Helocarpaceae is a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

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 ...

-forming

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

in the subclass Lecanoromycetidae. The family is

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

, and contains the single

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Helocarpon''.

Systematics

The family is classified as

incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

with respect to ordinal placement in the class Lecanoromycetidae, as there is no reliable

molecular A molecule is a group of two or more atoms that are held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemistry, ...

data available to establish

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

relationships with similar

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

. Genus ''Helocarpon'' was

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

by Swedish botanist

Theodor Magnus Fries Theodor "Thore" Magnus Fries (28 October 1832 – 29 March 1913), was a Sweden, Swedish botanist, lichenologist, and Arctic explorer. The son of the renowned mycologist Elias Magnus Fries, he served as a professor of botany and applied economic ...

(1832–1913), in 1860, with ''Helocarpon crassipes'' assigned as the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

, which grows over

moss Mosses are small, non-vascular plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Wilhelm Philippe Schimper, Schimp. 1879) may also refer to the parent group bryo ...

. It was originally found in

Finnmark Finnmark (; ; ; ; ) is a counties of Norway, county in northern Norway. By land, it borders Troms county to the west, Finland's Lapland (Finland), Lapland region to the south, and Russia's Murmansk Oblast to the east, and by water, the Norweg ...

in Norway. Joseph Hafellner in 1984 described a new monotypic family, ''Helocarpaceae'' to contain the genus ''Helocarpon''. Then Eriksson et al in 2004, placed ''Helocarpon'' as a genus within the ''Micareaceae'' family, along with genera; ''

Micarea ''Micarea'' is a genus of lichen-forming fungi in the family Pilocarpaceae. The widely distributed genus contains 142 species and new species are described actively. Species in the genus are crustose lichens and their photobiont (the non-fungal o ...

'', ''

Psilolechia ''Psilolechia'' is a genus of four species of crustose lichens. It is the only member of Psilolechiaceae, a family (biology), family that was created in 2014 to contain this genus. Taxonomy The genus ''Psilolechia'' was established by Abramo Bar ...

'', '' Roccellinastrum'' and ''

Scutula ''Scutula'' is a genus of lichenicolous fungi in the family Ramalinaceae. Taxonomy The genus ''Scutula'' was circumscribed by French botanist Louis René Étienne Tulasne in 1862. The limits of the generic circumscription as well as the limits ...

''. In 2005, molecular phylogeny based on mitochondrial rDNA sequences showed that the genus was not related to the ''Micareaceae'' family. ''Helocarpaceae'' was re-instated to hold the genus ''Helocarpon''.

Distribution

The 2 species in the genus 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 regio ...

, as they are mainly found in northern

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

regions, especially in Europe, including

Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...

Slovakia Slovakia, officially the Slovak Republic, is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the west, and the Czech Republic to the northwest. Slovakia's m ...

, Italy,

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

Finland Finland, officially the Republic of Finland, is a Nordic country in Northern Europe. It borders Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bothnia to the west and the Gulf of Finland to the south, ...

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

, Russia,

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

, and Australia.Gerhard Rambold ''Helocarpon crassipes'' is also found in Japan. They are also found in North America in the coastal forests of

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

, USA. ''Helocarpon lesdainii'' has been found on ''

Picea sitchensis ''Picea sitchensis'', the Sitka spruce, is a large, coniferous, evergreen tree growing to just over tall, with a trunk diameter at breast height that can exceed 5 m (16 ft). It is by far the largest species of spruce and the fifth-l ...

'' trees in

Harris Beach State Park Harris Beach State Park is an Oregon State Park located on US Highway 101, north of Brookings. The day-use area offers a restroom and picnic area with tables, and the campground has RV sites, yurts and tent sites available year-round. Harri ...

, Oregon.

Description

Helocarpaceae species are

crustose lichen Crustose lichens are lichens that form a crust which strongly adheres to the Substrate (biology), substrate (soil, rock, tree bark, etc.), making separation from the substrate impossible without destruction. The basic structure of crustose lichen ...

s, with tube-like

amyloid Amyloids are aggregates of proteins characterised by a fibrillar morphology of typically 7–13 nm in diameter, a β-sheet secondary structure (known as cross-β) and ability to be stained by particular dyes, such as Congo red. In the human ...

structures. The genera are generally distinguished by a crustose

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 ...

and chlorococcoid photobiont (relating to

green algae The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ...

of the genus ''

Chlorococcum ''Chlorococcum'' is a genus of green algae, in the family Chlorococcaceae. The alga may be useful in the flocculation of lipids from wastewater. It can be found in fresh water, but is more commonly found in soil or subaerial habitats (such as gro ...

''). They are usually immarginate (not having a distinctive margin or border) and convex biatorine

apothecia An ascocarp, or ascoma (: ascomata), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. As ...

. When the margin of the spore body is pale or colorless, it is called . They also have a poorly developed proper exciple (margin), simple or sparsely branched to abundantly branched and

anastomosed An anastomosis (, : anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be normal (suc ...

(connected) paraphyses (the erect sterile filaments often occurring among the reproductive organs). The asci has an apical cushion surrounded by a tube-structure, colourless and simple (ellipsoid or tear-shaped) to transversely septate asco-spores which are lacking (outer covering of a spore). They have immersed (surrounded), sessile or stalked

pycnidia A pycnidium (plural pycnidia) is an asexual fruiting body produced by mitosporic fungi, for instance in the order Sphaeropsidales ( Deuteromycota, Coelomycetes) or order Pleosporales (Ascomycota, Dothideomycetes). It is often spherical or inve ...

(asexual fruiting body), and an abundance of conidial types.

Species

Species Fungorum ''Index Fungorum'' is an international project to index all formal names (Binomial nomenclature, scientific names) in the fungus Kingdom (biology), kingdom. As of 2015, the project is based at the Royal Botanic Gardens, Kew, one of three partn ...

accepts two species of ''Helocarpon''; *'' Helocarpon crassipes'' *'' Helocarpon lesdainii'' Former species; * ''H. arcticum'' = '' Frutidella caesioatra'',

Lecanoraceae The Lecanoraceae are a family of 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 c ...

family * ''H. gelatinosum'' = '' Trapeliopsis gelatinosa'',

Trapeliaceae Trapeliaceae is a family (biology), family of lichens in the order Baeomycetales. The family contains 12 genus, genera and about 125 species. Taxonomy Trapeliaceae was originally circumscription (taxonomy), circumscribed by French lichenologist ...

* ''H. granulosum'' = '' Trapeliopsis granulosa'', Trapeliaceae * ''H. granulosum'' f. ''escharoides'' = '' Trapeliopsis gelatinosa'', Trapeliaceae * ''H. sapineum'' = '' Trapeliopsis granulosa'', Trapeliaceae * ''H. viridescens'' = '' Trapeliopsis viridescens'', Trapeliaceae

References

{{Taxonbar, from1=Q28872276, from2=Q10520452 Lecanoromycetes Lichen families Lecanoromycetes families Taxa named by Josef Hafellner Taxa described in 1860 Monogeneric fungus families