The following feminine names occur in the matronymic field of the database; that is, they all appeared in the original source data in matronymic bynames following di 'of'. It is possible that some of these names are actually masculine names either in unusual forms or as typographical errors, but at least Maddelena has no masculine equivalent. Moreover, the number of them is sufficiently large that an explanation based on typographical errors seems unlikely.
These names are still quite uncommon; there are 55 examples listed below, out of 26,367 patronyms (i.e., 0.2% of names are matronyms). This is much lower than the incidence of matronymic bynames in languages like English.
The matronyms occuring in this data are found below:
Each of the following names occurs three times: Corda, Fidanza, Francesca, and Schiatta.
Each of the following names occurs twice: Apollonia, Bonta, Germia, Lorenza, Piera, and Rota.
Each of the following names occurs once: Badia, Bertella, Branecca, Campanara, Casiera, Cinella, Citerna, Daglia, Dea, Deldra, Derata, Frena, Gavanza, Gavazza, Geremia, Ghinaglia, Lona, Maddalena, Namoraza, Nencia, Pecciera, Pisa, Perilla, Recola, Rolliccia, Sandra, Spada, Sparta, Spina, Suana, and Torima.