[en] The relationships between water chemistry and aquatic bryoflora in the Vosges Mountains (Eastern France) were studied in an attempt to survey the processes of acidification. 6 chemical variables (pH, Mg2+, Ca2+, K+, N03-, Al) were used to explain the segregation of the bryophytic communities concerning 19 species in 31 study sites. Ca2+, Mg2+ and a lesser extend pH and Al are the four variables best explaining the relationships between the bryophytes and the chemical data. Acidophilus species as Marsupella emarginata seem to be sensitive to high cations concentrations. On the contrary neutrophilous species as Rhynchostegium riparioides may be more sensitive to the toxicity of protons or Al than to lacks of cations. The combinations of bryophytes are used to reconstitute the chemical variables and the precision of the modelling is assessed.