Parmelia is a genus of medium to large foliose (leafy) lichens. It has a global distribution, extending from the Arctic to the Antarctic continent but concentrated in temperate regions. There are about 40 species in Parmelia. In recent decades, the once large genus Parmelia has been divided into a number of smaller genera according to thallus morphology and phylogenetic relatedness.
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, Usnea, Parmotrema, and Hypotrachyna.
Flavoparmelia baltimorensis, the rock greenshield lichen, is a medium to large foliose lichen with a yellow green upper thallus surface when dry; its lobes are rounded without pseudocyphellae; and the upper surface is covered with globose, pustule-like growths resembling isidia. The lower surface is black with a narrow brown zone at the margins.
Parmelia sulcata, commonly known as the hammered shield lichen or cracked-shield lichen, is a foliose lichen in the family Parmeliaceae. First described by Thomas Taylor in 1836, it is one of the most prevalent lichen species globally, known for its resilience to pollution and cosmopolitan distribution across temperate and cold regions of both hemispheres. P. sulcata forms a circular thallus up to 10 cm (4 in) in diameter, with a glaucous white to grey upper surface and a black lower surface, featuring broadly lobed structures with both marginal and laminal soralia and a distinctive reticulate pattern of pseudocyphellae.
Pseudephebe is a genus of fruticose lichens in the family Parmeliaceae. It contains three species that grow on rocks.
Myelochroa is a genus of foliose lichens in the family Parmeliaceae. They are commonly known as axil-bristle lichens. It was created in 1987 to contain species formerly placed in genus Parmelina that had a yellow-orange medulla due to the presence of secalonic acids. Characteristics of the genus include tightly attached thalli with narrow lobes, cilia on the axils, and a rhizinate black lower surface. Chemical characteristics are the production of zeorin and related triterpenoids in the medulla. Myelochroa contains about 30 species, most of which grow on bark. The genus has centres of distribution in Asia and North America.
Melanohalea is a genus of foliose lichens in the family Parmeliaceae. It contains 30 mostly Northern Hemisphere species that grow on bark or on wood. The genus is characterised by the presence of pseudocyphellae, usually on warts or on the tips of isidia, a non-pored epicortex and a medulla containing depsidones or lacking secondary metabolites. Melanohalea was circumscribed in 2004 as a segregate of the morphologically similar genus Melanelia, which was created in 1978 for certain brown Parmelia species. The methods used to estimate the evolutionary history of Melanohalea suggest that its diversification primarily occurred during the Miocene and Pliocene epochs.
Parmelina is a genus of lichen belonging to the family Parmeliaceae. The genus was circumscribed in 1974 by American lichenologist Mason Hale with Parmelina tiliacea assigned as the type species.
Punctelia is a genus of foliose lichens belonging to the large family Parmeliaceae. The genus, which contains about 50 species, was segregated from genus Parmelia in 1982. Characteristics that define Punctelia include the presence of hook-like to thread-like conidia, simple rhizines, and point-like pseudocyphellae. It is this last feature that is alluded to in the vernacular names speckled shield lichens or speckleback lichens.
Xanthoparmelia is a genus of foliose lichens in the family Parmeliaceae. This genus of lichen is commonly found in the United States, as well as Australia, New Zealand and Ecuador.
Notoparmelia is a genus of foliose lichens in the family Parmeliaceae. It includes 18 species that grow on bark and rocks, and are mostly distributed in the Southern Hemisphere. The genus was created in 2014 as a segregate of Parmelia.
Punctelia reddenda is a widely distributed species of foliose lichen in the family Parmeliaceae. It occurs in Africa, Europe, North America, and South America, where it grows on bark and on rock.
Punctelia perreticulata is a widely distributed species of foliose lichen in the family Parmeliaceae. It occurs in Mediterranean Europe and Russia, North America, South America, Australia, and New Zealand, where it grows on rocks, bark, or wood. Its main distinguishing features are its thallus surface, marked with many shallow depressions, grooves, or pits, and sorediate pseudocyphellae. The lower side of the thallus is ivory to tan towards the centre and the major secondary metabolite in the medulla is lecanoric acid. A lookalike species with which it has been historically confused is Punctelia subrudecta; this lichen can be distinguished from Punctelia perreticulata by the texture of the thallus surface, or, more reliably, by the length of its conidia.
Punctelia borreri is a species of foliose lichen in the family Parmeliaceae. It is a common and widely distributed species, occurring in tropical, subtropical, and temperate regions of Africa, Asia, Europe, North America, Oceania, and South America. The lichen typically grows on bark of deciduous trees, and less commonly on rock. Some European countries have reported increases in the geographic range or regional frequency of the lichen in recent decades, attributed alternatively to a reduction of atmospheric sulphur dioxide levels or an increase in temperatures resulting from climate change.
Parmelia fraudans is a species of foliose lichen in the family Parmeliaceae. It is found in Europe and North America, where it grows on rocks.
Imshaugia aleurites, commonly known as the salted starburst lichen, is a species of foliose lichen in the family Parmeliaceae. It has a wide distribution in Europe and North America, and has also been recorded in China.
Melanelixia albertana is a species of corticolous (bark-dwelling), foliose lichen in the family Parmeliaceae. First described in 1969 from collections made in Alberta, Canada, it has undergone two taxonomic reclassifications before ultimately being placed in the genus Melanelixia in 2004. The species is characterised by the soralia on the margins of its lobes, a feature that is rare in brown parmelioid lichens. This feature is reflected in its common name, powder-rimmed camouflage lichen. Melanelixia albertana has an unusual Asian-North American disjunct distribution. The widespread presence of Melanelixia albertana across different regions is attributed to the similar climatic and vegetative conditions found in the northern parts of the interior prairies in North America, as well as in the forest steppe and ultracontinental taiga forests of northern Mongolia, Transbaikal, and Yakutia. It occurs in river valley and ravine systems, as well as aspen parkland.
Tuckermannopsis orbata, commonly known as the variable wrinkle lichen, is a species of foliose lichen in the family Parmeliaceae. It is a small cetrarioid lichen, an informal growth form category that denotes lichens with erect, foliose thalli, and apothecia and pycnidia on the margins of the ruffled lobes. Tuckermannopsis orbata is found in Asia and North America, growing primarily on the wood and bark of mostly birch and coniferous tree branches and twigs.
Melanelia hepatizon, commonly known as the rimmed camouflage lichen or the rimmed brown-shield, is a species of saxicolous (rock-dwelling), foliose lichen in the family Parmeliaceae. Its thallus, ranging in colour from brown to black, features narrow, elongated lobes that can be flat, convex, or concave. This lichen has a circumpolar distribution, occurring in Asia, Europe, North America, Iceland, and Greenland.
Melanohalea exasperatula, commonly known as the lustrous camouflage lichen or lustrous brown-shield, is a species of corticolous (bark-dwelling) foliose lichen in the family Parmeliaceae. It has a widespread global distribution and is common in both Europe and northern North America. Its thallus can grow up to 5 cm (2 in) in diameter, with marginal lobes up to 5 mm broad. The upper surface is pale olive-green to red-brown, with isidia that are unbranched, inflated, and hollow. It can be distinguished from similar species by the shape and structure of these isidia. The lower surface of the thallus is pale tan to pale brown with scattered, pale rhizines. Apothecia are uncommon, while pycnidia and secondary metabolites have not been observed in this species. The lack of defensive chemicals makes it vulnerable to grazing by slugs and snails. The evolutionary history of Melanohalea exasperatula is linked to major climatic events during the Miocene and Pliocene epochs.
