Friday, 16 March 2018

Brachythecium glareosum

Several Bryophyte guides mention the problems of distinguishing Brachythecium glareosum from Homalothecium lutescens and Brachythecium rutabulum in the field. All three species occur along forest tracks in NPT, sometimes together, and on more than one occasion I have mistaken  B. glareosum for one or other of the other two. This winter I've tried to sort this out and I thought it might be useful if I posted some comparative observations. However, there is nothing new here and I apologise if I appear to be teaching my grandmother how to suck eggs.
In its typical form, B. glareosum appears to be quite distinct with those long, slightly twisted acumens at the tips of the leaves, which form conspicuous, pointed clusters of bristles at the apex of the stems and branches. This is a major feature used by Smith to distinguish B. glareosum from all the other Brachytheciums. 

                                    Brachythecium glareosum, forest track, Glyncorrwg

                     Long, bristly stem tips of Brachythecium glareosum (note distinct pleats on leaves)

Confusion with H. lutescens arises because it too has a long fine point to its leaves and both species also have clearly pleated leaves.

                                                             Homalothecium lutescens

                                                         Homalothecium lutescens

The leaves of H. lutescens are narrower and more triangular than those of B. glareosum and the pleats on the leaves are very prominent and almost parallel. Also, H. lutescens can be distinguished from any Brachythecium if you examine a leaf under the microscope. Leaf cells are very narrow, and the basal cells of the leaf are distinctly thick walled (incrassate).

                  Part of Homalothecium lutescens leaf showing  thick-walled (porose) basal cells

'Typical' Brachythecium rutabulum is usually not a problem. Confusion occurs when you encounter specimens with long drawn out tips to their leaves, which happens frequently. Even then, however, B. rutabulum rarely exhibits the long, conspicuous, bristly stem tips that characterise B. glareosum. Most texts refer to the twisted leaf tips of B. glareosum, but this is not always a very prominent feature in my experience.

                                          Brachythecium rutabulum (note vaguely pleated leaves)

There are other subtle differences between B. rutabulum and B. glareosum that can be observed in the field. The leaves of B. glareosum are narrower than those of B. rutabulum, (although not as narrow as H. lutescens), and more noticeably pleated. The typical habit of B. rutabulum always seems to be plumper and more robust to me, compared to the slender, graceful and more prostrate habit of B. glareosum, reminiscent of Homalothecium. B. glareosum is a calcicole and on forest tracks usually occurs with species like Ctenidium molluscum, Ditrichum gracile and Trichostomum crispulum.
The leaves of B. glareosum and B. rutabulum look different under the microscope. The alar cells of B. rutabulum tend to be long-rectangular and form decurrent tongues (almost like auricles), and the upper leaf border is clearly toothed.

                                                  Long-rectangular alar cells of B. rutabulum

                                                        Teeth on upper part of leaf of B. rutabulum

The alar cells of B. glareosum are short rectangular and not decurrent, and the leaf has very indistinct teeth.

Short-rectangular alar cells of B. glareosum

Indistinct teeth on upper part of leaf of B. glareosum

Tuesday, 13 March 2018

Out and about

I've had a lean winter recording-wise, but at least February proved to be reasonably productive. Most records were made around Cardiff, Bridgend and Merthyr Tydfil, during stop offs on the way home from work trips. Nothing remarkable has been recorded but minor highlights have included:

Lophozia bicrenata growing with Lycopodium clavatum among sparse Calluna heath on the former dry ski slope at Troedyrhiw (SO0703). I first saw the clubmoss here back in 2007 and it was pleasing to see it still thrives at the site.

Bryum violaceum on gravelly roadside soil, also at Troedyrhiw (SO0603); note smooth violet rhizoids and small tubers.

Scapania compacta and Andreaea rothii ssp. falcata on sandstone quarry waste at Merthyr Vale (ST0899).

In Cardiff and Bridgend I've not seen anything noteworthy, though it has been good to confirm Ulota crispa s.s. from several localities (I've been unable to find either U. intermedia or U. crispula to date, despite microscope checking of quite a few samples).

I'll aim to prepare an updated tetrad map in the next couple of weeks, which should show at least a few recording gaps being filled.

Monday, 12 March 2018

Mosses over the sea

There is very little land in ST1971 but this monad does include the outer portion of Penarth Pier. A trip with the family last weekend revealed six species growing on the wooden deck of the pier, directly above the sea at high tide but presumably elevated enough to limit the influence of salt. The species were Bryum capillare, B. argentuem, B. dichotomum, Ceratodon purpureus, Hypnum cupressiforme and Dicranoweissia cirrata.

