''Haloplaca'' 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 ...

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.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 organisms are classified as a kingdom, separately from ...

in the subfamily Teloschistaceae of the family

Teloschistaceae The Teloschistaceae are a large family of mostly lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. The family, estimated to contain over 1800 species, was extensively revised in 2013, including the creation o ...

. It contains three species of

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. The genus was

circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius. Not every polyg ...

by Ulf Arup and colleagues in 2013, with ''Haloplaca britannica'' assigned as the

type species In 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 species that contains the biological type specimen ...

. The genus name alludes to the preference of its species for salt-rich environments. All three species occur in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

, but ''H. suaedae'' also occurs in Greece, Morocco and Turkey. ''Haloplaca'' species occur near the sea, either on rocks or on plant debris.

Description

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 ...

(the vegetative tissue of lichens) of ''Haloplaca'' is typically

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 ...

; in some species, the margin may extend slightly outward, giving it a more distinct shape. The colour ranges from yellow to pale yellow, and in certain instances, it can appear greyish. Frequently, the surface may be covered in small grain-like structures or soredia, which are reproductive structures in lichens. The , or the outer protective layer, is either not well-defined or is made up of interwoven () fungal tissues, which might be a special kind of cortex termed a . The apothecia, which are disc-like structures where the lichen produces spores, are in form, though they might be absent in some species. The spores are , meaning they develop in a way that the two ends are distinct, and have a medium-length dividing wall or

septum In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatri ...

. , which are small fruiting bodies for asexual reproduction, are observed in one species, ''H. suaedae''. The spores produced in the , known as , are oval or slightly elongated in shape.

Species

* '' Haloplaca britannica'' * '' Haloplaca sorediella'' * '' Haloplaca suaedae''

References

{{Taxonbar, from=Q25843272 Teloschistales Teloschistales genera Lichen genera Taxa described in 2013 Taxa named by Ulrik Søchting Taxa named by Patrik Frödén Taxa named by Ulf Arup