Pilophorus acicularis
Encyclopedia
Pilophorus acicularis, commonly known as the nail lichen or the devil's matchstick, is a species of lichen
in the Cladoniaceae
family. It was originally described in 1803, and transferred to the genus Pilophorus
in 1857. A fructicose (shrub-like) species, it grows directly on silicate
rocks in dense clusters. The lichen starts out as a granular crust on the rock surface, and develops stalks, or pseudopodetia, up to 3 cm (1.2 in) tall and about 1 mm thick that have rounded black apothecia at the tips. The stalks are erect and curved so as to appeared combed. It is found on the west coast of North America up to Alaska
, and in eastern Eurasia
. In addition to green algae
, the lichen contains cyanobacteria that help contribute to soil fertility by supplying fixed nitrogen
.
in 1803 as Baeomyces acicularis by the Swedish botanist and "father of lichenology" Erik Acharius
. The taxon was transferred to several different genera
in the next few decades resulting in several synonyms, including Cenomyces acicularis (by Acharius in 1810), Cladonia acicularis (Elias Magnus Fries
in 1831), and Stereocaulon aciculare (Edward Tuckerman
in 1845). Elias Fries's son Thore Magnus transferred the species to his then newly created genus Pilophorus
in 1857. William Nylander
also published the combination Pilophorus acicularis in 1857, but later analysis suggested that Fries's combination was published first, and under the Principle of Priority
, the correct citation of the species is Pilophorus acicularis (Ach.) Th.Fr. (1857).
The genus Pilophorus was until recently considered to be a member of the Stereocaulaceae
family by some authors. Analysis of small subunit
ribosomal DNA
sequences showed P. acicularis to be more closely related to the Cladoniaceae
, rather than the Stereocaulaceae.
The specific epithet aciculare is derived from the Latin
acicularis, meaning "needle-like". The lichen is commonly
known as the "devil's matchstick"; the common name for the genus—"nail lichen"—is also used.
body of a lichen that contains the lichen mycobiont (fungus) and the photobiont (algae
and/or cyanobacteria). In P. acicularis, the primary thallus (thallus horizontalis) is spread out like a granular crust on the surface of its substrate
. It is light green when young, but becomes gray in age or when dry. The pseudopodetia (upright stalk-like extensions of the thallus made of vegetative tissue) range from 0.5 to 3 cm (0.196850393700787 to 1.2 in) high, and are about 1 mm thick; they grow in dense clusters. Most pseudopodetia are either unbranched or forked into two branches, with the stalks curved so as to appear as if combed; less frequently, they are erect like pins, and up to 1 cm (0.393700787401575 in) tall. Some specimens are highly branched in the upper part of the pseudopodetia, causing them to bear some resemblance to P. robustus, although this morphology
is uncommon. Internally, the pseudopodetia are solid when young, becoming hollow with age, and are composed of long, thin, highly gelatinized hypha
e with narrow cavities about 0.5 μm
wide. The lower part of older pseudopodetia becomes blackened internally. The algal layer is not continuous—contrasting with lichen species that have thalli that stratify into discrete tissue types, including a photobiont layer—and occurs with the mycobiont in the form of granules. These granules may be absent from some parts of the thallus surface. Pycnidia (flask-like structures, resembling perithecia, in which conidia are produced) occur in the tips of small sterile pseudopodetia or in the tips of small lateral branches of older pseudopodetia.
The conidiophores of P. acicularis are 30 μm long, and unbranched. They have terminal sickle-shaped conidia that measure 6 by 1 μm. The apothecia (reproductive structures covered with the spore
-producing asci
) are abundant, usually with one or several on the tips of the pseudopodetia. They are black, hemispherical or roughly triangular, and measure up to 1.5 mm in diameter. The hymenium
(the fertile spore-bearing layer of cells containing the asci) is up to 240 μm thick, and about two-thirds of it is pigment
ed; the lower part of the hymenium is sterile, consisting of only paraphyses
. The asci
are eight-spored. The ascospore
s are rounded when young, becoming spindle-shaped when mature, with dimensions of 21.0–29.5 by 4.5–5.5 μm. The generative tissue (hyphae that eventually forms the thallus) is closely interwoven with short, broad cells that have large cavities. The generative tissue is pigmented black-brown, with the color being most intense below the paraphyses, becoming less so towards the stalk region.
