Thursday, 13 November 2014

Trichostomum brachydontium on a wall top

On my way to a meeting in Brecon today I stopped in a lay-by on the A470 at Abercanaid to spend a few minutes recording bryophytes. There was a small section of mortared wall bearing a plaque, which supported the usual wall-top suspects but also Fissidens dubius on the shaded side of the wall and, more surprising to me, a small patch of what I'm fairly sure is Trichostomum brachydontium on mortar on the wall top. The Carms and Pembs floras don't seem to mention walls as a habitat for this species, but I note Barry has recorded it from limestone walls on Gower. In this case the wall wasn't calcareous but the mortar was obviously to its liking.


  1. T.b. is one those species which early on I could feasibly have misidentified, especially as I was initially focussed on the coast where it was pretty much the default acrocarp. Now you have raised the question I'll revisit one or two sites and re-examine these records.

  2. I don't think of Tb as a wall-top species; Gymnostomum aeruginosum is perhaps more likely, but Barbula unguiculata would be the most plausible lingulate acrocarp. Did you collect a bit, George?

  3. Yes I kept a sample. I don't think it's unguiculata, which I've seen lots of recently - the leaves look too long and the margins are only recurved basally.

    For Tb, Smith mentions crevices in walls, and Watson gives wall-tops as one of the habitats for this species, so perhaps it's not as unlikely as I thought. But I'll be sure to pass Sam the sample at some stage...