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Encyclopedia > Lichen
Lichen-covered tree, Tresco, Isles of Scilly, UK. Grey, leafy Parmotrema perlatum on upper half of trunk; yellowy-green Flavoparmelia caperata on middle and lower half and running up the extreme right side; and the fruiticose Ramalina farinacea
Lichen-covered tree, Tresco, Isles of Scilly, UK. Grey, leafy Parmotrema perlatum on upper half of trunk; yellowy-green Flavoparmelia caperata on middle and lower half and running up the extreme right side; and the fruiticose Ramalina farinacea
"Lichenes" from Ernst Haeckel's Artforms of Nature, 1904
"Lichenes" from Ernst Haeckel's Artforms of Nature, 1904

Lichens (IPA: /ˈlaɪkən/[1] or /lɪtʃ.ən/[2]) are symbiotic associations of a fungus (the mycobiont) with a photosynthetic partner (the photobiont also known as the phycobiont) that can produce food for the lichen from sunlight. The photobiont is usually either green alga or cyanobacterium. A few lichens are known to contain yellow-green algae or, in one case, a brown alga. Some lichens contain both green algae and cyanobacteria as photobionts; in these cases, the cyanobacteria symbiont component may specialize in fixing atmospheric nitrogen for metabolic use. Lichen is a symbiotic organism made up by the association of microscopic green algae or cyanobacteria and filamentous fungi. ... The view from the helicopter leaving Tresco Tresco (Cornish: ), is the second largest island of the Isles of Scilly, Cornwall, UK. It is 735 acres in size. ... Flavoparmelia caperata (L.) Hale, 1986 Binomial name Flavoparmelia caperata (L.) Hale, 1986 // Parmelia caperata (L.) Ach. ... Image File history File links Download high resolution version (2364x3294, 2023 KB) Summary The 83rd plate from Ernst Haeckels Kunstformen der Natur (1904), depicting organisms classified as Lichenes. ... Image File history File links Download high resolution version (2364x3294, 2023 KB) Summary The 83rd plate from Ernst Haeckels Kunstformen der Natur (1904), depicting organisms classified as Lichenes. ... Ernst Haeckel. ... The 8th print, Discomedusae. ... For other uses, see Symbiosis (disambiguation). ... For the fictional character, see Fungus the Bogeyman. ... Photosynthesis splits water to liberate O2 and fixes CO2 into sugar The leaf is the primary site of photosynthesis in plants. ... Divisions Chlorophyta Charophyta Green algae are microscopic protists; found in all aquatic environments, including marine, freshwater and brackish water. ... Orders The taxonomy is currently under revision. ... Yellow-green algae or xanthophytes are an important group of heterokont algae. ... Orders Ascoseirales Chordariales Cutleriales Desmarestiales Dictyosiphonales Dictyotales Ectocarpales Fucales Laminariales(kelps) Scytosiphonales Scytothamnales Sphacelariales Sporochnales Syringodermatales Tilopteridales The brown algae or phaeophytes are a large group of multicellular algae, including many notable seaweeds. ...


The body (thallus) of most lichens is quite different from that of either the fungus or alga growing separately, and may strikingly resemble simple plants in form and growth (Sanders 2001). The fungus surrounds the algal cells, often enclosing them within complex fungal tissues unique to lichen associations; however, in almost all kinds, the algal cells are never enclosed inside the fungal cells themselves. The fungus may or may not penetrate into the algal cells with fine hyphal protrusions. A hypha (plural hyphae) is a long, branching filament that, with other hyphae, forms the feeding thallus of a fungus called the mycelium. ...


In the natural environment, lichen provides the alga with water and minerals that the fungus absorbs from whatever the lichen is growing on, its substrate. As for the alga, it uses the minerals and water to make food for the fungus and itself. For other uses, see Substrate. ...


