''Pleopsidium chlorophanum'' (gold cobblestone lichen)The Laws Field Guide to the Sierra Nevada, John Muir Laws , 2007 is a distinctively colored, bright lemon-yellow to chartreuseCrustose Rock Lichens, Wayne P. Armstrong, Wayne's World online textbook of natural history

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crustose Crustose is a Habit (biology), habit of some types of algae and lichens in which the organism grows tightly appressed to a substrate, forming a biological layer. ''Crustose'' adheres very closely to the Substrate (biology), substrates at all poin ...

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

, which favors dry

arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

or alpine

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

cliffs and boulders. It is a rare alpine lichen in Europe. It is in the genus ''

Pleopsidium ''Pleopsidium'' is a genus of lichen-forming fungi in the family Acarosporaceae. The widespread genus, which contains four species, was circumscription (taxonomy), circumscribed by lichenologist Gustav Wilhelm Körber in 1855. Description ''Ple ...

'' of the family

Acarosporaceae The Acarosporaceae are a family of fungi in the order Acarosporales. Members of this family have a widespread distribution, and are mostly lichenized with green algae. According to a 2021 estimate, the family contains 11 genera and about 260 spe ...

. This lichen is one of the few species able to survive at high altitudes in Antarctica, at altitudes of up to . It is able to cope with high UV, low temperatures and dryness. In its Antarctic habitat, it can be found on the surface, but it is mainly found in cracks, where just a small amount of scattered light reaches it. This is probably an adaptive behaviour to protect it from UV light and desiccation. It remains metabolically active in temperatures down to , and can absorb small amounts of liquid water in an environment with ice and snow. It is of especial interest for

astrobiology Astrobiology (also xenology or exobiology) is a scientific field within the List of life sciences, life and environmental sciences that studies the abiogenesis, origins, Protocell, early evolution, distribution, and future of life in the univ ...

since this is one of the most Mars-like environments on the Earth. In a 34-day experiment when placed in a Mars simulation chamber, it continued to

photosynthesize Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metaboli ...

, and it adapted to Mars conditions and even adapted physiologically by increasing its photosynthetic activity, and producing new growth. It is similar to ''

Acarospora schleicheri ''Acarospora schleicheri'', the soil paint lichen, is a bleached to bright yellow areolate to squamulose lichen that commonly grows to on soil (terricolous) in arid habitats of southern California and Baja California, also in Europe and Africa.F ...

'', which grows on soil (

terricolous lichen A terricolous lichen is a lichen that grows on the soil as a substrate. Examples include some members of the genus ''Peltigera ''Peltigera'' is a genus of approximately 100 species of foliose lichens in the family Peltigeraceae. Commonly known ...

) and rarely on rock, and to '' Pleopsidium flavum''. that grows in high elevations (

montane Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures lapse rate, fall as elevation increases, causing the ecosystem to stratify. This stratification is ...

alpine Alpine may refer to any mountainous region. It may also refer to: Places Europe * Alps, a European mountain range ** Alpine states, which overlap with the European range Australia * Alpine, New South Wales, a Northern Village * Alpine National P ...

) on vertical or overhanging hard

felsic In geology, felsic is a grammatical modifier, modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz.Marshak, Stephen, 2009, ''Essentials of Geology,'' W. W. Norton & Company, 3rd ed. It is contrasted ...

rock (e.g.

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

) in western North America.Mosses Lichens & Ferns of Northwest North America, Dale H. Vitt, Janet E. marsh, Robin B. Bovey, Lone Pine Publishing Company, Its

thallus Thallus (: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. A thallus usually names the entir ...

grows in a circular, outwardly radiating pattern (), with 1 mm wide lobed edges. It differs from '' Pleopsidium flavum'' in having a smooth, smaller squamulose thallus and larger apothecia (spore producing structures).

References

Acarosporales Lichen species Lichens described in 1803 Taxa named by Göran Wahlenberg Lichens of the Antarctic Lichens of Europe {{Lecanoromycetes-stub