This name is a synonym of Malus florentina (Zuccagni) C.K.Schneid..
The record derives from RJP
(data supplied on 2011-10-18)
which reports it as a synonym (record 11197) with original publication details: Hortus dendrologicus Hortus dendrologicus; 1853 176 1853.
This name record (from RJP) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Sorbus florentina in version 1 of The Plant List.