Revision of numerous collections from Mongolia revealed 15 species of Grimmia. Most of them are high-mountain species, known mainly from the western part of the country, especially in Mongolian Altai. The most widespread is Grimmia longirostris, that avoids however xeric regions of Gobi (although occurring in Gobi Altai in very high mountains). Very similar is the distribution of G. elatior, that is however widespread, but somewhat less common. The most common in the xeric regions of Gobi (and occurring in other parts of Mongolia as well), are G. tergestina and G. anodon. The latter species is relatively more common in western parts of country, whereas distribution of G. tergestina is especially associated with flat xeric territories. East Asian (and Eastern North American) G. pilifera is common, but in a rather restricted area of Mongolian Dauria and Khentei and westward to Khubsugul and East Khangai.