the Council Oaks, a grove of 14 trees that served as a sacred meeting place for Comanche and Tonkawa tribes prior to European settlement of the area.

Reference: Wikipedia