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.
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.
Cetrelia is a genus of leafy lichens in the large family Parmeliaceae. They are commonly known as sea-storm lichens, alluding to the wavy appearance of their lobes. The name of the genus, circumscribed in 1968 by the husband and wife lichenologists William and Chicita Culberson, alludes to the former placement of these species in the genera Cetraria and Parmelia.
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.
Psiloparmelia is a genus of lichen belonging to the family Parmeliaceae. It contains 13 Southern Hemisphere species, most of which are found growing on rocks at high elevations in South America. There are several characteristic features of the genus that are used to distinguish it from the morphologically similar genera, such as Arctoparmelia, Flavoparmelia, and Xanthoparmelia. These include a dark, velvety lower thallus surface that usually lacks rhizines, a negative test for lichenan, and a high concentration of usnic acid and atranorin in the cortex.
Coelopogon is a genus of lichen-forming fungi in the family Parmeliaceae. The genus contains two species found in southern South America and South Africa.
Usnea glabrata is a species of beard lichen in the family Parmeliaceae. It was first described as a variety of Usnea plicata by Erik Acharius. Finnish lichenologist Edvard August Vainio transferred it to the genus Usnea in 1915. The lichen grows on bark and is widespread throughout Europe, although it is probably locally extinct in a few locations. It is characterized by small shrubby thallus, constriction of secondary branches at their base, presence of large soralia, and the absence of both papillae and isidia.
Punctelia ulophylla is a species of foliose lichen in the family Parmeliaceae. It is found in Europe, where it grows on the bark of a variety of trees.
Punctelia hypoleucites, commonly known as the southwestern speckled shield lichen, is a species of foliose (leafy) lichen in the family Parmeliaceae. First formally described by Finnish botanist William Nylander as a species of Parmelia, it was transferred to the genus Punctelia in 1982. The lichen is found in Africa, North America, and South America, where it grows on the bark of both hardwood and coniferous trees. Its greenish-grey thallus is covered with tiny white pseudocyphellae – minute holes in the thallus surface that facilitate gas exchange. Some macroscopic features that help distinguish this species from other related members of the genus include the presence and the structure of the apothecia, the absence of asexual surface propagules, and the light brown color of the thallus undersurface. Chemically, the presence of lecanoric acid in the medulla and atranorin in the cortex help distinguish it from lookalikes.
Punctelia bolliana, the eastern speckled shield lichen, is a species of foliose lichen in the family Parmeliaceae. It is found in North America, with a distribution extending from the Canadian province of Ontario south to the central and northeastern United States and Mexico. It grows on the bark of both deciduous trees and coniferous trees. The combination of characteristics that distinguishes this species from others in genus Punctelia are the absence of the vegetative propagules isidia and soralia, a pale brown lower thallus surface, and the presence of the secondary chemical protolichesterinic acid in the medulla.
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.
Usnocetraria is a small genus of lichen-forming fungi in the family Parmeliaceae. It contains two species of corticolous (bark-dwelling), foliose lichens.
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 mayi is a species of foliose lichen in the family Parmeliaceae. It is found in the northern Appalachian Mountains of eastern North America, where it grows on rocks and on the trunks of paper birch and balsam fir. Parmelia mayi is morphologically indistinguishable from Parmelia saxatilis, but is distinct in its distribution, chemistry, and genetics.
Parmelia barrenoae is a species of foliose lichen in the large family Parmeliaceae. It was formally described as a new species in 2005. Before this, it was lumped together as one of several lichens in the Parmelia sulcata group—a species complex of genetically distinct lookalikes. Parmelia barrenoae is widely distributed, occurring in Europe, western North America, Africa, and Asia.
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.
Parmelia rojoi is a species of foliose (leafy), saxicolous (rock-dwelling) lichen in the large family Parmeliaceae. It is known to occur in a couple of humid forests in southern Spain. It is quite similar in appearance to the more widespread Parmelia saxatilis, but has a more fragile thallus and smaller isidia.
Parmelia squarrosa, commonly known as the bottlebrush shield lichen, is a species of foliose lichen in the family Parmeliaceae. It occurs in east Asia, Europe, and eastern North America, where it typically grows on tree bark, much less frequently on rocks, and rarely on moss. Because of its abundance, widespread distribution, and stable populations, it has been assessed as a species of least concern by the International Union for Conservation of Nature. Parmelia saxatilis is quite similar in appearance Parmelia squarrosa and the latter was quite often confused with the former, especially in herbarium collections. Molecular phylogenetic analysis proved the genetic distinctness between the two species, which are morphologically distinguished by difference in rhizine structure.
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.
