This name is a synonym of Luma chequen (Molina) A.Gray.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 454408) with original publication details: Linnaea 25: 652 1853.
This name record (from WCSP) 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 Myrtus uliginosa in version 1 of The Plant List.