Usnea
Encyclopedia
Usnea is the generic and scientific name for several species of lichen
in the family Parmeliaceae
, that generally grow hanging from tree branches, resembling grey or greenish hair. It is sometimes referred to commonly as Old Man's Beard, Beard Lichen, or Treemoss. Usnea looks very similar to Spanish moss
, so much so that the latter plant's Latin name is derived from it (Tillandsia usneoides, the 'Usnea-like Tillandsia
').
Usnea grows all over the world. Like other lichens it is a symbiosis
of a fungus
and an alga. The fungus belongs to the division Ascomycota
, while the alga is a member of the division Chlorophyta
.
varieties and adaptations to local circumstances. The taxonomic categorization of many members of this genus remains uncertain. The number of recognized species in Finland
is decreasing for this reason, from 34 in 1951 to 25 in 1963 and only 12 in 2000. It is now noted as including more than 600 species and being one of the largest genera within the Parmeliaceae.(Ref. Wirtz, N. et al. 2006.)
. Under bad conditions they may grow no larger than a few millimetres, if they survive at all. Where the air is unpolluted, they can grow to 10–20 cm long.
for at least 1000 years. Usnic acid
(C18H16O7), a potent antibiotic
and antifungal agent is found in most species. This, combined with the hairlike structure of the lichen, means that Usnea lent itself well to treating surface wounds when sterile gauze and modern antibiotics were unavailable. It is also edible and high in vitamin C
.
In modern American herbal medicine, Usnea is primarily used in lung and upper respiratory tract infections, and urinary tract infections. There are no human clinical trials to either support or refute either practice, although in vitro research does strongly support Usnea's antimicrobial properties.
Usnea lichen is important to note because it has life-saving potential. Native Americans employed it as a compress to severe battle wounds to prevent infection and gangrene, and it was also taken internally to fight infections. Usnea contains potent antibiotics which can halt infection and are broad spectrum and effective against all gram-positive and tuberculosis bacterial species. Usnea has several unique characteristics which make its identification easy if stranded in the wilderness far from a hospital. Usnea lichens can be easily identified by pulling back the outer sheath on the main stem. Usnea lichens have an elastic pure white cord running through the center of the main stem. Lichen species which resemble Usnea do not have this white cord, and appear grey-green throughout. Usnea lichens do not change color throughout the growing season as do lichen species which closely resemble Usnea.
Usnea also has shown usefulness in the treatment of difficult to treat fish infections in aquariums and ponds; in part due to the Usnic Acid for digestive internal infections or external infections, and as well for gill infections/stress due to Mucilage which is also contained in Usnea.
Usnea was one ingredient in a product called Lipokinetix, promoted to induce weight loss via increase in metabolic rate. Lipokinetix has been the topic of an FDA warning in the USA, due to potential hepatotoxicity, although it is unclear yet if any toxicity would be attributable to the Usnea. Lipokinetix also contained PPA, caffeine, yohimbine and diiodothyronine. There is reason to believe that usnic acid, in high concentrations, could possess some toxicity. The National Toxicology Program is currently evaluating the issue.
There is no formal scientific information on the safety or efficacy of oral use of Usnea, although its long history of use strongly suggests value.
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 family Parmeliaceae
Parmeliaceae
The Parmeliaceae is a large and diverse family of Lecanoromycetes. With over 2000 species in roughly 87 genera, it is currently regarded as the largest family of lichen forming fungi...
, that generally grow hanging from tree branches, resembling grey or greenish hair. It is sometimes referred to commonly as Old Man's Beard, Beard Lichen, or Treemoss. Usnea looks very similar to Spanish moss
Spanish Moss
Spanish moss is a flowering plant that grows upon larger trees, commonly the Southern Live Oak or Bald Cypress in the southeastern United States....
, so much so that the latter plant's Latin name is derived from it (Tillandsia usneoides, the 'Usnea-like Tillandsia
Tillandsia
Tillandsia is a genus of around 540 species in the Bromeliad family , found in the forests, mountains, and deserts, of Central and South America, and Mexico and the southern United States in North America....
').
Usnea grows all over the world. Like other lichens it is a symbiosis
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...
of a fungus
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
and an alga. The fungus belongs to the division Ascomycota
Ascomycota
The Ascomycota are a Division/Phylum of the kingdom Fungi, and subkingdom Dikarya. Its members are commonly known as the Sac fungi. They are the largest phylum of Fungi, with over 64,000 species...
, while the alga is a member of the division Chlorophyta
Chlorophyta
Chlorophyta is a division of green algae, informally called chlorophytes. The name is used in two very different senses so that care is needed to determine the use by a particular author...
.
Taxonomy
Many species have been described. A monography by Józef Motyka from 1947 distinguished 451 species. Many of these are now regarded as morphologicalMorphology (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....
varieties and adaptations to local circumstances. The taxonomic categorization of many members of this genus remains uncertain. The number of recognized species in Finland
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...
is decreasing for this reason, from 34 in 1951 to 25 in 1963 and only 12 in 2000. It is now noted as including more than 600 species and being one of the largest genera within the Parmeliaceae.(Ref. Wirtz, N. et al. 2006.)
Ecology
Usnea is very sensitive to air pollution, especially sulfur dioxideSulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
. Under bad conditions they may grow no larger than a few millimetres, if they survive at all. Where the air is unpolluted, they can grow to 10–20 cm long.
Uses
Usnea has been used medicinallyMedicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
for at least 1000 years. Usnic acid
Usnic acid
Usnic acid is a naturally occurring dibenzofuran derivative found in several lichen species. It was first isolated by German scientist W. Knop in 1844 and first synthesized between 1933-1937 by Curd and Robertson. Usnic acid was identified in many genera of lichens including Usnea, Cladonia,...
(C18H16O7), a potent antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
and antifungal agent is found in most species. This, combined with the hairlike structure of the lichen, means that Usnea lent itself well to treating surface wounds when sterile gauze and modern antibiotics were unavailable. It is also edible and high in vitamin C
Vitamin C
Vitamin C or L-ascorbic acid or L-ascorbate is an essential nutrient for humans and certain other animal species. In living organisms ascorbate acts as an antioxidant by protecting the body against oxidative stress...
.
In modern American herbal medicine, Usnea is primarily used in lung and upper respiratory tract infections, and urinary tract infections. There are no human clinical trials to either support or refute either practice, although in vitro research does strongly support Usnea's antimicrobial properties.
Usnea lichen is important to note because it has life-saving potential. Native Americans employed it as a compress to severe battle wounds to prevent infection and gangrene, and it was also taken internally to fight infections. Usnea contains potent antibiotics which can halt infection and are broad spectrum and effective against all gram-positive and tuberculosis bacterial species. Usnea has several unique characteristics which make its identification easy if stranded in the wilderness far from a hospital. Usnea lichens can be easily identified by pulling back the outer sheath on the main stem. Usnea lichens have an elastic pure white cord running through the center of the main stem. Lichen species which resemble Usnea do not have this white cord, and appear grey-green throughout. Usnea lichens do not change color throughout the growing season as do lichen species which closely resemble Usnea.
Usnea also has shown usefulness in the treatment of difficult to treat fish infections in aquariums and ponds; in part due to the Usnic Acid for digestive internal infections or external infections, and as well for gill infections/stress due to Mucilage which is also contained in Usnea.
Usnea was one ingredient in a product called Lipokinetix, promoted to induce weight loss via increase in metabolic rate. Lipokinetix has been the topic of an FDA warning in the USA, due to potential hepatotoxicity, although it is unclear yet if any toxicity would be attributable to the Usnea. Lipokinetix also contained PPA, caffeine, yohimbine and diiodothyronine. There is reason to believe that usnic acid, in high concentrations, could possess some toxicity. The National Toxicology Program is currently evaluating the issue.
There is no formal scientific information on the safety or efficacy of oral use of Usnea, although its long history of use strongly suggests value.
Species
Some of the species of Usnea include:- Usnea barbata
- Usnea dasypoga
- Usnea florida
- Usnea hirta
- Usnea rubicundaUsnea rubicundaUsnea rubicunda , is a type of arboreal lichen native to temperate regions in North, Central and South America, as well as Europe, Eastern Asia, and North Africa. This fruticose species forms hair-like hanging clusters that are orange to red in color. It is at risk of extirpation in Canada....
- Usnea rubiginea
- Usnea scabrida
- Usnea subfloridana
- The species Usnea longissima was renamed Dolichousnea longissimaDolichousnea longissimaDolichousnea longissima, Old Man's Beard or Methuselah's Beard Lichen, is a lichen in the family Parmeliaceae. It was previously known as Usnea longissima.-Distribution:...
in 2004.
External links
- FDA letter to Health Care Professionals on Hazardous Dietary Supplement Lipokinetix, 2001-11-01
- Usnea as a Fish Remedy
- Pekka Halonen, Studies on the lichen genus Usnea in East Fennoscandia and Pacific North America (PDF)