THE VEGETATION OF THE SEDIMENTARY COAST OF FRIULI-VENEZIA GIULIA (NE-lTALY) WITH
PARTICULAR REFERENCE TO THE NORTHERN ADRIATIC REGION. This paper is devoted to the study of the psammophilous and halophilous vegetation of the Northern Adriatic Sea (from Sefovlje, Republic of Slovenia, to the mouth of the Po river) and particularly to the definition of a phytosociological scheme for the vegetation of the sedimentary coast of Friuli-Venezia Giulia. Due to its alluvial origin, the study area is geomorphologically homogeneous, being constituted by lagoons bordered by sandy shorelines, and in the Mediterranean basin it is distinctive because of a strong Eurosiberian climatic influence, high tides and wet salted soils. About 900 relevés taken from the literature and 65 unpublished relevés from Friuli-Venezia Giulia
were considered. The multivariate analysis of the relevés allowed to reassess the syntaxonomical position of several associations, placed by some Authors into other classes of vegetation. Some problems arised with the halophilous vegetation, as some species, although characteristic of their classes, are present with high frequencies also in other classes. Furthermore, the boundaries between classes are rather vague if only the floristic composition is considered. However, this problem can be overcome by taking into account also structural data (life form and growth form). These syntaxonomical difficulties reflect the peculiar character of a vegetation which seems monotonous, but is on the contrary very heterogeneous, being constituted by a fine scale mosaic. The vegetation of the study area is more similar to that of the western than to that of the Eastern Mediterranean coast, and. has a strong affinity with the vegetation of Atlantic Europe.
