Further taxonomic rearrangements in the Brachytheciaceae (Bryophyta): Frahmiella, a new genus segregated from Rhynchostegiella

peer reviewedThe taxonomic position of Rhynchostegiella acicula, a local endemic of Shaanxi Province of China, is investigated by means of cladistic analyses employing nrITS sequences. The analyses show that R. acicula does not belong to Rhynchostegiella s.str. (Helicodontioideae) but is resolved within the Homalothecioideae as sister to Eurhynchiastrum, from which it differs by a soft and slender habit; narrow lanceolate and acuminate leaves; a percurrent costa; and an autoicous condition. It differs from Brachytheciastrum and Brachythecium in a longly rostrate operculum, and from Homalothecium in a small plants that lack thick-walled basal laminal cells characteristic of this genus, as well as in an autoicous inflorescence. As a consequence, R. acicula is transferred into its own, monospecific genus Frahmiella Ignatov, Vanderpoorten & Wang You-fang, gen. nov