''Candelaria concolor'', commonly known as the candleflame lichen or the lemon lichen, is an

ascomycete Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The def ...

of the genus '' Candelaria''. It is a small

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 ...

lichen dispersed globally.

Description and morphology

The vegetative body, or

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 ...

, of the lichen is foliose, and its color ranges from bright-yellow to yellow-green. Thallus is minute (less than 1cm wide), but aggregates to form extensive colonies. Lobes of the thallus are flattened and divided.

Soredia Soredia are common reproduction, reproductive structures of lichens. Lichens asexual reproduction, reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungus, fung ...

are granular and are found in margins between or at the end of lobes.

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 ...

are rare and minute (under 1 mm). Asci are clavate and contain over 30

ascospores In fungi, an ascospore is the sexual spore formed inside an ascus—the sac-like cell that defines the division Ascomycota, the largest and most diverse division of fungi. After two parental nuclei fuse, the ascus undergoes meiosis (halving of ...

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 ...

are much more common and are found as wart-like structures on the upper-surface of the thallus. Pycnidia are often the same color as the thallus, with darker

conidia A conidium ( ; : conidia), sometimes termed an asexual chlamydospore or chlamydoconidium (: chlamydoconidia), is an asexual, non- motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also ...

. Lower surface of the thallus is whitish-pink with white

rhizines In lichens, rhizines are multicellular root-like structures arising mainly from the lower surface. A lichen with rhizines is termed rhizinate, while a lichen lacking rhizines is termed erhizinate. Rhizines serve only to anchor the lichen to their s ...

Green modules

''Candelaria concolor'' has been used as in anatomical studies of lichen looking at green modules, clusters of

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

and

hyphae A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

Electron micrograph A micrograph is an image, captured photographically or digitally, taken through a microscope or similar device to show a magnify, magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken ...

images has revealed pockets of a protein called

hydrophobin Hydrophobins are a group of small (~100 amino acids) cysteine-rich proteins that were discovered in filamentous fungi that are lichenized or not. Later similar proteins were also found in Bacteria. Hydrophobins are known for their ability to fo ...

surrounding these modules. It has been postulated that these pockets allow for gas and water exchange to the algal layer of the lichen.

Distinctions

''Candelaria concolor'' is often misidentified as a member of '' Xanthoria'', however ''C. concolor'' is K−, whereas ''Xanthoria'' species are K+ with a bright red to purple reaction. ''Candelaria concolor'' can be distinguished from ''

Candelaria pacifica ''Candelaria pacifica'' is a widely distributed corticolous (bark-dwelling), leprose lichen. It was formally described as a species in 2011. Taxonomy ''Candelaria pacifica'' was formally described as a species in 2011 by Martin Westberg and Ulf ...

'' due to its larger lobes, distinct lower cortex, and relatively large white rhizines. Asci of ''C. pacifica'' also contain only 8 ascospores. Notable secondary metabolites created by ''C. concolor'' include: pulvinic dilactone,

vulpinic acid Vulpinic acid is a natural product first found in and important in the symbiosis underlying the biology of lichens. It is a simple methyl ester derivative of its parent compound, pulvinic acid, and a close relative of pulvinone, both of which de ...

, calycin.

Habitat and distribution

Globally distributed. Very common species in

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

. One of the most common lichen species in the Chihuahuan and Sonoran Deserts. Most commonly found of the bark of trees, especially that of '' Acer,

Fraxinus ''Fraxinus'' (), commonly called ash, is a genus of plants in the olive and lilac family, Oleaceae, and comprises 45–65 species of usually medium-to-large trees, most of which are deciduous trees, although some Subtropics, subtropical specie ...

Salix Willows, also called sallows and osiers, of the genus ''Salix'', comprise around 350 species (plus numerous hybrids) of typically deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions. Most species are known ...

,'' and ''

Ulmus Elms are deciduous and semi-deciduous trees comprising the genus ''Ulmus'' in the family Ulmaceae. They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical- montane regions of North America and Eurasia, ...

.'' Also found on wooden fences and poles. Less often seen on rocks and walls. Prefer well lit areas. Can be found in the emergent layer of forests in through birds dispersing both soredia and nutrients, however a different study found that ''C. concolor'' becomes more and more rare as canopy height increases.

Ecology and conservation

Listed as

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

Least Concern in

Great Britain Great Britain is an island in the North Atlantic Ocean off the north-west coast of continental Europe, consisting of the countries England, Scotland, and Wales. With an area of , it is the largest of the British Isles, the List of European ...

and

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

. Regularly found in eutrophicated habitats, and can be an indicator of high

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

in the environment when found as the dominant lichen species. Quite tolerant to

pollution Pollution is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the component ...

, found in many urban environments.

References

{{Taxonbar, from=Q1663978 Candelariales Lichen species Taxa named by James Dickson (botanist) Lichens of Europe Lichens of North America Lichens described in 1793