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Nell'ambito di ricerche fitosociologiche nell'area egea vengono presentati i risultati relativi alle formazioni forestali attualmente osservabili nelle isole dell'Egeo meridionale. Questo tipo di vegetazione è stato in precedenza oggetto di studio da parte di vari autori, fra cui in particolare Krause et al. (1963), Zohary & Orshan (1966), Barbero & Quezel (1980), Costa et al. (1984) e Géhu et al. (1989, 1990, 1992), che hanno esaminato sotto il profilo fitosociologico alcune isole dell'Egeo quali Eubea, Creta, Rodi e Karpatos. Allo scopo di ampliare le conoscenze su quest'area del Mediterraneo, ancora poco nota dal punto di vista vegetazionale, sono state effettuate indagini su numerose isole dell'arcipelago delle Cicladi e del Dodecaneso e a Creta. Sulla base dei dati di letteratura e di numerosi rilievi personali inediti, in questo territorio si rinvengono boschi termofili sempreverdi rappresentati da querceti a Quercus ilex e a Q. calliprinos, pinete a Pinus brutia, cipresseti a Cupressus sempervirens, come pure boschi decidui a Quercus brachyphylla, Q. macrolepis e Q. crispata. Frequenti sono pure varî tipi di macchia a Juniperus turbinata, a J. macrocarpa, a Pistacia lentiscus, ad Euphorbia dendroides e a Ceratonia siliqua. Altre formazioni presenti sono le ripisilve a Platanus orientalis e le boscaglie igrofile a Nerium oleader e a Vitex agnus-castus. Per quanto riguarda il loro inquadramento fitosociologico, è da rilevare che con l’eccezione delle formazioni igrofile, gli aspetti forestali rientrano tutti nella classe Quercetea ilicis. In seno a quest’ultima si distinguono formazioni più mesofile, appartenenti ai Quercetalia ilicis ed all’alleanza Erico-Quercion ilicis, e formazioni più xerofile dei Pistacio-Rhamnetalia alaterni. Quest’ultimo ordine è rappresentato nell’area studiata da diverse alleanze, quali il Ceratonio-Pistacion lentisci, relativo agli arbusteti marcatamente xerofili prevalentemente costieri o semirupestri, il Quercion calliprini, comprendente le formazioni boschive del piano basale e submontano, il Cupresso-Acerion sempervirentis, del piano montano, lo Juniperion turbinatae dei litorali sabbiosi ed infine l’Ericion arboreae, raggruppante gli aspetti arbustivi di degradazione del Quercion calliprini e dell’Erico-Quercion ilicis.I boschi ripariali rientrano invece nel Platanion orientalis, alleanza dei Populetalia albae, mentre gli arbusteti frequenti lungo i corsi d’acqua sono da ascrivere ai Nerio-Tamaricetea, in seno alla quale è stata individuata una nuova aleanza, il Rubo sancti-Nerion oleandri, vicariante orientale del Rubo-Nerion oleandri.

Invasive alien plants are a major threat to biodiversity and they contribute to the unfavourable conservation status of habitats of interest to the European Community. In order to favour implementation of European Union Regulation no. 1143/2014 on invasive alien species, the Italian Society of Vegetation Science carried out a large survey led by a task force of 49 contributors with expertise in vegetation across all the Italian administrative regions. The survey summed up the knowledge on impact mechanisms of invasive alien plants in Italy and their outcomes on plant communities and the EU habitats of Community Interest, in accordance with Directive no. 92/43/EEC. The survey covered 241 alien plant species reported as having deleterious ecological impacts. The data collected illustrate the current state of the art, highlight the main gaps in knowledge, and suggest topics to be further investigated. In particular, the survey underlined competition as being the main mechanism of ecological impact on plant communities and Natura 2000 habitats. Of the 241 species, only Ailanthus altissima was found to exert an ecological impact on plant communities and Natura 2000 habitats in all Italian regions; while a further 20 species impact up to ten out of the 20 Italian administrative regions. Our data indicate that 84 out of 132 Natura 2000 Habitats (64%) are subjected to some degree of impact by invasive alien plants. Freshwater habitats and natural and semi-natural grassland formations were impacted by the highest number of alien species, followed by coastal sand dunes and inland dunes, and forests. Although not exhaustive, this research is the first example of nationwide evaluation of the ecological impacts of invasive alien plants on plant communities and Natura 2000 Habitats.