Pilophorus acicularis is a tripartite lichen—containing a fungus, a green alga, and a cyanobacterium. Cephalodia (lichenized aggregations of nitrogen-fixing
cyanobacteria) are present on the primary thallus; smaller cephalodia are also on the pseudopodetia. Hemispherical to irregularly shaped, and light to dark brown in color, they contain species from the genus Nostoc
. The green algal photosynthetic symbiont (photobiont) associated with P. acicularis is Asterochloris magna (formerly Trebouxia magna).
late in P. robustus versus dichotomous in P. acicularis) and the lack of a columella (an internal, column-shaped structure) in longitudinal sections of the pseudopodetia of P. acicularis make it relatively easy to distinguish between the two.
Pilophyllus clavatus, a species found in Western North America, Japan, Taiwan and South Korea, resembles P. acicularis, but it has much shorter pseudopodetia—up to 1.5 cm (0.590551181102362 in) long.
stone, rarely on decaying wood. It is usually in partial shade in openings in low to mid-elevation moist forests, and is also frequently found in rocky roadcuts. Lichens with cephalodia are capable of fixing nitrogen
, and contribute nitrogen to the ecosystem.
P. acicularis is probably the most abundant species of the genus. Most specimens have been found on the west coast of North America as far North as Alaska, but it is been reported most frequently from British Columbia
and Washington. The species is found in China, Japan, Korea, and Taiwan, and has also been reported from the Russian arctic. In general, P. acicularis seems to prefer an oceanic climate
without extremely low temperatures, at least in comparison with other species of the genus. This assumption is supported by the fact that P. acicularis is found more southerly (34 findings in California) than all other species and is less frequently found in northern Alaska where, for example, P. robustus and P. vegae are more common. P. acicularis is rare east of the Rocky Mountains
.
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...
in the Cladoniaceae
Cladoniaceae
The Cladoniaceae are a family of lichenized fungi in the order Lecanorales. The reindeer moss and cup lichens belong to this family.-Genera:*Calathaspis*Carassea*Cetradonia*Cladia*Cladonia*Gymnoderma*Heterodea...
family. It was originally described in 1803, and transferred to the genus Pilophorus
Pilophorus
Pilophorus is a genus of lichenized fungi in the Cladoniaceae family. The genus has a widespread distribution, especially in temperate regions, and contains 11 species.-Species:*Pilophorus acicularis*Pilophorus cereolus*Pilophorus clavatus...
in 1857. A fructicose (shrub-like) species, it grows directly on silicate
Silicate
A silicate is a compound containing a silicon bearing anion. The great majority of silicates are oxides, but hexafluorosilicate and other anions are also included. This article focuses mainly on the Si-O anions. Silicates comprise the majority of the earth's crust, as well as the other...
rocks in dense clusters. The lichen starts out as a granular crust on the rock surface, and develops stalks, or pseudopodetia, up to 3 cm (1.2 in) tall and about 1 mm thick that have rounded black apothecia at the tips. The stalks are erect and curved so as to appeared combed. It is found on the west coast of North America up to Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
, and in eastern Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
. In addition to green algae
Green algae
The green algae are the large group of algae from which the embryophytes emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic...
, the lichen contains cyanobacteria that help contribute to soil fertility by supplying fixed nitrogen
Nitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...
.
History, taxonomy and phylogeny
The species was first describedSpecies description
A species description or type description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species which have been described previously, or are...
in 1803 as Baeomyces acicularis by the Swedish botanist and "father of lichenology" Erik Acharius
Erik Acharius
Erik Acharius was a Swedish botanist who pioneered the taxonomy of lichens and is known as the "father of lichenology"....
