|*Some botanists include the Oleaceae|
in the order Lamiales.
An ash can be any of three different tree species from three very distinct families (see end of page for disambiguation), but originally and most commonly refers to trees of the genus Fraxinus in the olive family Oleaceae. The ashes are usually medium to large trees, mostly deciduous though a few subtropical species are evergreen. The leaves are opposite (rarely in whorls of three), and mostly pinnately-compound, simple in a few species. The seeds, popularly known as keys, are a type of fruit known as a samara.
Ashes of eastern North America
Ashes of western and southwestern North America
Ashes of the Western Palearctic (Europe, north Africa and southwest Asia)
Ashes of the Eastern Palearctic (central & eastern Asia)
The wood is hard, tough and very strong but elastic, extensively used for tool handles, quality wooden baseball bats and other uses demanding high strength and resilience. It also makes excellent firewood. The two most economically important species for wood production are White Ash in eastern North America, and Common Ash in Europe. The Green Ash is widely planted as a street tree in the United States. The inner bark of the Blue Ash has been used as a source for a blue dye.
In Norse mythology, the World Tree Yggdrasil was an ash tree, and the first man, Ask, was formed from an ash tree (the first woman was made from alder). Elsewhere in Europe, snakes were said to be repelled by ash leaves or a circle drawn by an ash branch. Irish folklore claims that shadows from an ash tree damage crops. In Cheshire, it is said that ash could be used to cure warts or rickets.
In North America, the name ash is also given to species of Sorbus, more accurately known as Rowans and Whitebeams. In Australia, many common eucalyptus species are called ash because they too produce hard, fine-grained timber. The best known of these is the Mountain Ash, one of the tallest trees in the world.