old-man’s-beard

Old-man's-beard refers to a genus of lichens, Usnea, characterized by their long, thread-like, bushy, and branched appearance, resembling tangled threads. These lichens are typically yellow or greenish and grow on trees, often hanging down like tassels.12

Beard lichens are a symbiotic relationship between fungi and algae. They are found worldwide, from the Arctic to the tropics, and are sensitive to air pollution, making them indicators of clean air. Historically, various species have been used for medicinal purposes, including remedies for coughs, epilepsy, and as astringents or diuretics. Some species can also produce dyes. It's important to note that beard lichens are not true mosses, though they are sometimes confused with Spanish moss.1