This name is a synonym of Isothecium alopecuroides (Lam. ex Dubois) Isov..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 35118476) with original publication details: Sp. Musc. Frond. 266 1801.
This name was in version 1 of The Plant List, record tro-35118476.