Irish lichens

Aspicilia calcarea
Order: Pertusariales       Family: Megasporaceae

Species: Circinaria calcarea (Aspicilia calcarea)

Growth type crustose.
Photos: On gravestones and limestone pavement. Ireland.

The thallus is smooth, white to pale-grey, usually areolate and often surrounded by a zoned, cracked, grey prothallus. Black discs with distinct margin that usually does not persist as the apothecia mature. The asci are 4-8 spored, spores simple, 18-30 x 14-27 Ám.
Chemical reactions negative.

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

Similar: Aspicilia contorta (K-,C-) and A. cinerea agg (K+ red)

Aspicilia calcarea. On gravestones and limestone pavement.

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