''Rhizocarpon'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 and ...

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, give ...

(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 to ...

), lichens in the family

Rhizocarpaceae Rhizocarpaceae is a family (biology), 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'' * ' ...

. 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 The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...

, 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 other ...

'').

Taxonomy and phylogeny

Together with three small genera (''

Catolechia ''Catolechia'' is a genus of lichen-forming fungi in the family Rhizocarpaceae. It is a monotypic genus, containing the single species ''Catolechia wahlenbergii''. The genus was circumscribed by German botanist Julius von Flotow in 1850. He did n ...

'', ''

Poeltinula ''Poeltinula'' is a genus of lichenized fungi in the family Rhizocarpaceae. The genus name of ''Poeltinula'' is in honour of Josef Poelt (1924-1995), who was a German-Austrian botanist (Bryology, Mycology and Lichenology) and was Professor of Sys ...

'' and ''

Epilichen ''Epilichen'' is a genus of lichenized fungi within the Rhizocarpaceae family. References External links *Epilichen' at Index Fungorum ''Index Fungorum'' is an international project to index all formal names (scientific names) in the fung ...

''), ''Rhizocarpon'' constitutes the family

. 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 or s ...

, 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 Mi ...

(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 Info ...

) 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 region ...

'' *''

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 region ...

'' *''

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 region ...

'' *''

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 region ...

'' *''

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 region ...

'' – 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 regio ...

'' *'' Rhizocarpon bicolor'' – Australia *''

Rhizocarpon caeruleoalbum ''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 caesium ''Rhizocarpon'' is a genus of crustose lichen, crustose, saxicolous lichen, saxicolous (or sometimes lichenicolous fungus, lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs t ...

'' – Europe *'' Rhizocarpon chioneum'' *''

Rhizocarpon cinereonigrum ''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 cinereovirens ''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 clausum ''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 cleptophilum'' – Greenland *''

Rhizocarpon copelandii ''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 dahlii ''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 dimelaenae'' *'' Rhizocarpon diploschistinum'' *'' Rhizocarpon disporum'' *''

Rhizocarpon distinctum ''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 eupetraeoides'' *'' Rhizocarpon exiguum'' – Australia *'' Rhizocarpon expallescens'' *''

Rhizocarpon ferax ''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 flavomedullosum ''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 furfurosum'' *'' Rhizocarpon geminatum'' *''

'' *'' Rhizocarpon grande'' *''

Rhizocarpon haidense ''Rhizocarpon haidense'' is a species of crustose lichen in the family Rhizocarpaceae. Found in Canada, it was described as a new species in 2020 by lichenologists Irwin Brodo and Alan Fryday. The type specimen was collected from the Skincuttle ...

'' *'' Rhizocarpon hochstetteri'' *'' Rhizocarpon inarense'' *'' Rhizocarpon infernulum'' *''

Rhizocarpon intermediellum ''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 jemtlandicum'' *'' Rhizocarpon johnstonii'' *'' Rhizocarpon kerguelense'' *''

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

Rhizocarpon malvinae ''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 regio ...

'' –

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 Dubouzet ...

*'' Rhizocarpon mawsonii'' *'' Rhizocarpon ochrolechiae'' *'' Rhizocarpon oederi'' *'' Rhizocarpon oxydatum'' – New Zealand *''

Rhizocarpon pallidum ''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 petraeum ''Rhizocarpon petraeum'' is a species of lichen in the family Rhizocarpaceae. It contains stictic acid.Flóra Íslands lora of Iceland(no year)Hringflikra - ''Rhizocarpon petraeum''(in Icelandic). Retrieved on April 14th 2021. It was first des ...

'' *'' Rhizocarpon polycarpum'' *'' Rhizocarpon postumum'' *'' Rhizocarpon purpurascens'' – New Zealand *''

Rhizocarpon quinonum ''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 ...

'' –

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 richardii ''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 ridescens'' *''

Rhizocarpon roridulum ''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 saurinum'' *''

Rhizocarpon simillimum ''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 sipmanianum'' *''

Rhizocarpon smaragdulum ''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 ...

'' – Siberia *''

Rhizocarpon subareolatum ''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 ...

'' – Greenland *''

Rhizocarpon subgeminatum ''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 sublavatum'' – Europe *''

Rhizocarpon submodestum ''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 subpostumum ''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 sulphurosum'' *''

Rhizocarpon sunchonense ''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 ...

'' – South Korea *''

Rhizocarpon superficiale ''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 tephromelae ''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 regio ...

'' *'' Rhizocarpon timdalii'' – Europe; North America *''

Rhizocarpon tinei ''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 torquatum ''Rhizocarpon'' is a genus of crustose lichen, crustose, saxicolous lichen, saxicolous (or sometimes lichenicolous fungus, lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs t ...

'' / *''

Rhizocarpon transiens ''Rhizocarpon'' is a genus of crustose lichen, crustose, saxicolous lichen, saxicolous (or sometimes lichenicolous fungus, lichenicolous), lichens in the family Rhizocarpaceae. The genus is common in arctic-alpine environments, but also occurs t ...

'' *'' Rhizocarpon tungurahuae'' *''

Rhizocarpon umbilicatum ''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 umense ''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 vigilans'' – Australia *'' Rhizocarpon viridiatrum'' *''

Rhizocarpon vulcani ''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 ...

'' – 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