Geologic History

The Ginkgo tree is the only living representative of the order Ginkgoales, a group of gymnosperms composed of the family Ginkgoaceae consisting of about 18 members with its earliest leaf fossils dating back to the Permian period. Fossil leaves and vegetative organs show that at that time there were at least two species. During the Middle Jurassic there was a great increase in species (5 or 6) with a maximum diversity (at least 11 species) during the Cretaceous period in areas such as Asia, Europe and North America. Only one species was left in the Tertiary (65 million years ago). The extinction of the dinosaurs and large reptiles as important seed dispersers of the large seeds may also have influenced this decline. The term "living fossil" used by Darwin in his Origin of Species of 1859 definitely fits the Ginkgo.

Saratoga Springs, Saratoga County, New York

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