Yellow Splash Lichen Xanthoria parietina
On most rocky shores, different species of lichen have a marked vertical territory related to their tolerance of salt exposure. The yellow splash lichen is found in the splash zone and forms a bright orange band across the shore, with gray lichens above it and black lichens below. It has a leaflike (foliose) form, with slow-growing, leafy lobes held more or less parallel to the rock on which it lives. Usually bright orange in color, it tends to become greener if in shade. Lichens are widely used to monitor air pollution because they simply disappear when conditions deteriorate. The yellow splash lichen is particularly sensitive to sulfur dioxide, a by-product of industrial processes and of burning fossil fuels.