This name is a synonym of Crataegus pentagyna Waldst. & Kit. ex Willd..
The record derives from RJP
(data supplied on 2011-10-18)
which reports it as a synonym (record 1679) with original publication details: Flora taurico-caucasica Flora taurico-caucasica; 1808 386 1808.
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 melanocarpa in version 1 of The Plant List.