Cephaloziella konstantinovae (Cephaloziellaceae, Marchantiophyta), A New Leafy Liverwort Species from Russia and Mongolia Identified by Integrative Taxonomy

. In the course of a taxonomic study of the genus Cephaloziella (Spruce) Schiffn. (Cephaloziellaceae, Marchantiophyta) in Asia, the new species Cephaloziella konstantinovae Mamontov & Vilnet, sp. nov ., from the eastern regions of Russia and from the Republic of Mongolia was discovered. The new species is formally described and illustrated here. Morphologically it is similar to C. divaricata var . asperifolia (Taylor) Damsh. , but differs in its leaf shape and thin-walled, inflated stem and leaf cells. The new species can be distinguished from other Cephaloziella taxa by the following characters: ( i ) female bracts entirely free from each other and from bracteole, ( ii ) perianth campanulate, ( iii ) cells of perianth mouth subquadrate, ( iv ) capsule spherical, ( v ) seta with 8–10 + 4–6-seriate morphology, and ( vi ) elaters with 1–2 spiral bands. Molecular phylogenetic analyses of nrITS1-5.8S-ITS2 and chloroplast trn L-F sequences from 63 samples (34 species, 23 genera) confirm the taxonomical status of the new species. Five specimens of C. konstantinovae form a clade placed sister to a clade of C. elachista (J. B. Jack) Schiffn. and C. rubella (Nees) Warnst.