''Stereocaulon paschale'' is a species of

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.Stereocaulaceae The Stereocaulaceae are a family of lichen-forming fungi in the order Lecanorales. It contains five genera. Species of this family are widely distributed in temperate boreal and austral regions. Genera *'' Hertelidea'' – 6 spp. *''Lepraria' ...

. It has a

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext ...

. In

Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...

, it has the

conservation status The conservation status of a group of organisms (for instance, a species) indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservation ...

of a

vulnerable species A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, ...

(VU).Náttúrufræðistofnun Íslands celandic Institute of Natural History(1996).
Válisti 1: Plöntur.
' (in Icelandic) Reykjavík: Náttúrufræðistofnun Íslands.

Ecology

''Stereocaulon paschale'' is host to some

lichenicolous fungi A lichenicolous fungus is a parasitic fungus that only lives on lichen as the host. A lichenicolous fungus is not the same as the fungus that is the component of the lichen, which is known as a lichenized fungus. They are most commonly specific to ...

which infect various parts of the

thallus Thallus (plural: 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. Many of these organisms wer ...

. Most of these fungi have a

Holarctic distribution The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical region ...

. These fungi include: * ''

Arthonia stereocaulina ''Arthonia stereocaulina'' is a species of lichenicolous fungus in the family Arthoniaceae. Distribution ''Arthonia stereocaulina'' has been reported from Alaska, Canada, Iceland, Russia and Svalbard. Host species As the name suggests, ''Artho ...

'', Infects the phyllocladia but rarely causes disease. * ''

Catillaria stereocaulorum ''Catillaria'' is a genus of crustose lichens in the family Catillariaceae. The genus was circumscribed by Italian lichenologist Abramo Bartolommeo Massalongo in 1852. It is the type genus of Catillariaceae, which was circumscribed by Austrian l ...

'', Mainly infects the phyllocladia, which can become swollen and dark. It is common in the Arctic. * ''

Cercidospora stereocaulorum ''Cercidospora stereocaulorum'' is a species of lichenicolous fungus in the genus '' Cercidospora'' but it has not been assigned to a family. It is known to parasitise lichens of the genus ''Stereocaulon''. Similar species Cercidospora stereoca ...

'', Infects phyllocladia and sometimes on stems, cephalodia and apothecia. * ''

Endococcus nanellus ''Endococcus nanellus'' is a species of lichenicolous fungus in the order Dothideales. It is known from Alaska, Canada, Greenland, Hawaii, Japan, Russia, South-Korea, and Kazakhstan. Host species ''Endococcus nanellus'' is known to infect numero ...

'', Infects phyllocladia and sometimes on stems, cephalodia and apothecia. Often found in discolored apothecia but does probably not cause the discoloration. * '' Lasiosphaeriopsis stereocaulicola'', Usually found at the stem base which can turn brown but no other symptoms are known. * ''

Lichenopeltella stereocaulorum ''Lichenopeltella stereocaulorum'' is a species of lichenicolous fungus belonging to the class Dothideomycetes. It was described in 2010 from an infected specimen of '' Stereocaulon botryosum''. It has a similar appearance to ''Lichenopeltella ...

'', Most often found on stems. This species was only discovered in 2010. * ''

Opegrapha stereocaulicola ''Opegrapha'' is a genus of lichenized fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organis ...

'', Infects stems which may become darker. * '' Phaeosporobolus alpinus'', Commensal. Most commonly found on species of ''

Pertusaria ''Pertusaria'' is a large genus of warty crustose lichens in the Pertusariaceae family.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, The fruiting bodies are usually modified apothecia that immersed in warts ...

'' or ''

Ochrolechia ''Ochrolechia'' is a genus of crustose lichens in the family Ochrolechiaceae. Species , Species Fungorum accepts 38 species of ''Ochrolechia'': *'' Ochrolechia aegaea'' *'' Ochrolechia africana'' *'' Ochrolechia alaskana'' *'' Ochrolechia a ...

''. * ''

Polycoccum trypethelioides ''Polycoccum'' is a genus of lichenicolous fungi A lichenicolous fungus is a parasitic fungus that only lives on lichen as the host. A lichenicolous fungus is not the same as the fungus that is the component of the lichen, which is known as a l ...

'', Produces galls on stem which change colour with time turning cinnamon colour or brown.

References

Stereocaulaceae Lichen species Taxa named by Carl Linnaeus Lichens described in 1753 Cosmopolitan species {{Lecanorales-stub