Pseudocyphellaria
Encyclopedia
Pseudocyphellaria is a genus
of large, leafy lichen
s that are sometimes referred to as "specklebelly" lichens. The genus has a widespread distribution, especially in south temperate regions, and contains about 170 species. They resemble Lobaria
, except that all species of Pseudocyphellaria have conspicuous pseudocyphella
e on their lower surface, a characteristic that is unique to this genus. Some species contain pulvinic acid-related pigments
; in these species the soredia
and pseudocyphellae can be bright yellow.
as a photobiont, which allows nitrogen fixation
. In some species of Pseudocyphellaria the cyanobacterium is the sole photobiont, while other species also contain the green alga Dictyochloropsis
and restrict the cyanobacterium to warty cephalodia on the lower surface of the lichen.
Some species of Pseudocyphellaria appear to be able to use either a cyanobacterium or a green algae as their photobiont. DNA tests have shown that the fungal symbionts in P. murrayi (which is in a symbiosis with a cyanobacterium) and P. rufovirescens (which is in a symbiosis with a green alga) are actually the same species. This means that P. murrayi-P. rufovirescens is actually one species of fungus that is capable of forming two very different lichens, one with a cyanobacterium and one with a green alga. Two other possible pairs of Pseudocellaria species that may be capable of choosing their photobiont are P. knightii-P. lividofusca, and P. kookeri-P. durietzii.
Pseudocyphellaria rainierensis is listed as vulnerable in Canada by COSEWIC
. Pseudocyphellaria crocata has disappeared from much of Scandinavia
, a development that has been partly attributed to an increase in grazing from snails, presumably as a result of global warming. In the areas of Scandinavia where P. crocata is still found, it seems restricted to growing on smaller twigs that are harder for the snails to reach.
Warning: Besides being yellow, pulvinic acid derivatives
are highly toxic. Any species of Pseudocyphellaria that has yellow structures probably contains one of these compounds, and may be toxic if ingested.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of large, leafy lichen
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...
s that are sometimes referred to as "specklebelly" lichens. The genus has a widespread distribution, especially in south temperate regions, and contains about 170 species. They resemble Lobaria
Lobaria
Lobaria is a genus of lichens commonly known as "lungwort" or "lung moss" as their physical shape somewhat resembles a lung. Lobaria species are unusual in that they have a three-part symbiosis, containing a fungus, an alga and a cyanobacterium, the presence of the cyanobacterium allowing nitrogen...
, except that all species of Pseudocyphellaria have conspicuous pseudocyphella
Pseudocyphella
Pseudocyphellae are structures in lichens that appear as tiny pores on the outer surface of the lichen. They are caused when there is a break in the cortex of the lichen, and the medullary hyphae extend to the surface...
e on their lower surface, a characteristic that is unique to this genus. Some species contain pulvinic acid-related pigments
Vulpinic acid
Vulpinic acid is a naturally occurring pulvinic acid derivative found in several lichen species, as well as some non-lichenized fungi. It was first isolated in 1925. It is bright yellow, and relatively toxic.-Occurrence in Lichen:...
; in these species the soredia
Soredium
Soredia are common reproductive structures of lichens. Lichens reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungal hyphae wrapped around cyanobacteria or green algae. Fungal hyphae make up the basic body...
and pseudocyphellae can be bright yellow.
The Pseudocyphellaria symbiosis
Many species of Pseudocyphellaria are cyanolichens and contain the cyanobacterium NostocNostoc
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...
as a photobiont, which allows nitrogen fixation
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...
. In some species of Pseudocyphellaria the cyanobacterium is the sole photobiont, while other species also contain the green alga Dictyochloropsis
Dictyochloropsis
Dictyochloropsis is a genus of algae of the order Microthamniales.-Description:Species in this genus are characterized by single uninucleate cells, and asexual reproduction takes place by means of naked zoospores with typical insertion of the flagella...
and restrict the cyanobacterium to warty cephalodia on the lower surface of the lichen.
Some species of Pseudocyphellaria appear to be able to use either a cyanobacterium or a green algae as their photobiont. DNA tests have shown that the fungal symbionts in P. murrayi (which is in a symbiosis with a cyanobacterium) and P. rufovirescens (which is in a symbiosis with a green alga) are actually the same species. This means that P. murrayi-P. rufovirescens is actually one species of fungus that is capable of forming two very different lichens, one with a cyanobacterium and one with a green alga. Two other possible pairs of Pseudocellaria species that may be capable of choosing their photobiont are P. knightii-P. lividofusca, and P. kookeri-P. durietzii.
Ecological significance
Most Pseudocyphellaria grow on trees in coastal areas, from the subtropics to the boreal zones, although some species can occasionally be found growing on mossy rocks or growing inland. Many species of Pseudocyphellaria are restricted to old-growth forests in humid areas, and are therefore threatened by logging. The limited light conditions of dense young forests can severely decrease the growth of Pseudocyphellaria crocata compared to more open, old-growth forests, and the excess of light from clearcuts can also cause damage to the lichen. Because they are often restricted to humid forests in undisturbed areas, species of Pseudocyphellaria are often used as indicators of valuable old growth forests.Pseudocyphellaria rainierensis is listed as vulnerable in Canada by COSEWIC
Committee on the Status of Endangered Wildlife in Canada
The Committee on the Status of Endangered Wildlife in Canada ; French: Le Comité sur la situation des espèces en péril au Canada, is an independent committee of wildlife experts and scientists whose "raison d’être is to identify species at risk" in Canada...
. Pseudocyphellaria crocata has disappeared from much of Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
, a development that has been partly attributed to an increase in grazing from snails, presumably as a result of global warming. In the areas of Scandinavia where P. crocata is still found, it seems restricted to growing on smaller twigs that are harder for the snails to reach.
Traditional use by humans
Several species of Pseudocyphellaria can be utilized to produce a brown to orange-brown dye, and some of them have been used to dye wool in Britain and Scandinavia. One species of Pseudocyphellaria is used in Madagascar to make a tea used to treat indigestion.Warning: Besides being yellow, pulvinic acid derivatives
Vulpinic acid
Vulpinic acid is a naturally occurring pulvinic acid derivative found in several lichen species, as well as some non-lichenized fungi. It was first isolated in 1925. It is bright yellow, and relatively toxic.-Occurrence in Lichen:...
are highly toxic. Any species of Pseudocyphellaria that has yellow structures probably contains one of these compounds, and may be toxic if ingested.
External links
- Picture of Pseudocyphellaria aurata on Lichens of North America webpage
- Picture of Pseudocyphellaria crocata on Lichens of North America webpage
- Picture of Pseudocyphellaria rainierensis on Lichens of North America webpage