Twenty-some-odd years ago I received from a hiker friend a little wreath she’d crafted from items she’d gathered from the woods. Twigs, fir cones, striped shelf fungus, and lots of lichen–especially Old Man’s Beard.
Visitors often remark on our “Spanish moss” draped in little tufts from the limbs and trunks of higher elevation trees. However, this is a misnomer. True “Spanish moss” is a flowering plant in the bromeliad family which grows only in the deep South. But Spanish moss and bearded lichens are both epiphytes which means they use other plants as supports and to the casual eye bear some resemblance, especially in vacation photographs.
Lichens, however, are not a single organism at all but a more complex partnership of a fungus and either algae or bacteria. The fungal cells provide the structure and often give the resulting “plant” it’s general shape. But the alga is the metabolic engine that provides food through it’s photosynthesis and usually the color you see in a given lichen partnership. The charming statement I remember reading years ago was that ‘lichens were what happened when fungi discovered agriculture’.
Classifying lichens precisely is just as complex as the organism itself. In addition to its general appearance, a lichenologist must examine the fruiting parts of the “plant” (the soridia), the spores produced, perform chemical tests and determine whether the fungus has partnered with an alga or cyanobacterium. Most of this happens in a laboratory, not the field. I am content these days to speak in more general terms which describe more general characteristics but for those interested, see this fascinating link : http://www.anbg.gov.au/lichen/classification.html
Our local “Old Man’s Beard” is rather a collection of species (nearly identical to the naked eye) grouped under the genus Usnea which enjoys a world-wide distribution. It grows in light green to yellowish tufts and strands, preferring to grow on the bark or twigs of conifers whether living or dead. It is especially prevalent where the drying effects of sun are not so harsh so the old saw about “moss growing on the north side of trees” actually does apply here.
Traditional uses for this particular lichen are numerous. It produces usnic acid and other compounds which have antibiotic and anti-fungal properties, so has been used like a natural gauze for dressing wounds or made into a tea for treating other ailments. Modern researchers are investigating its use in treating particularly difficult fungal infections and even cancer. If boiled to remove the bitter compounds, Usnea may be eaten like a pot green although reviews of its palatability are less than four-star. And is has also been used as natural, traditional dye for yarn as it produces a range of soft brown colors.
I prefer to see my Old Man’s Beard decorating the trees in the woods but I still think on that beautiful little woodland wreath that helped spark my curiosity about it so many years ago.
[Author's Note: In other places in the U.S., the common name "Old Man's Beard" may refer to other lichens, a wild vine (Clematis), or even a beautiful little Southern shrub (Chionanthus). Thus the peril of common names.]