. The taxon was transferred to several different genera
Genera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
in the next few decades resulting in several synonyms, including Cenomyces acicularis (by Acharius in 1810), Cladonia acicularis (Elias Magnus Fries
Elias Magnus Fries
-External links:*, Authors of fungal names, Mushroom, the Journal of Wild Mushrooming.*...
in 1831), and Stereocaulon aciculare (Edward Tuckerman
Edward Tuckerman
Edward Tuckerman was an American botanist and professor who made significant contributions to the study of lichens and other alpine plants. He was a founding member of the Natural History Society of Boston and most of his career was spent at Amherst College...
in 1845). Elias Fries's son Thore Magnus transferred the species to his then newly created genus Pilophorus
Pilophorus
Pilophorus is a genus of lichenized fungi in the Cladoniaceae family. The genus has a widespread distribution, especially in temperate regions, and contains 11 species.-Species:*Pilophorus acicularis*Pilophorus cereolus*Pilophorus clavatus...
in 1857. William Nylander
William Nylander
William Nylander was a Finnish botanist and entomologist.Nylander taught at the University of Helsinki for a number of years before later moving to Paris, where he was to live until his death in 1899....
also published the combination Pilophorus acicularis in 1857, but later analysis suggested that Fries's combination was published first, and under the Principle of Priority
Principle of Priority
thumb|270px|Boa manditraIn zoology, the scientific study of animals, the Principle of Priority is one of the guiding principles of the International Code of Zoological Nomenclature, defined by Article 23....
, the correct citation of the species is Pilophorus acicularis (Ach.) Th.Fr. (1857).
The genus Pilophorus was until recently considered to be a member of the Stereocaulaceae
Stereocaulaceae
The Stereocaulaceae are a family of lichenized fungi in the order Lecanorales. Species of this family are widely distributed in temperate boreal and austral regions.-External links:*...
family by some authors. Analysis of small subunit
18S ribosomal RNA
18S ribosomal RNA is a part of the ribosomal RNA. The S in 18S represents Svedberg units. 18S rRNA is a component of the small eukaryotic ribosomal subunit...
ribosomal DNA
Ribosomal DNA
Ribosomal DNA codes for ribosomal RNA. The ribosome is an intracellular macromolecule that produces proteins or polypeptide chains. The ribosome itself consists of a composite of proteins and RNA. As shown in the figure, rDNA consists of a tandem repeat of a unit segment, an operon, composed of...
sequences showed P. acicularis to be more closely related to the Cladoniaceae
Cladoniaceae
The Cladoniaceae are a family of lichenized fungi in the order Lecanorales. The reindeer moss and cup lichens belong to this family.-Genera:*Calathaspis*Carassea*Cetradonia*Cladia*Cladonia*Gymnoderma*Heterodea...
, rather than the Stereocaulaceae.
The specific epithet aciculare is derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
acicularis, meaning "needle-like". The lichen is commonly
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
known as the "devil's matchstick"; the common name for the genus—"nail lichen"—is also used.
Description
The thallus is the vegetativeVegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
body of a lichen that contains the lichen mycobiont (fungus) and the photobiont (algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
and/or cyanobacteria). In P. acicularis, the primary thallus (thallus horizontalis) is spread out like a granular crust on the surface of its substrate
Substrate (biology)
In biology a substrate is the surface a plant or animal lives upon and grows on. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be substrate for another animal that lives on top of the algae. See also substrate .-External...
. It is light green when young, but becomes gray in age or when dry. The pseudopodetia (upright stalk-like extensions of the thallus made of vegetative tissue) range from 0.5 to 3 cm (0.196850393700787 to 1.2 in) high, and are about 1 mm thick; they grow in dense clusters. Most pseudopodetia are either unbranched or forked into two branches, with the stalks curved so as to appear as if combed; less frequently, they are erect like pins, and up to 1 cm (0.393700787401575 in) tall. Some specimens are highly branched in the upper part of the pseudopodetia, causing them to bear some resemblance to P. robustus, although this morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
is uncommon. Internally, the pseudopodetia are solid when young, becoming hollow with age, and are composed of long, thin, highly gelatinized hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
e with narrow cavities about 0.5 μm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
wide. The lower part of older pseudopodetia becomes blackened internally. The algal layer is not continuous—contrasting with lichen species that have thalli that stratify into discrete tissue types, including a photobiont layer—and occurs with the mycobiont in the form of granules. These granules may be absent from some parts of the thallus surface. Pycnidia (flask-like structures, resembling perithecia, in which conidia are produced) occur in the tips of small sterile pseudopodetia or in the tips of small lateral branches of older pseudopodetia.
The conidiophores of P. acicularis are 30 μm long, and unbranched. They have terminal sickle-shaped conidia that measure 6 by 1 μm. The apothecia (reproductive structures covered with the spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
-producing asci
Ascus
An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain eight ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can number one , two, four, or multiples...
