It is always a relief with difficult species groups to encounter one that is unmistakable and the compact bog moss (Sphagnum compactum) certainly comes in to that category. It is a species of moss one can easily take for granted living here in Purbeck surrounded by heath where there are wet bogs and poos which make this seem quite a common plant but because its habitat requirements are quite strict it is not actually a common species across the country or, indeed, across the county. It thrives best where a thin layer of peat lies over a bed of sand or gravel but where, despite the porous under soil it remains wet or, at least, damp.
This moss has tightly compacted bunches of stems that are so tightly woven together that the individual stems are not visible. This forms a dense carpet of the moss that can cover quite large areas. This species also gives the impression it is dying when actually it is doing very well because it has a brownish tinge to it.Sphagnum compactum: the compact bog moss