This name is a synonym of Rhytidophyllum exsertum subsp. villosulum (Urb.) Borhidi.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50261382) with original publication details: Brittonia 9(1): 23 1957.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:220794-2.
This name was in version 1 of The Plant List, record tro-50261382.