Abstract
We present the first vascular flora of the municipality of Pisa. The floristic inventory was built on previous literature and field observations deposited in the online database Wikiplantbase #Toscana, integrated by observations from iNaturalist. The established flora of Pisa includes a total of 1404 specific and subspecific taxa (594 genera, 123 families), out of which 112 are alien species. Silene subconica is excluded from the regional flora of Tuscany, while Solanum nitidibaccatum is reported as a new regional casual alien, and the regional alien status of Salpichroa origanifolia shifts from naturalized to invasive. Native taxa exceed species-area predictions by 33.3%, attesting for a high floristic richness, and there are taxa of high biogeographical and conservation interest. However, also alien taxa exceed predictions by 34.9%, and there are many invasive species, pointing out a high anthropogenic impact in the territory of Pisa, mostly due to urbanization. The biological and chorological spectra reflect the coexistence of typical Mediterranean and central European habitats in this territory, especially within the Migliarino-San Rossore-Massaciuccoli Regional Park. The vascular flora of the municipality is quite rich, although threatened by anthropic pressures, fostering the arrival and establishment of invasive alien species.