Caloplaca saxicola

I'm attempting to identify and list all the lichens in a local churchyard as a project to help me become more confident in identifying species in this group. This one is the first:

Pre microscopic clues:

Thallus yellow, crustose and lobed

Apothecia yellow, lecanorine and up to 1mm.

Apothecia K+ magenta

The above K+ magenta reaction suggests that the Lichen is Caloplaca or Protoblastenia.

Hymenium 100µm

Ascus 57x12µm

Spores 10x6µm and polaricular

Spores are colourless and simple with Protoblastenia which leaves us with just Caloplaca:

Thallus corticate (having a cortex)

On Rock

Cortex yellow K+ purple

Placodioid-lobate

Lobes less than 2mm, Ascospores ellipse shaped

Marginal lobes 2-5 times longer than wide with no blackening

Lobes 1mm or more

Lobes yellow with some white pruina, bloated, about 2x longer than wide on calcareous rock

Caloplaca saxicola

Caloplaca saxicola apothecia section

Caloplaca saxicola ascospore