''Pseudevernia furfuracea'', commonly known as tree moss, is a

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, ...

fir Firs (''Abies'') are a genus of 48–56 species of evergreen coniferous trees in the family (biology), family Pinaceae. They are found on mountains throughout much of North America, North and Central America, Europe, Asia, and North Africa. The ...

s and

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...

s. The lichen is rather sensitive to

air pollution Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different types ...

, its presence usually indicating good air conditions in the growing place. The species has numerous human uses, including use in perfume, embalming and in medicine. Large amounts of tree moss is annually processed in France for the perfume industry.

Description

''Pseudevernia furfuracea'' is associated with

photobiont A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.green algae The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...

genus ''

Trebouxia ''Trebouxia'' is a unicellular green alga.Silverside, A. J. (2009). Retrieved from http://www.bioref.lastdragon.org/Chlorophyta/''Trebouxia''.html It is a photosynthetic organism that can exist in almost all habitats found in polar, tropical, and ...

''. It reproduces asexually by

isidia An isidium is a vegetative reproductive structure present in some lichens. Isidia are outgrowths of the thallus surface, and are corticated (i.e., containing the outermost layer of the thallus), usually with a columnar structure, and consisting o ...

. The

ontogeny Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the stu ...

of isidia development and its role in CO₂ gas exchange in ''P. furfuracea'' has been investigated. The preferred growing surfaces for ''P. furfuracea'' are the so-called "nutrient poor" bark trees, including

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus ''Betula'' contains 30 ...

and

spruce A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfami ...

. The species has two morphologically identical varieties that are distinguished by the secondary metabolites they produce: var. ''ceratea'' Zopf. produces olivetoric acid and other physodic acids, while var. ''furfuracea'' produces physodic but not olivetoric acid. Some authors (e.g., Hale 1968) have separated the

chemotype A chemotype (sometimes chemovar) is a chemically distinct entity in a plant or microorganism, with differences in the composition of the secondary metabolites. Minor genetic and epigenetic changes with little or no effect on morphology or anatomy m ...

s at the species level, designating the olivetoric acid-containing specimens as ''Pseudevernia olivetorina'', but more recent literature separates them at the varietal level.

Uses

Perfumes

Large amounts of tree moss (approximately 1900 tons in 1997) are processed in Grasse,

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

for the

perfume Perfume (, ; french: parfum) is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent. Th ...

industry.

Embalming

In ancient Egyptian embalming, ''P. furfuracea'' was found packed into the body cavity of

mummies A mummy is a dead human or an animal whose soft tissues and organs have been preserved by either intentional or accidental exposure to chemicals, extreme cold, very low humidity, or lack of air, so that the recovered body does not decay furth ...

, although it is not certain whether this was done because of the supposed preservative properties or the aromatic properties of the lichen.

Antimicrobial activity

Soluble extracts from ''P. furfuracea'' var. ''furfuracea'' and var. ''ceratea'', as well as specific compounds found therein, have antimicrobial activity against a variety of microorganisms.

Medicinal use

Alfacar Alfacar is a historic town approximately from the city of Granada, in the autonomous Spanish region of Andalucia. In the 2005 census, INE reported its population as 5107 inhabitants. The town is on the edge of the Sierra de Huétor Natural Pa ...

and Viznar, Andalucia (

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

), ''P. furfuracea'' is used for respiratory complaints. The

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms wer ...

is washed and boiled for a long time to prepare a decoction that is drunk. Water extracts of this species have been shown to have a potent protective effect on

genotoxicity Genotoxicity is the property of chemical agents that damage the genetic information within a cell causing mutations, which may lead to cancer. While genotoxicity is often confused with mutagenicity, all mutagens are genotoxic, but some genotoxic sub ...

caused by bismuth compounds such as colloidal bismuth subcitrate.

Heavy metal sorption

''Pseudevernia furfuracea'' has been investigated for its ability to absorb heavy metals from solution. The metal-binding biosorption for

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

(II) and

nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...

(II) was shown to follow the Langmuir and Freundlich isotherm models, suggesting it may have potential as a biosorbent for treatment of heavy metal wastes.

Pollution monitors

Because specimens of ''P. furfuracea'' tend to bioaccumulate heavy metals like Cr, Zn, Cd, Pb, Ni, Fe, Mn and Cu proportional to their concentration in airborne particulates, they may be used as a

biomonitor A bioindicator is any species (an indicator species) or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other sm ...

of air quality, although it has been noted that both

trace metal Trace metals are the metals subset of trace elements; that is, metals normally present in small but measurable amounts in animal and plant cells and tissues and that are a necessary part of nutrition and physiology. Many biometals are trace me ...

accumulation and major element accumulation is partly dependent on the hydration level of the specimen. Also, the species is sensitive to

ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...

concentrations: ozone fumigation results in biophysical, physiological, and structural impairment of specimens. ''P. furfuracea'' has also been used to monitor the levels of

radionuclide A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transfer ...

s such as Cesium-137 in

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

after the

Chernobyl nuclear accident The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the No. 4 nuclear reactor, reactor in the Chernobyl Nuclear Power Plant, near the city of Pripyat in the north of the Ukrainian Soviet Socialist Republic, Ukrainia ...

Conservation status

Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...

, ''P. furfuracea'' is found in only two locations and is classified as critically endangered (CR).Náttúrufræðistofnun Íslands celandic Institute of Natural History(1996).
Válisti 1: Plöntur.
' (in Icelandic) Reykjavík: Náttúrufræðistofnun Íslands.

Bioactive compounds

In addition to the physodic acid mentioned above, ''P. furfuracea'' also contains 2-hydroxy-4-methoxy-3,6-dimethyl benzoic acid, atranorin, oxyphysodic acid, and virensic acid. Of these compounds, atranorin showed the highest inhibition of

proteolytic Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids. Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called proteases, ...

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

trypsin Trypsin is an enzyme in the first section of the small intestine that starts the digestion of protein molecules by cutting these long chains of amino acids into smaller pieces. It is a serine protease from the PA clan superfamily, found in the dig ...

and porcine pancreatic elastase. Research suggests that the biosynthesis of both atranorin and physodic acid is influenced by the cooperation of

epiphytic An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...

bacteria. A number of

sterol Sterol is an organic compound with formula , whose molecule is derived from that of gonane by replacement of a hydrogen atom in position 3 by a hydroxyl group. It is therefore an alcohol of gonane. More generally, any compounds that contain the go ...

compounds have been identified from ''P. furfuracea'', including ergosterol peroxide,

ergosterol Ergosterol (ergosta-5,7,22-trien-3β-ol) is a sterol found in cell membranes of fungi and protozoa, serving many of the same functions that cholesterol serves in animal cells. Because many fungi and protozoa cannot survive without ergosterol, the ...

and lichosterol.

References

{{Taxonbar, from=Q630042 Parmeliaceae Lichen species Lichens described in 1753 Fungi of Europe Taxa named by Carl Linnaeus