Aspicilia calcarea Megasporaceae
Circinaria calcarea (Aspicilia calcarea)

Growth type: Crustose
Chemical results: Negative

Common on limestone walls and tombstones where it can form large patches to 40cm diameter but not found on cement or mortar.

Smooth white to pale-grey thallus, usually areolate and often surrounded by zoned, cracked, grey prothallus. Black, lecanorine, apothecia have distinct but non-persistent margins. Ascus 4-8 spored, spores 18-30 x 14-27 Ám.
Sometimes host to Toninia episema and Opegrapha parasitica

Similar: Aspicilia contorta. Common on limestone, mortar and cement

Aspicilia calcarea

Aspicilia calcarea
Aspicilia calcarea
On limestone wall. Westbourne, Dorset. November 2012

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