Hilpertia tibetica J.Kou, X.-M.Shao & C.Feng (Pottiaceae), a new species from Tibet, China

A new species, Hilpertia tibetica J.Kou, X.-M.Shao & C.Feng from Chara Mountain, Dagzê County, Tibet, China, is described and illustrated. It is similar to Hilpertia velenovskyi (Schiffn.) R.H.Zander, but its erect to erecto-patent leaves when moist, the quadrate to short-rectangular, strongly bulging ventral epidermal cells forming a bulliform ridge on the adaxial surface of the costa, not or slightly thickened superficial abaxial laminal cell walls, the annulus consisting of 2–3 rows of rectangular to elongate cells, much smaller spores and yellow-orange laminal KOH colour reaction, readily separate it from the latter. This new species is compared with closely related species and its ecology is discussed.