New Alien Plant Taxa for Italy and Europe: An Update.

Despite the wide amount of scientific contributions published on alien plant species, their diffusion dynamics, and their interactions with native taxa, it is increasingly difficult to slow down their spreading and their negative impact on habitats. Last recent years, in fact, a sharp rise in the number of new alien plant taxa introduced in Italy and Europe has been recorded. The aim of this work is to investigate most of the Italian territory in order to verify whether this alarming trend is still underway. Specimen collections and/or observations of alien plants have been performed in as many as 12 Italian regions. All the collected specimens are stored in public or private herbaria. Taxa have been identified according to the literature from the countries of origin of the investigated taxa, while the nomenclature followed the current international references. Updates on 106 taxa are reported. In particular, among 117 new records, 89 are first records, 27 are changes to status and there is 1 extinction. Seven new taxa for Italian alien flora are reported, two of which are new to Europe. The administrative regions with the highest number of records are Calabria (48), Sardegna (17) and Sicilia (15). Five of the surveyed taxa, for the first time, have been considered invasive aliens to Italian territory. The unfrequent amount of original results provided by this work, over the simple importance of data itself, proves how floristic investigation, still today, represents one of the most effective tools in broadening the current knowledge about alien taxa and their dynamics.

New Data on Native and Alien Vascular Flora of Sicily (Italy): New Findings and Updates.

In this paper, based on fieldwork and herbaria surveys, new data concerning the presence of 32 native and alien vascular species for Sicily (Italy) are provided. Among the native species, the occurrence of the following taxa is reported for the first time or confirmed after many decades of non-observation: Aira multiculmis, Arum maculatum, Carex flacca subsp. flacca, Mentha longifolia, Oxybasis chenopodioides, Najas minor and Xiphion junceum. Furthermore, we document the presence of three native species (Cornus mas, Juncus foliosus and Limonium avei) that, despite being repeatedly observed in Sicily and reported in the literature, are inexplicably omitted by the most recent authoritative checklists regarding the flora of Italy. Finally, fifteen alien species new to Sicily (including one new to Europe, i.e., Pyrus betulifolia) are reported and seven poorly documented allochthonous taxa are confirmed for the island, and for two of them, a status change is proposed. These new or confirmed records allow us to better define the European and national distribution of the targeted taxa and offer new insights on the native and alien flora of Sicily.

Carpological Analysis of Two Endemic Italian Species: Pimpinella anisoides and Pimpinella gussonei (Apiaceae).

This study aims to clarify the taxonomic doubts, which have varied over the centuries, on the only two endemic species of the genus Pimpinella growing in Italy: P. anisoides and P. gussonei. For this purpose, the main carpological characters of the two species were examined, analyzing the external morphological traits and their cross-sections. Fourteen morphological traits were identified, obtaining datasets for the two groups using 40 mericarps (20 per species). The obtained measurements were subjected to statistical analysis (MANOVA and PCA). Our results highlight that at least 10 of the 14 morphological traits analyzed support the distinction between P. anisoides and P. gussonei. In particular, the following carpological characters are very significant ways to distinguish between the two species: monocarp width and length (Mw, Ml), monocarp length from base to maximum width (Mm), stylopodium width and length (Sw, Sl), length/width ratio (l/w) and cross-section area (CSa). In particular, the fruit of P. anisoides is larger (Mw 1.61 ± 0.10 mm) than that of P. gussonei (Mw 1.27 ± 0.13 mm), the mericarps of the first species are longer (Ml 3.14 ± 0.32 vs. 2.26 ± 0.18 mm) and the cross-section area (CSa) of P. gussonei is larger (0.92 ± 0.19 mm) than that of P. anisoides (0.69 ± 0.12 mm). The results also highlight the importance of the morphological traits of the carpological structures for the specific discrimination of similar species. The findings of this study contribute to an evaluation of the taxonomic significance of this species within the genus Pimpinella, and also provide valuable information for the conservation of these two endemic species.

