This name is a synonym of Crataegus × polyacantha Jan.
The record derives from RJP
(data supplied on 2011-10-18)
which reports it as a synonym (record 1778) with original publication details: Flora sicula Flora sicula; 1889 209, t.18,f.2 1891.
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 Crataegus destefani in version 1 of The Plant List.