The ginkgo seems to have outlived whatever animal it grew its seeds for. The fleshy coat smells of rot, the way fruit meant for a scavenger might, and the creature that once ate it and carried the stone away is gone, perhaps a very long time ago. People took over the job. They ate the kernels, planted the trees by houses and temples across China, Japan and Korea, and for a while Western botanists thought gardens were the only place ginkgo still grew. (Wild stands may survive in remote parts of southwest China. Whether monks saved the species is a nicer story than the evidence supports.) Now the ginkgo is a favourite street tree, because it shrugs off smog, and many cities plant only males, often cuttings from one male tree, so that nothing falls on the pavement. A female sold by mistake can take fifteen or twenty years to give herself away. So the tree that lost its partner found a new one, and the new one has kept it alive in cities around the world on one condition: that it stop doing the thing the partner was for.