White thallus with yellow apothecia

White thallus with yellow apothecia

Observation - White thallus with yellow apothecia - UK and Ireland. Description: White, crustose thallus with yellow lecideine apothecia (K+ crimson) growing on south facing, sloping limestone ledge in church wall. Thallus seems to follow possible water drainage pattern (picture 5). Pictures 1 and 2 show same apothecia wet then dry fr

White, crustose thallus with yellow lecideine apothecia (K+ crimson) growing on south facing, sloping limestone ledge in church wall. Thallus seems to follow possible water drainage pattern (picture 5). Pictures 1 and 2 show same apothecia wet then dry from thallus shown in picture 5. Pictures 3 and 4, from 50cm along ledge, show same apothecia wet then dry. (‘Wet’ from 15 Jan after overnight thaw of 3cm snow, ‘dry’ after windy, sunny day at end of Jan.) Possibly Caloplaca lactea.