Nigel Cattlin / Apples (Malus domestica) with scab caused by Ascomycetes fungus (Venturia inaequalis). Berkshire, England, UK. September.

Bruno D'Amicis / Detail of centuries-old Beech tree (Fagus sylvatica) covered in lichens and mosses. Val Cervara old-growth beech forest. Europe's oldest beech forest. Abruzzo, Lazio and Molise National Park / Par...

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

Solvin Zankl / Lichen (Usnea dasypoga) on English oak tree (Quercus robur) near Norra Kvill National Park in Rumskulla socken, Smaland, Sweden

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

Alex Hyde / Beech jellydisc fungus (Neobulgaria pura) growing on the fallen trunk of a Beech tree (Fagus sylvatica). Peak District National Park, Derbyshire, UK. October.

Alex Hyde / Beech jellydisc fungus (Neobulgaria pura) growing on the fallen trunk of a Beech tree (Fagus sylvatica). Peak District National Park, Derbyshire, UK. October.

Alex Hyde / Beech jellydisc fungus (Neobulgaria pura) growing on the fallen trunk of a Beech tree (Fagus sylvatica). Peak District National Park, Derbyshire, UK. October.

Erlend Haarberg / Scots pine (Pinus sylvestris) forest in fog, with rocks covered by arctoparmelia lichen (Arctoparmelia centrifuga), Stora Sjofallet National Park, Laponia, Lapland, Sweden, July.

Erlend Haarberg / Scots pine (Pinus sylvestris) forest, with rocks covered by arctoparmelia lichen (Arctoparmelia centrifuga), Stora Sjofallet National Park, Laponia, Lapland, Sweden, July.

Erlend Haarberg / Scots pine (Pinus sylvestris) forest with rocks covered by arctoparmelia lichen (Arctoparmelia centrifuga), Lapland, Sweden, June.

Adrian Davies / Brown rot fungus (Monilinia fructicola) growing on Apples (Malus sp.), Surrey, UK. July.