Growing on Elm and likely other tree species. Thallus upper surface greyish-white, doesn't seem maculate (important for key), K+ yellow, mostly weakly pruinose, without ciliate hairs, pycnidia common. Lower surface corticate, pale, with sparse whitish rhizines. Apothecia abundant, disc brown to black, margin +/- pruinose. Soredia...possibly marginal on the lobe tips, I can't quite tell and couldn't get a photo. The very tip of some lobes darken and seem to have soredia. Isidia...probably not, but I'm not experienced enough to say for sure.