They are remarkably hardy and adorn the streets in Manhattan and withstand almost any pollutants, which makes one wonder why they became extinct in the wild perhaps a millennium or more ago. I looked up and I was actually sitting under a very old ginkgo whose trunk was of immense girth. It was an exciting moment because I knew that trees of the same species are found in fossil coals and rocks and date back to the era of early reptiles when dinosaurs did not yet exist. Ginkgoes are also interesting because they come in separate sexes, half the trees being XX females and half being XY males, just like humans. The sex chromosomes are difficult to distinguish and some clever botanist will no doubt devise a quick DNA test for the small blip of material that distinguishes the X from the Y chromosome.
Female trees produce a yellow orange fruit with a single white nut.
Both the flesh and the nut are edible but not tasty enough to attract commercial interest outside of health food stores. Like peaches, when ginkgo fruit rots on the ground, it produces an odor of unwashed feet, or what the biochemist would call butyric acid. One of my favorite sites to read at Indiana University was under a 150 year old ginkgo tree in the oldest part of the campus. At least four of them are females and their fruit can be recognized in early summer as green spheres, like unripe grapes. They are still young trees and their branches are gangling and going every which way.