Edited by Dava Sobel
What we all learned in high school about lichen—that it's the synergistic collaboration of a fungus and algae or cyanobacteria—is simplified in many ways. For one thing, the original organisms are changed utterly in the compact. They can't return to what they were. For another, according to Anne Pringle, one of the leading contemporary mycologists (with whom I had the lucky opportunity to collaborate), it may be that lichen do not, given sufficient nutrients, age. Anne says that our sense of the inevitability of death may be determined by our mammalian orientation. Perhaps some forms of life are immortal. The thought of two things that come together and alter each other collaboratively—two things becoming one thing that does not age—roused me toward considering lichen a kind of model and metaphor for the intricacies of intimacy.—F.G.