Fruticose lichen

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Letharia vulpina, a species of fruticose lichen Letharia vulpina JHollinger crop.jpg
Letharia vulpina , a species of fruticose lichen

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. [1] Fruticose lichens are not a monophyletic and holophyletic lineage, but are 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.

Contents

Characteristics

Characteristic of fruticose lichen is the shape of the thallus. Like crustose lichen, fruticose lichen is composed of a holdfast which will act as an anchor for the lichen to grow in rock fissures, over loose sand or soil. [2]

Growth and structure

Teloschistes chrysophthalmus Fruticose Lichen (Teloschistes chrysophtalmus) (8558189274).jpg
Teloschistes chrysophthalmus

Fruticose or ‘shrubby’ lichens differ from other forms of lichen because their bushy form is attached to the substrate only at the base of the lichen. A continuous algal layer grows around the circumference of the branches of the lichen. [3] Many fruticose lichens have fine, round, hair-like structures and are loosely attached to rocks and trees. [3] Although fruticose lichens are defined as being bushy, some can exhibit a flattened and strap-like appearances. [3] Highly branched fruticose lichen have a high surface to volume ratio that results in a rapid drying and wetting pattern compared to lichens that have a lower surface to volume ratio. [2]

The internal structure of a fruticose lichen branch has a dense outer cortex, a thin algal layer, a medulla and a hollow center or a dense central cord. The structure of fruticose lichens depends also on their mycobionts. [4] Lichen undergoes diffuse growth and the thallus elongates over time. [5] New branch cells grow through the wall materials of older neighboring cells. [5] [6] Microenvironmental conditions influence individual thalli and branches, causing non-uniform growth. [5] There may be many stages of growth for fruticose lichen from the beginning to end of their life cycle. [7]

Diversity

There are many different varieties of fruticose lichen. They are encountered in the following classes: Arthoniales, Licinales, Baeomycetales, Candelariales, Lecanorales, Peltigerales, Pertusariales, Teloschistales, and Mycocaliciales, among others. Each type of fruticose lichen will differ in structure, and some types will be more dominant in a particular environment compared to other forms of fruticose lichen.

Distribution and accumulation

Group of fruiticose lichen Group of fruiticose Lichen.jpg
Group of fruiticose lichen

Fruticose growth forms can be found world-wide in wet humid climates, in temperate rainforests, or in arid conditions. [2] Fruticose lichens are most commonly distributed in mountains, forests and arctic tundra. The accumulation rate of lichen varies within different environments. Lichen biomass accumulation rates decrease from mountain to alpine belts and from tree top to base. [9]

Economic and ecological significance

Although they lack economic importance comparable to that of their algal and fungal components, some lichens play an important role in nitrogen cycling, providing critical winter forage for caribou and colonizing newly exposed surfaces. [10]

Related Research Articles

<span class="mw-page-title-main">Lichen</span> Symbiosis of fungi with algae or cyanobacteria

A lichen is a hybrid colony of algae or cyanobacteria living symbiotically among filaments of multiple fungi species, along with a yeast embedded in the cortex or "skin", in a mutualistic relationship.

<i>Cladonia rangiferina</i> Lichen, sometimes called reindeer lichen

Cladonia rangiferina, also known as reindeer cup lichen, reindeer lichen or grey reindeer lichen, is a light-coloured fruticose, cup lichen species in the family Cladoniaceae. It grows in both hot and cold climates in well-drained, open environments. Found primarily in areas of alpine tundra, it is extremely cold-hardy.

<i>Lobaria pulmonaria</i> Species of lichen

Lobaria pulmonaria is a large epiphytic lichen consisting of an ascomycete fungus and a green algal partner living together in a symbiotic relationship with a cyanobacterium—a symbiosis involving members of three kingdoms of organisms. Commonly known by various names like tree lungwort, lung lichen, lung moss, lungwort lichen, oak lungs or oak lungwort, it is sensitive to air pollution and is also harmed by habitat loss and changes in forestry practices. Its population has declined across Europe and L. pulmonaria is considered endangered in many lowland areas. The species has a history of use in herbal medicines, and recent research has corroborated some medicinal properties of lichen extracts.

<i>Pseudephebe</i> Genus of fungi

Pseudephebe is a genus of fruticose lichens in the family Parmeliaceae. It contains three species that grow on rocks.

