An order of gymnosperms in the class Ginkgoopsida (Pinophyta) with only one extant species, Ginkgo biloba (the maidenhair tree). Leaves identified as Ginkgo appeared first in the Upper Triassic, but Ginkgo-like leaves have been discovered as early as the Permian. During the Jurassic and Cretaceous periods, Ginkgo was a large taxon containing many species and having a circumpolar distribution in the Northern Hemisphere. The group diminished in size during the Early Cretaceous and into the Tertiary periods. It is probable that Ginkgo, considered sacred by the Chinese, would have become extinct had it not been cultivated in Chinese temple gardens, where the ginkgos became magnificent, old specimens several hundred feet tall.