Common Name: old man's beard, red beard lichen
Scientific Name: Usnea rubicunda Stirt.
Identification Note: For information on structure and terms describing Usnea species, see Brodo et al. (2001), p. 709-710. Measurements of layers in cross-sections of thalli are expressed as percentages of average cross-section measurement: axis/diameter x 100, medulla on radius /diameter x 100; and cortex on radius/diameter x 100 (see Brodo et al. 2001 for illustration).
Technical Description: Thallus bushy (fruticose), erect or shrubby-pendant, 3-10(20) cm long, attached to the substrate by a single holdfast at the base of the main stem, attachment remaining the same color as the rest of the stem, not turning black; with many branches to 1.5 mm diameter, round in cross-section, and short side branches about 1 cm long (fibrils) growing at right angles from the main branches, the distal portions of the thallus green but at least the lower half rose to brick red, the red color produced by coalescing red spots on the cortex; the basal part of the main stem circled with cracks revealing the white medulla; main stem and branches usually with distinct small bumps arising from the cortex (papillae). Soralia beginning as minute, white, circular raised areas contrasting with the dark cortex, later enlarging and merging to cover large parts of the branches, soralia with thin isidia-like structures (isidiomorphs) as well as soredia, isidiomorphs often appearing on soralia before soredia. Cortex 8-13% of the thallus diameter, shiny and almost translucent on the surface; medulla thin (18%), central cord (axis) white and moderately thick to thick (48%). Apothecia unknown. Photosynthetic partner (photobiont, phycobiont) is a green alga (Trebouxia).
Chemistry: K+ yellow becoming orange, C-, KC-, P+ deep orange
Distinctive Characters: Coastal Usnea with mostly reddish thallus and whitish soralia bearing isidomorphs. Similar species: Usnea flavocardia (synonym: Usnea wirthii) has a shiny cortex with small red spots that remain separate and are less extensive than those on U. rubicunda, but its central cord is pale yellow to orange-yellow. It grows inland as well as along the coast. Other species of Usnea may turn reddish when stressed or dead, including herbarium specimens. Other descriptions and illustrations: Aptroot (no date); Brodo et al. (2001): 723; Goward (1999): 261; Hinds and Hinds (2007): 503; McCune and Geiser (2009); Miller (2007); Nash (2007):328; Purvis et al. (1992):628; Villella (2006).
Life History: Details for Usnea rubicunda are not documented. Propagation is presumably by isidiomorphs, soredia and fragmentation. A different species of short-fruticose Usnea in the Willamette Valley grows at the rate of approximately 2mm per year (Stone 1986).
Range, Distribution, and Abundance: Widespread in suboceanic, oceanic temperate, and tropical areas. On the Pacific coast of North America, from British Columbia south through coastal Mexico. In British Columbia it is known from a single locality on Vancouver Island (Halonen et al. 1998).
National Forests: documented on Siuslaw NF (Oregon Dunes National Recreation Area; Sutton Creek Recreation Area); suspected on Olympic NF because of proximity to known site in Olympic NP, and by the Mt. Hood NF. BLM Districts: documented on Salem and Coos Bay Districts; suspected on Eugene District because of similar habitat and proximity to known sites.
Habitat Associations: On the bark of trees and shrubs along the coast. Forest types are Picea sitchensis, Pinus contorta ssp. contorta, and Pseudotsuga menziesii associations.
Threats: Epiphytic Usnea species are sensitive to air pollution (USDA Forest Service, no date). Usnea rubicunda is extinct in Belgium, Luxembourg and northern France (Diederich et al. 2009). Other threats are fire in coastal habitats, logging and residential or urban development.
Conservation Considerations: Air quality monitoring is important for the conservation of this and other Usnea species, many of which are sensitive (McCune & Geiser 2009, USDA Forest Service, no date). Known sites should be monitored, and action taken to maintain good air quality at these sites. Heavy off-road vehicle traffic near populations could emit enough sulfur dioxide to damage this lichen.
Conservation rankings: Global: G4G5; National: NNR; Oregon Natural Heritage Information Center: List 3 (S2).
Preparer: Daphne Stone, with edits from John A. Christy
Date Completed: March 2009
Final edits: Rob Huff, BLM/FS
Aptroot, A. No date. Pictures of tropical lichens. Usnea rubicunda Stirt. http://www.tropicallichens.net/default.aspx?q=large&id=2764. Accessed 9 January 2009.
Brodo, I.M, Sharnoff, S.D., & S. Sharnoff. 2001. Lichens of North America. Yale University Press, New Haven and London. 795 pp.
Diederich, P., D. Ertz, N. Stapper, E. Sérusiaux, D. Van den Broeck, P. van den Boom & C. Ries, 2009. The lichens and lichenicolous fungi of Belgium, Luxembourg and northern France. http://www.lichenology.info. Accessed 5 March 2009.
Goward, T. 1999. The Lichens of British Columbia. Part 2. Fruticose Species. British Columbia Ministry of Forests. Crown Publications Inc., Victoria, B.C. 319 pp.
Halonen, P., P. Clerc, T. Goward, I.M. Brodo, & K. Wulff. 1998. Synopsis of the genus Usnea (Lichenized Ascomycetes) in British Columbia, Canada. The Bryologist 101(1): 36-60.
Hinds, J.W. and P.L. Hinds. 2007. The Macrolichens of New England. Memoirs of the New York Botanical Garden 96: 1-584.
McCune, B. & L. Geiser. 2009. Macrolichens of the Pacific Northwest, 2nd Edition. Oregon State University Press. Corvallis, Oregon. 464 pp.
Miller, J. 2007. Photo of Usnea rubicunda. Crustose.net.
http://www.non-parametric.com/photos/main.php/v/Jesse+Miller/usnea+rubicunda.jpg.html. Accessed 9 January 2009.
Nash, T. H., C. Gries and F. Bungartz. 2007. Lichen Flora of the Greater Sonoran Desert Region, Volume 3. Lichens Unlimited, Arizona State University, Tempe. 567 pp.
Oregon Natural Heritage Information Center. 2007. Rare, threatened and endangered species of Oregon. Oregon Natural Heritage Information Center, Oregon State University. Portland. 100 pp. http://oregonstate.edu/ornhic/2007_t&e_book.pdf. Accessed 7 January 2009.
Purvis, O.W., B.J. Coppins, D.L. Hawksworth, P.W. James & D.M. Moore (eds.). 1992. The Lichen Flora of Great Britain and Ireland. Natural History Museum Publications, London. 710 p.
Stone, D. 1986. Succession of epiphytes on Quercus garryana branches in the Willamette Valley of western Oregon. Ph.D. dissertation, University of Oregon, Eugene. 118 pp.
United States Forest Service National Lichens & Air Quality Database and Clearinghouse. No date. R6 Lichens Homepage. http://www.fs.fed.us/r6/aq/lichen/. Accessed 24 March 2009.
Villella, J. 2006. Photo of Usnea rubicunda. Crustose.net. http://photos.crustose.net/main.php/v/jvillella/Usnea+rubicunda+NZ.JPG.html. Accessed 9 January 2009.