This study provides a first step toward the knowledge of the alien-dominated and co-dominated plant communities present in Italy. The first ever checklist of the alien phytocoenoses described or reported in literature for the Italian territory has been compiled, produced by data-mining in national and local thematic literature. The resulting vegetation-type draft-list has been checked in the light of the most recent syntaxonomic documentation and updated with regards to syntaxonomy and nomenclature, with special reference to the frame proposed in the Italian Vegetation Prodrome. The list includes 27 vascular and one bryophyte vegetation classes, hosting 194 low rank alien-dominated syntaxa. The different vegetation types detected for each syntaxonomic class and macro-vegetation group, defined by physiognomical and ecological attributes, are discussed.

A comparative analysis of the riparian vegetation dominated by Alnus glutinosa in Italy and Tyrrhenian islands, based on literature data and unpublished relevés, is presented. A total of 456 phytosociological relevés were processed. For the definition of plant communities and alliances, hierarchical clustering was performed by using Bray-Curtis coefficient and Detrended Correspondence Analysis ordination methods. Identification of diagnostic species of the vegetation units was performed by means of the phi fidelity index. Quantum GIS software version 3.6 was used for the interpolation of the bioclimatic variables and A. glutinosa communities. Overall, a total of 18 A. glutinosa-riparian wood communities were distinguished for Italy and Tyrrhenian islands, of which two new associations and one new subassassociation are described. The classification of the relevés showed two main vegetation groups: the first one including the plant communities of the Osmundo-Alnion alliance, and the other including the vegetation of the Ligustro vulgaris-Alnion glutinosae alliance. This latest includes the riparian meso-thermophilous communities of central and northern Italy. Within the Osmundo-Alnion alliance, two subgroups can be recognized: the first one includes the thermophilous communities of the Hyperico hircini-Alnenion glutinosae sub-alliance, mainly spread in the Tyrrhenian islands, while the second group includes the mesophilous communities attributed to the new suballiance Struthioptero-Alnenion glutinosae, widespread in central Italy and the Corsican mountains. The present paper provides the first comprehensive and exhaustive scheme of the A. glutinosa riparian woodlands diversity in Italy and Corsica.

Sphaeralcea bonariensis (Cav.) Griseb. is here reported for the first time as alien species in Italy and in the Mediterranean area. It is a perennial shrub native to Southern America, where it is often considered a ruderal species frequent in cultivated areas. It was found in a population of a few individuals within Opuntia ficus-indica groves of Rocca Palumba territory (Western Sicily). Actually, due to short-term observational period and the low number of plants, Sphaeralcea bonariensis should be considered as a casual species in Italy. The ecological characteristics of the growing stand and the consistency of the population, as well as the possible causes of its introduction, are briefly discussed.

A synthetic and updated overview about the vascular flora and vegetation of the Island of Capo Passero (SE-Sicily) is provided. These data issue from two series of field surveys—the first carried out between 1997 and 2000, and the second between 2005 and 2019 and mostly focused on refining and implementing vegetation data. The current islet’s flora consists of 269 taxa, of which 149 (58%) are annual plants. The Mediterranean species are largely prevailing, 108 (40%) of which have a strictly Mediterranean biogeographical status. The comparison with a species list published in 1919 and updated in 1957 suggest that, despite the overall prevalence of anemochorous taxa, the vertebrate fauna represents an important vector for the plant colonization of the island, while the immigration of myrmechocorous taxa does not compensate the extinction rate. As many as 202 phytosociological relevés, 191 of which issue from original recent field surveys, enabled identifying 12 different plant communities. The comparison with a vegetation map published in 1965 suggests a strong reduction in dune habitats (2120 and 2210 according to EU ‘Habitats’ Directive 92/43), as well as a deep disruption in the succession typical of the local psammophilous vegetation series. In order to preserve rare, endangered and protected plant species (such as Aeluropus lagopoides, Cichorium spinosum, Limonium hyblaeum, L. syracusanum, Poterium spinosum, Senecio pygmaeus and Spergularia heldreichii) and to stop the ongoing habitat degradation, urgent and effective conservation measures should be adopted for this tiny, yet precious islet.

