Robert Thompson / Lichen (Ochrolechia parella) Ballywhoriskey Point, County Donegal, Northern Ireland. October.

Guy Edwardes / Crawfish lichen (Ochrolechia parella) on a gravestone, Unst, Shetland Islands, Scotland, August.

Chris Mattison / Crawfish lichen (Ochrolechia parella) growing on a headstone. Gower, South Wales, UK.

Chris Mattison / Crab eye lichen (Ochrolechia parella) on headstone, Gower, South Wales, UK, June.

Chris Mattison / Two lichens on a headstone, Grab eye lichens (Ocrolechia parella) - pale grey, and Rusty shielded lichen (Caloplaca crenularia) Gower, South Wales, UK, June.

Adrian Davies / Lichens including Xanthoria parietina and Ochrolechia parella on tombstones in village churchyard. Slapton, Devon, England, UK, July 2013.

Adrian Davies / Lichen (Ochrolecia parella) on wall of church, Devon, UK, August

Adrian Davies / Crawfish Lichen (Ochrolechia parrella) Devon, England

Ross Hoddinott / Crab's-eye / Crawfish lichen {Ochrolechia parella} close-up, Devon, UK. September.