''Rhizocarpon'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

crustose Crustose is a 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 substrates at all points. ''Crustose'' is found on rocks a ...

saxicolous A saxicolous lichen is a lichen that grows on rock. The prefix "sax" from the Latin means "rock" or "stone". Characteristics Saxicolous lichens exhibit very slow growth rates. They may develop on rock substrates for long periods of time, giv ...

(or sometimes

lichenicolous 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 t ...

), lichens in the family

Rhizocarpaceae Rhizocarpaceae is a family of crustose, lecideoid, lichen-forming fungi and together with the family Sporastatiaceae it constitutes the order Rhizocarpales in the Ascomycota, class Lecanoromycetes. Genera * ''Catolechia'' * ''Epilichen'' * '' ...

. The genus is common in arctic-alpine environments, but also occurs throughout

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

, subtropical, and even

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

regions. They are commonly known as map lichens because of the

prothallus A prothallus, or prothallium, (from Latin ''pro'' = forwards and Greek ''θαλλος'' (''thallos'') = twig) is usually the gametophyte stage in the life of a fern or other pteridophyte. Occasionally the term is also used to describe the young ...

forming border-like bands between colonies in some species, like the common map lichen (''

Rhizocarpon geographicum ''Rhizocarpon geographicum'' (the map lichen) is a species of lichen, which grows on rocks in mountainous areas of low air pollution. Each lichen is a flat patch bordered by a black line of fungal hyphae. These patches grow adjacent to each othe ...

'').

Taxonomy and phylogeny

Together with three small genera ('' Catolechia'', '' Poeltinula'' and ''

Epilichen ''Epilichen'' is a genus 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.Rhizocarpaceae Rhizocarpaceae is a family of crustose, lecideoid, lichen-forming fungi and together with the family Sporastatiaceae it constitutes the order Rhizocarpales in the Ascomycota, class Lecanoromycetes. Genera * ''Catolechia'' * ''Epilichen'' * '' ...

. Historically, ca 389 names have been used. However, many species concepts are ill-defined, many names have been synonymized and new species are regularly being described, so true number of species is not entirely clear as of now, but is estimated to be around 200. In molecular work, the genus has also been shown to be paraphyletic, with closely related genera being nested within ''Rhizocarpon''.

Common traits

With so many species in a morphologically diverse genus it is difficult to say something general about morphology and anatomy and there will inevitably be some exceptions. However, they do share some key traits. They are all crustose and mostly saxicolous (rock-living), with some being lichenicolous (lichen parasites) on other saxicolous lichens. They are all lecideoid, meaning they have apothecia without a thallus margin containing algae.

Ascus and ascospores

The genus has a distinct type of

ascus An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera o ...

, the Rhizocarpon-type, which is bitunicate with the inner ascus-wall being slightly apically thickened. Ascospores are considered important characters for determining species within the genus. They are either 2-celled (1-septate) or multi-celled (muriform) and are either hyaline or pigmented (green or brown), often with a characteristic halo (or “perispore”) visible when viewed in a microscope. Asci contain eight, two or rarely one spore.

Species

Species Fungorum ''Index Fungorum'' is an international project to index all formal names ( scientific names) in the fungus kingdom. the project is based at the Royal Botanic Gardens, Kew, one of three partners along with Landcare Research and the Institute of ...

(in the

Catalogue of Life The Catalogue of Life is an online database that provides an index of known species of animals, plants, fungi, and microorganisms. It was created in 2001 as a partnership between the global Species 2000 and the American Integrated Taxonomic I ...

) accepts 75 species of ''Rhizopogon''. *''

Rhizocarpon advenulum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical reg ...

'' *''

Rhizocarpon alpicola ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical reg ...

'' *''

Rhizocarpon amphibium ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical reg ...

'' *''

Rhizocarpon anaperum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical reg ...

'' *''

Rhizocarpon austroalpinum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical reg ...

'' – Australia *''

Rhizocarpon austroamphibium ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' – Australia *''

Rhizocarpon badioatrum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical regi ...

'' *''

Rhizocarpon bicolor ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical ...

'' – Australia *'' Rhizocarpon caeruleoalbum'' *'' Rhizocarpon caesium'' – Europe *''

Rhizocarpon chioneum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical reg ...

