The ginkgo tree is a living fossil that belongs to its own class of Ginkgophyta. The oldest known examples date back 270 million years. The fossil ginkgo leaf shown here is between 54 and 37 million years old. These trees have been the same for hundreds of millions of years?a challenge to the theory of evolution. Fossil discoveries clearly disprove the claims regarding the evolution of plant species. One of these discoveries is of a 54- to 37-million-year-old fossil ginkgo leaf. Ginkgo trees that grew tens of millions of years ago are identical to those growing today.