Parmelia hygrophila

Parmelia hygrophila is a corticolous (bark-dwelling) foliose lichen in the Parmelia saxatilis group, described in 1983 from the Pacific Northwest of North America. It was segregated from material that had often been folded into a broad concept of P. saxatilis. The species is characterised by its greyish-green, leafy thallus that produces abundant tiny outgrowths called isidia along the lobe margins and upper surface for reproduction. It grows in the humid forests of the Pacific Northwest, growing on the bark of both coniferous and deciduous trees from coastal regions to mid-elevation mountain forests. The species was named from collections made in interior British Columbia and is now recorded from Alaska, British Columbia, Washington, and Idaho....read more on Wikipedia.