''Placomaronea candelarioides'' is a species of

saxicolous This glossary of mycology is a list of definitions of terms and concepts relevant to mycology, the study of fungi. Terms in common with other fields, if repeated here, generally focus on their mycology-specific meaning. Related terms can be found ...

(rock-dwelling),

foliose lichen A foliose lichen is a lichen with flat, leaf-like , which are generally not firmly bonded to the substrate on which it grows. It is one of the three most common growth forms of lichens. It typically has distinct upper and lower surfaces, each o ...

in the family

Candelariaceae ''Candelariaceae'' is a family of lichen-forming fungi in the order Candelariales. It contains seven genera and about 73 species of lichens that are typically characterised by their bright yellow colour. These lichens have diverse growth forms, ...

. It is found in South America. This lichen species can be recognised by its distinct (single attachment point), (single ) growth form.

Taxonomy

''Placomaronea candelarioides'' was

formally described A species description is a formal scientific description of a newly encountered species, typically articulated through a scientific publication. Its purpose is to provide a clear description of a new species of organism and explain how it differ ...

as a new species in 1944 by Finnish lichenologist

Veli Räsänen Veli Johannes Paavo Bartholomeus Räsänen (24 August 1888 – 16 July 1953) was a Finnish lichenologist who made contributions to the study and documentation of Nordic and Baltic lichen funga. As a lecturer at various agricultural institution ...

. It is 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 ...

of the genus '' Placomaronea'', which 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 Räsänen to contain this species. The

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

of ''P. candelarioides'' was found in

Mendoza, Argentina Mendoza (), officially the City of Mendoza (), is the capital of the Provinces of Argentina, province of Mendoza Province, Mendoza in Argentina. It is located in the northern-central part of the province, in a region of foothills and high plain ...

. A

variety Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

of this lichen, ''Placomaronea candelarioides'' var. ''lacinulata'', was proposed by

Rolf Santesson Rolf Santesson (1916–2013) was a Swedish lichenologist and university lecturer. He was awarded the Acharius Medal in 1992 for his lifetime contributions to lichenology. Early life and education Santesson was born in 1916 in Trollhättan, Sw ...

in 1944.

Description

''Placomaronea candelarioides'' has a leaf-like (

foliose A foliose lichen is a lichen with flat, leaf-like , which are generally not firmly bonded to the substrate on which it grows. It is one of the three most common lichen growth forms, growth forms of lichens. It typically has distinct upper and lo ...

) structure, uniquely anchored by a single point, a trait referred to as and . Though most specimens adhere to this typical appearance, some have shown variations, such as having numerous individual, little branched, and ascending lobes that attach to the at the base. The lichen's overall shape is circular and can span up to across. It has extensions or that radiate from its centre, each measuring between 0.4 and 1.7 mm in width and potentially growing up to 7 mm in length. These lobes sometimes have smaller offshoots or and can occasionally take on a round shape, layering over each other and forming cushion-like clusters. The colour of the lichen's upper surface ranges from dark yellow to brownish-yellow, presenting a smooth, shiny, and unpigmented appearance. The lichen's underside can display colours from white to grey or even brown, influenced by the dust it accumulates. Prominently, the lichen's apothecia appear as darker yellow spots that often densely populate the central regions of the lichen. They sit raised on the surface, measure between 0.5 and 1.6 mm in diameter, and sometimes have a slightly jagged or edge. Internally, the lichen comprises several layers. Just beneath the surface, there is a cortex layer about 15–35 μm thick. Below this, a white layer of medulla. The base of the lichen has another layer, which is similar in structure but slightly thicker, ranging between 25 and 45 μm. Each

ascus An ascus (; : asci) 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 gen ...

holds over 30 . These spores are narrowly oval in shape, measuring between 8–12.5 μm in length and 3–4 μm in width. Another distinguishing feature is the presence of , which appear as darker yellow dimples on the lichen's surface. In chemical spot tests, the lichen reacts weakly red when a solution of

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

(K) is applied, a feature helpful for its identification.

Habitat and distribution

''Placomaronea candelarioides'' thrives on

acidic rock Acidic rock or acid rock refers to the chemical composition of igneous rocks that has 63% wt% SiO2 content. Rocks described as acidic usually contain more than 20% of free quartz. Typical acidic rocks are granite or rhyolite. The term is used in ...

s within open

montane Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures lapse rate, fall as elevation increases, causing the ecosystem to stratify. This stratification is ...

environments. It has been identified in numerous locations along the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

, extending from Mendoza, Argentina in the south, up to

Ancash Ancash (; ) is a department and region in western Peru. It is bordered by the departments of La Libertad on the north, Huánuco and Pasco on the east, Lima on the south, and the Pacific Ocean on the west. Its capital is the city of Huaraz, an ...

, Peru in the north.

References

{{Taxonbar, from=Q17388226 Candelariales Lichen species Lichens described in 1944 Lichens of South America Taxa named by Veli Räsänen