• Proposed
  • Under Assessment
  • 3Preliminary Assessed
  • 4Assessed
  • 5Published

Usnea mutabilis Stirt.

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Scientific name
Usnea mutabilis
Common names
Bloody Beard Lichen
Pretty in Pink
IUCN Specialist Group
Assessment status
Under Assessment
Proposed by
Amanda Chandler
Giovanna Bishop
Giovanna Bishop
Jessica Allen, James Lendemer
Comments etc.
Amanda Chandler

Assessment Notes


This species is globally distributed and is abundant throughout its range.

Taxonomic notes

Considerable taxonomic uncertainty exists regarding the genus Usnea (Clerc 1998). Future taxonomic changes are likely which could further circumscribe the species’ range. However, it is extremely abundant and has a very broad distribution, some areas of the world considering it to be rare. Taxonomic changes are unlikely to result in changes to status of the species.
Synonomy: Usnea marocana Motyka, Lichenum Generis Usnea Studium Monographicum. Pars Systematica 2: 354 (1937) [MB#412152]

Why suggested for a Global Red List Assessment?

Geographic range

Bloody Beard Lichen (Usnea mutabilis) is a globally distributed species. It is broadly distributed in eastern North America ranging from Nova Scotia to Florida and west to Minnesota and Texas (Brodo et al. 2001). It also occurs in southern California and Baja California Norte (Nash et al. 2002). The species also occurs in southern Europe within France, Spain, Portugal, and Italy (Fos & Clerc 2000), northern Africa in Morocco (Azami et al. 2004), the Canary Islands, and Japan (CNALH 2020). Moreover it has been reported from southern portions of Far East Russia (Ohmura et al. 2017). One report from Jamaica has yet to be confirmed.

Population and Trends

Though the species is rare in some parts of its range, it is abundant in the southeastern United States (Clerc and Herrera-Campos 1997) and its population is not likely to meet any thresholds for listing under a threatened status.

Population Trend: Stable

Habitat and Ecology

Usnea mutabilis is a fruticose lichen species that prefers bark substrates and humid habitats. It rarely occurs on rock, and additionally can be found in the chaparral and other coastal shrub communities, on Quercus spp., and other diverse shrubs ( Brodo et al. 2001, Nash et al. 2007).

Temperate Forest


Like many other lichen species, the primary threat to Usnea species in North America is air pollution including heavy metal contamination, and acid rain derived from sulfur and nitrogen dioxides (Cameron et al. 2007). Usnea species are considered intermediate indicators of air quality and are somewhat tolerant of poor air quality. Impacts from industrial and urban pollution sources are likely to be most severe within a few tens of kilometers of urban and industrial sources. The specific impact of collection on the species is not well understood and additional study of harvest pressure is needed (American Herbal Products Association 2012). Recent observations of the species in urban areas have been noted as evidence of long term air quality improvements and suggest range expansion may be occurring in previously extirpated urban areas (Dorey et al. 2019).

Intentional use (species being assessed is the target)Type Unknown/UnrecordedHabitat shifting & alteration

Conservation Actions

The species incidentally occurs in several protected areas (IUCN and UNEP-WCMC 2020).

The Minnesota Department of Natural Resources listed U. mutabilis as threatened in 2013 under their states guidelines. Additionally other U.S. states have it on lists of concerns.

Research needed

Use and Trade

Members of the genus Usnea have long been used for medicinal, and cosmetic purposes and as dyes. Investigation into the pharmacological applications of the genus are ongoing and traditional medicines indicated the genus for use treating upper respiratory ailments, infection, and indigestion (Prateeksha et al. 2016). Difficulty distinguishing between taxa at the species level, and inadequate reporting requirements from harvesters prevents accurate assessments of the level of harvest for the species. Estimates of harvest levels at the genus level, derived from voluntary surveys of herb dealers in the United States demonstrates harvest levels exceed 1,000 pounds of material during most years between 1999 and 2010 (American Herbal Products Association 2012). The overwhelming majority of this material is derived from wild collection.

