Spongy liverworts

I can't find my Smith's Liverworts of Britain and Ireland and haven't looked at it since Jean Paton published her Liverwort Flora in 1999 - Jean's book seems to costs over £90 now, but it is worth every single penny.  I am pretty sure that early on in Smith's Riccia key the split is whether your specimen looks spongy or not - back in about 1994 I was sure the first Riccia I had come across in Carmarthenshire was R. sorocarpa, and to me it looked 'spongy' ....... I followed the key and think eventually ended up at R. cavernosa - this was clearly wrong and then it occurred to me that the reference to sponge probably meant natural sponge, which is probably unfamiliar to a lot of people today and was a bit of a rarity even when I was a kid in the 1960's (or perhaps it was expensive and we could only afford artificial sponge - actually we had a loofa which tended to take your skin off if you rubbed too hard!) - the only times I seem to see natural sponge these days is in art supply shops (usually as expensive tiny fragments).

Anyway, whilst at Llangorse Lake last week I glanced down and saw what I first took to be a thick layer of algae amongst open vegetation in the inundation zone (the lake level at Llangorse tends to be a lot higher in winter than in the summer months).   On closer examination the 'algae' turned out to be the largest population I have ever seen of what looked to be  R. cavernosa.   I had it in the back of my mind that Sam had recorded cavernosa at Llangorse when he mapped the marginal vegetation several years ago, but on reading his report he in fact had found R. subbifurca and, if Sam accepts the voucher, cavernosa will be a new addition to the Brecks bryophyte flora.

Pics below are a bit poor, but the close-up shows the large perforations on the surface - a bit like an old fashioned sponge.

Marvellous Merthyr Mawr

Prior to undertaking a search of the scraped slack habitats at this beautiful NNR, Sam's NRW colleagues, Duncan Ludlow and Emma Brown kindly showed me one of the known Petalophyllum ralfsii colonies at Merthyr Mawr yesterday, plus we also visited the spot where George made his nocturnal observation a week or two back. Given the very dry conditions at these locations, I was pleasantly surprised by how large and verdant the Petalophyllum plants were.

We also looked at one of this year's Portland Moth locations, where George recently discovered Riccia cavernosa and we estimated there must have been a few thousand small rosettes developing. As far as I'm aware this is a new species for the reserve. The largest specimens we could find are depicted below, but most were much smaller. Given the right conditions, there could be quite a display here. Duncan informed me that this area has been subjected to some scrub clearance work and its use as a bridleway stopped, so the occurrence of the moth and the liverwort highlights at least two significant benefits of the work and controls implemented here. I've marked the extent of the Riccia colony on the photo below.

Unfortunately there was no Petallophyllum or Riccia to be found in the two scraped areas I examined, though the larger slack is at a very early stage of colonisation and was well populated with non-fruiting Bryum species. In addition to frequent dichotomum and argenteum and occasional gemmiferum, there were patches of putative dyffrynense (photo below), which may be worth sending off to David Holyoak? At least two other Bryum leaf forms were present, so a site well worth revisiting as succession takes place...

...PS. does anyone know what causes these rings in the wet sand? I'm guessing it's fungal, but I never collected any to look under the miscroscope.

 

Bryos by night

Paul Parsons and I trapped at Merthyr Mawr last night in the hope of Portland Moth. We failed on that score (probably a little late now) but my trap was cited in a large dune slack, which gave me the chance to have a torchlit poke about for bryos while I was waiting for the moths to arrive.

I found three tiny plants of Petalophyllum in the slack which Karen Wilkinson had mentioned was the best place to find this species, but more interesting perhaps was some Riccia in a different slack (where I cited the trap). I'm pretty sure this is R. cavernosa but am posting photos here as I've not seen this species before and I don't think it's been recorded from Merthyr Mawr. The plants were scrappy and looked much older than the babies which Barry found at Kenfig.

 

Kenfig NNR scraped slacks

The deep scrape in the south-west of compartment 3

The above scrape is deeper than most slacks in the south of the reserve and the muddy, rather than usual sandy substrate is exposed much later than most adjacent slacks. The dry crusty margin visible in the photo mostly comprises dried up charophytes (Tolypella glomerata identifiable, but others too far gone), but various bryophytes are admixed, the most notable of which is Drepanocladus sendtneri (photos below - voucher retained if required for checking). After spending much time pondering over my specimen, it was relief to find Sam had already recorded the species at this location in December 2011, presumably in much wetter conditions than those shown above.

On the inward (i.e. deeper) edge of the Tolypella crust, in the south-west sector of the scrape, was an abundance of 'baby' (<1mm) Riccia cavernosa plants growing along with young Bryum sp. There were many thousands of plants, this was in contrast to recent observations in some other scrapes on the reserve which supported mature plants, but in much smaller numbers.

Elsewhere vascular plant interest included a reasonably good number of Liparis in Hedgehog Slack in compartment 1, though none in scraped areas. One scrape in this slack did have the miniscule Chaffweed Centunculus minimus and Dave Carrington took me on a quick visit to Sker to see the Field Gentians Gentianella campestris. Good numbers of the Nationally Scarce scarab Onthophagus nuchicornis were among the beetles found in fresh cow pats there too. Kenfig really is such a great place.

Cavernous Crytalwort

Spent a very windy, sand-blasted morning with Barry and Becky Sharp (NPT Wildlife Team) looking at  Margam Tip, a very biodiverse site and a fascinating example of sand dune remediation. During a whistle-stop tour of the open mosaic perimeter of the steelworks, we stopped to look at a wet sandy area with Ranunculus trichophyllus,  Juncus ranarius (= J. ambiguus) and Plantago coronopus, typical species of damp, brackish sand. I just happened to say 'this looks like a good place for Riccia cavernosa' before Barry exclaimed 'yes, and here it is'. There were approximately 500 individuals in an area of about 100 square meters.

Unfortunately this particular site will undergo development which will almost certainly result in the loss of this population. However, we are hopeful that habitat creation elsewhere will provide suitable habitat for it; i.e. wet, base-rich, sandy mud which is subject to winter flooding. Some inoculation may help. The occurrence of associates like R. trichophyllus, J. ranarius and P. coronopus seems to indicate the suitability of these habitats for this exquisite liverwort. There's something quite special about Crystalworts.