Circinaria calcarea

Circinaria calcarea is a species of crustose lichen in the family Megasporaceae. It was first described as a new species by Carl Linnaeus in his 1753 work Species Plantarum. Linnaeus named it Lichen calcareus, as he classified all lichens in the eponymously named genus.^[2] The species has had an extensive taxonomic history, resulting in dozens of synonyms.^[1] In 2010, it was placed in its current genus, Circinaria, following molecular phylogenetic analysis of the Megasporaceae.^[3]

Circinaria calcarea
Scientific classification
Kingdom:	Fungi
Division:	Ascomycota
Class:	Lecanoromycetes
Order:	Pertusariales
Family:	Megasporaceae
Genus:	Circinaria
Species:	C. calcarea
Binomial name
Circinaria calcarea (L.) A.Nordin, Savić & Tibell 2010
Synonyms[1]
Lichen calcareus L. (1753) Aspicilia calcarea (L.) Körb. (1861)

Circinaria calcarea has a cosmopolitan distribution, having been recorded from the Arctic, Asia, Australasia, Europe, Oceania, Central America, South America, and North America. It is a saxicolous lichen, and grows on calcareous, calciferous, and basic rock.^[4]