More around St David's

Almost any patch of clay ground appears to hold Ephemerum crassinervium ssp. sessile 

It's hard to believe that Ephemerum crassinervium ssp. sessile is Nationally Scarce, or that Bosanquet (2010) only listed two Pembrokeshire sites for it. Perhaps it's having a good year, but there are dozens of patches of it in any open clay ground in grassland, heath and pond edge on sites around St David's. It's often accompanied by Ephemerum stoloniferum, and sometimes closely admixed, but it can be reliably picked out by the longer, narrower perichaetel leaves even before a hand-lens reveals a nerve.

Another species apparently gaining ground is the Nationally Rare Acaulon mediterraneum, with a new site - the fourth in the county - found on St David's Airfield. This is the first that's not on an exposed headland, and in the same open clay patches as the Ephemerum.  In contrast, the Acaulon quickly colonising the new heathland creation field nearby was muticum.

After finding Cephaloziella integerrima new to the St David's area on the airfield heaths last week, checking the gemmae on various samples turned up another patch on the northern side of the runway. This one was in similar open clay / subsoil and also shaded by a gorse bush (a feature noted on a couple of Cornish records too). I also found a third population on a pile of clay-rich subsoil in Middle Mill Quarry near Solva.

Cephaloziella integerrima location, Waun Llechell

Acaulon mediterraneum spores

On the Bug Farm at Harglodd-isaf, a streamside boulder in rough pasture held a patch of Grimmia laevigata, like the Acaulon mediterraneum only otherwise known in the county from exposed coastal slopes. A good find here was a non-fruiting Physcomitrium in a recently created winter-wet scrape, which appears to be Physcomitrium sphaericum under the microscope. I would have expected the first county record of this to come from the reservoir at Llys y Fran, but it illustrates how good these things are at dispersing. 

Grimmia laevigata

apparent Physcomitrium sphaericum and habitat

 St David's Commons

Middle Pond on Dowrog Common

Thanks to Sarah Beynon at the Bug Farm, I've just started some work surveying commons and some associated land near St David's. Only two days in, but already some surprises.....

I'll confess I wasn't expecting much from Dowrog Common, as under-grazing has left much of it as a sea of rank heath and moor-grass pasture. Pleasing then to find Cladopodiella francisci by a cattle path near the northern fenceline, and some Ephemerum crassinervium ssp. sessile on the stone track to Trefadog. Both are Nationally Scarce - the latter is proving to be almost predictable in the right damp habitats in the county, but the former is only known from single locations on Carn Ingli and Mynydd Preseli.

The star find on Dowrog was a good population of Micromitrium tenerum on the dried-up bed of an ancient clay pit, 'Centre Pond', on the north side of the road. 'Turfs' of this tiny moss, complete with ripening capsules, dominate the silty-clay centre, and smaller patches are interspersed with Juncus bulbosus around this. It is absent from the Scirpus fluitans dominated fringe.  The only associated bryophyte is a small amount of Pseudephemerum nitidum. This represents the only extant Welsh population of this red-listed moss, the two tiny patches recorded at Wyndrush Pastures SSSI a couple of years ago having proved to be a transient occurrence from a long-buried spore bank. The several square metres occupied here may perhaps represent the strongest UK population. There are plenty of other ponds on Dowrog, but all appear to either be overly-trampled clay, or too strongly vegetated. It will be important to maintain the right grazing levels here, and to resist over-deepening or other works. Australian Swamp Stonecrop Crassula helmsii is now rife on parts of the nearby St David's Airfield Heaths, so poses a real threat here too. 

Millimetre Moss - Micromitrium tenerum

Over on the Airfield Heaths, I had no luck refinding the Drepanocladus sendtneri in the small fen-hollow on Waun Llandruidion, although the associates originally noted by Sam Bosanquet (Calliergon giganteum, Scorpidium scorpioides and Scorpidium cossonii) are still present under the Carex lasiocarpa. A small patch of open clay below a gorse bush on an old causeway around Waun Llechell held a tiny patch of Cephaloziella integerrima, which represents a third Welsh site for this rare liverwort, only recently found new to Pembs on the Castlemartin range. The biggest surprise, however, came from the edge of the limestone chip path a few metres away. Growing with Aloina aloides and common ruderal species such as Barbula unguiculata, Pseudocrossidium hornschuchianum and Bryum ruderale I collected four shoots of a non-fruiting Ephemerum. Under the microscope, the broad leaves, strong costa, prominent 'shoulders' and some cells in divergent lines all point to Ephemerum cohaerens. This would represent the first Welsh record (and an atypical habitat), so will shortly go to the referee for confirmation (subsequently confirmed by Sharon Pilkington)

Ephemerum cf. cohaerens and location

Lastly, I had a crawl about on the Bug Farm heathland creation project area that I designed and 'built' last winter. Pleasing to see plenty of open, damp clay as well as heather and gorse germinating well from the mowings from the adjoining Waun Fachelich. Ephemerum crassinervium ssp. sessile and Acaulon muticum were good early results here, amongst the abundant Trichodon cylindricus, Tortula truncata, Pseudephemerum nitidum and other pioneer species.

Heathland Creation field at the Bug Farm

 Pendine and Llanteg

A morning's work carrying out an ecological watching-brief at the Pendine Range this week, to ensure that the petalwort population doesn't get overly disturbed by ongoing works. Although the yard at the end of the test track here is the most heavily disturbed part of the dunes and carries the rarest species....

