This name is a synonym of Ruilopezia marcescens (S.F.Blake) Cuatrec..
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 19809978-9984-4763-87D0-E3FF804921DA) with original publication details: Contr. U. S. Natl. Herb. 20 536 1924.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:97720-2.
This name was in version 1 of The Plant List, record gcc-132766, and has not been changed.