| 词条 | Usnea | ||
| 释义 |
| image = Usnea australis.jpg | image_width = 240px | image_caption = Usnea australis | regnum = Fungi | divisio = Ascomycota | classis = Lecanoromycetes | ordo = Lecanorales | familia = Parmeliaceae | genus = Usnea | genus authority = Dill. ex. Adans. (1763) | type_species = Usnea florida | type_species_authority = (L.) F.H.Wigg. (1780) | subdivision_ranks = Species | subdivision = See text. }} Usnea is a genus of mostly pale grayish-green fruticose lichens that grow like leafless mini-shrubs or tassels anchored on bark or twigs.[1]{{rp|203}} The genus is in the family Parmeliaceae. It grows all over the world. Members of the genus are commonly called old man's beard, or beard lichen.[1]{{rp|203}} It resembles Evernia, which is also called tree moss.[2] Like other lichens it is a symbiosis of a fungus and an alga. In Usnea, the fungus belongs to the division Ascomycota, while the alga is a member of the division Chlorophyta. Members of the genus are similar to those of the genus Alectoria.[1]{{rp|148}} A distinguishing test is that the branches of Usnea are somewhat elastic, but the branches of Alectoria snap cleanly off.[1]{{rp|148}} Morphology and reproductionAs a fruticose lichen, Usnea appears as a shrub-like growth on host trees. Unlike other similar-looking fruticose lichens, species in this genus have an elastic chord or axis running through the middle of the thallus that can be revealed by gently pulling a filament apart from either end.[3] It reproduces via vegetative means through fragmentation, asexual means through soredia, or sexual means through ascogonium and spermatogonium.[4] The growth rate of lichens in nature is slow, but the growth rate has been sped up in laboratory conditions where Usnea is being cultured.[5] Usnea looks very similar to the plant Spanish moss, so much so that the latter's Latin name is derived from it (Tillandsia usneoides, the 'Usnea-like Tillandsia'). TaxonomyMany species have been described. A three-volume series by Józef Motyka published in 1936 and 1947 distinguished 451 species.[6] Many of these are now regarded as morphological 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.[7] It is now noted as including more than 600 species and being one of the largest genera within the Parmeliaceae.[8] The species Usnea longissima was renamed Dolichousnea longissima in 2004.[9] EcologyLike other lichens, Usnea often grows on sick or dying trees due to the pre-existing loss of canopy leaves, allowing for greater photosynthesis by the lichen's algae; this leads some gardeners to mistakenly blame the lichen for the tree's leaf loss and illness.[10] Usnea is very sensitive to air pollution, especially sulfur dioxide.[11] 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. It can sometimes be used as a bioindicator, because it tends to only grow in those regions where the air is clean[12], and of high quality. UsesMedical claimsAccording to Paul Bergner, Author of Medical Herbalism. "The usnic acid in Usnea is effective against gram positive bacteria such as Streptococcus and Staphylococcus, making Usnea a valuable addition to herbal formulas for sore throats and skin infections. It is also effective against a bacterium that commonly causes pneumonia"[13] There is reason to believe that Usnea, in high concentrations, could possess some toxicity.[14] The National Toxicology Program is currently evaluating the issue.[15] DyesUsnea species have been used to create orange, yellow, green, blue, and purple dyes for textiles.[16][17]CosmeticsUsnea barbata has been used in cosmetic production for its antimicrobial and antifungal properties as a preservative and deodorant.[18]CombustibleUsnea barbata when dry is extremely flammable and is often used as a firestarter. Species{{Wikispecies}}There are about 87 species of Usnea.[19]
Gallery{{Commons|Usnea|Usnea}}Notes1. ^1 2 3 Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, {{ISBN|978-0-300-19500-2}} {{Taxonbar|from=Q121799}}2. ^{{cite book|title=Pharmacist's Letter/Prescriber's Letter Natural Medicines Comprehensive Database|year=2000|publisher=Therapeutic Research Facility|location=Stockton, CA|isbn=0967613647|author=Jellin, JM|edition=3rd |author2=Gregory P. |author3=Batz F. |author4=Hitchens, K. |display-authors=etal |pages=1048–1049|chapter=USNEA}} 3. ^{{cite book|last=Brodo|first=Irwin M.|title=Lichens of North America|year=2001|publisher=Yale University Press|isbn=9780300082494|url=https://books.google.com/books?id=YyS-hS15Ty4C&pg=PA709|author2=Sylvia Duran Sharnoff |author3=Stephen Sharnoff |author4=Canadian Museum of Nature |accessdate=6 December 2012|pages=709–710}} 4. ^{{cite book|last=Marand|first=Sajan|title=A Text Book of Botany: Vol. III|publisher=Calicut University|url=http://content.yudu.com/Library/A1s6eg/PLANTWORLDSCANVOLUME/resources/44.htm|accessdate=6 December 2012|pages=87–90|date=5 January 2010|chapter=Usnea}} 5. ^{{cite journal|title=Optimization of Culture Conditions for Lichen Usnea ghattensis G. Awasthi to Increase Biomass and Antioxidant Metabolite Production|journal=Food Technol. Biotechnol.