Declining acidophiles

Just before Christmas I spotted three uncommon mosses at Dingestow: Plagiothecium latebricola was new for the area (bryophyte number 242), Bryum moravicum was the 2nd Dingestow record and the first in VC35 since 2008, and Aulacomnium androgynum used to be frequent at Dingestow in 1999/2000 but was last seen in VC35 in 2009.  The Plagiothecium is remarkably small and easily ignored/overlooked, but formed a dense cover over ca. 30 square cm of a huge log.

Llandogo Ravine

 

The rocky cascades of Cleddon Shoots/Llandogo Ravine near Tintern in the Wye Valley hold a remarkable array of bryophytes, including several that are disjunct from main populations further NW in Wales.  I haven't yet relocated the Platyhypnidium lusitanicum that was recorded there by Warburg in 1954, and it's possible that the water is now too base-rich for it, but most of the other notable species seen by previous generations of BBS members are still present, including Jungermannia paroica, Lejeunea patens, Plagiochila spinulosa, Fissidens rivularis and plenty of Jubula hutchinsiae.  I visited the site on Sunday with Bea & Johnny and photographed some Jubula, as well as taking some habitat shots for a putative VC35 Bryophyte Flora (in prep. in perpetuity?).  A couple of previously unrecorded species caught my eye in passing: a small patch of Plagiothecium latebricola on a huge log was the first VC35 record since 1995 and only the 6th ever, and some Oxystegus tenuirostris adjacent to a cascade was notable (although I've seen it in a couple of other Wye Valley woods).  This is a really special SSSI, and it was useful for me to see the clear link between cascades and the distribution of the Jubula.
 

Ty-du Moors SSSI

I spent a fascinating and enjoyable day on this Cardiff fen with Julian Woodman, trying to work out why base-rich areas (with Eriophorum latifolium, Epipactis palustris, Gymnadenia sp. and Triglochin palustris) are becoming increasingly dominated by Sphagnum subnitens and Aulacomnium palustre.  We concluded that more work is needed, with input from Gareth Farr (what a shame you couldn't join us today, Gareth), but probing revealed over 2.5m of peat near the centre of the moor, whilst test coring showed that the base-rich areas and associated Juncus subnodulosus fen are on continuous peat, whereas the edges of the moor with Carex acutiformis fen has a layer of organic-rich clay-silt above the peat.

Campylium protensum is locally abundant in the remaining good, base-rich areas, along with Fissidens adianthoides, Plagiomnium ellipticum, P. undulatum and one stand of Dicranum bonjeanii.  Chiloscyphus pallescens and Cratoneuron filicinum were only in one area.  Poached damp grassland held Pseudephemerum nitidum and one patch of Ephemerum serratum. 

A check of surrounding Willow scrub was worthwhile, with a fruiting patch of Pylaisia polyantha on one Willow, as well as commoner epiphytes.  I think this is the 2nd Glamorgan record, following one on south Gower.  It's a pity that I found this epiphyte after George had left us, following his visit in the morning.  Nearby Alder carr held a peculiar tiny, narrow-leaved moss with gemmae on the leaf tips, forming an extensive patch on a well-rotted log.  I'm 99% certain this is Plagiothecium latebricola. {sorry about the bad iPod photos, I wish I knew how to rotate them in Blogger}.
 

Julian and I ended the day with a visit to some wonderful damp arable fields that Nick, the owner of Ty-du Moors, manages.  We relocated the Anthoceros that Julian and George saw last autumn, and I have a specimen to measure (though it's 99% certain to be A. agrestis).  Alongside were several thalli of Phaeoceros sp. (probably P. carolinianus but needing more study), and abundant Riccia glauca and Fossombronia sp.

All in all a good day, and I hope a boost for tetrad ST17E.