Seen on a gatepost on Magdalen Hill Down butterfly reserve.
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.
Absence of apothecia so seems unlikely to be Xanthoria parietina.
Lat/Lng: 51.0608, -1.2831
OS grid ref: SU503292