Over 200 species of woody plants and greens are found in the limestone massif “Demir Kapija” and the immediate surrounding. This number would increase significantly if also the species that grow in the fields and in the abandoned agricultural areas are taken in consideration.

The highest floristic richness is located on the eastern slopes of Krastovec, in the drainage-basin of the river Klisurska. The most specific flora is concentrated on the northern slopes of Krastovec and on the steepness of the limestone gorge of Demir Kapija.

The researches made here have registrated: 17 species flora and Balkan endemics, 4 species sub-endemics, 16 Mediterranean species, 22 sub-mediterranean species and 19 Middle European flora elements species.

It should be noted that 11 species with southern or steppes distribution in the gorge Demir Kapija complete their range. According to Matveev and Puncer (1989) in Demir Kapija two landscape types (biomes): – are represented:

The area/Landscape of mediterranean, evergreen forests and plight;
The area/Landscape of sub-mediterranean broadleaf forest and shrublands.