I'd found Aloina rigida here before Christmas, and it was now fruiting happily on the top of a small sand pile. New to the site, and the county, was Bryum dyffrynense - two patches of which were in a particularly unglamorous location.

Bryum dyffrynense and location by concrete blocks

Aloina rigida and location

On my way home, I stopped near Llanteg on the Pembs / Carms border. I wanted to check on the Fissidens rivularis in the stream near Ledgerland which I'd found here a few years back - the only site in the county. It was still on two rocks, despite a new concrete bridge having been built between the two.  

Fissidens rivularis on rock in stream

Heading downstream, there are some rocks which I'd never been to - the frost-shattered remains of a valley-side tor in the Millstone Grit series. Sam had refound an old record of Dicranum scottianum here, as well as some D. fuscescens. However, I wasn't expecting it to be quite as interesting as it proved to be. 

Ledgerland boulder-field

After an hour, the list which I'd put together would have looked respectable for one of the tors on Mynydd Preseli. The two Dicranums, Plagiochila punctata, Scapania scandica, Bazzania trilobata, Barbilophozia attenuata, Frullania fragilifolia, Polytrichastrum alpinum, Bryum alpinum, Racomitrium lanuginosum, R. ericoides, R. fasciculare....most of these were new hectad records, and highly disjunct from the nearest populations. Lepidozia cupressina - a second county record - was a particularly nice find alongside the abundance of L. reptans. Straying off the bryophytes, there were a few patches of Hymenophyllum tunbrigense, new to the south of the county, and a good looking lichen flora to my untrained eye, including Bunodophoron melanocarpum.

Bunodophoron melanocarpum

Tunbridge Filmy-fern

A small shaded outcrop below the boulders had a few small tufts of an Orthodontium alongside the filmy fern, which should rightly and properly have been the rare O. gracile in this habitat. After some fiddly sectioning though, I sadly concluded that there were stereid cells, and it was instead the non-native O. lineare. There was some compensation however, as a few strands of Isopterygiopsis pulchella were included in the sample - a new VCR. 

The icing on the cake, however, came in the form of a Lophozia tipped with reddish-purple gemmae hiding under one boulder. Unless I'm very much mistaken, this is Lophozia longidens - previously considered extinct in Wales. (Subsequently confirmed by Nick Hodgetts as this - the first Welsh record since 1968, and a long way south of any previous record). I can honestly say that I thought Pembrokeshire's vegetation had lost the capacity to surprise me - it's nice that there are still a few secrets to reveal!

Isopterygiopsis pulchella

Lophozia longidens

 

Brownslade Burrows

I've been surveying dune bryophytes on Brownslade Burrows for Landmarc over the Christmas period. This is Pembrokeshire's most extensive dune system, and there is plenty of open, wet habitat in the former sand-pits here. The highlight was four small patches of Bryum dyffrynense, Nationally Rare and new to the county. 

Bryum dyffrynense and location

Other Bryums have proved more of a challenge, as they are lacking ripe fruits at this time of year. Some Bryum pallens could be confirmed through the presence of axillary gemmae. Bryum gemmiferum is here in one of its few county sites.  Bryum torquescens is occasional, sometimes in more mobile sand amongst marram. Slightly off the dunes on a limestone and clay track near Linney is some apparent Ptychostomum touwii, a recently recognised species which may be new to Wales.

axillary gemmae of Bryum pallens

Ptychostomum touwii

One surprise has been just how abundant Didymodon acutus is here. There's a huge population, surely the largest in the UK, and apparently all the Nationally Rare D. acutus sensu stricto, in comparison to the limestone tracks on the adjoining range where it's mostly D. icmadophilus.

Didymodon acutus

Also locally frequent are Preissia quadrata at its only site in the county, and Leiocolea badensis, not previously recorded here. Ditrichum flexicaule was new to the county from one slack. Distichium inclinatum is in two places, including on a slightly tufaceous soft-cliff above the beach. Although not fruiting it can be identified by the rectangular cells arranged in rows near the leaf shoulder.

Soft cliff with Didymodon tophaceous, Eucladium and a Distichium

Trichostomum crispulum is the most abundant moss in the slacks, and a few shoots were sporting a fungus - Bryostroma trichostomi. 

Bryostroma trichostomi

Oh, and there's some petalwort. Lots of it. Doing fine.

Petalwort

 

 Foel Drygarn

I went looking for Sam's small patch of Kiaeria blytti on the old hill-fort at Foel Drygarn, but mis-interpreted the location and found a new sub-population instead. There was a healthy population under a few rocks on the eastern cairn - at least 20 small tufts in one place, several with young fruits and a few old capsules as well. 

Kiaeria blyttii

Confusion reigned when I tried to confirm it using the key in Smith, as the basal cells on some shoot seemed too thick-walled and porose, the alar cells well-differentiated, and the old capsules were striate.  The nerve sections also seemed to be a closer match for one of the rare Scottish species, starkei or glacialis. 

Kiaeria 

Thankfully, Tom pointed out that either species would be desperately unlikely, and I eventually located a Czech key by Jan Kucera which seemed more authoritative than those in Smith or the Flora of North America. Transverse sections of the alar cells are needed, and these are unistratose in blytti and partially bistratose and bistratose in starkei and glacialis respectively.  Mine, unfortunately, were unistratose and order was restored....more lessons learned!

section of alar cells