'' *'' Rhizocarpon cinereonigrum'' *'' Rhizocarpon cinereovirens'' *'' Rhizocarpon clausum'' *''

Rhizocarpon cleptophilum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical ...

'' – Greenland *'' Rhizocarpon copelandii'' *'' Rhizocarpon dahlii'' *''

Rhizocarpon dimelaenae ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' *''

Rhizocarpon diploschistinum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical reg ...

'' *''

Rhizocarpon disporum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' *'' Rhizocarpon distinctum'' *'' Rhizocarpon eupetraeoides'' *''

Rhizocarpon exiguum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' – Australia *'' Rhizocarpon expallescens'' *'' Rhizocarpon ferax'' *'' Rhizocarpon flavomedullosum'' – Australia *'' Rhizocarpon furfurosum'' *''

Rhizocarpon geminatum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical reg ...

'' *''

'' *'' Rhizocarpon grande'' *'' Rhizocarpon haidense'' *'' Rhizocarpon hochstetteri'' *''

Rhizocarpon inarense ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical ...

'' *''

Rhizocarpon infernulum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical reg ...

'' *'' Rhizocarpon intermediellum'' *''

Rhizocarpon jemtlandicum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' *'' Rhizocarpon johnstonii'' *''

Rhizocarpon kerguelense ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' *'' Rhizocarpon lavatum'' *'' Rhizocarpon lecanorinum'' *''

Rhizocarpon lusitanicum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' *'' Rhizocarpon malvinae'' –

Falkland Islands The Falkland Islands (; es, Islas Malvinas, link=no ) is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and about from Cape Dubou ...

*''

Rhizocarpon mawsonii ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical reg ...

'' *''

Rhizocarpon ochrolechiae ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical reg ...

'' *''

Rhizocarpon oederi ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' *'' Rhizocarpon oxydatum'' – New Zealand *'' Rhizocarpon pallidum'' *'' Rhizocarpon petraeum'' *''

Rhizocarpon polycarpum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' *''

Rhizocarpon postumum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' *''

Rhizocarpon purpurascens ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical ...

'' – New Zealand *'' Rhizocarpon quinonum'' –

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S ...

*''

Rhizocarpon reductum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' *'' Rhizocarpon richardii'' *'' Rhizocarpon ridescens'' *'' Rhizocarpon roridulum'' *''

Rhizocarpon saurinum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' *'' Rhizocarpon simillimum'' *'' Rhizocarpon sipmanianum'' *'' Rhizocarpon smaragdulum'' – Siberia *'' Rhizocarpon subareolatum'' – Greenland *'' Rhizocarpon subgeminatum'' *'' Rhizocarpon sublavatum'' – Europe *'' Rhizocarpon submodestum'' *'' Rhizocarpon subpostumum'' *''

Rhizocarpon sulphurosum ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical region ...

'' *'' Rhizocarpon sunchonense'' – South Korea *'' Rhizocarpon superficiale'' *'' Rhizocarpon tephromelae'' *''

Rhizocarpon timdalii ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical ...

'' – Europe; North America *'' Rhizocarpon tinei'' *'' Rhizocarpon torquatum'' / *'' Rhizocarpon transiens'' *''

Rhizocarpon tungurahuae ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical re ...

'' *'' Rhizocarpon umbilicatum'' *'' Rhizocarpon umense'' *''

Rhizocarpon vigilans ''Rhizocarpon'' is a genus of crustose, saxicolous (or sometimes lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs throughout temperate, subtropical, and even tropical ...

'' – Australia *'' Rhizocarpon viridiatrum'' *'' Rhizocarpon vulcani'' – Japan

Gallery

File:Rhizocarpon.jpg, ''Rhizocarpon'' sp. on a mountain Zlatibor, Serbia File:Rhizocarpon pycnocarpoides (10.3897-mycokeys.11.6670) Figure 10.jpg, ''Rhizocarpon pycnocarpoides''

References

{{Taxonbar, from=Q3018582 Rhizocarpaceae Lichen genera Lecanoromycetes genera Taxa named by Augustin Pyramus de Candolle