The aspects and the types of competition between lichen species in epiphytic communities have been investigated. For this a special terminology was worked out on the types of contacts between foliaceus-foliaceus, Ioliaceus-crustose, foliaceus-fruticose and frut icose-fru ticose species. The results indicate that the competition between colonies is very strong, above all on the small surfaces, in the optimal and terminal phases of succession, It was found that the histological and morphological cons t ruct ion of thalli play a very important role in this aspect of the competition. This was most obvious in the types of contacts between laciniate foliose and frut icose species, The strap-shaped and thread-like fruticose species have supporting tissues which wit hst uud the lateral pressure. Thus these colonies always vertically overgrow other species which belong to other life forms