grey crustose lichen on wall

Observation - grey crustose lichen on wall - UK and Ireland. Description: Grey powdery lichen, slightly raised 'profile'
Grey powdery lichen, slightly raised 'profile'
Observation - grey crustose lichen on wall - UK and Ireland. Description: Grey powdery lichen, slightly raised 'profile'
Grey powdery lichen, slightly raised 'profile'