<i>Pilophorus acicularis</i> Species of fungus

Pilophorus acicularis, commonly known as the nail lichen or the devil's matchstick lichen, is a species of matchstick lichen in the family Cladoniaceae.

<span class="mw-page-title-main">Crustose lichen</span> Growth form of lichen as a continuously adherent crust

Crustose lichens are lichens that form a crust which strongly adheres to the substrate, making separation from the substrate impossible without destruction. The basic structure of crustose lichens consists of a cortex layer, an algal layer, and a medulla. The upper cortex layer is differentiated and is usually pigmented. The algal layer lies beneath the cortex. The medulla fastens the lichen to the substrate and is made up of fungal hyphae. The surface of crustose lichens is characterized by branching cracks that periodically close in response to climatic variations such as alternate wetting and drying regimes.

<span class="mw-page-title-main">Lichen growth forms</span> Gross morphological classification

Lichens are symbiotic organisms made up of multiple species: a fungus, one or more photobionts and sometimes a yeast. They are regularly grouped by their external appearance – a characteristic known as their growth form. This form, which is based on the appearance of vegetative part of the lichen, varies depending on the species and the environmental conditions it faces. Those who study lichens (lichenologists) have described a dozen of these forms: areolate, byssoid, calicioid, cladoniform, crustose, filamentous, foliose, fruticose, gelatinous, leprose, placoidioid and squamulose. Traditionally, crustose (flat), foliose (leafy) and fruticose (shrubby) are considered to be the three main forms. In addition to these more formalised, traditional growth types, there are a handful of informal types named for their resemblance to the lichens of specific genera. These include alectorioid, catapyrenioid, cetrarioid, hypogymnioid, parmelioid and usneoid.

<span class="mw-page-title-main">Lichen morphology</span>

Lichen morphology describes the external appearance and structures of a lichen. These can vary considerably from species to species. Lichen growth forms are used to group lichens by "vegetative" thallus types, and forms of "non-vegetative" reproductive parts. Some lichen thalli have the aspect of leaves ; others cover the substrate like a crust, others such as the genus Ramalina adopt shrubby forms, and there are gelatinous lichens such as the genus Collema.

<i>Usnea articulata</i> Species of lichen

Usnea articulata, commonly known as the string-of-sausage lichen, is a pale greenish-grey, densely branched lichen with a prostrate or pendant growth form. It grows on bark, on branches and twigs, and is often unattached to a branch and merely draped over it. It grows up to 100 cm (40 in) in length.

<i>Usnea trichodea</i> Species of lichen

Usnea trichodea, commonly known as bony beard lichen, is a pale straw-colored fruticose lichen with a pendant growth form. It grows on trees and is native to eastern North America.

<i>Dolichousnea</i> Genus of lichen

Dolichousnea is a genus of fruticose lichens in the family Parmeliaceae. It has three species. The widely distributed type species, Dolichousnea longissima, is found in boreal regions of Asia, Europe, and North America.

Usnea patriciana is a rare species of fruticose lichen in the family Parmeliaceae. It is endemic to the Galápagos Islands. This beard lichen has a shrubby appearance with cylindrical branches and distinct black pigmentation at its base.

Usnea subcomplecta is a species of fruticose lichen in the family Parmeliaceae. It is found in the Galápagos Islands. It is characterized by its flaccid branches, blackened trunk, and pruinose cortex surface.

<i>Usnea sphacelata</i> Species of lichen

Usnea sphacelata is a species of saxicolous (rock-dwelling), fruticose lichen in the large family Parmeliaceae. It is found in both polar regions of Earth, as well as in southern and northern South America and in New Zealand.

Pseudephebe mariensis is a species of fruticose lichen in the family Parmeliaceae. It is found on Mount Maria in the Falkland Islands, where it grows in grassland and Empetrum-heath. The lichen is found from elevations ranging from 500 to 650 m.

<i>Anaptychia ciliaris</i> Species of lichen

Anaptychia ciliaris, commonly known as the great ciliated lichen or eagle's claws, is a species of fruticose lichen in the family Physciaceae. It is predominantly found in Northern Europe, with its range extending to European Russia, the Caucasus, Central and Southern Europe, the Canary Islands, and parts of Asia. First mentioned in botanical literature by the Italian botanist Fabio Colonna in 1606, the species was formally described by Carl Linnaeus in 1753, who highlighted its unique physical characteristics such as its grey colour, its unusual leafy form with linear fringe-like segments, and the presence of hair-like structures. This lichen is adaptable in its choice of substrates, mostly growing on tree barks and less commonly on rocks.

