Language: German, with bilingual abstract in English and French
16 calcareous grassland areas (Mesobrometa) on Triassic dolomitic marls ("Keuper a marnolites") of the Gutland have been visited; 13 are located in the G.D. of Luxembourg and 3 in Rheinland-Pfalz (F.R.G.). Bryfloristic work yielded 81 mosses and 5 hepatics. Several species rare in the two parts of the Gutland have been recorded, among which are Ephemerum recurvifolium, Fissidens incurvus and Trichostomum crispulum. The study of the bryophyte vegetation was carried on mostly by floristic and ecological methods, supported by 24 sociological releves; 6 main "niches" or biotope types have been discovered: small moist valleys, mesophytic grassland, nude marl slopes and open grassland in xeric sites, xeric pioneer sites of fine-grained soil (principally ant hills), soil crevices and earthy overhangs, rocky soil due to "marnolites". For each of these microniches the bryophyte cover has been examined from a phytogeographical point of view; lifeforms and strategies were also examined. General comments on bryogeography and some opinions relating to conservancy problems close the paper.