Taxonomic reevaluation of Didymodon nigrescens (Pottiaceae) in Japan

Abstract

  Based on morphological investigation and molecular phylogenetic analysis, we find that the previous concept of Didymodon nigrescens (Mitt.) K.Saito sensu Saito in Japan includes D. nigrescens and D. subandreaeoides (Kindb.) R.H.Zander, the latter newly reported from Japan. Morphological and phylogenetic data from Japanese material clearly segregate these species from each other. In addition, Japanese D. nigrescens shows two groups, with morphological traits supporting the phylogeny, requiring further morpho-molecular evaluation based on broad sampling. Descriptions with analytical illustrations are provided based on Japanese material. Andreaea takakii Sakurai is proposed as a synonym of D. subandreaeoides.