Lichen are collaborations. By working together fungi and algae (and often cyanobacteria) have managed to go places neither could have gone on their own. It's inspirational.

Many lichens, however, are exceedingly sensitive to anthropogenic pollution and thus those hardy explorers of the far reaches of the earth find our cities and our other places to be hostile environments they cannot penetrate.

Humans use robots to explore places that are inhospitable to their sorts of bodies, notably the vast spans of outer space and the surfaces of planets and moons. In Lichen Excursion Module (L.E.M.), I imagined the lichen in the arctic expanse surrounding the Kilpisjarvi research station in northern Finland would band together to form a space agency of sorts to make their own exploration robots and send them to the human cities to find out what the hell was going on there making all this pollution.

I figure lichen are as given to lichen-ocentrism as we are to anthropocentrism and that therefore their robots would mimic themselves in form, action, and attention. The L.E.M. thus clings close to the surface of objects, uses a machine learning image classifier trained only on the animals, plants, and other entities of the environment the lichen are familiar with in arctic Finland, and has one sole mechanical action on its environment: the wearing away of the substrate it sits upon.

Landing on rooftops and back alleys in Copenhagen and Los Angeles, the L.E.M. misinterprets everything it sees to be the mountain birches, reindeer, snow, lemmings, rocks, and other lichens of the landscape the fictional lichen engineers who built it would know, grinding a record of its observations into the brick, galvanized steel gutter, or cinder block it has adhered to, using file-tipped robotic arms.