Friday, 8 July 2016

Maen Llia Leucodon

I was surveying near Ystradfellte on Wednesday and couldn't resist a quick visit to the famous Leucodon sciuroides colony which grows on the Maen Llia standing stone. I was impressed by the quantity of Leucodon on both sides of the stone, growing with a range of calcicoles (I didn't have a lens or take any samples - but I assume the assemblage has been well recorded by Graham and Sam in any case).

The most striking thing is that this scarce moss survives in one of the bleakest, most 'sheepwrecked' parts of the Beacons - apart from the odd hawthorn there was barely a tree in site.

I only had my cheapo work camera so the photos aren't the best - I'm sure some of you have better ones! The Leucodon stands out as the dark patches among the paler green of Homalothecium sericeum. It would be fascinating to accurately map the distribution of the mosses on the stone to see how they change over time (maybe old photos of the stone would help with this?).
East face
West face


  1. I remember seeing it there over 30 years ago and Roy (Perry) knew it from there before that. There was quite a bit of it on one side of the rock as I recall. It's nice to see it doing so well. Roy also told me that he had recorded Haplomitrium in the vicinity but I was unable to find that.

  2. There's Haplomitrium on fine gravelly soil by the Afon Llia. It's a pretty tough thing to spot anywhere, but with a bit of luck you'll find it by the Llia. As an illustration, when I was interviewed by Mary Colwell for "A life with mosses" on Radio 4, we visited the Haplomitrium colony and I found it on the first rock we checked!

  3. The other thing I remember about that Leucodon colony was its abundant branchlets - something that is variably abundant in this species.

  4. Darn I wish I'd remembered that when I was up there as I spent a bit of time by the Llia. I remember it from Sam's interview now (first found by Jean Paton?).

  5. mmm maybe this could be a good candidate for a 3D laser scanner. This could create a 3D model that could be used as a baseline for the future. I think you could digitally annotate the different mosses.....I recon this could be useful for the achaeological monitoring too. Ill ask around, Cardiff Uni have one and may want a left field project !>? There is another standing stone nearby at SN 91811 15763 just up the old roman road (now footpath) to Plas y Gors.