Life after extinction: Ginkgo biloba

The ginkgo tree, Ginkgo biloba, is well-known and highly distinctive. Its elegant fan-shaped leaves and oddly knobbly twigs make it easily recognizable all year round; its stately silhouette and general beauty make it quite popular in temperate cities' landscaping. Its cherrylike seeds are edible, as long as you discard the foul-smelling flesh before eating the nut, and have a long history of use in traditional Chinese medicine. The tree is sacred to several Buddhist traditions as a symbol of long life.

It should also, by all rights, be extinct.

Ginkgo biloba is the very last of its line. Back in the Jurassic period, there were dozens, maybe hundreds, of ginkgo species: entire fossil strata are positively saturated with their leaves. With the explosive rise of the flowering plants, though, the ginkgoes went into decline and fell one by one to extinction. When humans finally came on the scene, there was only one species left, and it was fading fast.

Fortunately for that elegant relic, though, humans decided that we really, really liked it. For its symbolism, Japanese Buddhist monks planted the trees on their monastery grounds and tended them lovingly even as their wild sisters faded. About a thousand years ago, the last of the wild ginkgoes died out, and those monastery trees became the last of their species.

Today, ginkgoes are planted along streets and in parks and lawns all over the world. Every one of them is descended, recently or farther back, from one of those rescued monastery trees. They are living proof that humans have the capacity to save species as well as destroy them.