Ginkgo (Ginkgo biloba; in Chinese and Japanese , romanization: yín xìng, : ich or ginnan), also known as the Maidenhair Tree after , is a unique of with no close living relatives. The ginkgo is classified in its own , the Ginkgophyta, comprising the single class Ginkgoopsida, order Ginkgoales, family , genus and is the only within this group. It is one of the best-known examples of a , because Ginkgoales other than G. biloba are not known from the fossil record after the .
For centuries it was thought to be extinct in the wild, but is now known to grow in at least two small areas in province in Eastern , in the Tian Mu Shan Reserve. However, recent studies indicate high genetic uniformity among ginkgo trees from these areas, arguing against a natural origin of these populations and suggesting that the ginkgo trees in these areas may have been planted and preserved by Chinese monks over a period of about 1000 years. Whether native ginkgo populations still exist has not been demonstrated unequivocally.
The relationship of Ginkgo to other plant groups remains uncertain. It has been placed loosely in the divisions and , but no consensus has been reached. Since Ginkgo seeds are not protected by an wall, it can morphologically be considered a . The apricot-like structures produced by female ginkgo trees are technically not , but are seeds that have a shell that consists of a soft and fleshy section (the ), and a hard section (the ).