I'm sure I'm not the first person to suffer this affliction.
There was a nice big patch of fruiting Bryum on sandy ground behind the beach at Rest Bay, Porthcawl on Saturday.
Capsules ranged from unripe to ripe so I took a sample to have a bash at getting it to species. An evening in front of the microscope, however, has left me non-plussed as I was unable to satisfactorily key it out using Smith. Below are a few photos and notes which I hope, in combination with the sandy habitat, will enable one of you to alleviate my suffering.
Capsules: exostome teeth with vertical as well as horizontal divisions, not oblique. Cilia appendiculate. Synoecious (I think - there are what look like male organs at the base of the seta). Spores 15 microns diam.
I hope it's not just B. dichotomum! Hopefully the reddish leaf base rules this species out.