Tuesday, 6 January 2015

Penclawdd copperworks revisit 1

Plagiomnium cuspidatum with a few scraps of Lophozia excisa
I nipped down to Penclawdd to take Alfie for his constitutional walk today and spent 40 minutes on part of the ridge mentioned below. I was very pleased to relocate Sam's Plagiomnium cuspidatum, although P. affine/undulatum? [see below] was more frequent and I also found a few scraps of Lophozia excisa. In the process of producing a more complete list for the site I was struck by the Bryum below, which looks very kunzei-like to me. Whilst calcifuge species were more prominent, there were scattered patches of calcicoles; associates in the immediate vicinity of the Bryum included P. affine, B. capillare, Hypnum cupressiforme var. lacunosum, H. jutlandicum, Ceratodon purpureus & Barbula convoluta. Under the microscope the leaf margins are very weakly bordered with a few tiny, but sharply pointed teeth distally. the margins are weakly recurved towards the leaf base which is pigmented red. The single unripe sporophyte may be a bit of a negative as I'm not sure if fruiting is known in Britain? As always any comments are welcome.
Bryum caespiticium and spot the Lophozia excisa!
Re: Plagiomniun aff/und - I often get muddled by these two as stunted undulatum looks very similar to affine to me - what is the best way to separate them in the field?


  1. That Bryum does look interesting, but I doubt it will prove identifiable. It looks rather like B caespiticium to me, so if you are feeling brave you could try dissecting the base of the seta to establish whether there are any antheridia there...

    Plagiomnium undulatum has much smaller leaf cells than the other British Plagiomnium spp. Through a x10 it looks very densely celled, whereas P affine (and P elatum, P ellipticum and P rostratum) look much more open-celled.

  2. Phew, that's what I have been basing my id's on and just checked so my initial id of affine was correct. The reason for my query was that I recorded the non-cuspidatum plants as affine, but got home to find you'd recorded undulatum at the site, however I suspect your plants were in adjacent habitat as undulatum is frequent along the fp, plus you recorded a few other things more likely to have been on the marsh edge, e.g. Phil.font, Phys.pyri, etc... Excluding these and what I suspect is non-fruiting Bryum pallescens the list for the slag currently stands at 39 species.

    Just checked and the Bryum does have antheridia at the base of the seta, but not sure what that means in respect of id? Smith makes out kunzei is straight forward on vegetative characters?

  3. Sorry I may have jumped the gun there, they look more like archaegonia - I clearly need to go on the next Bryum workshop!

  4. I had another good poke around with the spec again first thing and all I could find were archegonia and paraphyses. I'll keep the spec for what it's worth, but I'll need go back when the capsules ripen.

  5. You've posted a nice photo of archegonia at the base of the seta, but no sign of antheridia. One more poke might be necessary to confirm there aren't any male branches below the perichaetium, but I think there is a very good chance that you have dioicous female Bryum caespiticium which would be an excellent record. If you can't see any obvious branches below the perichaetium then we can record it confidently as B caespiticium, which is also what the long-excurrent nerve and general appearance suggest.

  6. I've a had a very thorough poke around the bases of this and a couple of other shoots with sporophytes and can't find any sign of antheridia, so have logged it as caespiticum. This has been a good lesson - Thanks.