Yva Momatiuk & John Eastcott / Purple Saxifrage (Saxifraga oppositifolia) and Reindeer Moss (Cladonia rangiferina) in tundra, Langanes Peninsula, Iceland

Yva Momatiuk & John Eastcott / Purple Saxifrage (Saxifraga oppositifolia) and Reindeer Moss (Cladonia rangiferina) in tundra, Langanes Peninsula, Iceland

Nick Upton / Wolf's milk slime mould (Lycogala terrestre) spore forming reproductive phase, near lichen (Cladonia sp), GWT Lower Woods reserve, Gloucestershire, UK, October.

Kerstin Hinze / Garden dormouse (Eliomys quercinus) amongst cup lichens (Cladonia sp) at night, Germany, captive, August.

Kerstin Hinze / Garden dormouse (Eliomys quercinus) amongst cup lichens (Cladonia sp) at night, Germany, captive, August.

Alex Hyde / Lichen (Cladonia diversa) showing red apothecia (spore-producing structures). Cairngorms National Park, Grampian Mountains, Scotland, UK, February.

Bryan and Cherry Alexander / Reindeer lichen (Cladonia sp.) and the autumn russet catkins of Dwarf birch (Betula nana) on the tundra in Hurry Inlet. Scoresbysund, East Greenland, September.

Robert Thompson / Lichen (Cladonia ficerkeana) with red spore producing reproductive structures, Killarney National Park, County Kerry, Republic of Ireland, April

Philippe Clement / Pixie-cup lichen (Cladonia fimbriata) on wood, Belgium

Philippe Clement / Pixie-cup lichen (Cladonia fimbriata) on wood, Belgium

Robert Thompson / Lichen {Cladonia squamosa} amongst moss, Mucross Wood, County Fermanagh, Northern Ireland, February

Robert Thompson / Lichen {Cladonia polydactyla} Ballymote, County Sligo, Republic of Ireland, February

Robert Thompson / Lichen {Cladonia ramulosa} Rehaghy Mountain, County Tyrone, Republic of Ireland, January.

Robert Thompson / Lichen {Cladonia portentosa} Rehaghy Mountain, County Tyrone, Republic of Ireland, January

Robert Thompson / Lichen {Cladonia uncialis subsp. biuncialis} Fawhaboy, County Donegal, Republic of Ireland, March

Robert Thompson / Lichen {Cladonia ramulosa} Crom Estate, County Fermanagh, Northern Ireland, March

Robert Thompson / Lichen {Cladonia cervicornis subsp. verticillata} Fawhaboy, County Donegal, Republic of Ireland, March

Robert Thompson / Lichen {Cladonia foliacea} Northern Ireland

Robert Thompson / Lichen {Cladonia cervicornis subsp. verticillata} Fawhaboy, County Donegal, Republic of Ireland, March

Robert Thompson / Lichen {Cladonia portentosa} Rehaghy Mountain, County Tyrone, Republic of Ireland, January

Robert Thompson / Lichen {Cladonia portentosa} Argory Estate, County Armagh, Northern Ireland, December

Scott Leslie / Reindeer Moss (Cladonia rangiferina) on tundra, southern Labrador, Canada

Scott Leslie / Reindeer Moss (Cladonia rangiferina), Sheep's Laurel (Kalmia angustifolia), and Black Spruce (Picea mariana) at sunset, Canada

Konstantin Mikhailov / Cladonia sp lichen growing in Russky Sever NP, Vologda Oblast, N Russia, October 2008

Konstantin Mikhailov / Cladonia sp lichen growing in Russky Sever NP, Vologda Oblast, N Russia, October 2008

Luiz Claudio Marigo / Lichens (Cladonia sp) growing on the rainforest floor in the "campina" vegetation, at Campina Biological Reserve of the National Institute for Research in the Amazon, Amazonas State, Northern Brazil.

Russell Cooper / Pixie cup lichen {Cladonia sp} with fruiting bodies, UK

Chris O'Reilly / Lichen {Cladonia rangiformis} heathland, Wales

Niall Benvie / Lichen {Cladonia sp} formed into polygons after drought, Norway

Niall Benvie / Lichen {Cladonia sp} formed into polygons after drought, Norway

Niall Benvie / Fruiting bodies of lichen (Cladonia sp) Scotland. Tomatin, Inverness-shire

Larry Michael / Pixie-cups lichen {Cladonia pyxidata} Michigan, USA

Duncan Mcewan / Lichen {Cladonia sp} on tree branch, Inverness-shire Scotland

Duncan Mcewan / Lichens {Cladonia spp} on moorland, Inverness-shire, Scotland

Ingo Arndt / Cup Lichen (Cladonia sp) growing on fallen tree trunk, Germany

Ingo Arndt / Cup Lichen (Cladonia sp) growing on fallen tree trunk, Germany

Jim Brandenburg / Cup Lichen (Cladonia sp) covering boreal forest floor, Minnesota

Konrad Wothe / Reindeer Moss (Cladonia rangiferina) with pine cone, Sweden

Michio Hoshino / Bearberry (Arctostaphylos uva ursi) and Cup Lichen (Cladonia sp) in tundra, Alaska

Ross Hoddinott / Close up of cups of Lichen {Cladonia fimbriata} UK

Yva Momatiuk & John Eastcott / Reindeer Moss (Cladonia rangiferina), lichen, moss, and dry grass stems, Ontario, Canada

Jan Vermeer / Bengal Match Lichen (Cladonia floerkeana) in snow, Europe

Orsolya Haarberg / Aerial photograph of mixed Downy birch (Betula pubescens) and Scots pine (Pinus sylvestris) forest with thick layer of lichen (Cladonia sp.) covering most of exposed ground in early autumn. Rondane...

Orsolya Haarberg / Aerial photograph of mixed Downy birch (Betula pubescens) and Scots pine (Pinus sylvestris) forest with thick layer of lichen (Cladonia sp.) covering most of exposed ground in early autumn. Rondan...

Orsolya Haarberg / Aerial photograph of mixed Downy birch (Betula pubescens) and Scots pine (Pinus sylvestris) forest with thick layer of lichen (Cladonia sp.) covering most of exposed ground in early autumn. Rondane...

Orsolya Haarberg / Aerial photograph of Downy birch (Betula pubescens) forest with thick layer of lichen (Cladonia sp.) covering most of exposed ground in early autumn. Rondane National Park, Norway. September. non-e...

Orsolya Haarberg / Aerial photograph of mixed Downy birch (Betula pubescens) and Scots pine (Pinus sylvestris) forest with thick layer of lichen (Cladonia sp.) covering most of exposed ground in early autumn. Rondane...

Orsolya Haarberg / Aerial photograph of Downy birch (Betula pubescens) forest with thick layer of lichen (Cladonia sp.) covering most of exposed ground in early autumn. Rondane National Park, Norway. September. non-e...

Laurie Campbell / Reindeer lichen (Cladonia portentosa) on background of sphagnum moss (Sphagnum sp.), HIghlands, Scotland, UK. September.

Alex Hyde / Reindeer lichen (Cladonia sp.) growing through Sphagnum moss (Sphagnum sp.) in blanket bog. Glen Affric, Scotland, UK. October. Focus stacked image.

Alex Hyde / Commuity of mosses predominately red Sphagnum Moss (Sphagnum sp.), with Reindeer Lichen (Cladonia sp.) growing alongside, in blanket bog. Glen Affric, Scotland, UK. October. Focus stacked image.