This name is a synonym of Brachythecium plumosum var. nitidum (Sakurai) Takaki.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 35115741) with original publication details: Bot. Mag. (Tokyo) 55: 210. 11 1941.
This name was in version 1 of The Plant List, record tro-35115741, and has not been changed.