Chris Mattison / Lichen (Physcia aipolia) growing on fence pole. Catbrook, Monmouthshire, Wales, UK, September

Chris Mattison / Lichen (Physcia aipolia), growing on fence pole. Catbrook, Monmouthshire, September

Paul Harcourt Davies / Hoary rosette lichen (Physcia aipolia) lichen on tree bark, Podere Montecucco, Orvieto, Umbria, Italy. January.

Robert Thompson / Branch covered with different lichens including Xanthoria parietina, Lecanora chlarotera with a lichenicolous fungus, Evernia prunastri and Physcia sp, Banbridge, County Down, Northern Ireland.

Robert Thompson / Branch covered with different lichens Xanthoria parietina, Physcia tenella, Physcia adscendens, Peatlands & Annagarriff Wood NNR, County Armagh, Northern Ireland.