A moss often found in wet, base-rich flushes, frequently with Drepanocladus revolvens (to which small forms can be superficially similar). It is usually robust, with a swollen appearance, and coloured purple or dark red, going to almost black in its lower parts. The leaves are wide, concave in the middle, tapering abruptly to a short point. They are wrinkled, and usually have only a very short, forked nerve.