Schaereria bullata is a species of lichen in the family Schaereriaceae. It is found in the alpine regions of Tasmania, Australia. This lichen species is characterized by its dark brown to grey-brown thallus, which forms irregular patches over soil or bryophytes, and consists of granules that coalesce to create convex to bullate squamules. The lichen also features distinctive apothecia, which are roundish and typically superficial, and spherical spores.

Usnea galapagona is a species of beard lichen in the family Parmeliaceae. It is endemic to the Galápagos Islands. The lichen is easily recognized by its special structure. It has a tough, glass-like outer layer, a thick central core, and a very faint, almost invisible inner layer. This lichen stands upright and has a reddish colour near its base. Its branches split unevenly and are generally few in number, without any small, hair-like structures.

Usnea pallidocarpa is a species of saxicolous (rock-dwelling) beard lichen in the family Parmeliaceae. It is known from Argentina.

References

  1. ↑ Spribille, Toby (21 July 2016). "Basidiomycete yeasts in the cortex of ascomycete macrolichens". Science. 353 (6298): 488–92. Bibcode:2016Sci...353..488S. doi:10.1126/science.aaf8287. PMC   5793994 . PMID   27445309.
  2. 1 2 3 Nash, Thomas, ed. (2010). Lichen Biology (Second ed.). Cambridge, New York: Cambridge University Press. ISBN   9780521871624.
  3. 1 2 3 Baron, George (1999). Understanding Lichens. Slough, England: Richmond Publishing Co. Ltd. ISBN   978-0855462529.
  4. ↑ Hawksworth, D.L.; Hill, David J. (1984). The lichen-forming fungi . Tertiary Level Biology. Glasgow : New York: Blackie: Chapman & Hall. ISBN   978-0412006418.
  5. 1 2 3 Sanders, William B.; Tokamov, Sherzod A. (2015-01-01). "Diffuse growth in the fruticose beard lichen Ramalina usnea (L.) R. Howe". The Lichenologist. 47 (1): 51–58. doi:10.1017/S0024282914000504. ISSN   1096-1135. S2CID   86505939.
  6. ↑ Sanders, William B.; Ríos, Asunción de los (2012-06-01). "Development of thallus axes in Usnea longissima (Parmeliaceae, Ascomycota), a fruticose lichen showing diffuse growth". American Journal of Botany. 99 (6): 998–1009. doi: 10.3732/ajb.1100287 . ISSN   0002-9122. PMID   22623609.
  7. ↑ Suetina, Yu G.; Glotov, N. V. (2010-02-09). "Ontogeny and morphogenesis of the fruticose lichen Usnea florida (L.) Weber ex F.H. Wigg". Russian Journal of Developmental Biology. 41 (1): 24–31. doi:10.1134/S1062360410010030. ISSN   1062-3604. PMID   20184119. S2CID   12566798.
  8. 1 2 Huiskes, A.h.l.; Gremmen, N.j.m.; Francke, J.w. (1997-03-01). "Morphological effects on the water balance of Antarctic foliose and fruticose lichens" (PDF). Antarctic Science. 9 (1): 36–42. Bibcode:1997AntSc...9...36H. doi:10.1017/S0954102097000059. hdl: 20.500.11755/ebe4e2c2-a5bf-47dc-93b8-c3edbc603297 . ISSN   1365-2079. S2CID   86157689.
  9. ↑ Arseneau, Marie-Josée; Ouellet, Jean-Pierre; Sirois, Luc (1998-10-01). "Fruticose arboreal lichen biomass accumulation in an old-growth balsam fir forest". Canadian Journal of Botany. 76 (10): 1669–1676. doi:10.1139/b98-144. ISSN   0008-4026.
  10. ↑ Nelson, Peter R.; McCune, Bruce; Swanson, David K. (2015-08-17). "Lichen traits and species as indicators of vegetation and environment". The Bryologist. 118 (3): 252–263. doi:10.1639/0007-2745-118.3.252. S2CID   83809971.
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