The dataset refers to 4535 selected floristic collections mainly done by the first author in southern Tuscany (Maremma, Italy) during the last 35 years (1989-2024, Herbarium F. Selvi). The collections are largely unpublished and currently kept in the Herbarium Centrale Italicum at the Natural History Museum of Florence University (FI, H.C.I.). The collections belong to 1766 specific and subspecific taxa with updated names according to the Portal to the Flora of Italy, in 122 families of vascular plants. Each record is associated with textual information on the collection locality, date, collector(s), number and geographical coordinates in the WGS84 system. Many collections were made in floristically poorly known parts of the region and mostly in the province of Grosseto, documenting new sites of several uncommon or phytogeographically relevant taxa. The information dataset allows to deepen the botanical knowedge of Tuscany and central Italy.