This name is a synonym of Pteridium aquilinum var. latiusculum (Desv.) Underw. ex A. Heller.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50276386) with original publication details: Acta Univ. Lund., n.s., 37(1): 43 1941.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:1097228-2.
This name was in version 1 of The Plant List, record tro-50276386.