A crustose species with a variable, leaden to brown-grey thallus that can be smooth and cracked or slightly warted, and that has a white, dark blue or black prothallus. The apothecia become sessile, and are very dark brown with a margin that first becomes darker and then excluded.
Thallus: C-, K-, UV-
Lecanora helicopis is widespread along the Scottish coast where it is found on slightly shaded and sheltered siliceous rock in mesic-supralittoral zone. BLS distribution map
Lecanora helicopis is often found alongside Hydropunctaria maura and Caloplaca marina.
scottishlichens.co.uk 