Usnea sphacelata

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Usnea sphacelata
2015-01-01 Usnea sphacelata R. Br 498107.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Lecanorales
Family: Parmeliaceae
Genus: Usnea
Species:
U. sphacelata
Binomial name
Usnea sphacelata
R.Br. (1823)
Synonyms [1]
  • Usnea melaxantha var. sphacelata(R.Br.) Hook.f. & Taylor (1847)
  • Usnea sulphurea var. sphacelata(R.Br.) Vain. (1903)
  • Neuropogon sphacelatus(R.Br.) D.J.Galloway (1992)

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.

Contents

Taxonomy

The lichen was formally described as a new species in 1823 by Scottish botanist Robert Brown. The type specimen was collected from Melville Island in the Canadian Arctic Archipelago. [2]

A 2007 study using phylogenetic and morphological analysis of a large number of Antarctic Usnea specimens suggests that Usnea sphacelata comprises at least two genetically distinct groups with no clear differences in morphology. [3]

Description

Usnea sphacelata has a range of distinctive morphological characteristics. Its central axis is relatively thin, accounting for about 20–40% of its structure. Soralia, which are numerous, are typically restricted to the ultimate branches . Minute papillae , which are often pigmented, can be observed on its surface. Fibrils are usually absent from this species. Additionally, its pigmentation is noteworthy; the upper portion is conspicuously variegated, or it can be continuously pigmented towards the tips. This set of features helps to distinguish Usnea sphacelata from other sympatric Antarctic Usnea species, including U. antarctica , U. aurantiaco-atra , U. subantarctica , and U. trachycarpa . [3]

Distribution and habitat

The lichen has a bipolar distribution; that is, it occurs in both the Antarctic and the Arctic. It is also found in southern South America, the northern Andean regions of South America, and the South Island of New Zealand. [3] In the Windmill Islands area of continental Antarctica, Usnea sphacelata tends to grow in drier sun-exposed areas where snow does not tend to persist. Typical lichen associates at this location include Buellia frigida , Buellia soredians , Pseudephebe minuscula , and Umbilicaria decussata . [4] In some regions, the crustose Buellia frigida is often the only species that can become established on smooth, ice-polished rock. Once its thallus is about 2 cm or more in diameter, Pseudephebe minuscula or Usnea sphacelata often start growing near the centre of the thallus. [5]

Related Research Articles

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Usnea is a genus of mostly pale grayish-green fruticose lichens that grow like leafless mini-shrubs or tassels anchored on bark or twigs. The genus is in the family Parmeliaceae. It grows all over the world. Members of the genus are commonly called old man's beard, beard lichen, or beard moss.

<i>Parmelia</i> (fungus) Genus of lichens

Parmelia is a genus of medium to large foliose 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.

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<i>Pseudephebe</i> Genus of fungi

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<span class="mw-page-title-main">Caliciaceae</span> Family of lichen-forming fungi

The Caliciaceae are a family of mostly lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. Although the family has had its classification changed several times throughout its taxonomic history, the use of modern molecular phylogenetic methods have helped to establish its current placement in the order Caliciales. Caliciaceae contains 36 genera and about 600 species. The largest genus is Buellia, with around 300 species; there are more than a dozen genera that contain only a single species.

<i>Menegazzia</i> Genus of fungi

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<span class="mw-page-title-main">Fruticose lichen</span> Form of 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. 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.

<i>Pseudephebe pubescens</i> Species of lichen

Pseudephebe pubescens, also known as 'fine rock wool', is a temperate alpine lichen. It is a member of the genus Pseudephebe, a lichen group characterized by dense mats of brown to near-black "hairs".

<i>Umbilicaria hyperborea</i> Species of lichen

Umbilicaria hyperborea, commonly known as blistered rock tripe, is a species of foliose lichen in the family Umbilicariaceae. It is widely distributed in arctic and alpine regions.

<i>Pseudephebe minuscula</i> Species of lichen

Pseudephebe minuscula is a species of fruticose lichen in the family Parmeliaceae. In North America, it is known colloquially as coarse rockwool. It has an antitropical distribution.

<i>Schaereria</i> Genus of lichen

Schaereria is a genus of lichen-forming fungi. It is the sole genus in the family Schaereriaceae, which itself is the only family in the Schaereriales, an order in the subclass Ostropomycetidae of the class Lecanoromycetes. Schaereria contains 11 species, most of which are crustose lichens that live on rocks.

