Taxonomic revision of the Peyssonneliales (Rhodophyta): Circumscribing the authentic Peyssonnelia clade and proposing four new genera and seven new species.

The Peyssonneliaceae represents the only family in the order Peyssonneliales, a clade of red encrusting algae distributed worldwide, including 136 species in eleven currently accepted genera. Delineation of genera in the Peyssonneliaceae has mostly been based on vegetative characteristics. Previous molecular phylogenies have shown that some traditionally circumscribed genera are not monophyletic and relationships among them are uncertain.