The tradition of floristic studies in Italy has made it possible to obtain a good knowledge of plant diversity both on a national and regional scale. However, the lack of knowledge for some areas, advances in plant systematics and human activities related to globalization, highlight the need for further studies aimed at improving floristic knowledge. In this paper, based on fieldwork and herbaria and literature surveys, we update the knowledge on the Italian vascular flora and analyze the floristic similarities between the administrative regions. Four taxa, all exotic, were recorded for the first time in Italy and Europe. In detail, Elaeodendron croceum, Kalanchoë blossfeldiana, and Sedum spathulifolium var. spathulifolium were found as casual aliens, while Oxalis brasiliensis was reported as historical record based on some herbarium specimens. Furthermore, Kalanchoë laxiflora was confirmed as a casual alien species for Italy and Europe. Status changes for some taxa were proposed at both national and regional levels, as well as many taxa were reported as new or confirmed at the regional level. Currently the Italian vascular flora comprises 9150 taxa of which 7547 are native (of which 1598 are Italian endemics) and 1603 are exotic at the national level. The multivariate analysis of updated floristic data on a regional scale showed a clear distribution along the latitudinal gradient, in accordance with the natural geographical location of the regions in Italy. This pattern of plants distribution was not affected by the introduction of alien species. Despite some taxonomic and methodological issues which are still open, the data obtained confirm the important role of floristic investigations in the field and in herbaria, as well as the collaborative approach among botanists, in order to improve the knowledge of the Italian and European vascular flora.

We present the first inventory of the segetal flora of Italian winter cereal crops and allied crop types. The database consists of over 30,000 records, derived from different sources. We provide information and analyses on life forms, chorotypes, Ellenberg indicator values and preferential habitats of the flora. The inventory includes 987 vascular taxa and nothotaxa (868 species, 118 subspecies and 1 nothosubspecies), belonging to 354 genera and 55 families. Characteristic segetal species are 128, while 740 are generalist or accidental species from other habitats. Species exclusive of segetal habitats are 47. One species is extinct, and one is not confirmed in Italy. We recorded 42 neophytes, 15 archaeophytes and 10 cryptogenic species. Segetal species that are threatened in Europe are 45. Species in the Italian Red List are four, and five are threatened endemic species. The most frequent species are Papaver rhoeas (1,045 records), Convolvulus arvensis (623) and Ranunculus arvensis (571). Most species are therophytes (64%) and have a Mediterranean (36%), wide (14%) or eastern (13%) distribution range. Mean Ellenberg indicator values revealed relevant ecological affinities between the inventoried flora and cultivated winter cereals. Our work represents the basis for future applied studies in botany, ecology and agronomy.

In this contribution, Italian new data concerning the distribution of the Annex I Habitats 3150, 3170*, 3260, 4090, 91L0, 91M0, 9340 are reported. In detail, 20 new occurrences in Natura 2000 sites are presented and 30 new cells are added in the EEA 10 km × 10 km reference grid. The new data refer to the Italian administrative regions of Campania, Lazio, Sardinia, Sicily, Tuscany, and Umbria.

Changes in agricultural practices represent one of the main causes of shift in species composition of arable plant communities. In particular, the intensification of agriculture going on worldwide since several decades led to heavy transformations of arable plant diversity. Basing on a study conducted in 1964 in Latium (central Italy), we re-surveyed the arable plant communities of 21 maize fields in order to assess the shifts that occurred over 50 years. The results showed a relevant decrease in the number of species (both in the total number and in the mean number per relevé), accompanied by a major species turnover. An increase in neophyte, wide-distribution, geophyte, C4 photosynthetic pathway, and monocot species was observed, while the incidence of insect-pollinated taxa decreased. The calculation of the mean Ellenberg indicator values per relevé showed an increase, in particular, of nutrients and moisture levels.

The main purpose of the 92/43/EEC Habitats Directive is to contribute to the conservation of biodiversity, understood as habitat types and species of the flora and fauna of the European Union. To achieve this goal, natural and semi-natural biodiversity as a whole must be recognized and included in its annexes. As for the conservation of biotopes, named habitat types, Italy is unfortunately lacking as it the Annex I does not include important ecosystems that are typical of its territory, rare for biogeographical reasons or threatened. Therefore, the opportunity to identify a first list of significant habitats for central Italy is discussed here. For each of the new proposed types (new habitats or new subtypes) a sheet has been prepared to highlight their salient characteristics. The new proposals concern seven habitat types and one subtype: sedge and reeds formations (Freshwater large sedge and reed beds), willow shrublands (Shrubby willow formations of river banks and fens), Apennine garrigues (Apennine hilly and montane garrigues), a new subtype of Annex I Habitat 6130 (Communities of herbaceous and dwarf shrub-suffrutescent plants of Italian ultramafic substrates), ancient olive groves ("Centuries-old olive groves" with evergreen Quercus spp. and arborescent matorral), secondary meadows (Italian submontane and montane pastured meadows dominated by Cynosurus cristatus), badlands (Pioneer halophilous and sub-halophilous communities of “calanchi” and “biancane” badlands) and hop-hornbeam woods (Italian-Balkan hop-hornbeam woods).

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions of taxa in the generaAcalypha,Acer,Canna,Cardamine,Cedrus,Chlorophytum,Citrus,Cyperus,Epilobium,Eucalyptus,Euphorbia,Gamochaeta,Hesperocyparis,Heteranthera,Lemna,Ligustrum,Lycium,Nassella,Nothoscordum,Oenothera,Osteospermum,Paspalum,Pontederia,Romulea,Rudbeckia,Salvia,Sesbania,Setaria,Sicyos,Styphnolobium,Symphyotrichum, andTradescantia. Nomenclature and distribution updates, published elsewhere, and corrigenda are provided as supplementary material.