Thallus smooth to cracked and warted, pale grey or brownish grey, surface usually isidiate, the isidia brown-tipped, constricted at the base and like minute balloons, breaking away to leave raised, rounded scars resembling minute white apothecia; actual apothecia rare, several per wart.

On base-poor rocks, often common on sea cliffs.

All year round.

Widespread and fairy frequent in the west of Britain, uncommon elsewhere.

Status in Leicestershire and Rutland not known.