Medicine - human & veterinaryHandicrafts, jewellery, etc.


American Herbal Products Association 2012. Tonnage Surveys of Select North American Wild-Harvested Plants, 2006–2010. American Herbal Products Association, Silver Spring, MD.
Azami, N., Seriñá, E., & Arroyo, R. (2004). The Usnea Species of Morocco in R.-G. Werner’s Herbarium. The Bryologist, 107(2), 180-188. Retrieved May 19, 2020, from http://www.jstor.org/stable/3244842
Brodo, I. M., Sharnoff, S. D., Sharnoff, S., & Canadian Museum of Nature. (2001). Lichens of North America. New Haven: Yale University Press.
Cameron, R. P., Neily, T. and Richardson, D. H. S. 2007. Macrolichen Indicators of Air Quality for Nova Scotia. Northeastern Naturalist, 14, 1, 1–14.
Clerc, P. 1994. Comment Usnea mutabilis Stirton, une espèce nord-américaine, se cache en Europe sous le nom d’Usnea marocana Motyka - Une contribution à la systématique du genre Usnea (Ascomycètes lichénisés). Bulletin de la Société linnéenne de Provence. 45. 309-316.
Clerc, P. 1998. Species Concepts in the Genus Usnea (Lichenized Ascomycetes). The Lichenologist, 30, 4–5, 321–40.
Clerc, P. and Herrera-Campos, M. A. 1997. Saxicolous Species of Usnea Subgenus Usnea (Lichenized Ascomycetes) in North America. The Bryologist, 100, 3, 281–301.
DNR State of Minnesota Rare Species Guide. Available online at https://www.dnr.state.mn.us/rsg/profile.html?action=elementDetail&selectedElement=NLT0030760
Dorey, J. E., Hoffman, J. R., Martino, J. L., Lendemer, J. C. and Allen, J. L. 2019. First Record of Usnea (Parmeliaceae) Growing in New York City in Nearly 200 Years. The Journal of the Torrey Botanical Society, 146, 1, 69.
Fos, S. & Clerc, P. (2000): The lichen genus Usnea on Quercus suber in Iberian cork-
oak forests. – Lichenologist 32: 67–88.
GBIF 2020. Global Biodiversity Information Facility.
GBIF 2019. Global Biodiversity Information Facility.
IUCN and UNEP-WCMC 2020. The World Database on Protected Areas (WDPA). UNEP-WCMC/ IUCN World Commission on Protected Areas (WCPA), Cambridge, UK.
Nash, T. H., Gries, C. and Bungartz, F. 2007. Lichen flora of the greater Sonoran Desert region. Vol. 3, Vol. 3,. Lichens Unlimited, Arizona State University, Tempe.
Nash, T. H., Ryan, B. D., Gries, C. and Bungartz, F. (eds) 2002. Lichen Flora of the Greater Sonoran Desert Region Vol. 1. Arizona State University Lichen Herbarium, Tempe, AZ.
Ohmura, Y., Skirina, I. and Skirin, F. 2017. Contribution to the Knowledge of the Genus Usnea (Parmeliaceae, Ascomycota) in Southern Far East Russia. Bulletin of the National Museum of Nature and Science Series B, Botany, 43, 1–10.
Prateeksha, Paliya, B. S., Bajpai, R., Jadaun, V., Kumar, J., Kumar, S., Upreti, D. K., Singh, B. R., Nayaka, S., Joshi, Y. and Singh, B. N. 2016. The genus Usnea: a potent phytomedicine with multifarious ethnobotany, phytochemistry and pharmacology. RSC Advances, 6, 26, 21672–96.
Randlane, T., Tõrra, T., Saag, A., Saag, L., 2009.  Key to European Usnea species.  Bibliotheca Lichenologica, 100, 419- 462
SEINet 2019. SEINet Portal Network. Available online at http//:swbiodiversity.org/seinet/index.php [Accessed 1 April 2019].

Country occurrence

Regional Population and Trends

Country Trend Redlisted