Identification notes
This is our only strictly aquatic Fissidens (although F. pusillus, F. crassipes and F. rufulus are all predominately or almost exclusively aquatic) and it’s a distinctive-looking species too. It can be quite hard to find unless you’re actually in the water yourself as it often grows submerged on various surfaces, although rarely very deeply. When out of the water the shoots cannot support themselves and are limp and flaccid. In the water, the shoots have quite a fine-textured appearance and, especially when covered in silt, can easily be overlooked for the kind of filamentous algae that sometimes grow in the same habitat.
Read the Field Guide account
