''Parmelia saxatilis'', commonly known as the salted shield lichen or crottle, is a species of foliose lichen in the family

Parmeliaceae The Parmeliaceae is a large and diverse family of Lecanoromycetes. With over 2700 species in 71 genera, it is the largest family of lichen-forming fungi. The most speciose genera in the family are the well-known groups: '' Xanthoparmelia'' ( 82 ...

. Several morphologically similar species, formerly lumped together, are now distinguished by their DNA.

Taxonomy

It was first described in 1753 by

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

with the name ''Lichen saxatilis''.

Erik Acharius Erik Acharius (10 October 1757 – 14 August 1819) was a Swedish botanist who pioneered the Taxonomy (biology), taxonomy of lichens and is known as the "father of lichenology". Acharius was famously the last pupil of Carl Linnaeus. Life Ac ...

transferred it to '' Parmelia'' in 1803.

Molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

studies have shown that ''Parmelia saxatilis'' is a member of a

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

–a group of morphologically similar but genetically distinct species. '' P. discordans'', '' P. ernstiae'', '' P. hygrophila'', '' P. imbricaria'', '' P. mayi'', '' P. omphalodes'', '' P. pinnatifida'', '' P. serrana'', '' P. submontana'', '' P. sulymae'', and '' P. rojoi'' are other members of this complex. In the case of the European members of this complex, there is no reliable set of morphological and chemical characteristics that can be used to distinguish between these species, and therefore DNA analysis is the only reliable way to identify them. This has been demonstrated in studies conducted in Scotland and Italy.

Description

The lichen has a greenish-gray to bluish-gray

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 ...

that can turn brown in exposed locations. It typically grows on rock, although it is sometimes found on bark or wood. ''Parmelia saxatilis'' is used to make

dyes Juan de Guillebon, better known by his stage name DyE, is a French musician. He is known for the music video of the single "Fantasy (DyE song), Fantasy" from his first album ''Taki 183 (album), Taki 183''. This video became popular, attracting ...

with deep red-brown and rusty-orange colors. Known as "crotal" in Scotland, it was used to dye traditional cloths including Harris tweed. J.C.T. Uphof, ''Dictionary of Economic Plants'', Hafner, New York, p. 210, cited a
Bibliographical database of the human uses of lichens
retrieved 20 May 2007 A somewhat similar species complex with a

cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en ...

is the '' Parmelia sulcata'' group, generally growing on trees.

Conservation

In 2021, ''Parmelia saxatilis'' was assessed for the global

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

. Because the lichen is common, abundant, and widely distributed with a stable population size, it is considered of

least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

References

{{Taxonbar, from=Q2053697 saxatilis Lichen species Lichens described in 1753 Lichens of Europe Lichens of North America Taxa named by Carl Linnaeus Plant dyes