Saturday, 24 February 2018


Actually more like ton-down: I have fewer than 100 tetrads left unsurveyed for bryophytes in Monmouthshire (VC35)!  Bea had a birthday party just across the border yesterday, so I had nearly 4 hours to record 1.5 tetrads in the White Castle area.  Both were good examples of typical NE Monmouthshire - lovely rolling landscape with deep-cut streams and lane banks exposing neutral Old Red Sandstone.  Highlights among the 77 species recorded in SO31Y (Upper Cwm lanes) were (+indicates photo): +Eurhynchium schleicheri (abundant on one lane bank), +Plagiothecium curvifolium (fruiting on a large tree-stump), +Pylaisia polyantha (one large patch on a fallen canopy Ash branch), Platygyrium repens (a few patches on roadside Clematis), Rhynchostegiella teneriffae (frequent on ORS rocks in a stream gully) and Mnium stellare (large patches on stream bank), as well as the full suite of regular epiphytic Orthotrichum and some wall, track and tarmac 'grots'. 

I made a start on SO31Z in 2007 (Bont), so topped up that lanes list with a visit to a locality where a footpath crossed a deep-cut stream (Red Castle cwm), taking the tetrad total up to 79 spp.  Yesterday's highlights included +Plagiochila porelloides & +Scleropodium cespitans sharing sandstone outcrops, Rhynchostegiella teneriffae in the stream, and Mnium stellare on the stream bank.  It's really good to know what the background bryophyte flora of this part of the county is like.

Aphanolejeunea in Brechfa Forest

On Friday I spent a few hours revisiting the lichen hotspot in the valley of the Afon Marlais, a few miles upstream of Brechfa, to record some previously unexplored sections of the site.  The lichens were excellent, with 3 spp of Sticta (including really large S. fuliginosa sl), some beautiful patches of Pannaria conoplea (only 4 sites in S Wales), and a few new lichens for the site such as Thelotrema lepadinum and Megalaria pulverea.  I didn't look at bryophytes too much, but couldn't help noticing that many of the riverside Ash trees were plastered with Aphanolejeunea microscopica as well as Colura.

The only previous Carmarthenshire record of Aphanolejeunea came from the Mynydd Mallaen area nearly 15 years ago, and the abundance of Aphanolejeunea along the Afon Marlais was reminiscent of its abundance in the Waterfalls area of the Nedd/Mellte valleys of VC42.  I couldn't find any Drepanolejeunea on Friday, but did see it by a waterfall in a tributary of the Afon Marlais a few years ago.  Earlier last week I revisited Cwm Marydd, where Tritomaria exsecta is still doing well.


Tuesday, 20 February 2018

Syntrichia virescens?

A small Syntrichia growing on the trunk of a street lime caught my eye as I was walking to the woodland south of Llanishen Reservoir for a quick square bash. It looks reasonably convincing for S. virescens, with toothed hairpoints and notched leaf apices, though the length of the basal cells (30-62 microns, averaging 37-45 microns) straddles the ranges given in Smith for differentiating S. virescens and S. montana. It was certainly smaller than typical montana, but as virescens would be new for VC41 I'm being cautious and seeking the opinion of others - thoughts welcome.

Monday, 19 February 2018

A Grave subject

Churchyards provide habitat for a number of bryophytes that are rare or absent from the typical farmed landscape of lowland Monmouthshire, including rock-dwellers like Racomitrium aciculare (which is quite frequent on flat sandstone gravestones), woodland species like Cirriphyllum piliferum and Rhytidiadelphus triquetrus, unimproved grassland mosses such as Pseudoscleropodium purum, and acidophiles including Dicranum scoparium.  The last of these can be abundant on graves surfaced with acid gravel, as was the case at Llanddewi Rhydderch where I took the photo above.

Tetrad recording in the Llanddewi Rhydderch square (SO30L) produced just over 50 rather mundane species.  Highlights away from the churchyard included a few epiphytes in a lane, with a single tuft of Orthotrichum anomalum (sadly with all but one of its capsules slugged, so I can't be 100% certain it wasn't O. consimile) being the most unusual record.  Anyway, this is another tetrad ticked off the list, leaving 101 which I haven't yet visited.