Algal and fungal components of some lichens have been cultured separately under laboratory conditions, but in the natural environment of a lichen, neither can grow and reproduce without a symbiotic partner. Indeed, although strains of cyanobacteria found in various cyanolichens are often closely related to one another, they differ from the most closely related free-living strains [1]. The lichen association is a close symbiosis: It extends the ecological range of both partners and is obligatory for their growth and reproduction in natural environoments. Propagules ("diaspores") typically contain cells from both partners, although the fungal components of so-called "fringe species" rely instead on algal cells dispersed by the "core species".


There has nonetheless been controversy as to whether the lichen combination should be considered an example of mutualism or commensalism or even parasitism. An observation offered in support of this is that cyanobacteria in laboratory settings can grow faster when they are alone rather than when they are part of a lichen. The same, however, might be said of isolated skin cells growing in laboratory culture, which grow more quickly than similar cells that are integrated into a functional tissue. In biology, mutualism is an interaction between two or more species, where both species derive benefit. ... In ecology, commensalism is a kind of relationship between two organisms where one benefits and the other is not significantly harmed or helped (like a bird living in a tree). ... This article is about a relationship between organisms. ...


Lichens are named based on the fungal component, which plays the primary role in determining the lichens form. The fungus typically comprises the majority of a lichen's bulk, though in filamentous and gelatinous lichens this is not always the case. The lichen fungus is typically a member of the Ascomycota—rarely a member of the Basidiomycota, and then termed basidiolichens to differentiate them from the more common ascolichens. Formerly, some lichen taxonomists placed lichens in their own division, the Mycophycophyta, but this practice is no longer accepted because the components belong to separate lineages. Neither the ascolichens nor the basidiolichens form monophyletic lineages in their respective fungal phyla, but they do form several major solely or primarily lichen-forming groups within each phylum[3]. Even more unusual than basidiolichens is the fungus Geosiphon pyriforme, a member of the Glomeromycota that is unique in that it encloses a cyanobacterial symbiont inside its cells. Geosiphon is not usually considered to be a lichen, and its peculiar symbiosis was not recognized for many years. The genus is more closely allied to endomycorrhizal genera. Subphyla/Classes Archaeascomycetes Euascomycetes Hemiascomycetes or Pezizomycotina Laboulbeniomycetes Eurotiomycetes Lecanoromycetes Leotiomycetes Pezizomycetes Sordariomycetes Dothideomycetes (and many more) Saccharomycotina Saccharomycetes Taphrinomycotina Neolectomycetes Pneumocystidomycetes Schizosaccharomycetes Taphrinomycetes The Ascomycota, formerly known as the Ascomycetae, or Ascomycetes, are a Division of Fungi, whose members are commonly known as the Sac Fungi, which produce spores... Subphyla/Classes Pucciniomycotina Ustilaginomycotina Agaricomycotina Incertae sedis (no phylum) Wallemiomycetes Entorrhizomycetes Basidiomycota is one of two large phyla, that together with the Ascomycota, comprise the subkingdom Dikarya, which were in general what were called the Higher Fungi within the Kingdom Fungi. ... Basidiolichens are lichenized members of the Basidiomycota, a much smaller group of lichens than the far more common ascolichens in the Ascomycota. ... For other uses, see Scientific classification (disambiguation). ... Species xx Geosiphon is a genus of the Phylum Glomeromycota, Order Glomerales, and Family Geosiphonaceae. ... Orders Archaeosporales Diversisporales Paraglomerales Glomerales The division (phylum) Glomeromycota is a taxon within the kingdom Fungi that includes those species that form arbuscular mycorrhizae with plants. ... A mycorrhiza (typically seen in the plural forms mycorrhizae or mycorrhizas, Greek for fungus roots) is the result of a mutualistic association between a fungus and a plant. ...


