The variability of mires (Scheuchzerio-Caricetea fuscae) and subalpine springs (Montio-Cardaminetea) was evaluated in the Vitosha Mt, a region with well developed wetland habitats. Fifty-three phytosociological relevés were classified using formal definitions, i.e. combination of species groups extracted from data set from throughout Bulgarian mountain wetlands. The major compositional gradient in the Vitosha mires was found to be the developmental gradient from initial, long-term sucessionally arrested stages of spring fens to the advanced species-rich vegetation of the Sphagnum-rich fens and the wet meadows. The unclear high-rank classification of Bulgarian subalpine fens, recently assigned to the Caricion fuscae alliance, is discussed.