Erik Acharius

Cetraria islandica, also known as true Iceland lichen or Iceland moss, is an Arctic-alpine lichen whose erect or upright, leaflike habit gives it the appearance of a moss, where its name likely comes from.

Oakmoss (scientific name Evernia prunastri) is a species of lichen. It can be found in many mountainous temperate forests throughout the Northern Hemisphere. Oakmoss grows primarily on the trunk and branches of oak trees, but is also commonly found on the bark of other deciduous trees and conifers such as fir and pine. The thalli of oakmoss are short and bushy, and grow together on bark to form large clumps. Oakmoss thallus is flat and strap-like. They are also highly branched, resembling the form of antlers. The colour of oakmoss ranges from green to a greenish-white when dry, and dark

Lecanora is a genus of lichen commonly called rim lichens. Lichens in the genus Squamarina are also called rim lichens. Members of the genus have roughly circular fruiting discs (apothecia) with rims that have photosynthetic tissue similar to that of the nonfruiting part of the lichen body (thallus). Other lichens with apothecia having margins made of thallus-like tissue are called lecanorine. It is in the family Lecanoraceae in the suborder Lecanorineae.

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. It is a foliaceous lichen, resembling a leaf in shape. The ends of the leaf-like lobes are often squarish-tipped. The upper surface is pale bluish-gray to light brown in direct sunlight, with a network web-like

Cetraria is a genus of fruticose lichens that associate with green algae as photobionts. Most species are found at high latitudes, occurring on sand or heath, and are characterised by their "strap-like" form with spiny lobe edges. The lobes can range from narrow and linear to broader and flattened, often forming loose or densely packed cushions. Their distinctive spiny margins serve both a defensive role and aid in vegetative reproduction through fragmentation. The genus was created by Erik Acharius in 1803 and belongs to the large family Parmeliaceae. While originally a species-rich genus,

Ramalina is a genus of greenish fruticose lichens that grow in the form of flattened, strap-like branches. Members of the genus are commonly called strap lichens or cartilage lichens. Apothecia are lecanorine. It is in the family Ramalinaceae and in the suborder Lecanorineae.

Evernia is a genus of bushy lichens in the family Parmeliaceae. Oakmoss Evernia prunastri is used as a fixative agent in Eau de Cologne within the perfume industry. It is green on top and white on bottom, and divides evenly into "forks"; it becomes very soft when wet. It is not to be confused with Ramalina, which is straplike, stiff and bristly, green on top and bottom, and divides unevenly. Evernia is an abundant genus, found growing on trees.

Nephroma is a genus of medium to large foliose lichens. The genus has a widespread distribution. They are sometimes called kidney lichens, named after the characteristic kidney-shaped apothecia that they produce on the lower surface of their lobe tips, which often curl upwards and thus are visible from above. Sterile specimens that do not have apothecia can look somewhat like Melanelia, Peltigera, Platismatia, or Asahinea. Most species grow either on mossy ground or rocks, or on trees. All species of Nephroma contain cyanobacteria (in the genus Nostoc) as a photobiont, which allows the

Arthonia is a genus of crustose lichens in the family Arthoniaceae. They are commonly called comma lichens.

Alectoria sarmentosa (common witch's-hair lichen) is a long-lived, perennial witch's-hair lichen. It is a light greenish colored and fruticose or bushy bodied. This epiphytic lichen belongs to the family Parmeliaceae and the suborder Lecanorineae, which includes six similar species. A. sarmentosa grows draped or strung over conifer tree limbs and deciduous shrub branches in Northern temperate rainforest. This lichen favors mature and old growth, wet conifer and hardwood forests with clean air. A. sarmentosa is sensitive to air pollution and used for air quality monitoring. Areas required by

Ramalina farinacea is a species of fruticose lichen in the family Ramalinaceae. It appears as small, shrub-like tufts typically 3–6 cm (1.2–2.4 in) long that hang from tree branches and trunks, particularly in woodland areas and on isolated trees. Distinguished by its flattened, yellow-green to grey-green branches with powdery white spots along the edges, this lichen is widespread throughout temperate regions, especially in coastal areas with oceanic climates. First scientifically described by Carl Linnaeus in 1753 and later reclassified by Erik Acharius in 1810, it is remarkably tolerant of

Parmelia saxatilis, commonly known as the salted shield lichen or crottle, is a species of foliose lichen in the family Parmeliaceae. Several morphologically similar species, formerly lumped together, are now distinguished by their DNA.

Ramalina fraxinea, the cartilage lichen, is a fruticose lichen with erect or pendulous thalli and branches that are flattened. Colour varies from pale green though yellow-grey to white-grey; apothecia are frequent and soralia may also be present.

