The ginkgo according to Wikipedia is "also known as the Maidenhair Tree after Adiantum, is a unique species of tree with no close living relatives. The ginkgo is classified in its own division, the Ginkgophyta, comprising the single class Ginkgoopsida, order Ginkgoales, family Ginkgoaceae, genus Ginkgo and is the only extant species within this group. It is one of the best-known examples of a living fossil, because Ginkgoales other than G. biloba are not known from the fossil record after the Pliocene."
Seems a little heavy, but that's the official defintion of ginkgo. There is also an article about the ginkgo in the New Yorker from the summer of 2008. You can check it out here. That may simplify things for you.
Now check out the amateur masterpiece below. It may be corny, but it works for this blogger.