) are abundant, usually with one or several on the tips of the pseudopodetia. They are black, hemispherical or roughly triangular, and measure up to 1.5 mm in diameter. The hymenium
Hymenium
The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some cells develop into sterile cells called cystidia or...
(the fertile spore-bearing layer of cells containing the asci) is up to 240 μm thick, and about two-thirds of it is pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
ed; the lower part of the hymenium is sterile, consisting of only paraphyses
Paraphyses
Paraphyses are part of the fertile spore-bearing layer in certain fungi. More specifically, paraphyses are sterile filamentous hyphal end cells composing part of the hymenium of Ascomycota and Basidiomycota interspersed among either the asci or basidia respectively, and not sufficiently...
. The asci
Ascus
An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain eight ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can number one , two, four, or multiples...
are eight-spored. The ascospore
Ascospore
An ascospore is a spore contained in an ascus or that was produced inside an ascus. This kind of spore is specific to fungi classified as ascomycetes ....
s are rounded when young, becoming spindle-shaped when mature, with dimensions of 21.0–29.5 by 4.5–5.5 μm. The generative tissue (hyphae that eventually forms the thallus) is closely interwoven with short, broad cells that have large cavities. The generative tissue is pigmented black-brown, with the color being most intense below the paraphyses, becoming less so towards the stalk region.
Pilophorus acicularis is a tripartite lichen—containing a fungus, a green alga, and a cyanobacterium. Cephalodia (lichenized aggregations of nitrogen-fixing
Nitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...
cyanobacteria) are present on the primary thallus; smaller cephalodia are also on the pseudopodetia. Hemispherical to irregularly shaped, and light to dark brown in color, they contain species from the genus Nostoc
Nostoc
Nostoc is a genus of cyanobacteria found in a variety of environmental niches that forms colonies composed of filaments of moniliform cells in a gelatinous sheath.The name "Nostoc" was invented by Paracelsus...
. The green algal photosynthetic symbiont (photobiont) associated with P. acicularis is Asterochloris magna (formerly Trebouxia magna).
Similar species
Pilophorus acicularis can be separated from similar species by its tall pseudopodetia. It may be confused with P. robustus, especially in material from Alaska where both species occur together. Usually, the different branching (umbelUmbel
An umbel is an inflorescence which consists of a number of short flower stalks which are equal in length and spread from a common point, somewhat like umbrella ribs....
late in P. robustus versus dichotomous in P. acicularis) and the lack of a columella (an internal, column-shaped structure) in longitudinal sections of the pseudopodetia of P. acicularis make it relatively easy to distinguish between the two.
Pilophyllus clavatus, a species found in Western North America, Japan, Taiwan and South Korea, resembles P. acicularis, but it has much shorter pseudopodetia—up to 1.5 cm (0.590551181102362 in) long.
Habitat and distribution
The lichen typically grows on silicateSilicate
A silicate is a compound containing a silicon bearing anion. The great majority of silicates are oxides, but hexafluorosilicate and other anions are also included. This article focuses mainly on the Si-O anions. Silicates comprise the majority of the earth's crust, as well as the other...
stone, rarely on decaying wood. It is usually in partial shade in openings in low to mid-elevation moist forests, and is also frequently found in rocky roadcuts. Lichens with cephalodia are capable of fixing nitrogen
Nitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...
, and contribute nitrogen to the ecosystem.
P. acicularis is probably the most abundant species of the genus. Most specimens have been found on the west coast of North America as far North as Alaska, but it is been reported most frequently from British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
and Washington. The species is found in China, Japan, Korea, and Taiwan, and has also been reported from the Russian arctic. In general, P. acicularis seems to prefer an oceanic climate
Oceanic climate
An oceanic climate, also called marine west coast climate, maritime climate, Cascadian climate and British climate for Köppen climate classification Cfb and subtropical highland for Köppen Cfb or Cwb, is a type of climate typically found along the west coasts at the middle latitudes of some of the...
without extremely low temperatures, at least in comparison with other species of the genus. This assumption is supported by the fact that P. acicularis is found more southerly (34 findings in California) than all other species and is less frequently found in northern Alaska where, for example, P. robustus and P. vegae are more common. P. acicularis is rare east of the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
.