White Tip, Merthyr Tydfil

I was passing Merthyr's 'White Tip' yesterday and couldn't resist spending an hour and a bit to look for the Riccia beyrichiana found last winter. I managed to find good numbers of plants between SO03590721 & SO03560723, which although past their best were recognisable (photos 2 & 3). To illustrate the community, the following species were all direct associates recorded within a 50cm quadrat: Aphanes arvensis, Archidium alternifolium, Arenaria serpyllifolia agg., Bryum dichotomum, Cephaloziella divaricata, Cladonia rangiformis, Danthonia decumbens, Erophila majuscula, Festuca ovina, Fragaria vesca, Hieracium agg., Hypnum cupressiforme var. lacunosum, Linum catharticum, Lotus corniculatus, Luzula campestris, Peltigera canina, Pilosella officinarum, Plantago lanceolata, Poa annua, Prunella vulgaris, Pseudocrossidium hornschuchianum, Racomitrium ericoides, Racomitrium lanuginosum, Saxifraga tridactylites, Senecio jacobaea, Streblotrichum convolutum var. convolutum, Taraxacum sp., Thymus polytrichus, Tortella inclinata, Trichodon cylindricus & Trifolium dubium. 

 Additional bryos represented in this odd assemblage, with its muddled mix of calcicoles and calcifuges, included Bryum pallens, Campylium protensum, Didymodon tophaceus, Flexitrichum gracile, Gymnostomum aeruginosum, Lophozia excisa, Pseudocrossidium revolutum (photo 4) & Solenostoma gracillimum. 

However, it was the abundance of Tortella inclinata that was particularly notable at the site (dominant species in photo 1). This is a species that seems to be particularly well adapted to furnace slag (photo 4) and several sites in Glamorgan support huge populations of this Nationally Scarce species. Without question, brownfield sites are a stronghold in our area. It was interesting to see it growing with Racomitrium lanuginosum, both species being locally abundant here.

Brownfield slack surprise

On my way out to Witford yesterday it was spitting and looking very threatening, so I decided to make a pit stop in an area of the old BP works where I'd previously recorded the vascular plants several years back and have been meaning to return to check for bryos. The substrate is pure furnace slag that floods in the winter and consequently supports rather nice dune slack vegetation with elements of the NVC communities SD13-SD14.

The main bryos in the winter-wet areas were Drepanocladus aduncus and Hymenostylium recurvirostrum var. recurvirostrum, with locally frequent Calliergonella cuspidata, D. polygamus, Didymodon tophaceus, Cratoneuron filicinum, Bryum pseudotriquetrum & Fissidens adianthoides. I didn't have long, but in the area I walked over, I estimated the Hymenostylium colony extended to at least 1500m² (centred at SS74069208) being frequent throughout. There are similar areas in this part of the site I didn't look at, so the colony could be even bigger. Hymenostylium is not something I was expecting in this situation, but I read in the atlas that it grows at mine sites in Cornwall, so perhaps isn't too much out of context. Unfortunately, there's an inevitability this area will be redeveloped at some point, such is the nature of brown field land. [I'm pretty busy at present, but I'll add some microscope pics and better macro shots when I get a chance]

In the evening, on the way back through the site, I rechecked the general area where I saw the Tortella inclinata last month and discovered it also forms an extensive colony, being locally dominant in an area at least 40m x 4m. The main part of the colony is on tarmac, where it grows as mono-specific stands (actually discernable on the Google aerials SS73189138). Here the colony appears to be spreading over the tarmac from the edges, presumably extending by trapping wind-blown sand and gritty slag. Off the tarmac, in adjacent areas of coarser gravelly slag, the species grows as clumps in a more diverse mosaic of short dune vegetation.

Other tarmac colonists with burgeoning populations thriving on these abandoned roads, noted whilst driving across the site yesterday, included Drepanocladus aduncus (photo 1 below) and Didymodon ferrugineus (photo 3 below). The Drepanocladus hosted a fungus, which I have a specimen of - I don't know if Charles is able to point me in the right direction, if so I'll try and key it out?

Baglan worm farm stop

Last week, following surveys at Baglan Burrows, I stopped to look at the birds feeding at the worm farm and noticed an odd-looking Tortella, which proved to be inclinata. There was 70% cover within a 1m square patch at SS7316291405, though I didn't check elsewhere on this extensive brown field site (formerly part of the BP Baglan land), so it would seem likely the species is more widespread here.

The area supports a diverse flora with numerous dune and calcareous grassland elements which are managed by a healthy rabbit population. Areas of slag substrate with drifts of wind-blown sand support species-rich vegetation including areas with Clinopodium acinos, the main associated bryophytes being Encalypta streptocarpa and Hypnum cupressiforme var. lacunosum.

Tortella torment

Cliffs at Penmaen overlooking Threecliffs Bay
where all of Glamorgan's four Tortella species grow

Below left: Tortella sp. growing with Pleurochaete squarrosa (in centre of the image) becoming crisped. Below right: T. flavovirens sample collection point.

My records show the Nationally Scarce Tortella inclinata was first recorded in the Penmaen-Threecliffs area by Sam in 2010, who subsequently found it to be locally abundant on a section of cliff slope with scattered patches elsewhere in the vicinity. Although I recorded it nearby last year for my first time, the collection was more fortuitous than anything else and in an attempt to learn the field appearance of this species, yesterday, I took a few images and collected a sample of what I thought was probably inclinata growing abundantly on a sandy cliff slope about 100m east of Sam’s large colony. Under the microscope it was clear I was wrong as the costa on the adaxial side was covered by quadrate cells (except the third near the base). Furthermore, the leaves became highly crisped upon drying so unfortunately all I'd photographed and collected was flavovirens. [At least that's what I thought! After making this post I found a second sample I'd left in my coat pocket, which I was convinced at the time was probably inclinata; to my relief this turned out to be the case. Which species is represented in the general shot above alongside the Pleurochaete I'm now not sure as there's not really enough detail in the image. The difference between the two species using a lens is in fact rather striking when they are side-by-side, the shoots of inclinata being larger and more erect, with a stronger nerve appearing more prominent in a more boat-shaped leaf apex, reminiscent of Trichostomum crispulum]. Plants showing these characters were widespread on the cliff I looked at, but it's interesting that both species grow mixed in together.

Tortella flavovirens

Tortella inclinata

T. flavovirens foreground, T. inclinata behind

After reading Smith I'm now wondering how similar the resemblance is between flavovirens and the short-leaved form of tortuosa and if there is a safe way of separating the two, as he only mentions the degree of crisping upon drying; this was considerable in my specimen, which might indicate tortuosa?

For interest here are the vc41 distribution maps of our four Tortella species: