Usnea

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Usnea

Usnea is the generic and scientific name for several species of lichen

Lichen

Lichens are composite organisms consisting of a symbiosis association of a fungus with a Photosynthesis partner , usually either a green algae or Cyanobacteria ....
in the family Parmeliaceae

Parmeliaceae

The Parmeliaceae are a family of lichens . It is the largest family of lichen-forming fungi, with over 2000 species and 83 genera. Species of this family have a cosmopolitan distribution and may be found in a wide range of climatic regions....
, 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.

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Encyclopedia

Usnea is the generic and scientific name for several species of lichen

Lichen

Lichens are composite organisms consisting of a symbiosis association of a fungus with a Photosynthesis partner , usually either a green algae or Cyanobacteria ....
in the family Parmeliaceae

Parmeliaceae

Spanish Moss

Spanish moss closely resembles its namesake . However, Spanish moss is not biologically related to either mosses or lichens. Instead, it is a flowering plant in the family Bromeliaceae that grows hanging from tree branches in full sun or partial shade....
, so much so that the latter plant's Latin name is derived from it (Tillandsia usneoides, the 'Usnea-like Tillandsia

Tillandsia

The plant genus Tillandsia, a member of the Bromeliad family , is found in the deserts, forests and mountains of Central America 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

The term symbiosis commonly describes close and often long-term interactions between different biological species. The term was first used in 1879 by the Germany mycology Heinrich Anton de Bary, who defined it as "the living together of unlike organisms"....
of a fungus

Fungus

A fungus is a Eukaryote organism that is a member of the Kingdom Fungi . The fungi are a monophyletic group, also called the Eumycota , that is phylogeny distinct from the morphologically similar slime molds and water molds ....
and an alga. The fungus belongs to the division Ascomycota

Ascomycota

The Ascomycota are a Phylum of the kingdom Fungi, and subkingdom Dikarya, whose members are commonly known as the Sac Fungi. They are the largest phylum of Fungi, with over 30,000 species....
, while the alga is a member of the division Chlorophyta

Chlorophyta

Chlorophyta, a division of green algae, includes about 7000 species of mostly Aquatic ecosystem photosynthetic eukaryotic organisms. Like the land plants , green algae contain chlorophylls a and b, and store food as starch in their plastids....
.

Taxonomy

Many species have been described. A monography by Józef Motyka from 1947 distinguished 451 species. Many of these are now regarded as morphological

Morphology (biology)

The term morphology in biology refers to form, structure and configuration of an organism. This includes aspects of the outward appearance as well as the form and structure of the internal parts like bones and organs....
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 countries situated in the Fennoscandian region of northern Europe. It borders Sweden on the west, Russia on the east, and Norway on the north, while Estonia lies to its south across the Gulf of 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.)

Ecology

Usnea is very sensitive to air pollution, especially sulfur dioxide

Sulfur dioxide

Sulfur dioxide is the chemical compound with the formula SO2. It is produced by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide....
. 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 medicinally

Medicine

Medicine is the art and science of healing. It encompasses a range 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....
(C₁₈H₁₆O₇), a potent antibiotic

Antibiotic

In common usage, an antibiotic is a substance or compound that kills or inhibits the growth of bacteria. Antibiotics belong to the group of antimicrobial compounds used to treat infections caused by microorganisms, including fungus and protozoa....
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 ascorbic acid is an essential nutrient for humans, a large number of simian species, a small number of other mammalian species , a few species of birds, and some fish....
.

This lichen, promoted to induce weight loss via increase in metabolic rate, has been the topic of in the USA, due to hepatotoxicity in a product called Lipokinetix. Lipokinetix also contained PPA, caffeine, yohimbine and diiodothyronine. There is no scientific information on the safety or efficacy of oral use of Usnea.

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 chord 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.

Species

Some of the species of Usnea include:

Usnea barbata
Usnea dasypoga
Usnea florida
Usnea hirta
Usnea rubicunda
Usnea rubicunda

Usnea rubicunda , is a type of arboreal lichen native to temperate regions in North America, Central America and South America, as well as Europe, East Asia, and North Africa....
Usnea rubiginea
Usnea subfloridana
The species Usnea longissima was renamed Dolichousnea longissima
Dolichousnea longissima

Dolichousnea longissima, Old Man's Beard or Methuselah's Beard Lichen, is a lichen in the family Parmeliaceae. It was previously known as Usnea longissima....
in 2004.

External links

Pekka Halonen, in East Fennoscandia and Pacific North America (PDF)