''Xanthoparmelia mexicana'', commonly known as the salted rock-shield, is a

foliose Foliose lichen is one of the morphological classes of lichens, which are complex organisms that arise from the symbiotic relationship between fungi and a photosynthetic partner, typically algae. This partnership allows lichen to live in diverse ...

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.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'' ( 822 ...

. It grows in 4–10 cm diameter rosettes of gray-green to yellow-green lobes in arid climates all over the world.

Taxonomy

It was originally described in 1931 as a species of ''

Parmelia Parmelia may refer to: * Parmelia (barque), the vessel that in 1829 transported the first settlers of the British colony of Western Australia * ''Parmelia'' (fungus), a genus of lichens with global distribution * Parmelia, Western Australia Pa ...

'' by Hungarian lichenologist

Vilmos Kőfaragó-Gyelnik Vilmos Kőfaragó-Gyelnik (March 30, 1906 – March 15, 1945) was a Hungarian botanist and lichenologist. Prior to earning his PhD in 1929 from Budapest University, he spent a year in Cairo to help organize a botanical museum. In 1930 he started ...

. It was one of 93 species that was transferred to ''Xanthoparmelia'' when

Mason Hale Mason Ellsworth Hale, Jr. (September 23, 1929 – April 23, 1990) was one of the most prolific lichenologists of the 20th century. Many of his scholarly articles focused on the taxonomy of the family Parmeliaceae. Hale was one of the first liche ...

promoted that taxon from

subgeneric In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...

to generic status in 1974. It is commonly known as the salted rock-shield.

Description

''Xanthoparmelia mexicana'' grows in diameter rosettes consisting of small lobes. The lower surface is pale to medium brown.

Apothecia An ascocarp, or ascoma (), 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. Ascocarps are mo ...

are uncommon; when present, they are cinnamon to dark-brown colored discs with smooth margins, and no

pruina Pruinescence , or pruinosity, is a "frosted" or dusty-looking coating on top of a surface. It may also be called a pruina (plural: ''pruinae''), from the Latin word for hoarfrost. The adjectival form is pruinose . Entomology In insects, a "blo ...

. Lichen spot tests are negative for the upper cortex (K−, C−, KC−, P−). For the

medulla Medulla or Medullary may refer to: Science * Medulla oblongata, a part of the brain stem * Renal medulla, a part of the kidney * Adrenal medulla, a part of the adrenal gland * Medulla of ovary, a stroma in the center of the ovary * Medulla of th ...

they are K+ yellow to dark red, C−, KC−, and P+ orange. It produces

secondary metabolite Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the norm ...

s including

usnic acid Usnic acid is a naturally occurring dibenzofuran derivative found in several lichen species with the formula C18H16O7. It was first isolated by German scientist W. Knop in 1844 and first synthesized between 1933-1937 by Curd and Robertson. Usnic a ...

and

salazinic acid Salazinic acid is a depsidone with a lactone ring. It is found in some lichens, and is especially prevalent in ''Parmotrema'' and ''Bulbothrix'', where its presence or absence is often used to help classify species in those genera. History I ...

Habitat and distribution

''Xanthoparmelia mexicana'' grows in open and arid climates all over the world. It may loosely cling to the substrate (

adnate Adnate may refer to: * Adnation, in botany, the fusion of two or more whorls of a flower * Adnate, in mycology, a classification of lamellae (gills) * Conjoined twins Conjoined twins – sometimes popularly referred to as Siamese twins – are ...

). In the

Sonoran Desert The Sonoran Desert ( es, Desierto de Sonora) is a desert in North America and ecoregion that covers the northwestern Mexican states of Sonora, Baja California, and Baja California Sur, as well as part of the southwestern United States (in Arizona ...

, it may be the most commonly found member of its genus. The lichen has been recorded from western North America, Mexico, the Dominican Republic, South America, Africa, Asia, Australia, and New Zealand.

References

{{Taxonbar, from=Q10721416 mexicana Lichen species Lichens described in 1931 Lichens of Africa Lichens of Asia Lichens of Australia Lichens of New Zealand Lichens of the Caribbean Lichens of South America Lichens of North America Taxa named by Vilmos Kőfaragó-Gyelnik

Taxonomy

Description

Habitat and distribution

See also

References