Common Names: Common greenshield lichen
A medium to large foliose lichen that has a very distinctive pale yellow green upper cortex when dry. The rounded lobes, measuring 3 to 8 mm wide, usually have patches of granular soredia arising from pustules. The lobes of the thallus may be smooth, but quite often have a wrinkled appearance especially in older specimens. The lower surface is black except for a brown margin; rhizomes attached to the lower surface are black and unbranched.
Typically found on bark of trees, but occasionally on rock.