St Govan's

Bryum kunzei habitat on top of slope

With Weissia capsules starting to ripen, I thought I'd have a good look at the slope tops on the valley at Trevallen, near St Govan's Head. Weissia angustifolia is a local rarity known from the Castlemartin Coast, and I found occasional small patches amongst the rocks on both sides of the valley. I was hoping for Weissia levieri but it wasn't to be. There were good patches of Bryum torquescens, and some Porella platyphylla. Highlights were finding Bryum kunzei to be reasonably frequent in a few places on the top of the slope - previously known from the Gower limestone but not Pembrokeshire. Another new moss for the county was a single small patch of Phascum cuspidatum var. papillosum, or Tortula acaulon var. papillosa as it is now known. This variety is back in favour, apparently rare and southern in distribution. The papillose cells are quite striking in section.

Tortula acaulon var. papillosa, showing ventral nerve cells

 
Bryum kunzei

Funaria pulchella was fruiting well on ledges towards the head, and I found a reasonably strong patch of Platydictya jungermannioides tucked away in a recess on a crag. Just for good measure, an even tinier pleurocarp, Amblystegium confervoides was amongst larger mosses at the base of a crag in the valley. This would have been new to Pembs if I hadn't found a few wisps of it amongst Zygodon on a lime-mortared stream culvert near Martletwy a few days ago. This area is certainly some of the richest limestone country in south Wales.

Platydictya jungermannioides