horsehair lichen(n = noun.plant) horsetail lichen - any of several lichens of the genus Alectoria having a thallus consisting of filaments resembling hair;
is a kind of lichen
is a member of alectoria, genus alectoria

beard lichen, horsehair, horsehair fabric, horsehair wig, horsetail lichen, iceland lichen, lichen, lichen planus, lichen ruber planus, manna lichen, reindeer lichen