The Park’s flora owing to the extreme diversification of the landscape, variety of soil, favourable thermopluviometric balance, morphology and relief orientation, is particularly rich in species, especially in the external south-western sector only partially involved in the quaternary glaciation. This area’s high rainfall, combined with the subsidence-prone nature of the calcareous rock, determines a considerable reduction (over 400 m) in the altimetrical limits of the vegetation, flora as well as the fauna. The influx of warm and damp winds that blow, across the Friuli Plane from the nearby Adriatic sea enable numerous Mediterranean thermophilic and Illyrian-Balkan elements, such as Frangula rupestris, to survive.

Asparagus acutifolius, Ruscus aculeatus, Satureja variegata, Micromeria thymifolia, Cotinus coggygria , Campanula pyramidalis, Genista sericea, Cytisus pseudoprocumbens, Plantago argentea, Athamanta turbith, that become established in the base and/or external relief sectors and others that push into more internal sectors such as the Grafia golaka, Molopospermum peloponnesiacum, Ligusticum lucidum seguieri, Peucedanum schottii, Adenophora liliifolia, Lilium carniolicum, Campanula cespitosa Knautia drymeia, Pedicularis hoermanniana, Homogyne sylvestris, Euphorbia carnolica and Astrantia carniolica.

There is the highest concentration of Phytoendemites on M. Plauris than in the rest of the region, in particular those of the «julico» type such as the Saxifraga tenella, Campanula zoysii, Gentiana froelichii, Ranunculus traunfellneri, Pedicularis julica, Festuca calva and Cerastium subtriflorum or more range type such as the Spiraea decumbens, Festuca laxa, Centaurea haynaldii julica, C. dichroantha, Senecio pseudocrispus, Knautia ressmannii, Euphorbia triflora kerneri, Bupleurum canalense as well as significant species such as the Artemisía nitida, Eryngium alpinum, Geranium argenteum, Astragalus carniolicus albiflorus, Matthiola carnica, Viola pinnata, Polygala nicaeensis foroiulensis, Iris cengialti, Arabis vochinensis, Asplenium fissum, Gentianella pilosa and Physoplexis comosa.

Whereas the more internal ranges, such as those of M. Canin, host more «endoalpine» or Artic alpine elements such as the Trifolium noricum, Loiseleuria procumbens, Saxifraga stellaris, Lloydia serotina, Astragalus australis, endemites of the south-westerly Alps such as the Alyssum ovirense, Saussurea pygmaea, Gentiana pumila, Anemone baldense, Phyteuma sieberi, Juncus jacquinii, Valeriana supina, Crepis kerneri and Papaver julicum, that coexists with the P. rhaeticum. Other species of interest include the Thlaspi kerneri (M. Zaiavor), Saxifraga petraea (Val Uccea), S. burserana, S. squarrosa, S. incrustata and Asplenium seelosii.