A crustose species that usually forms distinctive thick, and usually granulose, crusts that may be buff to yellow-grey or greenish yellow. Apothecia appear innate at first, but become sessile and convex with excluded margins. The brown to black disc contrasts sharply with the lighter thallus.
Thallus: C+ orange, K+- yellow
Lecidella asema can be found along the Scottish coast on exposed, siliceous rocks in the xeric-supralittoral zone. BLS distribution map
scottishlichens.co.uk 