Noun | 1. | Alectoria - lichens having dark brown erect or pendulous much-branched cylindrical thallus fungus genus - includes lichen genera family Usneaceae, Usneaceae - fruticose lichens having prostrate or erect or pendulous thalli: genera Usnea, Evernia, Ramalina, Alectoria horsehair lichen, horsetail lichen - any of several lichens of the genus Alectoria having a thallus consisting of filaments resembling hair |