Usnea

Usnea is a common name for several species of lichen that generally grow hanging from tree branches, resembling grey or greenish hair. It is sometimes referred to as Old Man's Beard, or Beard Lichen. Usnea looks very similar to spanish moss, so much so that the moss's latin name is derived from it (usneoides ).

Usnea has been used medicinally for at least 1000 years. Usnic acid, a potent antibiotic and antifungal agent is found in most species. This, combined with the hairlike structure of the lichen, means that Usnea lent itself well to treating surface wounds when sterile gauze and modern antibiotics were unavailable.

Some of the species commonly referred to as Usnea include:

Usnea hirta, U. barbata, U. florida, U. longissima and U. dasypoga