'Usnea barbata' definitions:

Definition of 'Usnea barbata'

From: WordNet
noun
Greenish grey pendulous lichen growing on trees [syn: beard lichen, beard moss, Usnea barbata]

Definition of 'Usnea barbata'

From: GCIDE
  • Treebeard \Tree"beard`\, n. (Bot.) A pendulous branching lichen (Usnea barbata); -- so called from its resemblance to hair. [1913 Webster]