Tuesday, 19 December 2017

Bryum headache

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.
Leaves 0.75mm long, broad, strongly concave. Costa longly excurrent. Leaf margins strongly recurved but appear not to be bordered (unless border hidden in recurved section). Mid leaf cells c. 12 microns diam. Leaf base pinkish red.

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.


  1. It does look rather small, so I'm afraid I'd err towards B dichotomum. Sorry, that's not going to help your misery!

  2. Thanks Sam! Before I saw your reply I'd posted the query on the bryophytes Facebook group. Des Callaghan replied wondering if it might be B. archangelicum. Later on Graham Motley emailed me with a pdf copy of David Holyoak's 2013 Bryum key, so I tried that and it did key out as archangelicum. The crucial mistake I'd made was confusing the endostome processes with cilia...on re-checking I couldn't find any cilia, so I think they must be absent or rudimentary.

    It seems to fit archangelicum pretty well (synoecious, reddish leaf base, longly excurrent costa). The spores are on the small side but perhaps not fully mature?