Toninia aromatica

I spent some time with this one and a had difficulty coming to a satisfactory conclusion. All the clues were giving me several options none of which seemed right at first but a photo of a Toninia following a saxicolous crack got me finally to the right group. Other groups considered were Catillaria, Cliostomum and Lecania. The reaction of K+ y put Cliostomum in the picture but it turned out to be a red herring. The spores are 17µm long and 3-septate. The paraphyses are with a swollen apex with pigmented tip.

Toninia aromatica