Growing on bark. It took many time to get the genus for these specimens, but at the end I came to the conclusion that it must be Pyxine. I already found species in this genus, either in rock or on bark, but all had 1) Yellow medulla, 2) Lobes with a "frosen" appearance. These specimens don't have any of these features. Let me summarize: - Thallus clearly bright yellow, - Lobes narrow, flat except at the margin where are slightly elevated with the tips turned down, appressed to the substact, - Soredia present, pustulate, disperse (maybe due to youth) mainly at the confluence of lobes and in older part of thallus; - Lacking isidia and polysidiangia; - Some black dots spread by the thallus, that can be pycnidia and that I already found in different species of pyxine; - Underside dark in the middle becoming pale (almost white) at margins, with black, short, strong and furcated rhizines; - Medulla white; - Chemistry on thallus and on medulla: C-, K-, KC-.