Hoefkenia hunsrueckensis, a New Genus and Species from Europe, and the Identity of Virescentia vogesiaca (F.W.Schultz ex Skuja) Necchi, D.C.Agostinho & M.L.Vis (Batrachospermales, Rhodophyta)

Freshwater red algae from Hunsrück-Hochwald National Park previously identified as Virescentia vogesiaca are described as Hoefkenia hunsrueckensis gen. et sp. nov. They cluster in the phylogenetic tree together with Kumanoa and form its sister clade. Virescentia is rendered monophyletic by exclusion of these samples. The taxonomic history of Virescentia vogesiaca is described. The species was named by Skuja referring to the description of Batrachospermum vagum var. flagelliforme Sirodot and the specimens all come from Western France and Spain. The name Batrachospermum vogesiacum was erroneously applied referring to a specimen from the North Vosges close to Germany collected and annotated by F.W. Schultz and representing the new Hoefkenia hunsrueckensis. However, this specimen was never cited in the protologue of Virescentia vogesiaca. We provide evidence that the real Virescentia vogesiaca is endemic to Western France and Spain, and that Hoefkenia hunsrueckensis is restricted to Eastern Belgium, Eastern France and SW Germany, differing in morphological and molecular characters.