Mnium hornum is one of the mosses found in our woodlands that is fairly distinctive in that it has large 'leaves' that are almost fern like. It is a rather dull, dark green moss but, nonetheless, an attractive species. In spring the new and almost yellow leaves are in stark contrast to the older ones.
My book describes it as a common species but I have not encountered it that often on my travels. In Dorset it is undoubtedly a woodland species (it can grow at high levels in other parts of the country) that forms large carpets on earth banks, rotting logs and tree stumps and on tree bases. It is described as liking acid, well drained soil conditions and is considered to favour birch woodland. There is much of that in the Poole basin but still I have not found it to be common. That said, not being a moss expert, I may have missed it of course.
It has recently been given the common name of the forest star. I personally cannot quite see the connection, forest yes but star? However, I did not name it so who am I to argue!