Any of several lichens, of the genus Usnea, that generally grow hanging from tree branches, resembling grey or greenish hair.
Usnea, a type of lichen.
Used other than figuratively or idiomatically: see old, man, -'s, beard.
Tillandsia usneoides, a bromeliad; Spanish moss.
Clematis aristata, an Australian climbing plant.
Clematis vitalba, a climbing plant.
Chionanthus virginicus, a tree.