We are Russian dolls, our lives made possible by other lives within us. But whereas dolls can be taken apart, our cellular and genetic helpers cannot be separated from us, nor we from them. We are lichens on a grand scale.

Lichens are amalgams of two creatures: a fungus and either an alga or a bacterium. The fungus spreads the strands of its body over the ground and provides a welcoming bed. The alga or bacterium nestles inside these strands and uses the sun’s energy to assemble sugar and other nutritious molecules. As in any marriage, both partners are changed by... See more