Hi Arno! Would you say the lobes turning up at the ends and the pale prothallus are the characteristic features to look out for?
I always look for a combination of characters. In an ideal situation H. lucida has rather large dimensions, wide, very flat lobes with indeed sometimes upturned lobes, generally with a clear rim of transparent ‘glue’ surrounding the margins. The laminal soralia originate from pustules that are often situated on folds on the thallus. Hyperphyscia adglutinata can rarely (in shaded habitats?) also have somewhat upturned margins, but I have never seen this extensive borders of ‘glue’. The neat rounded, isolated crateriform soralia are typical for H. adglutinata. Less well developed forms of H. lucida can be difficult to separate. Naming from photos can also be tricky.
