This name is a synonym of Cymbopogon bombycinus (R.Br.) Domin.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50169810) with original publication details: Biblioth. Bot. 85: 273 1915.
This name record (from Tropicos) 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 Cymbopogon exaltatus in version 1 of The Plant List.