Robert Thompson / Lichen (Xanthoria aureola) Ballywhoriskey Point, County Donegal, Northern Ireland. October.

Robert Thompson / Lichen (Xanthoria aureola) Ballywhoriskey Point, County Donegal, Northern Ireland. October.

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.

Adrian Davies / Lichen (Usnea florida) Snowdonia, North Wales, October.

Adrian Davies / Lichen (Usnea florida) Snowdonia, North Wales, October.

Adrian Davies / Lichen (Usnea florida) Snowdonia, North Wales, October.

Adrian Davies / Lichen on old tombstone (Parmelia caperata) in village churchyard. Slapton, Devon, UK, August 2016.

Chris Mattison / Foliose lichen (Lobaria scrobiculata) on birch bark. Sensitive to pollution. Drumnadrochit, Inverness, Scotland

Chris Mattison / Coastal lichen (Xanthoria aureola) Isle of Mull, Scotland, UK, June.

Solvin Zankl / Lichens (Usnea filipendula, Evernia prunasti, Bryoria fuscescens, Hypogymnia physodes and Parmelia sulcata) on English oak tree (Quercus robur) near Norra Kvill National Park, Smaland, Sweden, August.

Solvin Zankl / Lichen (Evernia prunasti) on English oak tree (Quercus robur) near Norra Kvill National Park in Rumskulla socken, Smaland, Sweden, August.

Alex Hyde / Lichen (Parmelia saxatilis) growing on a gritstone boulder in shady woodland, Peak District National Park, Derbyshire, UK. October.

Alex Hyde / Lichen (Parmelia saxatilis) interspersed with orange patches of a Green alga (Trentepohlia sp.) that gets its unusual colouration from the haematochrome (-carotene) it contains. Found growing on a gr...

Philippe Clement / Oakmoss / stag lichen (Evernia prunastri) close up, La Brenne, France, June.

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.

Chris Mattison / Gold dust lichen (Chrysothrix candelaris) growing around and over Shield lichen (Parmelia sulcata) on sycamore bark, Padley Woods, Derbyshire, England, UK, December.

Alex Hyde / Lichen (Parmelia saxatilis) found growing on gritstone boulder, Peak District National Park, Derbyshire, UK. May.

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

Chris Mattison / Common orange lichen (Xanthoria parietina) on Hawthorn twig (Crataegus monogyna) together with a Shield lichen (Parmelia sulcata) England, UK. April.

Adrian Davies / Lichen (Parmelia caperata) on gravestone, Devon, England, July

Adrian Davies / Lichen (Parmelia caperata) close up of surface, on gravestone, Devon, England, July

Alex Hyde / Lichen (Parmelia saxatilis) growing on gravestone in churchyard. Peak District National Park, Derbyshire, UK, March 2012.

Guy Edwardes / 2020VISION / Lichen covered oak tree branches. Northumberland National Park, England, UK, March.

Ross Hoddinott / 2020VISION / Lichen {Parmelia sulcata} growing on bench wood, Denmark Farm Conservation Centre, Lampeter, Wales, UK, June 2011.

Ross Hoddinott / Lichen {Usnea ceratina} and {Parmelia sulcata} Devon, UK. October

Elio Della Ferrera / Lichen {Parmelia centrifuga} growing on stone, Alps, Italy

Duncan Mcewan / Lichen {Hypogymnia tubulosa} and {Parmelia sp} on Larch {Larix sp} Scotland, UK

Duncan Mcewan / Lichen on moorland rock {Parmelia saxitilis}Inverness-shire, Scotland

Duncan Mcewan / Lichen {Usnea sp} and {Parmelia sp} on birch bark {Betula sp} Scotland, UK Inverness-shire

Duncan Mcewan / Crottle lichen {Parmelia saxitalis} on rock Scotland, UK Inverness-shire

Duncan Mcewan / Lichen {Parmelia sp} on Larch {Larix sp} with cone Scotland, UK

Robert Thompson / Lichens (Parmelia sulcata) and (Xanthoria parietina) growing on apple twigs, Peatlands and Annagarriff wood National Nature Reserve, Portadown, County Armagh, Northern Ireland, UK. September.

Chris Mattison / Salted shield lichen / Crottle (Parmelia saxatilis) on gritstone, Derbyshire, UK. April.

Robert Thompson / A fallen Sweet chestnut fruit (Castanea sativa) lying on the woodland floor, with a tree trunk covered in Textured lungwort (Lobaria scrobiculata) lichen, UK. October.

Chris Mattison / Black stone flower (Parmotrema perlatum) and a small piece of Shield lichen (Parmelia sulcata) growing on Apple tree. Focus-stacked image.

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.