Thamnolia tundrae is a species of lichen in the family Icmadophilaceae. Its distribution covers the arctic tundra of Eurasia and extends to the North American Aleutian Islands. It was formally described as a new species in 2018 by Ioana Brännström and Leif Tibell. The type specimen was collected from Täljstensvalen mountain. Its thallus features white, hollow, cylindrical tufts, which are morphologically the same as the other members of genus Thamnolia. Thamnolia tundrae, however, is phylogenetically distinct from these other similar species. Secondary compounds found in the lichen include baeomycesic acid and squamatic acid. The species is suspected to have survived the latest glaciation in coastal refugia in regions close to its current range.

Bellemerea elegans is a species of saxicolous (rock-dwelling) and crustose lichen in the family Lecideaceae. Found in Antarctica, it was formally described as a new species in 2009 by Norwegian lichenologist Dag Øvstedal. The type specimen was collected from the Admiralty Bay area of King George Island. Here, at an altitude of 105 m (344 ft), it was found growing on boulders that were overgrown with the beard lichen Usnea aurantiacoatra. Bellemerea elegans is only known from the type specimen. It has a crustose, grey, areolate thallus measuring 1–2 cm (0.4–0.8 in) wide. Its apothecia are more or less immersed in the thallus (aspicilioid), measuring up to 1.1 in diameter, with a dull brown disc. Ascospores number eight per ascus, and measure 12–14 by 5–7 μm. The lichen contains porphyrilic acid, a lichen product.

Amundsenia austrocontinentalis is a species of saxicolous (rock-dwelling), crustose lichen in the family Teloschistaceae, and the type species of genus Amundsenia. Found in Antarctica, it was formally described as a new species in 2014 by Isaac Garrido-Benavent, Ulrik Søchting, Sergio Pérez-Ortega, and Rod Seppelt. The type specimen was collected by the last author from Mule Peninsula, where it was found growing on small stones in glacial till. The species epithet austrocontinentalis refers to its distribution in continental Antarctica.

Buellia peregrina is a species of saxicolous (rock-dwelling), crustose lichen in the family Caliciaceae. It is found in the Namib desert in Namibia.

Usnea leana is a species of fruticose lichen in the family Parmeliaceae. Found in the Galápagos Islands, it characterized by its pendulous thallus, branches covered with point-like pseudocyphellae, and the presence of galbinic acid. This lichen is currently known to be endemic to the Galápagos, with only two known localities representing its distribution.

<i>Buellia frigida</i> Species of lichen

Buellia frigida is a species of saxicolous (rock-dwelling), crustose lichen in the family Caliciaceae. It is endemic to maritime and continental Antarctica. This resilient lichen has a characteristic appearance, typically featuring shades of grey and black divided into small polygonal patterns. The crusts can generally grow up to 7 cm in diameter, although neighbouring individuals may coalesce to form larger crusts. One of the defining characteristics of the lichen is a textured surface with deep cracks, creating the appearance of radiating lobes. These lobes, bordered by shallower fissures, give the lichen a unique visual texture.

References

  1. "Homotypic Synonyms. Basionym Name: Usnea sphacelata R. Br., Chloris Melvilliana: 49 (1823)". Index Fungorum . Retrieved 25 September 2023.
  2. Parry, William Edward (1822). Chloris Melvilliana : a list of plants collected in Melville Island, (latitude 74–75 N., longitude 110–112 W.) in the year 1820. London: W. Clowes. p. 49.
  3. 1 2 3 Seymour, Fabian A.; Crittenden, Peter D.; Wirtz, Nora; Øvstedal, Dag O.; Dyer, Paul S.; Lumbsch, H. Thorsten (2007). "Phylogenetic and morphological analysis of Antarctic lichen-forming Usnea species in the group Neuropogon". Antarctic Science. 19 (1): 71–82. doi:10.1017/s0954102007000107. S2CID   83614402.
  4. Hancock, R.J.; Seppelt, R.D. (1988). "3.10 Habitat specificity and morphological variation in two Antarctic Usnea species" (PDF). Polarforschung. 58 (2/3): 285–291.
  5. Lewis Smith, R.I. (1988). "Classification and ordination of cryptogamic communities in Wilkes Land, Continental Antarctica". Vegetatio. 76 (3): 155–166. doi:10.1007/BF00045476. S2CID   246454366.