Orange-yellow crustose lichen

Orange-yellow crustose lichen

Observation - Orange-yellow crustose lichen - UK and Ireland. Description: Large placodioid thallus of orange-yellow crustose lichen growing on limestone. Middle of thallus areolate with bright orange lumps (possibly isidia). No apothecia. No other similar thalli seen in the area. Chemical test K+ crimson. I have seen a more l

Large placodioid thallus of orange-yellow crustose lichen growing on limestone. Middle of thallus areolate with bright orange lumps (possibly isidia). No apothecia. No other similar thalli seen in the area. Chemical test K+ crimson.
I have seen a more lemon yellow coloured Caloplaca verruculifera at the coast . Although Severn Estuary was visible to the south, this location is still a long way from the coast but the thallus does look a lot like an orange C verruculifera and hence identification possibility suggested.