Although

is the

of ginkgos today, many ginkgo relatives have been found in the fossil record. The Ginkgoales are a group of

gymnosperms

that date back to the Permian. The group is thought to be more closely related to conifers than to any other gymnosperms. During the middle Jurassic, the Ginkgoales experienced a great increase in species and reached their maximum diversity during the Cretaceous with several species identifiable in what is now Asia, Europe and North America. During the Paleocene, Ginkgoalean diversity was reduced to a single polymorphic species referred to as

. This species is almost indistinguishable from the extant

.