Caution: Do NOT use iSpot to identify fungi to eat!
Some fungi are very poisonous so a mistaken ID could have serious consequences.
No interactions present.
It's a bad photo (awkward crevice), but rather than C. cristatum, might this be C. polycarpon?
I have got to know C. polycarpon since I added agreement to this being C. cristatum. Yes, with my own developing experience I support this being C. polycarpon. I would not be positive without examination of the spores but yes, it doesn't look like C. cristatum.
Many thanks, Alan. I am trying to understand more about these cyanolichens myself, and it was only my more recent encounter with C. polycarpon that made me rethink this one. Thanks, by the way, for confirming that recent encounter; I can now record it.
I've revised the ID, but only to tidy up the linking etc.
Lat/Lng: 54.0670037, -2.1346308
OS grid ref: SD912634