This name is a synonym of Equisetum × schaffneri Milde.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50065010) with original publication details: Monogr. Equiset. 444 1867.
This name was in version 1 of The Plant List, record tro-50065010, and has not been changed.