The ‘Chara hispidaspecies complex’ (Charales, Charophyceae) kept in the Herbarium RO of the Sapienza University of Rome

Seventy-seven specimens of the Chara hispida species complex, stored in the Herbarium of Sapienza University of Rome (RO), identified over time with different names, have been examined. This paper reports: (1) the most important information recognised on the labels, (2) images of selected specimens, (3) a nomenclatural update of the names according to the most recent monograph on Characeae, (4) a distribution map of the collection sites in Europe, and (5) a revision of the Italian exsiccata of this complex.