A crustose species with a pale grey to pale yellow-brown thallus that is surrounded by a black prothallus. In the centre the thallus is areolate, but the cracks are less prominent near the edge. The abundant apothecia are innate and have black, often white-pruinose discs and persistent margins. Sometimes, the apothecia become convex.
Thallus: C+ red, K-, UV-
Lecidea grisella is widespread throughout Scotland and found on smooth, slightly nutrient-rich siliceous rocks. BLS distribution map
scottishlichens.co.uk 