Scilly exotics

I've enjoyed other recent holiday reports on this blog so I hope you'll indulge me writing another one, from a bit closer to home...

It's a bit of a cliche to say that the Isles of Scilly feel like a world away from mainland Britain, despite being just 28 miles off the end of Cornwall. But after my first visit to the archipelago earlier this month I could hardly disagree with the sentiment. The flora in particular felt very exotic, with the bryophytes being no exception. Many species that are common in South Wales were scarce, as would be expected on a series of small, remote islands. The epiphyte flora in particular seemed impoverished, with most tree trunks being lichen-dominated instead - even Frullania dilatata was somewhat localised. This was adequately compensated for by the plethora of exotic species (liverworts mostly) which are scarce or absent on the mainland, some of which are imports from the Southern Hemisphere and some possibly from the Mediterranean.

The fun started at Lower Moors nature reserve on St Mary's, where I got excited by an extensive yellowy patch of Telaranea murphyae growing by a path to a bird hide (photos below). I thought this liverwort was restricted to Tresco but I later discovered that the population at Lower Moors had been found in 2003. It appears that the taxonomic position of T. murphyae remains somewhat uncertain; it has not been found as a native in the Southern Hemisphere and was described new to science from Tresco, though it may just be a form of T. tetradactyla. A potentially new population was found later in the week by a path near the lifeboat station at Hugh Town (lower photo).

The excitement really started on Tresco, where a flowerbed in the Abbey Gardens was dotted with the lovely rosettes of Riccia crystallina intermingled with numerous Sphaerocarpos plants (photos below). I collected three Sphaerocarpos samples and after a few days incubation each produced mature spores to enable species identification; pleasingly both species were represented with two samples being S. michelii (spore photo bottom left) and one S. texanus (bottom right).

 

Telaranea murphyae was seen in a few locations within the gardens, along with Lophocolea semiteres and L. bispinosa, but was much more abundant along Abbey Drive where extensive yellow sheets of it covered the ground wherever there was shade from trees (upper photos, below). Growing with it was Calyptrochaeta apiculata (lower photos) - in the Britain Isles this Southern Hemisphere species is known only from here and single sites in Sussex and Ireland.

Bulb fields on St Mary's revealed more Sphaerocarpos michelii, Riccia crystallina and a single rosette of Riccia subbifurca (unless it is R. crozalsii - but I don't think so).

Even the small garden of our cottage had a flowerbed with plenty of fruiting Anthoceros punctatus (photo) and a stone covered in Scorpiurium circinatum.

I'm already looking forward to making another visit sometime...

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.
 

Distichium inclinatum

As I was driving home on the A470 this afternoon I remembered the population of Distichium inclinatum which Barry found in a cutting near the road in 2015. I pulled off at the Gethin Woodland Park roundabout for a look and there it was - easy to find on the flushed coal spoil, and fruiting nicely (albeit somewhat sparsely).

Trostre sidings

Snippets of interest from wet woodland near the railway sidings at Trostre included a little Ulota calvescens on the willows plus Calliergon cordifolium with capsules mounted upon impressively long setae, the latter a first for me of this normally barren species. However, at the same site, a crude estimate of 500+ emerging Twayblades in a 50m x 50m area stole the show.

Bwlch-y-clawdd (SS9494)

We intended to square bash in SS99N (RCT) only to find that the A4061 above Cwmparc was closed for roadworks - the suggested diversion would have taken ages. We decided to have a look at a small north-facing, sandstone outcrop just off the road and below Mynydd Ton (SS942946).

The scree below the outcrop is populated with large amounts of Racomitrium lanuginosum,  R. fasciculare and Stereocaulon vesuvianum but there are some nice patches of Huperzia selago here too. Much of the Andreaea on the slabs is A. rothii ssp falcata, but there is also a small amount of A.  rupestris.

Huperzia selago and Stereocaulon vesuvianum

Also of interest below the main outcrop is the frequent occurrence of Barbilophozia floerkii and lots of Lophozia ventricosa. We searched for L. sudetica but failed to find any convincing material.

Barbilophozia floerkii

With optimism we climbed up to the outcrop, but the best we could find was a small patch of Hymenophyllum wilsonii, which is frequently present on north-facing sandstone in RCT (and never disappoints). Other stuff included Heterocladium heteropterum, Pohlia nutans and Racomitrium aquaticum. All in all it is a typical, if not spectacular, collection of upland species on a relatively small outcrop which is quite near to a very busy road. You might expect Oreoweisia bruntonii and Bartramia here too, but if they are there they escaped us.

Tony Smith (in A Bryophyte Flora of Glamorgan) describes the Rhondda sandstone outcrops as mostly east-facing and relatively species-poor. I don't know to what extent that has deterred people from exploring these cliffs, but it might explain why species like B. floerkii have been regarded as rare in Glamorgan. In my experience even the small outcrops are worth a look.

D'Arcy Didymodon diversity

A 30-40 minute stop to check out a patch of 'wasteground' by D'Arcy Business Centre yesterday revealed a rich diversity of Didymodon spp., those recorded being fallax, ferrugineus, luridus, tophaceus, umbrosus (below, photos 1 & 2) plus what might be icmadophilus, which will be the first time I've seen it away from the Gorseinon area if confirmed. There was also some Pellia endiviifolia which was fruiting in patches denser than I recall seeing before (photo 3) and a little Bryoerythrophyllum ferruginescens. No Funaria was seen! Vascular plant interest was provided by a strong colony of 300+ seedlings of what could be Filago vulgaris (photos 5 & 6), though needs checking in Poland and/or by growing on my specimen - unless anyone knows this species at this age?

Funaria hygrometrica in Glamorgan

Couldn't resist doing the same analysis for our Glamorgan data set, which is suitable for the last seven years only. Very interesting topic and as I suggested on your Twitter post, I wonder how much habitat survey bias might effect the frequency of recording. We probably examine a lot more brown field sites in Glamorgan than you do in Pembs, Carms & Mons (as we have a lot more of them!), a habitat in which the species seems to do well, as shown by my Felindre photo below, where Fun.hyg. was dominant in some areas. This might help explain the difference between our plots and I suspect an analysis of specific habitats might be more revealing?