Ginkgo biloba

Ginkgo biloba, commonly known as ginkgo or gingko (ˈɡɪŋkoʊ,_ˈɡɪŋkɡoʊ ), also known as the maidenhair tree, is a species of gymnosperm tree native to China. It is the last living species in the order Ginkgoales, which first appeared over 290 million years ago. Fossils very similar to the living species, belonging to the genus Ginkgo, extend back to the Middle Jurassic epoch approximately 170 million years ago. The tree was cultivated early in human history and remains commonly planted. Ginkgo leaf extract is commonly used as a dietary supplement, but there is no scientific evidence that it supports human health or is effective against any disease. The genus name is regarded as a misspelling of the Japanese pronunciation gin kyo (ɡiŋkjoː) for the kanji 銀杏 meaning "silver apricot", which is found in Chinese herbology literature such as 日用本草 (Daily Use Materia Medica) (1329) and Compendium of Materia Medica 本草綱目 published in 1578. Despite its spelling, which is due to a complicated etymology including a transcription error, "ginkgo" is usually pronounced ˈɡɪŋkoʊ, which has given rise to the common alternative spelling "gingko". The spelling pronunciation ˈɡɪŋkgoʊ is also documented in some dictionaries. Engelbert Kaempfer first introduced the spelling ginkgo in his book Amoenitatum Exoticarum. It is considered that he may have misspelled "Ginkjo" or "Ginkio" (both consistent with his treatment of Japanese kyo in the same work) as "Ginkgo". This misspelling was included by Carl Linnaeus in his book Mantissa plantarum II and has become the name of the tree's genus. The specific epiphet biloba is New Latin for "two-lobed". Ginkgos are large trees, normally reaching a height of , with some specimens in China being over . The tree has an angular crown and long, somewhat erratic branches, and is usually deep-rooted and resistant to wind and snow damage. Young trees are often tall and slender, and sparsely branched; the crown becomes broader as the tree ages.