The biota of the Nature Park comprises species of different ecology, age, and origin. Particularly numerous are the Euro-Asian and central European species, but warm habitats on serpentinites are suitable for many sub-Mediterranean and Pontic-central Asian species as well.
Of a total of 800 species and subspecies of flowering plants and ferns of this region, 7.5% are endemic or subendemic taxa. Most of these endemics are the Balkan endemics, which do not go beyond the boundaries of the Balkan Peninsula. Such species are, for example, the Yugoslav bellflower (Edraianthus jugoslavicus), Haynald's athamant (Athamanta haynaldi), Croatian savory (Micromeria croatica),Panćić's spurge(Euphorbia pancicii),Serbian onion (Allium tenuiflorum), hawkweed (Hieracium gymnocephalum),toadflax (Linaria rubioides), and many other endemics.
The edaphic endemism is one of the characteristics of the flora of this region, influenced by the specific serpentine soil. This particular group of plants include the endemic relic Halascya sendtneri, and many other Balkan serpentinophytes: Serbian moor grass (Sesleria serbica), Markgraf's alyssum (Alyssum markgrafii), lamb's ear (Stachys chrysophaea), rock rose (Fumana bonapartei), cinquefoil (Potentilla mollis), Novak's feather grass (Stipa novakii), serpentine sea thrift (Аrmeria canescens var. serpentini), serpentine chickweed (Cerastium malyi subsp. serpentini), etc.
In the Red Data Book of Flora of Serbia, Vol. 1 (Stevanović, ed., 1999), which describes extinct and critically endangered species, one species from the Nature Park is also listed. It is the Alpine knapweed (Centaurea alpina), which is placed within the category of critically endangered species (CR) of Serbia and Montenegro. Limestone slopes of Ograđenica represent its only habitat in Serbia.
According to the criteria of the International Union for Conservation of Nature (IUCN), there are 6 regionally critically endangered species (CR) in this area (Phyteuma orbiculare, Centaurea alpina, Reichardia macrophylla, Euphorbia pancicii, Aquilegia nigricans, and Allium ericetorum), as well as 9 regionally endangered species (ЕN) (Paeonia officinalis, Lathyrus binatus, Genista sylvestris, Lathyrus luteus, Frangula rupestris, Limodorum abortivum, Maianthemum bifolium, Ophrys scolopax ssp. cornuta, and Pyrola rotundifolia). Furthermore, there are 6 plant species that represent natural rarities of Serbia and are under the protection regime of the first degree. These are the Turk's cap lily(Lilium martagon),violet limodore (Limodorum abortivum), lizard orchid (Himantoglossum hircinum), woodcock orchid (Ophrys cornuta), lady orchid (Orchis purpurea), and round-leaf wintergreen (Pyrola rotundifolia).All these species give a particular significance to the region of Mokra Gora from the aspect of the floral diversity conservation.