usnea Meaning, Definition & Usage

  1. noun widely distributed lichens usually having a greyish or yellow pendulous freely branched thallus
    genus Usnea.

WordNet

Us"ne*a noun
Etymology
NL., from Ar. usnah moss.
Definitions
  1. (Bot.) A genus of lichens, most of the species of which have long, gray, pendulous, and finely branched fronds. Usnea barbata is the common bearded lichen which grows on branches of trees in northern forests.

Webster 1913