An updated inventory of the native vascular flora of Italy, providing details on the occurrence at regional level, is presented. The checklist includes 8195 taxa (6417 species and 1778 subspecies), distributed in 1092 genera and 152 families; 23 taxa are lycophytes, 108 ferns and fern allies, 30 gymnosperms and 8034 angiosperms. The taxa currently occurring in Italy are 7483, while 568 taxa have not been confirmed in recent times, 99 are doubtfully occurring in the country and 19 are data deficient. Out of the 568 not confirmed taxa, 26 are considered extinct or possibly extinct.

An updated inventory of the vascular flora alien to Italy, providing details on the occurrence at regional level, is presented. The checklist includes 1597 species, subspecies, and hybrids, distributed in 725 genera and 152 families; 2 taxa are lycophytes, 11 ferns and fern allies, 33 gymnosperms, and 1551 angiosperms. 157 taxa are archaeophytes and 1440 neophytes. The alien taxa currently established in Italy are 791 (570 naturalized and 221 invasive), while 705 taxa are casual aliens, 4 are not assessed, 7 are of unknown regional distribution, 47 have not been confirmed in recent times, 3 are considered extinct or possibly extinct in the country, and 40 are doubtfully occurring in Italy. This checklist allows to establish an up-to-date number (9792) of taxa constituting the whole (native and alien) Italian flora.

In this paper we present a comprehensive inventory of the non‐native vascular flora of Italy, which was produced within the project “A survey of the Italian non‐native flora”, funded by the Italian Ministry for the Environment. Previously published floristic accounts were the main source of information. Historical records were critically revised and integrated with recent literature, data from herbaria and some unpublished information, so as to obtain a complete, up‐to‐date catalogue of the non‐native vascular plant species that occur spontaneously in Italy. The inventory lists 1023 non‐native species and subspecies, which account for 13.4% of all the Italian flora. The Italian non‐native flora was divided, according to its residence time, into 103 archaeophytes and 920 neophytes. According to its current invasion status, it was classified into 437 casual (42.7% of all non‐native) and 524 established taxa, the latter being divided into 361 naturalized non‐invasive (35.3%) and 163 invasive taxa (15.9%). The inventory includes a group of 62 species (6.1%) that lack recent records (i.e. since 1950). By combining local expertise into a unified, nationwide scheme using a standardized method and terminology, the inventory provides the essential scientific basis for the development of plant invasion research and management in the country.

For the purpose of the present study we considered as Italian endemics those specific and subspecific taxa occurring in Italy that are not found elsewhere with the exception of Corsica (France) and Malta. This study presents an updated list of the endemic taxa in the Italian flora, including their geographical distribution at regional level. Italy is characterized by 1371 endemic species and subspecies (18.9% of the total vascular flora): three taxa belong to Lycopodiidae, one to Polypodiidae, two to Pinidae and 1365 to Magnoliidae (three paleoherbs, 221 monocots and 1144 eudicots). The endemic flora belongs to 29 orders, 67 families and 304 genera. Sicily, Sardinia, Calabria and Abruzzo are the four regions richest in endemics. About 58% of endemics are confined to a single administrative region. The most represented orders, families and genera are: Asterales, Caryophyllales and Asparagales, Asteraceae, Plumbaginaceae and Caryophyllaceae, Limonium, Centaurea and Hieracium, respectively. The phytogeographic isolation of Sardinia and Sicily and the separation of peninsular Italy from Northern Italy is confirmed. The relative isolation of Puglia with respect the remaining southern Italian pensinsular regions is also confirmed. Alpine region endemics (from northern Italy) are underrepresented.

The census of the loci classici of 1,400 Italian endemic vascular plants (i.e. not thriving elsewhere with the exception of Corsica and Malta) is here presented and described. The effective place of publication of accepted names, basionyms and homotypic synonyms were identified and critically verified. This often resulted in some change in authorship attribution and, in seven cases, in validation problems (Asperula cynanchica var. lactea var. nov., A. lactea comb. nov., Biscutella laevigata subsp. raffaelliana subsp. nov., Ferulago nodosa subsp. geniculata comb. & stat. nov., Limonium tineoi comb. nov., L. usticanum sp. nov., Noccaea torreana comb. nov.). The geographic information on the loci classici was excerpted from the protologues, as well as information on typification for the taxa described before 1 January 1958. The names without holotype are 796. For 347 names a lecto- or neo-typification is available in literature, while 449 currently accepted taxa still need of type designation.