Sunday, 12 March 2017

Llyn Eiddwen

More news from distant West Wales.  Llyn Eiddwen is a NNR up in central Ceredigion, it has extensive mires on two sides which are owned by WTSWW and there are some quite choice bryophytes there.

I went in hope of refinding Sam's record of Pseudobryum cinclidioides but soon realised that it was unlikely to be above water since the lake was at least 1 or 2 feet higher than normal and much of the mire at the outflow end of the lake was submerged.  Still it was more than made up by finding numerous colonies of Scapania paludicola.

This distinctive species (did I just write that about a Scapania?) was growing on the tops of many of the Sphagnum hummocks scattered across the mire.  The keel is strongly arcuate but otherwise it is probably closest to S. irrigua although larger than many forms of that variable species.
Also of note were two patches of Cephalozia pleniceps, a rare species in Ceredigion, a hyper-abundance of Straminergon stramineum and a fine patch of Hamatocaulis vernicosus.  The mire is decidedly base enriched, at least in part, but I couldn't see any S. contortum or even Campylium stellatum although Sam had recorded the latter.  A nice patch of Riccardia palmata was a fairly good find for the county too but I was probably most pleased with some scraps of Cladopodiella francisci on a peaty bank at the edge of the mire as I had guessed it would be there if a scraping of liverworts from a vertical bank were examined but only a couple of shoots were present amongst a mat of Ceph bicusp and it would have needed a miracle to have spotted them in the field.

The site now has 144 species and there will undoubtedly be more to come.


  1. Some lovely records there Tom. If you have any tips that will help increase our chances of finding C. francisci in our area we'd love to hear.

  2. I've almost always found C. francisci on vertical but damp cut peat surfaces such as edges of ditches by tracks across acid moorland or where vehicles have eaten into the peaty soil a bit. You need to find a patch where Cephalozia bicuspidata is beginning to get a toehold but where there is still some alga present as that seems to help the liverwort to develop. I sometimes have to sample such alga / Cephalozia mats and then use a dissecting microsope to find the Cladopodiella as individual shoots can be very small. It usually has gemmae though so identification once you've found a candidate is normally straightforward and the concave leaves with rounded lobes are distinctive. When you find a good patch it's easier to spot and even identify in the field. Hope that helps!

  3. Thanks Tom, that's great advice. Hopefully one of us will put it to good use in Glamorgan!