Thursday, 10 March 2016

River Tawe

Yesterday afternoon we explored a nice stretch of the River Tawe between Pontardawe and Ystalyfera, all of which is in Neath Port Talbot. We've recorded Mnium marginatum there before, but it was nice to find some significant clusters in the vicinity of SN74350568. Nearby river banks had small amounts of Mnium stellareTrichostomum tenuirostre and some Homalia trichomanoides which is not common on the Tawe in our experience. Large riverside boulders had Cinclidotus fontinaloides, Schistidium apocarpum, S. platyphyllum and S. rivulare and on some there were  photogenic cushions of Orthotrichum cupulatum. It's a good time to look out for this smart 'rocky' Orthotrichum, which is often conspicuously dressed in abundant capsules.

Orthotrichum cupulatum on a riverside boulder near Ynysmeudwy

What we didn't find was Leskea polycarpa. It seems to be genuinely scarce on the 3 main rivers in NPT where we have only found a few colonies along the lower stretches above the tidal reach.


  1. L.polycarpa seems to prefer the siltier rivers, such as the Loughor, where it can be very frequent - some other nice records on what's been a glorious day

  2. There'll be a couple of other Leskea dots around Cardiff too, when I send you this year's records. It's certainly quite frequent here and I expect to find it whenever I do riverbank searches (though often in small quantity).

    O. cupulatum, on the other hand, is conspicuous in its absence from the east. I expect I may have overlooked it to some extent, though I have recorded it elsewhere.

  3. I think comments like yours on the relative abundance are really valuable, as sometimes distribution maps only paint half the picture - the map does not reflect the relative abundance on the Tawe and Loughor. I know adding comments to records is time consuming, but it's a very valuable exercise and something I know I should to do more often.

    I'm guessing the distribution of cupulatum in the county reflects recording effort?

  4. Ha ha we must have posted at the same time George!