The ground cover species assemblages in rocky, roadside and forest habitats in Trabzon (north-eastern Turkey), were studied to describe floristic structures and disclose diversity pattern. To provide a quantitatively based classification of these assemblages, both two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA) were used. Nine groups for rocky habitats sampled from 100 sites, 10 groups for 100 roadside sites and four groups for 50 forest sites were classified. These groups primarily correspond to different effects of altitude, pH, sand, cover, skeleton and moisture content. Some alpha and beta diversity indices for each habitat and TWINSPAN groups at different altitudinal zones were assessed. Our results supported the hypothesis that altitudinal and other environmental properties have significant influences on species composition and diversity in three habitats, being similar to that on major vegetation composition.