Didymodonmanhanensis (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, Didymodonmanhanensis 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.