The plateau of the Giara is a strategic location for the floristic biodiversity of Sardinia. The particular ecological conditions in this area allow a high botanical heterogeneity, which is notable for the number of species of high conservation and biogeographical value.
There is, in fact, the Marsilea strigosa, Willd, which is a species listed in Annex II of the Habitats Directive and included in the Red List of Italian Flora as a vulnerable species and, therefore, is subject to special safeguards and protection. Its importance is enhanced by its role as one of the diagnostic entities of the priority Habitat "Mediterranean temporary ponds (Isoeto-Nanojuncetea)" (code 3170) and "Oligotrophic waters containing very few minerals generally on sandy soils of the West Mediterranean, with Isoetes spp" (code 3120), both included in Annex I of Directive 92/43/EEC.
The plateau has more than 350 species of flora.
The territory of the Giara also hosts 14 endemic species, making it unique from a systematic and ecological point of view in this small geographic context and demonstrating the great diversity on the plateau.
The following table lists the endemic species that grow on the Giara, with their geographical distributions:
Apium crassipes (Koch) Rchb. f. SA-SI-LA (Sardinia, Sicily, Lazio)
Aristolochia rotunda L. ssp. insularis (Nardi & Arrigoni) Gamisans SA-CO-AT (Sardinia, Corsica, The Tuscan Archipelago)
Arum pictum L. f. ssp. pictum SA-CO-AT-BL (Sardinia, Corsica, The Island of Montecristo, Balearic Islands)
Crocus minimus DC. SA-CO-AT (Sardinia, Corsica, The Tuscan Archipelago)
Euphorbia pithyusa L. ssp. cupanii (Guss.) A.R.Sm. - SA-CO-SI (Sardinia, Corsica, Sicily)
Genista corsica (Loisel) DC. SA-CO (Sardinia, Corsica)
Morisia monanthos (Viv.) Asch. SA-CO (Sardinia, Corsica)
Ornithogalum corsicum Jord. & Fourr. SA-CO (Sardinia, Corsica)
Pancratium illyricum L. SA-CO-AT (Sardinia, Corsica, The Tuscan Archipelago)
Ranunculus cordiger Viv. ssp. cordiger SA-CO (Sardinia, Corsica)
Ranunculus revelierei Boreau SA-CO-GA (Sardinia, Corsica, Southern France)
Romulea requienii Parl. SA-CO (Sardinia, Corsica)
Scrophularia trifoliata L. SA-CO-BL-GA (Sardinia, Corsica, The Balearic Islands, Southern France)
Stachys glutinosa L. SA-CO-AT (Sardinia, Corsica, The Tuscan Archipelago)