Occurrence of Chara spp. in the Bussento and Calore rivers of the “Cilento, Vallo di Diano e Alburni” National Park (Salerno, southern Italy)

Charophyte are freshwater algae constituting the monophyletic clade in which land plants evolved (1). The Italian flora, according to the most recent revision (2), includes 33 species belonging to 6 genera: Chara, Lamprothamnium, Lycnothamnus, Nitella, Nitellopsis and Tolypella. Species distributional data, however, are often incomplete and outdated, especially for the Campania region, where only 3 species (Chara intermedia A.Braun, Ch. braunii C.C.Gmel., Lamprothamnium papulosum J.Groves) were historically reported (2). With the aim to contribute to the understanding of the Charophyte flora of the “Cilento, Vallo di Diano e Alburni” National Park, the largest protected area in Campania and one of the largest in Italy, extensive field surveys were carried out during the years 2016-2018 on the two main river systems of the area: the Bussento and the Calore Salernitano. Overall, 8 populations belonging to 4 taxa were observed, encompassing 3 species new for the Campania region (Ch. vulgaris L., Ch. gymnophylla A. Braun, Ch. globularis Thuill.) and one new infraspecific taxon for the Italian flora (Ch. vulgaris var. papillata K.Wallroth). Detailed analyses of each population, involving morphological (number of branches and branch segments, cortication, size of internodes, branch segments, spines, stipuloides, oogonia), biochemical (photosynthetic pigments, nitrogen balance index), and physiological (fluorescence parameters, carbonate encrustation) traits were performed in order to evaluate population variability and differentiation. The occurrence of most of the observed taxa in rivers, instead of the lentic systems usually colonized, further expands our understanding of the ecology of this peculiar and evolutionary pivotal group of algae. 1) J. De Vries, J.M. Archibald (2018) New Phytol., 217, 1428-1434 2) G. Bazzichelli, N. Abdelahad (2008) Ministero dell'Ambiente e della Tutela del Territorio e del Mar