Rocky coastal vegetation of the class Crithmo-Staticetea in the south-east of Italy

In the south-east of Italy, rocky coasts are almost entirely concentrated in the Apulia region. Several phytosociological papers have already dealt with the rocky coastal vegetation of the class Crithmo-Staticetea in some parts of the Apulian coast. However, there is still no overall revision carried out by using modern statistical treatments of phytosociological data. This paper aims to revise the syntaxonomy and nomenclature of the class Crithmo-Staticetea in the south-east of Italy. The revision is based on a data set of 225 relevés consisting of new and original phytosociological relevés (66) and others already published. The data matrix was classified with the use of flexible beta clustering. Indicator species analysis was employed to identify the indicator species of the main clusters of relevés. Results were interpreted from a syntaxonomic point of view. Non-metric multidimensional scaling ordination was performed in order to visualize the floristic relationships among associations. Rocky coastal vegetation of the Crithmo-Staticetea class in the south-east of Italy is represented by two orders, Crithmo maritimi-Staticetalia and Helichrysetalia italici. The first one includes two alliances, Crithmo-Staticion and Limonion anfracti-cancellati, with four associations and one, respectively. However, since they rely on very few character species, the floristic and syntaxonomic relationships between these two alliances need to be deepened by further investigations, involving a larger data set and investigation area. The second order, Helichrysetalia italici, includes two associations, well differentiated by their ecology, structure and floristic composition. For this reason, they were classified within two different alliances, Anthyllidion barbae-jovis and Helichrysion litorei. The Helichrysion litorei is here validated