The Orophilous Shrubby Vegetation of the Juniperetalia hemisphaericae Order in Sicily: A Refuge Habitat for Many Endemic Vascular Species.

An in-depth analysis of the orophilous vegetation dominated by Juniperus hemisphaerica in Sicily, based on literature data and unpublished relevés, is presented. A total of 156 phytosociological relevés were processed and analyzed using classification and ordination methods. Overall, 151 vascular plant species were recorded, of which 38% were endemic species, with a dominant hemicryptophytic biological form (49%). Classification of the relevés, supported by ordination, showed two main vegetation groups: one including the Juniperus communities of Mt. Madonie (Cerastio tomentosi-Juniperetum hemisphaericae and Pruno cupanianae-Juniperetum hemisphaericae), and the other including the vegetation of Mt. Etna (Bellardiochloo aetnensis-Juniperetum hemisphaericae and Roso siculae-Juniperetum hemisphaericae ass. nova). Furthermore, a new alliance, Berberido aetnensis-Juniperion hemisphericae, is proposed for 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.

Centaurealovricii, a new species of C. sect. Centaurea (Asteraceae) from Croatia.

A new species, Centaurealovricii, is described and illustrated from the island of Vis (Dalmatia, Croatia). It occurs on northwest-facing calcareous cliffs near the sea, where it grows with several other rare endemic species. Centaurealovricii is morphologically similar to C.glaberrima and C.divergens of C.sect.Centaurea, from which it differs in having more succulent leaves with larger and less incised leaflets, bigger capitula, larger phyllaries with more developed appendages and denser and undulate fimbriae, larger florets, bigger achenes, and longer pappus. Its morphological features, distribution, ecology, conservation status and taxonomic affinities are examined. In addition, a new iconography and lectotypification for C.glaberrima and C.divergens is provided.

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.

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.

Vascular plant species diversity of Mt. Etna (Sicily): endemicity, insularity and spatial patterns along the altitudinal gradient of the highest active volcano in Europe.

BACKGROUND: Altitudinal variation in vascular plant richness and endemism is crucial for the conservation of biodiversity. Territories featured by a high species richness may have a low number of endemic species, but not necessarily in a coherent pattern. The main aim of our research is to perform an in-depth survey on the distribution patterns of vascular plant species richness and endemism along the elevation gradient of Mt. Etna, the highest active volcano in Europe. METHODS: We used all the available data (literature, herbarium and seed collections), plus hundreds of original (G Giusso, P Minissale, S Sciandrello, pers. obs., 2010-2020) on the occurrence of the Etna plant species. Mt. Etna (highest peak at 3,328 mt a.s.l.) was divided into 33 belts 100 m wide and the species richness of each altitudinal range was calculated as the total number of species per interval. In order to identify areas with high plant conservation priority, 29 narrow endemic species (EE) were investigated through hot spot analysis using the "Optimized Hot Spot Analysis" tool available in the ESRI ArcGIS software package. RESULTS: Overall against a floristic richness of about 1,055 taxa, 92 taxa are endemic, of which 29 taxa are exclusive (EE) of Mt. Etna, 27 endemic of Sicily (ES) and 35 taxa endemic of Italy (EI). Plant species richness slowly grows up to 1,000 m, then decreases with increasing altitude, while endemic richness shows an increasing percentage incidence along the altitudinal gradient (attributed to the increased isolation of higher elevation). The highest endemic richness is recorded from 2,000 up to 2,800 m a.s.l., while the highest narrow endemic richness (EE) ranges from 2,500 up to 2,800 m a.s.l. Life-form patterns clearly change along altitudinal gradient. In regard to the life-form of the endemics, the most represented are the hemicryptophytes, annual plants (therophytes) are prevailing at lower altitudes and show a decreasing trend with increasing elevation, while chamaephytes are featured by an increasing trend up to 3,100 m of altitude. Furthermore, the results of the hotspot analysis emphasize the high plant conservation priority areas localized in oro-mediterranean (1,800-2,400 m s.l.m.) and cryo-mediterranean (2,400-2,800 m) bioclimatic belts, in correspondence of the oldest substrates of the volcano. CONCLUSIONS: High plant speciation rate caused by increasing isolation with elevation is the most plausible explanation for the largest active volcano in Europe. The high degree of endemic species on Mt. Etna is linked to its geographical, geological and climatic isolation, all important drivers of speciation acting on the population gene flows. The hot spot map obtained represents a useful support for help environmental decision makers to identify priority areas for plant conservation.

Seed Dormancy Breaking and Germination in Bituminaria basaltica and B. bituminosa (Fabaceae).

Most legumes are well-known for the physical dormancy of their seeds; hence, the implementation of appropriate scarification techniques is essential for introducing new legume crops within agricultural systems. This study investigated morpho-anatomical traits and dormancy-breaking requirements in two taxa of the genus Bituminaria: the widespread B. bituminosa and the point endemic B. basaltica. As the species under investigation show monospermic indehiscent legumes, pods were used in this research. We performed pod trait measurements, light microscopy observations on the seed coat anatomical structure, and germination tests after mechanical, thermal, and chemical scarification treatments for seed dormancy breaking. Moreover, germination performance at different pod maturity stages and storage times was tested. Differences in morpho-anatomical traits were found, with B. basaltica having a thicker palisade cell layer and B. bituminosa showing larger pods. All of the scarification treatments proved to be able to break physical dormancy, with mechanical and chemical scarification being the most effective methods in both species. Nevertheless, dormancy-breaking treatments performed better in B. bituminosa. Seeds at early pod maturity stages showed higher germination capacity in both species. Overall, this research provided background knowledge on seed collection time, storage strategy, and effective pre-sowing treatment, which might contribute to enhance propagation and use of Bituminaria species for multiple purposes. Under this perspective, the future characterization of additional Bituminaria genetic resources from other Mediterranean populations will have remarkable importance.