Le raccolte di Luigi Ceroni (1883−1951) all’ex scalo merci ferroviario di Milano Porta Sempione (Lombardia, Italia)

Unlike Central Europe, the Italian railway flora has never been seriously studied until the mid-20th century. Few botanists, mostly interested in the alien flora, ventured into these adverse and hardly accessible areas. One of them was Luigi Ceroni (1883-1951), psychiatrist at the Como mental hospital, who collected, between 1938 and 1940, 56 herbarium specimens at the former Milano Porta Sempione freight yard. These exsiccata, now stored at the University of Pavia “Erbario Lombardo” (PAV), represent 38 species, many of which are still common today in the Northern Italy railway system; further taxa, linked to the previous loading/unloading activity of the yard, are now very rare or disappeared from the Milan urban flora. Besides a detailed list of the studied specimens, this paper provides a history of the Sempione freight yard (operating from 1883 until 1931) as well as a survey of the Luigi Ceroni neglected figure, who, for half of a century, was active as a methodical and prolific plant collector all over the Italian peninsula