The Top and the Bottom of Lobaria pulmonaria, Lungwort.
In our area the only time we see this lichen is after a strong wind. The lichen grows somewhat epiphytically on Largeleaf Maples in our mature forests. The Pacific Sideband snail feeds on this lichen and in the spring sometimes gets blown off the maple trees along with the lichen. The soredia appear as white balls on the ridges and the apothecia appear as brown saucers on the edges of the thallus.
''Lobaria pulmonaria'' is a large epiphytic lichen consisting of an ascomycete fungus and a green algal partner living together in a symbiotic relationship with a cyanobacterium—a symbiosis involving members of three kingdoms of organisms. Commonly known by various names like tree lungwort, lung lichen, lung moss, lungwort lichen, oak lungs or oak lungwort, it is sensitive to air pollution and is also negatively affected by habitat loss and changes in forestry practices.