A taxonomic revision of the populations belonging to the Dianthus sylvestris Wulfen group (Caryophyllaceae) occurring in central and southern Italy, Sardinia and Sicily has been made. This group is represented in the surveyed territories by 17 morphologically and ecologically well differentiated species: Dianthus arrosti C. Presl, D. siculus C. Presl, D. graminifolius C. Presl, D. cyathophorus Moris, D. gasparrinii Guss., D. longicaulis Ten., D. virgatus Pasquale, D. tarentinus Lacaita, D. morisianus Vals., D. japygicus Bianco & Brullo, D. sardous Bacch., Brullo, Casti & Giusso, D. busambrae Soldano & F. Conti, D. brachycalyx Huet sp. nov., D. oliastrae sp. nov., D. insularis sp. nov., D. genargenteus sp. nov. and D. ichnusae sp. nov. Besides, two new subspecies are recognized within D. ichnusae (subsp. ichnusae and subsp. toddei). This taxonomical treatment is supported by a multivariate analysis based on 25 morphological characters and 1 phenological character. Each of the taxa is described and illustrated. In addition, notes on nomenclature, ecology, chorology, taxonomical relationships and conservation status are given. Lectotypes are designated for those taxa that are based on material from the investigated territories.

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The vegetation of mining dumps of SW-Sardinia includes\ud several endemic or rare species, that have\ud been confined to such artificial habitats by a millennial\ud mining activity. The extreme edaphic specialization\ud of these species reflects with unusual fidelity the\ud heterogeneity of substrata, therefore creating a system\ud of plant communities that largely contributes to\ud the environmental diversity of this part of the island.\ud The phytosociological study presented in this paper\ud recognized eight associations, distinguished by the\ud cluster analysis in two main groups, the first including\ud hemicrypto-chamaephytic vegetation, the second\ud including nanophanerophytic garigues.\ud Six associations are belonging to the first group,\ud five of which newly described: Helichryso tyrrhenici-\ud Dianthetum sardoi ass. nova occurring on\ud gross-grained, hard-sloping dumps deriving from the\ud geologic unit of Gonnesa; Coincyo recurvatae-\ud Helichrysetum tyrrhenici ass. nova colonizing\ud dumps made of metamorphitic flakes and finer particles;\ud Resedo luteolae-Limonietum merxmuelleri\ud ass. nova colonizing small-grained mining dumps\ud with high concentrations in sulphides and heavy\ud metals; Ptilostemono casabonae-Iberidetum integerrimae\ud ass. nova replacing the previous one on\ud older and more consolidated dumps, where the concentration\ud of phytotoxic elements was reduced by\ud the meteoric agents; Epipactidetum tremolsii ass.\ud nova colonizing muddy deposits originating from\ud ferrous clay; Euphorbio cupanii-Santolinetum insularis\ud ANGIOLINI & BACCHETTA 2003, occurring on\ud very old, stabilized dumps. All these associations\ud can be ascribed to the class Scrophulario-Helichrysetea\ud BRULLO, SCELSI & SPAMPINATO 1998. Within\ud this class, a new Sardo-Corsican alliance, Ptilostemono\ud casabonae-Euphorbion cupanii all. nov. is\ud here proposed, differentiated by a pool of rare or\ud endemic species. In addition to the above-mentioned associations, it is proposed, as well, to include into\ud the new alliance the Polygono scoparii-Helichrysetum\ud tyrrhenici BIONDI, VAGGE, FOGU & MOSSA 1996\ud corr., that was described for the gravelly riverbeds of\ud Central-Southern Sardinia.\ud As concerns the second group, two new association\ud have been recognized: Dorycnio suffruticosi-\ud Genistetum corsicae ass. nova, found on abandoned,\ud well consolidated mining dumps, with an upper\ud layer altered by pedogenetic processes; Polygalo\ud sardoae-Linetum muelleri ass. nova, occurring in\ud the vicinities of the mines on steep rocky slopes\ud made of Paleozoic metalliferous limestones. Both of\ud them can be ascribed to the alliance Teucrion mari\ud GAMISANS & MURACCIOLE 1985, grouping the\ud Sardo-Corsican aspects of Cisto-Lavanduletea BR.-\ud BL. in BR.-BL., MOLINIER & WAGNER 1940.\ud Two taxa are new for science: Dianthus sardous\ud BACCHETTA, BRULLO, CASTI & GIUSSO, sp. nova and\ud Helichrysum microphyllum (WILLD.) CAMB. subsp.\ud tyrrhenicum BACCHETTA, BRULLO & GIUSSO, subsp.\ud nova

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Habitat monitoring in Europe is regulated by Article 17 of the Habitats Directive, which suggests the use of typical species to habitat conservation status. Yet, the Directive uses the term “typical” species but does not provide a definition, either for its use in reporting or for its use in impact assessments. To address the issue, an online workshop was organized by the Italian Society for Vegetation Science (SISV) to shed light on the diversity of perspectives regarding the different concepts of typical species, and to discuss the possible implications for habitat monitoring. To this aim, we inquired 73 people with a very different degree of expertise in the field of vegetation science by means of a tailored survey composed of six questions. We analysed the data using Pearson's Chi-squared test to verify that the answers diverged from a random distribution and checked the effect of the degree of experience of the surveyees on the results. We found that most of the surveyees agreed on the use of the phytosociological method for habitat monitoring and of the diagnostic and characteristic species to evaluate the structural and functional conservation status of habitats. With this contribution, we shed light on the meaning of “typical” species in the context of habitat monitoring.