The algal or cyanobacterial cells are photosynthetic, and as in higher plants they reduce atmospheric carbon dioxide into organic carbon sugars to feed both symbionts. Both partners gain water and mineral nutrients mainly from the atmosphere, through rain and dust. The fungal partner protects the alga by retaining water, serving as a larger capture area for mineral nutrients and, in some cases, provides minerals obtained from the substratum. If a cyanobacterium is present, as a primary partner or another symbiont in addition to green alga as in certain tripartite lichens, they can fix atmospheric nitrogen, complementing the activities of the green alga. Photosynthesis splits water to liberate O2 and fixes CO2 into sugar The leaf is the primary site of photosynthesis in plants. ... ed|other uses|reduction}} Illustration of a redox reaction Redox (shorthand for reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... This article does not cite any references or sources. ... Orders The taxonomy is currently under revision. ... Nitrogen fixation is the process by which nitrogen is taken from its natural, relatively inert molecular form (N2) in the atmosphere and converted into nitrogen compounds (such as, notably, ammonia, nitrate and nitrogen dioxide)[1] useful for other chemical processes. ...

Contents

Morphology and structure

Crustose and foliose lichens on a wall
Crustose and foliose lichens on a wall

Lichens are often the first to settle in places lacking soil, constituting the sole vegetation in some extreme environments such as those found at high mountain elevations and at high latitudes.[citation needed] Some survive in the tough conditions of deserts, and others on frozen soil of the Arctic regions.[citation needed] Recent ESA research shows that lichen can even endure extended exposure to space.[4] Some lichens have the aspect of leaves (foliose lichens); others cover the substratum like a crust (crustose lichens); others adopt shrubby forms (fruticose lichens); and there are gelatinous lichens (illustration, right).[5] Image File history File linksMetadata Download high resolution version (2048x1536, 613 KB) Description: On the wall outside the church at St Pauls Walden, Hertfordshire. ... Image File history File linksMetadata Download high resolution version (2048x1536, 613 KB) Description: On the wall outside the church at St Pauls Walden, Hertfordshire. ... Secondary succession: trees are colonizing uncultivated fields and meadows. ... This article is about the European Space Agency. ...


Although the form of a lichen is determined by the genetic material of the fungal partner, association with a photobiont is required for the development of that form. When grown in the laboratory in the absence of its photobiont, a lichen fungus develops as an undifferentiated mass of hyphae. If combined with its photobiont under appropriate conditions, its characteristic form emerges, in the process called morphogenesis (Brodo, Sharnoff & Sharnoff, 2001). In a few remarkable cases, a single lichen fungus can develop into two very different lichen forms when associating with either a green algal or a cyanobacterial symbiont. Quite naturally, these alternative forms were at first considered to be different species, until they were first found growing in a conjoined manner. The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Hyphae of Penicillium A hypha (plural hyphae) is a long, branching filamentous cell of a fungus, and also of unrelated Actinobacteria. ... Morphogenesis (from the Greek morphê shape and genesis creation) is one of three fundamental aspects of developmental biology along with the control of cell growth and cellular differentiation. ...


There is evidence to suggest that the lichen symbiosis is parasitic rather than mutualistic (Ahmadjian 1993). The photosynthetic partner can exist in nature independently of the fungal partner, but not vice versa. Furthermore, photobiont cells are routinely destroyed in the course of nutrient exchange. The association is able to continue because photobiont cells reproduce faster than they are destroyed. (ibid.) This article is about a relationship between organisms. ... In biology, mutualism is an interaction between two or more species, where both species derive benefit. ... A nutrient is a substance used in an organisms metabolism which must be taken in from the environment. ...


