Lepraria caesiella

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Lepraria caesiella
Lepraria caesiella 37582391.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Lecanorales
Family: Stereocaulaceae
Genus: Lepraria
Species:
L. caesiella
Binomial name
Lepraria caesiella
R.C.Harris (2005)

Lepraria caesiella is a species of leprose lichen in the family Stereocaulaceae. [1] It forms a thin, gray-blue powdery crust composed of granular aggregations and lacks a true cortex or lobes . The species is widespread throughout northeastern North America, occurring primarily on tree bark, especially hardwoods like oaks, though it can also be found on non-calcareous rocks in sheltered locations. It was formally described by Richard C. Harris in 2005 and is characterized by its production of atranorin, zeorin, and pallidic acid. phylogenetics studies have helped distinguish it from the morphologically similar L. harrisiana , which was previously considered part of the same species.

Contents

Taxonomy

The species was described by Richard C. Harris in 2005, [2] and was previously known as "Lepraria sp. 3" in North America. The type specimen was collected in Monroe County, Pennsylvania, where it was found growing on birch, and is housed in the New York Botanical Garden herbarium (NY). [3] Molecular phylogenetics analysis has confirmed that L. caesiella represents a distinct evolutionary lineage from morphologically similar species. Initially, some populations with placodioid thalli were included within L. caesiella due to their identical chemistry, but DNA sequence data later showed these to represent a separate species, which was described as L. harrisiana . [4]

Description

This lichen forms a powdery crust with edges that are either diffuse or poorly defined. It lacks lobes and has no medulla or base layer ( hypothallus ). [3] The thallus is crustose, leprose, and aggregated, appearing discontinuous and not stratified. It initially forms isolated granules that divide to form aggregations, eventually merging to form a thin crust (less than 0.1 mm thick), gray-blue in color. [4]

The reproductive structures consist of well-organized and discrete spherical ( globose ) granules, typically 35–59  μm in diameter (range 24–76 μm). These granules are ecorticate and remain distinct rather than forming compound units. The photobiont is green and coccoid, with globose cells typically 8–12 μm in width (range 6–16 μm). The hyphae are hyaline, typically 2–4 μm in width (range 1.8–5 μm), and are septate and obscured by a thick layer of crystals that appear bright under polarized light (POL+), which dissolve in KOH solution and recrystallize as thin bent needles. [4]

The main chemical constituents are atranorin, zeorin, and pallidic acid. Some specimens have been found to also contain roccellic/angardianic acid or an unidentified fatty acid. The expected results of chemical spot tests are K+ (yellow), C−, KC−, and P+ (weak yellow), and UV−. [4]

Habitat and distribution

Lepraria caesiella is common and widely distributed throughout temperate and boreal northeastern North America, extending southward in the Appalachian Mountains. The species occurs on a wide diversity of bark-bearing (corticolous) substrates, including both conifers and hardwoods, though the majority of corticolous collections are from hardwoods, particularly oaks (Quercus). Disjunct saxicolous populations also occur in the Ozark ecoregion. [4]

While primarily a corticolous species, it can also be found on noncalcareous rocks. These saxicolous populations are ecologically distinct from other sympatric Lepraria species because they occur on dry, protected rock faces that are sheltered from rain but still exposed to some light. This differs from most other species which occur either on rock faces fully exposed to the elements, or in shaded overhangs that are completely protected and always shaded. [4]

Related Research Articles

<i>Lepraria</i> Genus of lichens

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. There are no known mechanisms for sexual reproduction, yet members of the genus continue to speciate. Some species can form marginal lobes and appear squamulose. Because of the morphological simplicity of the thallus and the absence of sexual structures, the composition of lichen products are important characters to distinguish between similar species in Lepraria.

Lepraria pacifica, the Pacific dust lichen, is a whitish-blue-green leprose crustose lichen that grows on its substrate like patches of granular, caked-up, mealy dust grains. Like other members of the Lepraria genus, it only reproduces asexually.

<i>Lepraria incana</i> Species of lichen

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 presence of the secondary chemicals known as divaricatic acid and zeorin.

<i>Lepraria harrisiana</i> Species of lichen

Lepraria harrisiana is a species of leprose lichen in the family Stereocaulaceae. It is widespread in the eastern United States where it occurs in humid habitats, such as conifer swamps and riparian forests.

Lepraria salazinica is a species of rock-dwelling, leprose lichen in the family Stereocaulaceae. It is found in the eastern United States.

Lepraria santosii is a species of crustose lichen in the family Stereocaulaceae. It occurs in Tenerife, in the Canary Islands.

