This name is a synonym of Scleria tonkinensis C.B.Clarke.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 453366) with original publication details: Fl. Hongk. 400 1861.
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 Scleria levis in version 1 of The Plant List.