Under magnification, a section through a typical foliose lichen thallus reveals four layers of interlaced fungal filaments. The uppermost layer is formed by densely agglutinated fungal hyphae building a protective outer layer called the cortex, which can reach several hundred μm in thickness.[6] This cortex may be further topped by an epicortex 0.6-1μm thick in some Parmeliaceae, which may be with or without pores, and is secreted by cells - it is not itself cellular.[6] In lichens that include both green algal and cyanobacterial symbionts, the cyanobacteria may be held on the upper or lower surface in small pustules called cephalodia/cephalodium. Beneath the upper cortex is an algal layer composed of algal cells embedded in rather densely interwoven fungal hyphae. Each cell or group of cells of the photobiont is usually individually wrapped by hyphae, and in some cases penetrated by an haustorium.[citation needed] Beneath this algal layer is a third layer of loosely interwoven fungal hyphae without algal cells. This layer is called the medulla. Beneath the medulla, the bottom surface resembles the upper surface and is called the lower cortex, again consisting of densely packed fungal hyphae. The lower cortex often bears rootlike fungal structures known as rhizines, which serve to attach the thallus to the substrate on which it grows.[citation needed] Lichens also sometimes contain structures made from fungal metabolites, for example crustose lichens sometimes have a polysaccharide layer in the cortex.[citation needed] Although each lichen thallus generally appears homogeneous, some evidence seems to suggest that the fungal component may consist of more than one genetic individual of that species. This seems to also be true of the photobiont species involved.[citation needed] Thallus is an undifferentiated vegetative tissue (without specialization of function) of some non-mobile organisms, which were previously known as the thallophytes. ... In botany the cortex is the outer portion of the stem or root of a plant, bounded on the outside by the epidermis and on the inside by the pericycle. ... Haustorium, plural Haustoria, is the hyphal tip of a parasitic fungus that penetrates the hosts tissue, but stays outside the host cell membrane. ... Medulla in general means the inner part, and derives from the Latin word for marrow. In medicine it is contrasted to the cortex. ... A metabolite is the product of metabolism. ... Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ...


Reproduction

Thalli and apothecia on a foliose lichen
Thalli and apothecia on a foliose lichen

Many lichens reproduce asexually, either by vegetative reproduction or through the dispersal of diaspores containing algal and fungal cells. Soredia (singular soredium) are small groups of algal cells surrounded by fungal filaments that form in structures called soralia, from which the soredia can be dispersed by wind. Another form of diaspore are isidia, elongated outgrowths from the thallus that break off for mechanical dispersal. Fruticose lichens in particular can easily fragment. Due to the relative lack of differentiation in the thallus, the line between diaspore formation and vegetative reproduction is often blurred. Many lichens break up into fragments when they dry, dispersing themselves by wind action, to resume growth when moisture returns. Photo taken and modified by User:Petaholmes File links The following pages link to this file: Lichen Categories: GFDL images ... Photo taken and modified by User:Petaholmes File links The following pages link to this file: Lichen Categories: GFDL images ... Production of new individuals along a leaf margin of the air plant, Kalanchoë pinnata. ... This article or section is in need of attention from an expert on the subject. ...


Many lichen fungi appear to reproduce sexually in a manner typical of fungi, producing spores that are presumably the result of sexual fusion and meiosis. Following dispersal, such fungal spores must meet with a compatible algal partner before a functional lichen can form. This may be a common form of reproduction in basidiolichens, which form fruitbodies resembling their nonlichenized relatives. Among the ascolichens, spores are produced in spore-producing bodies, the three most common spore body types are the apothecia, perithecia and the pycnidia. [2] For the figure of speech, see meiosis (figure of speech). ... This article or section is in need of attention from an expert on the subject. ...


For reproduction, lichen possess insidia, soredia, and undergo simple fragmentation. These structures are also composed of a fungal hyphae wrapped around cyanobacteria. (Eichorn, Evert, and Raven, 2005) While the reproductive structures are all composed of the same components(Mycobiont and Photobiont) they are each unique in other ways. Insidia are small outgrowths on the exterior of the lichen. Soredia are powdery propagules that are released from the top of the thallus(1). In order to establish the lichen, the soredia propagules must contain both the photobiont and the mycobiont(2). [7]


Ecology

Lichens must compete with plants for access to sunlight, but because of their small size and slow growth, they thrive in places where higher plants have difficulty growing.


