This name is a synonym of Rheum nanum Siev. ex Pall..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50136447) with original publication details: Nova Acta Acad. Sci. Imp. Petrop. Hist. Acad. 10: 381 1797.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:696749-1.
This name was in version 1 of The Plant List, record tro-50136447, and has not been changed.