lichen was thought to be a partnership between one alga and one fungus, the classic symbiotic relationship. Then came the observation than in fact lichen harbors two types of fungi—an ascomycete and a ...

Lichens are nearly everywhere — odd growths that appear as crusty patches and splotches on tree trunks, limbs, rocks, bare soil, stone walls, tombstones, wooden fences. Regardless, lichens often get ...