Large Circular Lichen - White

Large Circular Lichen - White

Observation - Large Circular Lichen - White. Description: White lichen in imprecise circle. About five inches across. Flat. On the flat top of a garden wall. Several similar ones. If one is at the edge of a wall, it maintains its shape by curving over the edge as if it has been crisply folded to fit. (See second

White lichen in imprecise circle. About five inches across. Flat. On the flat top of a garden wall. Several similar ones. If one is at the edge of a wall, it maintains its shape by curving over the edge as if it has been crisply folded to fit. (See second picture.)

Have wondered if it might be Tephromela atra but, although it is not far from the sea, it is on a garden wall, set back from the cliff - far from any possible contact with sea water even in the worst of weathers.