''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 defi ...

of the genus '' Candelaria''. It is a small foliose lichen dispersed globally.

Description and morphology

The vegetative body, or thallus, 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 are granular and are found in margins between or at the end of lobes. Apothecia are rare and minute (under 1 mm). Asci are clavate and contain over 30

ascospores An ascus (; ) 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 genera or ...

. Pycnidia 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 ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to the ...

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

rhizines In lichens, rhizines are multicellular root-like structures, arising mostly 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 ...

Green modules

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

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

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 or ...

. Electron micrograph images has revealed pockets of a protein called

hydrophobin Hydrophobins are a group of small (~100 amino acids) cysteine-rich proteins that are expressed only by filamentous fungi that are lichenized or not. They are known for their ability to form a hydrophobic (water-repellent) coating on the surface ...

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'' 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 and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

and Europe. 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'' (), common name, commonly called ash, is a genus of flowering plants in the olive and lilac family, Oleaceae. It contains 45–65 species of usually medium to large trees, mostly deciduous, though a number of Subtropics, subtropic ...

, Salix,'' and '' Ulmus.'' 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 Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

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; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

Least Concern in Great Britain and Ireland. Regularly found in eutrophicated habitats, and can be an indicator of high nitrogen in the environment when found as the dominant lichen species. Quite tolerant to pollution, found in many urban environments.

References

{{Taxonbar, from=Q1663978 Candelariales