|volume=47|issue=1|year=2009|url=http://hrcak.srce.hr/file/52602|issn=1330-9862 |pages=7–12}} 6. ^{{cite book|last=Motyka|first=Józef|title=Lichenum generis usnea|url=http://openlibrary.org/works/OL11077113W/Lichenum_generis_Usnea_studium_monographicum}} 7. ^{{cite book|last=Halonen|first=Pekka|title=Studies on the lichen genus Usnea in East Fennoscandia and Pasific North America|year=2000|publisher=Oulu University Library|location=Oulu, Finland|isbn=9514255232|issn=0355-3191|url=http://herkules.oulu.fi/isbn9514255240/isbn9514255240.pdf|accessdate=6 December 2012|page=13}} 8. ^{{cite journal|last=Wirtz|first=Nora|author2=Printzen, Christian |author3=Sancho, Leopoldo G. |author4= Lumbsch, Thorsten H. |title=The phylogeny and classification of Neuropogon and Usnea (Parmeliaceae, Ascomycota) revisited|journal=Taxon|date=1 May 2006|volume=55|issue=2|pages=367–376|url=http://www.ingentaconnect.com/content/iapt/tax/2006/00000055/00000002/art00010|accessdate=5 December 2012|issn=0040-0262}} 9. ^{{cite journal|last=Articus|first=Kristina|title=Neuropogon and the phylogeny of Usnea s.l. (Parmeliaceae, Lichenized Ascomycetes)|journal=Taxon|date=November 2004|volume=53|issue=4|pages=925–934|url=http://herbarium-ren-abb-lichen.univ-rennes1.fr/Neuropogon925.pdf|accessdate=5 December 2012|issn=0040-0262}} 10. ^{{cite book|last=Brodo|first=Irwin M.|title=Lichens of North America|year=2001|publisher=Yale University Press|isbn=9780300082494|url=https://books.google.com/books?id=YyS-hS15Ty4C&pg=PA57|author2=Sylvia Duran Sharnoff |author3=Stephen Sharnoff |author4=Canadian Museum of Nature |accessdate=6 December 2012|pages=57–58}} 11. ^{{cite book|title=Ecology of Industrial Pollution|year=2010|publisher=Cambridge University Press|isbn=9780521514460|url=https://books.google.com/books?id=t4yauYHrCRoC&pg=PA49|editor=Batty, Lesley C. |editor2=Hallberg, Kevin B.|accessdate=4 December 2012|page=49|series=Ecological Reviews|quote=Usnea spp., at one time widespread and luxuriant, almost entirely disappeared from a major area of England and Wales covering at least 68 000 km² and at least 6 000 km² of lowland Scotland, mainly as a result of the increase in atmospheric pollution.}} 12. ^{{Cite web|url=http://www.lichens.net/2018/01/usnea-lichens.html|title=Usnea Lichens|website=www.lichens.net|access-date=2018-04-06}} 13. ^http://medherb.com/Therapeutics/Immune_-_Lymphatics_and_antibiotics.htm 14. ^{{cite book|title=Pharmacist's Letter/Prescriber's Letter Natural Medicines Comprehensive Database|year=2000|publisher=Therapeutic Research Facility|location=Stockton, CA|isbn=0967613647|author=Jellin, JM|edition=3rd |author2=Gregory P. |author3=Batz F. |author4=Hitchens, K. |display-authors=etal |pages=1048–1049|chapter=USNEA|quote=Adverse reactions are uncommon in appropriate amounts. Poisoning can be possible, although signs of poisoning have not yet been described.}} 15. ^{{cite web|title=Testing Status: Usnea lichen 09063|url=http://ntp.niehs.nih.gov/go/TS-09063|work=Testing Status of Agents at NTP|publisher=National Toxicology Program|accessdate=5 December 2012}} 16. ^{{cite book|last=Bolton|first=Eileen M.|title=Lichens for Vegetable Dying|year=1991|publisher=Julia Bolton Holloway|isbn=9781566590013|url=https://books.google.com/books?id=n5icsHmGVVIC&pg=PA27|edition=2|page=27}} 17. ^{{cite book|title=Lichen Dyes: The New Source Book|pages=33–36|last=Casselman|first=Karen Diadick|url=https://books.google.com/books?id=wBfBpSXo_8AC|publisher=Courier Dover Publications|year=2001|isbn=9780486412313}} 18. ^{{cite book|last=Ash|first=Michael|title=Handbook of Preservatives|year=2004|publisher=Synapse Info Resources|isbn=9781890595661|url=https://books.google.com/books?id=XZ2QB7bu5LwC&pg=PA437|author2=Irene Ash |accessdate=6 December 2012|page=437|chapter=Lichen (Usnea barbata) extract}} 19. ^{{cite web|title=PLANTS profile for Usnea (beard lichen)|url=http://plants.usda.gov/java/profile?symbol=USNEA2|work=USDA PLANTS|publisher=United States Department of Agriculture, Natural Resources Conservation Service|accessdate=4 December 2012}} 20. ^{{cite web|title=Lichens of Wales|url=http://wales-lichens.org.uk/species-accounts/usnea-articulata|accessdate=3 December 2014}} 21. ^Gadea, A., Le Pogam, P., Biver, G., Boustie, J., Le Lamer, A. C., Le Dévéhat, F., & Charrier, M. (2017). "Which Specialized Metabolites Does the Native Subantarctic Gastropod Notodiscus hookeri Extract from the Consumption of the Lichens Usnea taylorii and Pseudocyphellaria crocata?". Molecules 22(3): 425. {{doi|10.3390/molecules22030425}} 4 : Fungi described in 1763|Usnea|Lichens|Lecanoromycetes genera |
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