A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. Lichens have properties different from those of their component organisms. They come in many colors, sizes, and forms and are sometimes plant-like, but are not plants. They may have tiny, leafless branches (fruticose); flat leaf-like structures (foliose); grow crust-like, adhering tightly to a surface (substrate) like a thick coat of paint (crustose); have a powder-like appearance (leprose); or other growth forms.
Xanthoria parietina is a foliose lichen in the family Teloschistaceae. It has wide distribution, and many common names such as common orange lichen, yellow scale, maritime sunburst lichen and shore lichen. It can be found near the shore on rocks or walls, and also on inland rocks, walls, or tree bark. It was chosen as a model organism for genomic sequencing by the US Department of Energy Joint Genome Institute (JGI).
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.
Trebouxia is a unicellular green alga. It is a photosynthetic organism that can exist in almost all habitats found in polar, tropical, and temperate regions. It can either exist in a symbiotic relationship with fungi in the form of lichen or it can survive independently as a free-living organism alone or in colonies. Trebouxia is the most common photobiont in extant lichens. It is a primary producer of marine, freshwater and terrestrial ecosystems. It uses carotenoids and chlorophyll a and b to harvest energy from the sun and provide nutrients to various animals and insects.
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.
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.
Niebla is a genus of yellow-green fruticose lichens that grow on rocks, trees, and shrubs within the fog zone of coastal North America, or more narrowly defined to occur on rocks and soil along the Pacific Coast from Mendocino County in California south to Baja California Sur.
Pilophorus acicularis, commonly known as the nail lichen or the devil's matchstick lichen, is a species of matchstick lichen in the family Cladoniaceae.
A fruticose lichen is a form of lichen fungi that is characterized by a coral-like shrubby or bushy growth structure. It is formed from a symbiotic relationship of a photobiont such as green algae or less commonly cyanobacteria and one, two or more mycobionts. Fruticose lichens are not a monophyletic and holophyletic lineage, but is a form encountered in many classes. Fruticose lichens have a complex vegetation structure, and are characterized by an ascending, bushy or pendulous appearance. As with other lichens, many fruticose lichens can endure high degrees of desiccation. They grow slowly and often occur in habitats such as on tree barks, on rock surfaces and on soils in the Arctic and mountain regions.
Lichen anatomy and physiology is very different from the anatomy and physiology of the fungus and/or algae and/or cyanobacteria that make up the lichen when growing apart from the lichen, either naturally, or in culture. The fungal partner is called the mycobiont. The photosynthetic partner, algae or cyanobacteria, is called the photobiont. The body of a lichens that does not contain reproductive parts of the fungus is called the thallus. The thallus is different from those of either the fungus or alga growing separately. The fungus surrounds the algal cells, often enclosing them within complex fungal tissues unique to lichen associations. In many species the fungus penetrates the algal cell wall, forming penetration pegs or haustoria similar to those produced by pathogenic fungi. Lichens are capable of surviving extremely low levels of water content (poikilohydric). However, the re-configuration of membranes following a period of dehydration requires several minutes at least.
Symbiosis in lichens is the mutually helpful symbiotic relationship of green algae and/or blue-green algae (cyanobacteria) living among filaments of a fungus, forming lichen.
Ramalina menziesii, the lace lichen or fishnet, is a pale yellowish-green to grayish-green foliose lichen. It grows up to a meter long, hanging from bark and twigs in a distinctive net-like or lace-like pattern that is unlike any other lichen in North America. It becomes a deeper green when wet. Apothecia are lecanorine. it is an important food source for deer in the Coast Range of California, and a source of nest material for birds. It is highly variable in its growth form, with branches sometimes so slender as to appear like strands, sometimes tiny, and sometimes large with broadly flattened branches.
Niebla homalea is a species of fruticose lichen that grows on rocks in foggy areas along the Pacific Coast of North America, from Mendocino County, California south to Bahía de San Quintín on the main peninsula of Baja California, with an isolated occurrence further south on vertical rock faces above Punta Camachos, and other occurrences in the Channel Islands and on Guadalupe Island. The epithet homalea, given by Acharius, suggests it was in regard to the branches appearing flattened.
Vermilacinia ceruchis is a fruticose lichen found on sand and rock in coastal fog areas of Peru and Chile.
Vermilacinia robusta is an olive green fruticose lichen that occurs on rocks near ocean mist along the foggy Pacific Coast of southern California to northern Baja California and offshore islands. The epithet, robusta, was probably adopted in recognizing a more robust form of V. comboides, originally described as a variety of Ramalina combeoides by R. Heber Howe, Jr. in 1913.
Vermilacinia cephalota is a fruticose lichen usually found on trees, shrubs and wooden fences in the fog regions along the Pacific Coast of North America from southeastern Alaska to the Vizcaíno Peninsula of Baja California.
Vermilacinia tigrina is a fruticose lichen that grows on branches of shrubs and on earth among cactus and shrubs in the fog regions along the Pacific Coast of North America and South America; in North America found in the Channel Islands and near San Diego, California, and in central and southern Baja California; in South America from Peru to Chile. The epithet is in reference to the irregular black spots or bands on the thallus branches.
Ramalina erosa is a species of fruticose lichen in the family Ramalinaceae. It was described as a new species by Hildur Krog in 1990. The type specimen was collected from Pico do Facho on Porto Santo Island (Portugal), where it was found growing on acidic rock at an elevation of 500 m (1,600 ft).
Sekikaic acid is an organic compound in the structural class of chemicals known as depsides. It is found in some lichens. First isolated from Ramalina sekika, it is a fairly common lichen product in the genera Ramalina and Cladonia. The species epithet of the powdery lichen Lepraria sekikaica refers to the presence of this substance—a rarity in genus Lepraria.
Ramalina americana, commonly known as the sinewed ramalina, is a pale green fruticose lichen that is found across the Northern US Midwest, extending into Southern Canada and the Eastern Seaboard. It is characterized morphologically by the presence of pseudocyphellae, straight spores, and its unique chemical diversity.