Opegrapha is a genus of mostly lichen-forming fungi in the family Opegraphaceae. These lichens form crusty patches on bark, rock, or other lichens, and are easily recognised by their distinctive black, slit-like or rounded fruiting bodies that look like tiny scribbles or dashes on the surface. The genus includes about 150 accepted species found worldwide, with most partnering with orange-pigmented green algae, though some live as parasites on other lichens. Opegrapha species are distinguished from similar genera by their combination of branched internal filaments, ascospores with multiple

Lepraria is a genus of leprose (powdery) crustose lichens that grows on its substrate like patches of granular, caked up, mealy dust grains. Members of the genus are commonly called dust lichens. The main vegetative body (thallus) is made of patches of soredia (little balls of algae wrapped in fungus). Sexual structures have not been observed in Lepraria, but genomic evidence indicates that the genus retains mating type and meiosis-associated genes, raising the possibility of cryptic sexual or parasexual recombination. Some species can form marginal lobes and appear squamulose. Because of the

Gyalecta is a genus of lichen-forming fungi in the family Gyalectaceae that contains 50 species. Gyalecta was circumscribed by lichenologist Erik Acharius in 1808. It forms associations with Trentepohlia algae.

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Alectoria is a genus of fruticose lichens belonging to the family Parmeliaceae. These lichens form shrub-like growths with slender, branching strands that can hang from trees or grow upright, typically appearing in colours ranging from greenish-yellow to brownish-black. They are commonly found growing on conifer trees in northern forests, where some species like Alectoria sarmentosa can reach lengths of up to a metre or more. The genus serves as an important food source for caribou during winter months, particularly in the inland temperate rainforests of British Columbia, Canada. Alectoria

Solorina saccata, commonly called chocolate chip lichen, is a lichen growing on calcareous rocks, usually in crevices and always in sheltered conditions. It is found from the mediterranean mountains up to the arctic. It differs from other alpine Solorina-species by the four two-cell spores in the asci.

Solorina crocea, commonly known as the orange chocolate chip lichen, is a species of terricolous (ground-dwelling) and foliose (leafy) lichen in the family Peltigeraceae. The lichen, which was first formally described by Carl Linnaeus in 1753, has an arctic–alpine and circumpolar distribution and occurs in Asia, Europe, North America, and New Zealand. It generally grows on the bare ground in sandy soils, often in moist soil near snow patches or seepage areas. Although several forms and varieties of the lichen have been proposed in its history, these are not considered to have any independent

Pyrenula is a genus of lichen-forming fungi in the family Pyrenulaceae. The genus has a widespread distribution, especially in tropical regions, and contains about 200 species. Most species grow on bark in moist, shaded habitats, especially in tropical regions. They usually form thin crusts on the surface and produce small black spore-bearing structures that are partly embedded in the lichen body. Research has shown that some species names in Pyrenula were once applied too broadly, and that the boundaries of the genus itself may still need refinement.

Lepraria incana is a species of dust lichen in the family Stereocaulaceae. First described scientifically by Johann Jacob Dillenius in 1741, and then formally by Carl Linnaeus in 1753, it is the type species of the genus Lepraria. The thallus of this species is green to greyish-green, and powdery – as if made of tiny granules. These granules are soredia, which are asexual reproductive structures. Like most members of genus Lepraria, the lichen has few distinguishing features, lacking both a medulla and sexual reproductive structures (apothecia). Chemically, the lichen is characterised by the

Solorina is a genus of 10 species of lichenized fungi in the family Peltigeraceae. The genus was first described by the Swedish botanist Erik Acharius in 1808. Members of the genus are commonly called socket lichens.

Nephroma parile is a species of foliose lichen belonging to the family Peltigeraceae. It has a cosmopolitan distribution.

Lecidea is a genus of crustose lichens with a carbon-black ring or outer margin (exciple) around the fruiting body disc (apothecium), usually (or always) found growing on (saxicolous) or in (endolithic) rock. Lichens that have such a black exciple are called lecideine, meaning "like Lecidea, even if they are not in this genus. Members of the genus are commonly called disk lichens or tile lichens.

Evernia divaricata is a species of lichen belonging to the family Parmeliaceae.

Thelotrema is a genus of lichen-forming fungi in the family Graphidaceae, the family to which all taxa in the former Thelotremataceae now belong. Members of the genus Thelotrema are commonly called barnacle lichens.

Roccella phycopsis is a species of fruticose lichen in the family Roccellaceae. A study of Roccella phycopsis in Tunisia revealed that it contains methyl orcellinate, a chemical compound of interest for its anti-inflammatory activity.

Pyrenula nitida is a species of crustose lichen belonging to the family Pyrenulaceae. It has a cosmopolitan distribution.

Nephroma resupinatum, commonly known as the pimpled kidney lichen, is a species of foliose lichen in the family Peltigeraceae. It was first described by Carl Linnaeus in his 1753 work Species Plantarum as Lichen resupinatus. Erik Acharius transferred it to the genus Nephroma in 1810. The lichen has a brown to greyish-brown thallus that is tomentose, especially at the tips of the lobes. The lobes, which measure 5–10 mm wide, are covered with lobules, particularly along the margins and the cracks in the thallus surface, as well as pimple-like bumps (sometimes clumped together) visible through