Hygroamblystegium fluviatile Brook-side Feather-moss

A dingy dark-green, aquatic, pleurocarpous moss which grows on rocks, stones, slabs, embankment walls and bridges and tree roots in or near to fast flowing rivers and streams, where it may be submerged. In fast flowing water the shoots can be quite long with short branches. The leaves are more or less egg-shaped and concave with a very stout nerve that reaches the leaf tip. It is very similar to Hygroamblystegium tenax, which is usually smaller with more obvious pinnate branching and leaves that have an acute leaf tip. Hygroamblystegium fluviatile prefers neutral or slightly base-rich water whereas Hygroamblystegium tenax tends to grow in more acidic water. It has a distinct western and northern distribution in Britain but is absent from most of northern Scotland. It is widespread throughout most of Wales, especially in the south, and it is found in most of the main river systems and many of the major streams in West Glamorgan. Sporophyte capsules are occasional in summer.