<i>Lepraria bergensis</i> Species of lichen

Lepraria bergensis is an uncommon crustose lichen in the family Stereocaulaceae. It occurs in Northern and Central Europe, where it grows on siliceous (silicon-rich) rock walls, particularly under small overhangs, and on mosses on vertical to slightly sloping rock surfaces. The lichen thallus forms as a pale bluish-grey crust-like growth on rocks and mosses. The lichen begins as small, rounded patches a few millimetres wide, which may eventually coalesce into larger areas exceeding 1 centimetre in diameter. The thallus has a powdery texture, consisting of minute granules known as soredia and consoredia, which facilitate the lichen's asexual reproduction. The chemical composition of Lepraria bergensis is distinguished by the presence of several secondary metabolites: atranorin, rangiformic acid or jackinic acid, trace amounts of their respective derivatives, and a variety of anthraquinones. These chemical components cause the lichen to fluoresce a dull yellow under long-wave ultraviolet light.

Lepraria aurescens is a species of leprose lichen in the family Stereocaulaceae. It occurs in Thailand.

Lepraria atlantica is a species of leprose lichen in the family Stereocaulaceae. Described as a new species in 2001, the lichen occurs in Australia, Europe, and Greenland, where it typically grows over rocks and associated mosses.

Lepraria caesioalba is a widely distributed species of leprose lichen in the family Stereocaulaceae.

Lepraria alpina is a species of leprose lichen in the family Stereocaulaceae. It is found in Europe, North and South America, Antarctica, and Greenland, where it typically grows on rocks and rock-dwelling mosses in cool habitats.

Lepraria celata is a species of leprose lichen in the family Stereocaulaceae. The powdery greyish-green lichen, described as a new species in 2006, occurs in eastern Europe.

<i>Leprocaulon adhaerens</i> Species of lichen

Leprocaulon adhaerens is a species of leprose lichen in the family Leprocaulaceae, found in North America. It was originally described in 2007 as Lepraria adhaerens and later transferred to the genus Leprocaulon in 2013 based on molecular and morphological studies. The lichen forms a granular crust that adheres tightly to both the substrate and itself, often growing over mosses and other lichens. It is chemically distinct due to its production of pannarin, zeorin, and several minor secondary metabolites. The species is known from coastal southern California, Pennsylvania, and Missouri, though its distribution may be more extensive than currently documented.

Lepraria borealis is a species of leprose lichen in the family Stereocaulaceae, found in cool climates across Northern Europe, northwestern North America, Greenland, and Antarctica. It primarily grows on acidic rock and moss-covered surfaces, occasionally occurring on soil or other lichens. The species forms a granular crust with abundant soredia and shows considerable chemical variation, typically containing atranorin and rangiformic acid.

Leprocaulon coriense is a species of leprose lichen in the family Stereocaulaceae. It is found in Asia and Australia where it grows on various substrates, including rock, wood, bark, mosses and soil.

Lepraria cupressicola is a species of leprose lichen in the family Stereocaulaceae. It occurs in east and southeast Asia, where it grows on rocks, soil and bark in shaded, damp locations.

Lepraria elobata is a species of leprose lichen in the family Stereocaulaceae. It occurs in Europe, North America, and Greenland. The bluish- to greenish-grey, powdery lichen grows on bark and sometimes on soil, wood, siliceous rock and mosses, usually in shady and humid habitats.

<i>Lepraria friabilis</i> Species of lichen

Lepraria friabilis is a species of leprose lichen in the family Stereocaulaceae. It has a disjunct distribution in the southeastern United States and southern California, where it grows exclusively on coniferous bark in humid environments such as swamps and stream valleys.

<i>Lepraria jackii</i> Species of lichen

Lepraria jackii is a species of leprose lichen in the family Stereocaulaceae, described by Tor Tønsberg in 1992. It forms a powdery thallus with variable colouration, ranging from pale green to straw-coloured, and grows on bark, mosses, wood, and rock surfaces in humid, sheltered environments. The species is characterised by its abundant soredia and distinctive secondary metabolites, including atranorin. Lepraria jackii has been recorded across Europe, North America, Asia, and Australia, preferring acidic substrates.

Lepraria lobata is a species of leprose lichen in the family Stereocaulaceae. It is found in Australia, where it grows on bark, mosses on rock, and soil.

References

  1. ↑ "Lepraria caesiella R.C. Harris". Catalogue of Life . Species 2000: Leiden, the Netherlands. Retrieved January 29, 2025.
  2. ↑ Lendemer, J.C. (2005). "Lichens of Eastern North America Exsiccati. Fascicle IV, nos. 151–200". Opuscula Philolichenum. 2: 37–52. doi:10.5962/p.381850.
  3. 1 2 Saag, Lauri; Saag, Andres; Randlane, Tiina (2009). "World survey of the genus Lepraria (Stereocaulaceae, lichenized Ascomycota)". The Lichenologist. 41 (1): 25–60. Bibcode:2009ThLic..41...25S. doi:10.1017/S0024282909007993.
  4. 1 2 3 4 5 6 Lendemer, James C. (2012). "Perspectives on chemotaxonomy: molecular data confirm the existence of two morphologically distinct species within a chemically defined Lepraria caesiella (Stereocaulaceae)". Castanea. 77 (1): 89–105. doi:10.2179/11-042.
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