Old man’s beard lichen (Usnea sp.)
If you look up into the branches of a stand of oak trees on Cape Cod, especially in the winter when the leaves are absent, you’ll likely notice that the tree is still essentially green. The branches are covered with something light green and fluffy. That “fluffy stuff” is a type of lichen called Usnea, or old man’s beard. Usnea is a genus of fruticose lichen that grows anchored to twigs and branches of trees and shrubs using a holdfast….