Usnea is the generic and scientific name for several species of lichen in the family Parmeliaceae that are found throughout most of the world. It is commonly referred to as Old Man’s Beard and Beard Lichen, favoring to grow on trees rather than rocks as some of its lichen counterparts. Often a green color due to its content of Usnic Acid, and having stemmed the name of the color ‘usnic green’, this lichen has been used medicinally for hundreds of years and it is this content of Usnic Acid that gives it these medicinal properties.
Usnic Acid (C18H16O7) is a potent antibiotic and antifungal chemical found within most Usnea species. It was traditionally used as a bandage due to these properties. In an emergency situation, Beard lichen could be used solely to bandage and keep clean a wound. Old Man’s Beard could perhaps be used in combination with balsam fir sap (which is a topical pain killer and adhesive) to secure the lichen to the wound, keep it clean, safe from infection, and reduce pain. Usnic Acid has been found to be extremely effective against microbes like Staphylococcus, streptococcus, pathogenic fungi, as well as exhibiting antiviral, antiprotozoal, anti-mitotic, anti-inflammatory, and its own analgesic properties. These characteristics allow Old Man’s Beard to be far superior in backwoods bandaging than that of Sphagnum moss which is antimicrobial only due to its acidic pH.
Another great property of this easily identified lichen is that it is high in vitamin C, making it of good use in the prevention and treatment of scurvy. This lichen is edible and often was used as a soup thickener by early settlers to North America.
Usnea is a lichen, which is a fascinating relationship between a photosynthetic algae and a fungus with entirely different morphology, physiology, and biochemistry than that of an isolated algae or fungus and occur in some of the most extreme environments on earth. While they may be capable of living in extreme conditions, they are very sensitive to air pollution and their presence may be a good indicator of air quality in the area. This quality should be taken into consideration when attempting to locate Old Man’s Beard as it is unlikely to be found near industrial cities.