The structure of plant communities on the example of an oak-pine forest (Pino-Quercetum) in Ratanica Valley (Carpathian Foothills) 1. The homotoneity of a forest floor vegetation in terms of the frequency and co-occurence of species

Mathematical methods of uniformity analysis were used to evaluate the results of classification of plant communities by the Braun-Blanquet method. This was done by both the freguency analysis method traditionally used in phytosociology and by the verification of the null hypothesis on the independent occurrence of species. The results obtained confirmed the validity of the following assumptions: 1) the number of high frequency species rises along with the decreasing rank of the syntaxon and 2) the proportion of species occurring interdependently (showing a positive or negative correlation) decreases.