Abstract
The Danube mountain gap valley between Romania and Serbia is known for its high biodiversity, represented by many xero-thermophilous species, phytocoenoses and habitats of Southern origin. The occurrence of these species and phytocoenoses is strongly related to the geographical position on the continent, with related climate conditions and the geomorphological structure. The different phyto-geographical regionalisation highlights the uniqueness of the area, being the meeting point of species with their Northern, Southern, Western or Eastern limit in the Danube Gorge break. Here are presented the identifying species of characteristic phytocoenoses, threatened species and typical habitats with relevance for the European Natura 2000 network.