The results of a phytosociological investigation regarding the orophilous cushion-like vegetation occurring in the top of the high mountains of central-southern Greece and in some Ionian (Lefkas, Cephalonia) and Aegean Islands (Euboea, Samos, Lesvos, Chios and Thassos) are provided. Based on 680 phytosociological relevès (460 unpublished and 220 from literature), a new syntaxonomical arrangement is proposed with the description of a new class, including two new orders, eight new alliances, and several associations (many of them new). Compared to the previous hierarchical framework usually followed in the literature, this study provides a more realistic and clear phytosociological characterization of this peculiar and archaic vegetation type, which is exclusive to the high mountains of the north-eastern Mediterranean. The new arrangement is mainly based on the phytogeographical role of the orophytes featuring this very specialized vegetation, which is essentially represented by endemics or rare species belonging to the ancient Mediterranean Tertiary flora. In addition, taxonomic research on the orophilous flora occurring in these plant communities allowed to identify six species new to science (i.e., Astragalus corinthiacus, Allium cremnophilum, A. cylleneum, A. orosamium, A. karvounis, and A. lefkadensis) and a new subspecies (i.e., Allium hirtovaginatum subsp. samium), and two new combinations (i.e., Astragalus rumelicus subsp. euboicus and subsp. taygeticus) are proposed.

In this paper, Allium sphaeronixum, a new species of the sect. Codonoprasum from Turkey, is described and illustrated. The new species is endemic to Central Anatolia, limited to the area of Nevşehir, where it grows on sandy or rocky soil at an elevation of 1000–1300 m a.s.l. Its morphology, phenology, karyology, leaf anatomy, seed testa micromorphology, chorology, and conservation status are examined in detail. The taxonomic relationships with the closest allied species, A. staticiforme and A. myrianthum, are also highlighted and discussed.

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.

Based on herbarium and field investigations, the taxonomic status of Solenopsis laurentia (Campanulaceae), hygrophilous species belonging to the subfam. Lobelioideae showing a Mediterranean distribution is here examined. According to literature, it can be considered as a species complex, within which several taxa at specific and infraspecific rank were described. Morphological and nomenclatural studies carried out on several living populations coming from many Italian localities allowed to recognize five subspecies. For each of them, a detailed description, iconography, micromorphology of the seed testa and pollen grains, taxonomical relationships, chorology, conservation status and nomenclatural notes are provided. The recognized subspecies of Solenopsis laurentia are the following: a) subsp. laurentia, which is the most widespread in Italy and also in the Mediterranean area; b) subsp. gasparrinii (Tineo) comb. nov., which is quite common in Sicily with scattered occurrence in other Mediterranean localities; c) subsp. caespitosa Brullo, it seems currently localized in Apulia and Sardinia; d) subsp. parvula Brullo, occurring in some localities of the Italian peninsula, Sardinia and Tunisia; e) subsp. hyblaea, described as new for science from Sicily with a punctiform distribution.

Allium croaticum, a new species from the island of Vis in Central Dalmatia (Croatia) is described and illustrated.\ud Its relationships with allied species belonging to the A. stamineum group (Allium section Codonoprasum) are\ud discussed. It is a diploid species (2n = 16), colonizing calcareous screes and flowering in early summer. Its\ud morphology, leaf anatomy, karyology, palynology, ecology and taxonomic position are examined