Poa jubata A. Kern., an annual South-eastern European species, is reported for the first time from Italy. It is a therophyte linked to temporary ponds with soils flooded during the winter period. It is a very rare and enigmatic species, currently known only from a few localities of the Balkan Peninsula. Recently, it was surveyed in an Apulian wetland, near Brindisi, where it grows with several other annual hygrophytes. For its taxonomical isolation, it is included in a monospecific section, as P. sect. Jubatae. In addition to a detailed description, the chromo-some complement (2n = 14) of this species is examined for the first time and a new iconography is provided.

This study is aimed at (1) producing a complete and updated inventory of the endemic vascular flora of Peloritani Mountains, (2) defining the geographical limits of Peloritani, regarded here as a biogeographical district and (3) highlighting possible paleogeographic connections with other Mediterranean lands. The heterogeneity analysis of the endemic flora was performed by means of contingency tables, through the x 2 test. The endemic flora of this area consists of 129 specific and infraspecific taxa, of which 15 are restricted to the Peloritani Mountains. The analysis of habitats revealed that endemic taxa are most abundant on cliffs, rangelands, woods and garrigues. A large number of surveyed taxa are endemic to central-southern Italy and Sicily, while the number of endemic taxa in common with Calabria, Etna and Aeolian Islands turned out to be rather low, in spite of the geographical proximity. The endemic flora of Peloritani allows to emphasize palaeogeographical relationships not only with the neighbouring Mediterranean territories, but also with currently remote ones, such as southern Spain, Sardinia and Corsica. The phytogeographical framework substantiates the hypothesis that the Peloritani floristic district coincides with the limit given to Peloritani Mountains by structural geologists.

Among the suffruticose cabbages of Brassica sect. Brassica, a new species from Sicily, named B. raimondoi, is described and illustrated. It is a chasmophyte restricted to some steep limestone cliffs near Taormina (NE Sicily) and is morphologically related to B. incana, with which it shares densely hairy, broad, amplexicaul leaves and winged petioles, but differs principally in its white corolla, larger floral pieces, more developed stigmatic papillae, shorter siliquae with keeled valves and a smaller, seedless beak, smaller seeds differing in testa microsculpture. A key for the identification of the currently known Sicilian taxa of the section is provided.

Psoralea palaestina is a critical and unappreciated species described from Palestinian territories, and currently treated as synonym of P. bituminosa, nowadays known as Bituminaria bituminosa. Nomenclatural investigations allowed to ascertain that it was validly described for the first time by Bassi (1768) and not by Gouan (1773), as previously thought. Extensive taxonomic investigations revealed that this very peculiar legume is morphologically well differentiated from the other allied known species. Therefore, it has to be properly treated at specific level and transferred to the genus Bituminaria, thus proposing a new combination: Bituminaria palaestina. Based on literature, herbarium and field data, this species occurs in some localities of the Middle East (e.g. Israel, Jordan and Lebanon) where it mainly grows in damp habitats (i.e. swamps, rivers, etc.), differing from other known species of Bituminaria for its ecological requirements. Diagnostic features, micro-morphology of pod and seed testa, pollen grains, ecology, conservation status, and chorology of this species are examined. Its chromosome number is reported. Furthermore, its relationships with the currently recognized species belonging to Bituminaria are considered, and an analytical key including all the species of this genus is provided.

As Sicily has been a central crossroads of human activity for thousands of years, it offers a major perspective on the Mediterranean weedy plant communities. This syntaxonomical survey of the Sicilian weedy vegetation groups together for the first time 30 plant associations, that have been described from the main and neighboring island in the last three decades. The surveyed vegetation is ascribed to the classes Papaveretea rhoeadis and Stellarietea mediae, whose floristic autonomy is here discussed, and to the orders Aperetalia spicae-venti and Papaveretalia rhoeadis for the former, Polygono-Chenopodietalia polispermi, Solano-Polygonetalia convolvuli, Thero-Brometalia and Urtico-Scrophularietalia peregrinae for the latter class. Most of the surveyed associations are linked to hoed cultivations. Major differences are determined by the tillage and watering regimes, on their turn related to the life-cycle of the cultivated plant.