Article

The flora of Il Bulgarian mountains, representing about 80% of total area of Balkan-Rhodope mountain system is analysed. In calculation are included 2018 taxa with populations in altitude range 1000 - 2925 m. Vertical distribution of the flora is valuated using altitudinal steps of 500 m. Hypsometric interval of 1000 - 2000 m shows more or less constant number of species (ab. 1300) and diversity decreases in altitude with about 400 taxa in every 500 m reaching value of 257 species in the highest part ofthe mountains. Indifferent species to basic rock prevails (62%) but flora on limestone terrains is Il % richer than that one on silicate. More than 50% of the species prefers terrains with moderate humidity and about 30% are xerophytes. Hemicryptophytes represent 60% of ali species and other life forrns show quite equal values (geophytes 10,1 %, chamaephytes 10,0%, therophytes 9,8% and phanerophytes 9,0%,). Analysis ofthe chorological spectra shows prevalence ofEuropean chorotype 26,9% followed by Balkan endemics 23,4%, Euro-Asiatic 13,2% and Sub-Mediterranean Il , I % species. Ali other chorological groups are less than 10% and ali together represent 25,3% of the ali species.