Usnea longissima

Usnea longissima

　　Usnea longissima, also known as tree hanging moss or pine epiphyte, is a lichen of the Usneaceae family. The main body is filamentous, reaching lengths of 20–100 cm. It attaches to tree bark at the base and hangs down, densely covered with small, short lateral branches that are 1–2 cm long. The entire organism is gray-green. When you walk through the shady and moist forests of Changbai Mountain at altitudes of 500–900 meters, you will often see these gray-green thread-like forms draped over coniferous trees, resembling beautiful tree hangings or the flowing veils left behind by immortals in the forest, creating a unique landscape of the Changbai Mountain woodland. The dried whole plant of Usnea longissima can be used as herbal medicine. Additionally, another species of lichen from the Usneaceae family found in the Changbai Mountain area is called Usnea diffracta, which also grows in the humid forests at elevations of 500–900 meters, parasitizing on old trees or cliff faces in valleys. Usnea diffracta is also known as “old man’s beard,” with a filamentous, soft, pale yellowish-green main body about 30–40 cm long. It has few branches at the base but denser branching toward the tip. From a distance, it truly resembles the white beard of an elderly man. The chemical composition and medicinal value of Usnea diffracta are similar to those of Usnea longissima.