A major ecophysiological advantage of lichens is that they are poikilohydric (poikilo- variable, hydric- relating to water), meaning that though they have little control over the status of their hydration, they can tolerate irregular and extended periods of severe desiccation. Like some mosses, liverworts, ferns, and a few "resurrection plants", upon desiccation, lichens enter a metabolic suspension or stasis (known as cryptobiosis) in which the cells of the lichen symbionts are dehydrated to a degree that halts most biochemical activity. In this cryptobiotic state, lichens can survive wider extremes of temperature, radiation and drought in the harsh environments they often inhabit. Desiccation is the state of extreme dryness, or the process of extreme drying. ... For other uses, see Moss (disambiguation). ... Orders Jungermanniopsida Metzgeriales (simple thalloids) Haplomitriales (Calobryales) Jungermanniales (leafy liverworts) Marchantiopsida Sphaerocarpales (bottle liverworts) Marchantiales (complex thalloids) Monocleales Liverworts are a division of plants commonly called hepatics, Marchantiophyta or liverworts. ... This article is about the group of pteridophyte plants. ... Binomial name Anastatica hierochuntica L. The Rose of Jericho, Resurrection plant, or Anastatica hierochuntica is a member of the family Brassicaceae (formerly Cruciferae) and the only member of the genus Anastatica. ... Cryptobiosis is an ametabolic state of life entered by some lower organisms in response to adverse environmental conditions such as desiccation, freezing, and oxygen deficiency. ...


Lichens do not have roots and do not need to tap continuous reservoirs of water like most higher plants, thus they can grow in locations impossible for most plants, such as bare rock, sterile soil or sand, and various artificial structures such as walls, roofs and monuments. Many lichens also grow as epiphytes (epi- on the surface, phyte- plant) on other plants, particularly on the trunks and branches of trees. When growing on other plants, lichens are not parasites; they do not consume any part of the plant nor poison it. Some ground-dwelling lichens, such as members of the subgenus Cladina (reindeer lichens), however, produce chemicals which leach into the soil and inhibit the germination of plant seeds and growth of young plants. Stability (that is, longevity) of their substratum is a major factor of lichen habitats. Most lichens grow on stable rock surfaces or the bark of old trees, but many others grow on soil and sand. In these latter cases, lichens are often an important part of soil stabilization; indeed, in some desert ecosystems, vascular (higher) plant seeds cannot become established except in places where lichen crusts stabilize the sand and help retain water. This article does not cite any references or sources. ... A parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it. ... Cladoniaceae is a family of lichens in the order Lecanorales. ... Divisions Non-seed-bearing plants †Rhyniophyta †Zosterophyllophyta Lycopodiophyta †Trimerophytophyta Pteridophyta Superdivision Spermatophyta †Pteridospermatophyta Pinophyta Cycadophyta Ginkgophyta Gnetophyta Magnoliophyta Vascular plants (also known as tracheophytes or higher plants) are those plants that have lignified tissues for conducting water, minerals, and photosynthetic products through the plant. ...

Pine forest with lichen ground-cover
Pine forest with lichen ground-cover

Lichens may be eaten by some animals, such as reindeer, living in arctic regions. The larvae of a surprising number of Lepidoptera species feed exclusively on lichens. These include Common Footman and Marbled Beauty. However, lichens are very low in protein and high in carbohydrates, making them unsuitable for some animals. Lichens are also used by the Northern Flying Squirrel for nesting, food, and a water source during winter. Image File history File links Download high resolution version (1740x1175, 557 KB) Description: Cladonio-Pinetum - very poor, sandy pine wood with many lichen on the ground. ... Image File history File links Download high resolution version (1740x1175, 557 KB) Description: Cladonio-Pinetum - very poor, sandy pine wood with many lichen on the ground. ... Caribou redirects here. ... For the ships, see USS Arctic, SS Arctic, MV Arctic The red line indicates the 10°C isotherm in July, sometimes used to define the Arctic region border Artificially coloured topographical map of the Arctic region The Arctic is the region around the Earths North Pole, opposite the Antarctic... A larval insect A larva (Latin; plural larvae) is a juvenile form of animal with indirect development, undergoing metamorphosis (for example, insects or amphibians). ... Subdivisions See Taxonomy of Lepidoptera and Lepidopteran diversity. ... Binomial name Eilema lurideola Zincken, 1817 The Common Footman (Eilema lurideola) is a moth of the family Arctiidae. ... Binomial name Cryphia domestica Hufnagel, 1766 The Marbled Beauty (Cryphia domestica) is a moth of the family Noctuidae. ... Binomial name Glaucomys sabrinus (Shaw, 1801) The Northern Flying Squirrel (Glaucomys sabrinus) is one of two species of the genus Glaucomys, the only flying squirrels found in North America (the other is the somewhat smaller Southern Flying Squirrel, ). Flying squirrels are strictly nocturnal. ...