The Plant Communities of the Class Isoëto-Nanojuncetea in Sicily.

A syntaxonomical revision of the Isoëto-Nanojuncetea class for the Sicilian territory is provided. This syntaxon gathers the ephemeral herbaceous hygrophilous plant communities linked to periodically submerged soils, widely distributed in the European, circum-Mediterranean and Macaronesian territories. Within this class, two orders are recognized, lsoëtetalia, with a prevalently Mediterranean distribution, and Nanocyperetalia chiefly occurring in the central-European and Atlantic territories, with scattered and marginal occurrence in the Mediterranean area. The order Isoëtetalia in Sicily is represented by four alliances, i.e., Isoëtion, Preslion cervinae, Cicendio-Solenopsion laurentiae and Agrostion salmanticae, while within Nanocyperetalia three alliances can be recognized, namely Nanocyperion, Verbenion supinae and Lythrion tribracteati. Overall, 32 plant communities are recognized, 11 of which are described for the first time. Each higher rank syntaxa and related associations are examined from a nomenclatural, floristic, ecological and chorological point of view. In particular, the associations were processed using cluster analysis in order to highlight the correlations between them. Regarding the floristic aspects, a checklist of the species occurring in the phytosociological relevés is provided, as well as a new combination concerning Solenopsis gasparrinii, a critical species of the Sicilian flora, is proposed.

Ecological Features and Conservation of Urtica rupestris Guss. (Urticaceae): A Narrow Endemic Species of Sicily.

The conservation actions of endangered plant species require a clear knowledge of their habitats. Urtica rupestris Guss. (Urticaceae) is a rare endemic plant species occurring on shady cliffs in the southern-eastern part of Sicily. In the last century, the extreme anthropogenic alterations of Hyblaean plateau have caused the continuous and unrestrained fragmentation of natural habitats and consequently the reduction and disappearance of some plant species. A total of 52 vegetation plots, of which 34 are unpublished, were analyzed in order to characterize the floristic composition of the U. rupestris community. All the relevés were classified using classification and ordination methods. The species is mainly linked to shady and wet rock habitats, and only secondarily colonizes the undergrowth shrubs. According to IUCN criteria, we propose a new risk status for this species and the establishment of a new habitat (92/43CEE) for correct long-term conservation. Finally, a new association, Urtico rupestris-Adiantetum capilli-veneris, which falls within the Polysticho setiferi-Phyllitidion scolopendrii alliance (Adiantetea capilli-veneris class), was described. This study can provide useful information for the management and conservation of U. rupestris.

Unexpected Discovery of Thelypteris palustris (Thelypteridaceae) in Sicily (Italy): Morphological, Ecological Analysis and Habitat Characterization.

Thelypteris palustris Schott (Thelypteridaceae), known as "marsh fern", is infrequent in the Mediterranean area. The occurrence of this species is known for almost all the Italian regions (except for Sardinia and Sicily), but with rare and declining populations. During floristic fieldwork on the Sicilian wetlands, a new unknown population was found. The aim of this paper is to analyze the morphological traits of the species, as well as its ecological features and the floristic composition of the plant communities where it lives. According to IUCN guidelines, here we provide the regional assessment (Sicily) of T. palustris. To analyze its morphological features, many living plants were examined, with particular attention to the spore structure. A total of 179 plots (110 species) and 34 pools were sampled. Our results highlight the relic character of the species which is at the southernmost border of its distribution range. The micro-morphological investigations on the spores show that the Sicilian population belongs to the subsp. palustris. The floristic analysis confirms the clear dominance of perennial temperate-cold zones Eurasian taxa. Finally, a new association, Thelypterido palustris-Caricetum paniculatae, within the Caricion gracilis alliance (Phragmito-Magnocaricetea class) is described.

Floristic and Vegetation Changes on a Small Mediterranean Island over the Last Century.

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.