This name is a synonym of Polypodium polypodioides var. michauxianum Weath..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 26615204) with original publication details: Contr. Univ. Michigan Herb. 19: 46 1993.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:1191331-2.
This name was in version 1 of The Plant List, record tro-26615204.