Psoraceae Protoblastenia rupestris Growth type crustose Chemical results: Apothecia K+ crimson Important indicator species of calcareous substrata. Common on mortar, limestone, cement and concrete. The grey, greyish-brown or green-grey thallus can be either scurfy, cracked or +/- absent. The dull-orange apothecia are not in pits and become +/- convex and distorted. Ascus 8-spored with ellipsoid spores, 8-17 x 5-8 µm. Similar: Protoblastenia calva, P. incrustans and P. lilacina

Protoblastenia rupestris
On concrete, Dorset. February 2014