Although lichens typically grow in naturally harsh environments, most lichens, especially epiphytic fruticose species and those containing cyanobacteria, are sensitive to manufactured pollutants. Hence, they have been widely used as pollution indicator organisms. When growing on mineral surfaces, some lichens slowly decompose their substrate by chemically degrading and physically disrupting the minerals, contributing to the process of weathering by which rocks are gradually turned into soil. While this contribution to weathering is usually benign, it can cause problems for artificial stone structures. For example, there is an ongoing lichen growth problem on Mount Rushmore National Memorial that requires the employment of mountain-climbing conservators to clean the monument. Air pollution Pollution is the introduction of pollutants (whether chemical substances, or energy such as noise, heat, or light) into the environment to such a point that its effects become harmful to human health, other living organisms, or the environment. ... Weathering is the decomposition of rocks, soils and their minerals through direct contact with the Earths atmosphere. ... The faces of (left to right) George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln Mount Rushmore National Memorial, located in Keystone, South Dakota, memorializes the birth, growth, preservation and development of the United States of America. ...


Many lichens produce secondary compounds, including pigments that reduce harmful amounts of sunlight and powerful toxins that reduce herbivory or kill bacteria. These compounds are very useful for lichen identification, and have had economic importance as dyes or primitive antibiotics. Extracts from many Usnea [3] species were used to treat wounds in Russia in the mid-twentieth century. Orcein and other lichen dyes have largely been replaced by synthetic versions [4]. A deer and two fawns feeding on some foliage Herbivory is a form of predation in which an organism known as an herbivore, consumes principally autotrophs[1] such as plants, algae and photosynthesizing bacteria. ... Look up dye in Wiktionary, the free dictionary. ... An antibiotic is a drug that kills or slows the growth of bacteria. ... Usnea is a common name for several species of lichen that generally grow hanging from tree branches, resembling grey or greenish hair. ... Orcein, also Archil, orchil, lacmus, litmus, and C.I. Natural Red 28 is a dye extracted from a lichen. ...


The European Space Agency has discovered that lichens can survive unprotected in space. In an experiment led by Leopoldo Sancho from the Complutense University of Madrid, two species of lichen – Rhizocarpon geographicum and Xanthoria elegans – were sealed in a capsule and launched on a Russian Soyuz rocket on 31 May 2005. Once in orbit the capsules were opened and the lichens were directly exposed to the vacuum of space with its widely fluctuating temperatures and cosmic radiation. After 15 days the lichens were brought back to earth and were found to be in full health with no discernible damage from their time in orbit. [5] ESA redirects here. ... Binomial name (L.) DC. The map lichen is a species of lichen, Rhizocarpon geographicum, which grows on rocks in mountainous areas of low pollution. ... is the 151st day of the year (152nd in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ...


