Smooth Rock Tripe - Umbilicaria mammulata
Large, brown foliose lichen with a black lower surface. It turns green when it gets wet. They ranged in size from about 1 - 9 cm in size. U. mammulata is one of the largest lichens in the world. The thallus can be up to 15cm in diameter.
Habitat: Rock in a mixed forest
''Umbilicaria mammulata'', or Smooth Rock Tripe, is a foliose lichen found on boulders and rock walls.