With its long, tapering leaves, this common species can easily be confused with Didymodon or several other similar-looking acrocarps. If red/brown pigments are present in the leaves, then that helps, but quite often these are poorly developed in shade forms.
A couple of reliable jizz characters will help to clinch the identification, or at least point you in the right direction. Firstly, dry leaves lack any shine or lustre (because they are densely papillose) and also look opaque. Secondly, look at the leaf margins – they are very strongly (but narrowly) recurved from base to leaf tip.
To separate short-leaved forms growing on the ground from B. ferruginascens, check the soil around the rhizoids – B. recurvirostrum lacks the distinctive bright red rhizoidal tubers of that species.Read the Field Guide account