Didymodon manhanensis (Pottiaceae, Bryophyta), a new species from Inner Mongolia steppe, China and its phylogenetic position, based on molecular data.

Inner Mongolia steppe is one of the suitable habitats for Didymodon species and a new species, Didymodon manhanensis C. Feng & J. Kou from Manhan Mountain in semi-arid region in Inner Mongolia, China is described and illustrated. It is characterised by leaves incurved and slightly twisted when dry, spreading when moist, narrowly lanceolate from an ovate base; subulate and fragile leaf apices; distally bistratose leaf margins that are recurved in proximal 2/3-3/4; excurrent costa with guide cells in 2-3 layers and without ventral stereids; smooth laminal cells and red KOH laminal colour reaction. Our morphological analyses and molecular results, based on DNA sequences of ITS, rps4 and trnM-trnV, confirm that D. manhanensis belongs to a group that includes D. obtusus J. Kou, X.-M. Shao & C. Feng and D. daqingii J. Kou, R.H. Zander & C. Feng. This new species is compared with similar species and its phylogenetic position and ecology are discussed. [ABSTRACT FROM AUTHOR]