Growth form

Lichens are informally classified by growth form into:

  • crustose (paint-like, flat), e.g., Caloplaca flavescens
  • filamentous (hair-like), e.g., Ephebe lanata
  • foliose (leafy), e.g., Hypogymnia physodes
  • fruticose (branched), e.g., Cladonia evansii, C. subtenuis, and Usnea australis
  • leprose (powdery), e.g., Lepraria incana
  • squamulose (consisting of small scale-like structures, lacking a lower cortex), e.g., Normandina pulchella
  • gelatinous lichens, in which the cyanobacteria produce a polysaccharide that absorbs and retains water.

A filament is a fine, thinly spun thread, fiber, or wire. ... Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ...

Paleontology

The extreme habitats that lichens inhabit are not ordinarily conducive to producing fossils.[8] Though lichens may have been among the first photosynthesizers to colonize land,[citation needed] the oldest fossil lichens in which both symbiotic partners have been recovered date to the Early Devonian Rhynie chert, about 400 million years old.[9] The slightly older fossil Spongiophyton has also been interpreted as a lichen on morphological[10] and isotopic[11] grounds, although the isotopic basis is decidedly shaky.[12] It has been suggested - although not yet proven - that the even older fossil Nematothallus was a lichen.[13] For the Celtic language, see Southwestern Brythonic language; for the residents of the English county, see Devon. ... Rhynie chert is the name for fossiliferous material from a uniquely well-preserved layer in one site near the village of Rhynie, Aberdeenshire, Scotland. ...


It has also been claimed that Ediacaran fossils were lichens;[14] although this claim was met with scepticism and has since been retracted by its author.[13] A lichen-like symbiosis, however, has been observed in marine[verification needed] fossils from the Ediacaran, 600 million years ago.[15] Dickinsonia costata, an Ediacaran organism of unknown affinity, with a quilted appearance. ... The Ediacaran[5][6]  â€¢  â€¢  | Neoproterozoic (last æon of the Precambrian) Phanerozoic Axis scale: millions of years ago. ...


Lichen examples

Binomial name Cetraria islandica Iceland moss (Cetraria islandica) is a lichen whose erect or ascending foliaceous habit gives it something of the appearance of a moss, whence probably the name. ... Binomial name Evernia prunastri (L.) Ach. ... Parmelia is a genus of lichen (strictly, a genus of fungus) with around 1000 species world wide. ... Reindeer moss (c. ... Species Umbillicaria americana (Frosted rock tripe) Umbillicaria angulata Umbillicaria aprina Umbillicaria arctica Umbillicaria caroliniana Umbillicaria cinereorufescens Umbillicaria crustulosa Umbillicaria cylindrica Umbillicaria decussata Umbillicaria deusta Umbillicaria havaasii Umbillicaria hirsuta Umbillicaria hyperborea (Blistered rock tripe) Umbillicaria krascheninnikovii (Salty rock tripe ) Umbillicaria lambii Umbillicaria leiocarpa Umbillicaria lyngei Umbillicaria mammulata Umbillicaria muehlenbergii Umbillicaria nylanderiana...

Gallery

See also

Ethnolichenology is the study of the relationship between lichens and people. ... Lichens are a symbiotic relationship between algal and fungal communities and they increase in size radially as they grow. ...

