Usnea

Usnea (Usnea barbata) Usnea barbata is a fruticose lichen formed by a symbiosis between a fungus and a green alga. It typically appears as a hanging, filamentous mass with a branched, hair-like structure, often described as “beard-like.” The thallus is usually grey-green to yellowish-green, with thin, elastic branches that can reach several...