Racodium rupestre

Racodium is a monotypic fungal genus in the family Racodiaceae, which is itself the sole family of the order Racodiales. The genus contains a single species, Racodium rupestre, a distinctive filamentous lichen that forms dark, thread-like growths on rocks by closely enveloping filaments of the green algal genus Trentepohlia. The name has a complex taxonomic history, having been used for both this rock-dwelling lichen and an unrelated cellar fungus, until nomenclature experts formally conserved Racodium for...