Notes

  1. ^ "Lichen". Oxford English Dictionary. Oxford University Press. 2nd ed. 1989.
  2. ^ Cambridge Advanced Learner's Dictionary Second Edition, page 731. Cambridge University Press, 2005
  3. ^ Lutzoni et al (2004). "Assembling the fungal tree of life: progress, classification, and evolution of subcellular traits". Amer J Bot 91: 1446-1480. doi:10.3732/ajb.91.10.1446. 
  4. ^ Sancho, L.G.; De La Torre, R.; Horneck, G.; Ascaso, C.; De Los Rios, A.; Pintado, A.; Wierzchos, J.; Schuster, M. (2007). "Lichens survive in space: results from the 2005 LICHENS experiment.". Astrobiology 7 (3): 443-54. doi:10.1089/ast.2006.0046. Retrieved on 2007-12-22. 
  5. ^ Smith, A.L. (1929). Lichens. Cambridge University Press. 
  6. ^ a b Büdel, B.; Scheidegger, C. (1996). "Thallus morphology and anatomy". Lichen Biology: 37-64. 
  7. ^ 1. Eichorn, Susan E., Evert, Ray F., and Raven, Peter H. 2005. Biology of Plants. New York (NY):W.H. Freeman and Company. 289 p.1. 2. Cook, Rebecca and McFarland, Kenneth. 1995. General Botany 111 Laboratory Manual. Knoxville (TN): University of Tennessee. 104 p.
  8. ^ (University of California at Berkeley) Fossil Records of Lichens.
  9. ^ Taylor, T.N.; Hass, H.; Remy, W.; Kerp, H. (1995). "The oldest fossil lichen". Nature 378 (6554): 244-244. doi:10.1038/378244a0. 
  10. ^ Taylor, Wilson A. (2004). "SEM Analysis of Spongiophyton Interpreted as a Fossil Lichen". Int. J Plant Sci. 165(5):875–881. 2004. 165: 875. doi:10.1086/422129. 1058-5893/2004/16505-0018$15.00. 
  11. ^ Jahren, A.H.; Porter, S.; Kuglitsch, J.J. (2003). "Lichen metabolism identified in Early Devonian terrestrial organisms". Geology 31 (2): 99-102. doi:10.1130/0091-7613(2003)031. 
  12. ^ Fletcher, B.J.; Beerling, D.J.; Chaloner, W.G. (2004). "Stable carbon isotopes and the metabolism of the terrestrial Devonian organism Spongiophyton". Geobiology 2 (2): 107-119. doi:10.1111/j.1472-4677.2004.00026.x. 
  13. ^ a b Retallack, G.J. (2007). "Growth, decay and burial compaction of Dickinsonia, an iconic Ediacaran fossil". Alcheringa: An Australasian Journal of Palaeontology 31 (3): 215-240. doi:10.1080/03115510701484705. Retrieved on 2008-02-04. 
  14. ^ Retallack, G.J. (1994). "Were the Ediacaran Fossils Lichens?". Paleobiology 20 (4): 523-544. Retrieved on 2008-02-04. 
  15. ^ Yuan, X.; Xiao, S.; Taylor, T.N. (2005). "Lichen-Like Symbiosis 600 Million Years Ago". Science 308 (5724): 1017. doi:10.1126/science.1111347. 

Those interested in lichens should see Banfield et al., 1999, "Biological impact on mineral dissolution: Application of the lichen model to understanding mineral weathering in the rhizosphere." Proc. Natl. Acad. Sci. 96:3404-3411. A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 356th day of the year (357th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 35th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 35th day of the year in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...


References

  • Ahmadjian, V. 1993. The Lichen Symbiosis. New York: John Wiley & Sons.
  • Brodo, I.M., S.D. Sharnoff, and S. Sharnoff, 2001. Lichens of North America. Yale University Press, New Haven.
  • http://www.newscientistspace.com/article/dn8297 Hardy lichen shown to survive in space
  • http://www.lichen.com
  • Gilbert, O. 2004. The Lichen Hunters. The Book Guild Ltd. England.
  • Hawksworth, D.L. and Seaward, M.R.D. 1977. Lichenology in the British Isles 1568 - 1975. The Richmond Publishing Co. Ltd., Richomd, 1977.
  • Knowles, M.C. 1929. "The lichens of Ireland." Proceedings of the Royal Irish Academy 38:1 - 32.
  • Purvis, O.W., Coppins, B.J., Hawksworth, D.L., James, P.W. and Moore, D.M. (Editors) 1992. The Lichen Flora of Great Britain and Ireland. Natural History Museum, London.
  • Sanders, W.B. 2001. "Lichens: interface between mycology and plant morphology." Bioscience 51: 1025-1035.
  • Seaward, M.R.D. 1984. "Census Catalogue of Irish Lichens." Glasra 81 - 32.

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