Monday, 27 November 2017

Bryophytes of Godstow Nunnery and Port Meadow, 19th November 2017

Although there are people looking at bryophytes in Oxfordshire and Berkshire, it has been a little while since any records were committed to the British Bryological Society’s database, and we (Oli Pescott, David Morris) have been trying to rectify this with occasional winter excursions. Last weekend we focused on on Godstow Nunnery and surrounds (v.c. 23, Oxfordshire), but with a brief look at Port Meadow to the east of the Thames at the end of the day. (We were almost entirely within SP40Z for the whole day). Surprisingly, there is only one record named in the BBS database as being from Godstow, a record of Syntrichia latifolia from 1951, although it must be the case that some of the older, hectad ‘mastercard’-type records from SP40 in the database would have been made there. The length of old walls at Godstow makes it unlikely that Oxford bryologists of yesteryear would have failed to visit it. Godstow is also a prime spot for list-makers, being one of the few established populations of Aristolochia clematitis (Birthwort) in Britain, making it doubly odd that no-one has made a clearly localised list of bryophytes there that has made it into the BBS database.

Godstow Abbey ruins
© Copyright Chris Gunns and licensed for reuse under this Creative Commons Licence.
But enough of what hasn’t been done, and on to the plants that we saw. Despite the lovely bright day, we conspired to spend most of the morning in the shade, examining the north-facing walls of the ruined abbey. The old damp stonework hosted some lovely populations of the liverwort Porella platyphylla (which we failed to photograph – apologies dear reader!), as well as other denizens of such places like Anomodon viticulosus and Neckera complanata. Of course, smaller acrocarps (the ‘cushion’-type mosses) were also in abundance, with, in random order, Bryum radiculosum, Didymodon vinealis, Syntrichia montana, Syntrichia ruralis, D. insulanus, D. luridus, Pseudocrossidium revolutum, and Orthotrichum anomalum all putting in appearances. There was plenty of Ceratodon purpureus too, and, in fact, the D. insulanus was only confirmed later on at home after ploughing through several collections of spindly C. purpureus (an impressively variable moss, but this plasticity more often draws sighs of frustration rather than admiration from field bryologists). After adding a range of other wall-dwelling bryophytes to our list, including some additional pleurocarps, we examined an area of stone embankment retaining the Thames: Cinclodotus fontinaloides, Lunularia cruciata, Crateneuron filicinum, and Platyhypnidium riparioides were added to the list in quick succession.

Post-lunch, we briefly examined some tarmac on the wrong side of Godstow Lock, adding a number of what the eminent bryologist Des Callaghan has been known to refer to as “townland treasures” (as opposed to the more frequently heard “grots”), before being asked to sling our hook by the lock keeper, and this wasn’t an invitation to sample a different hobby whilst water-side. The most interesting addition from the tarmac was Didymodon nicholsonii. Further south in a strip of mixed deciduous woodland (with an impressively large Field Maple), we added a small selection of epiphytes, including Syntrichia papillosa on Oak, S. latifolia (the one species previously localised from the area) on felled Salix, and a few more liverworts such as Metzgeria consanguinea, M. furcata, and Frullania dilatata. Investigations of Zygodon tufts at home later on revealed Z. conoideus and Z. viridissimus. These are species that are, by and large, quickly distinguished by dislodging gemmae from the leaves onto a slide; if you have a stereomicroscope but no compound microscope, the gemmae can even be distinguished at x40 on a white background (although one could miss rarer species in this fashion).

Syntrichia papillosa
By Des_Callaghan (Own work) [CC BY-SA 4.0]
Given that we were in the area, we decided to investigate a couple of spots on Port Meadow before heading home. This turned up the tuberous Bryum, B. klinggraeffii, from fine sand and gravel on a bend of the Thames. Sometimes called the Raspberry Bryum, the tubers on this species’ rhizoids are dark red and have large, protuberant cells; unlike some plants, the Raspberry Bryum is well-named, and the eye-of-faith needn’t enter into it. Although frequently recorded from Berkshire over the past 30 or so years, this is a species that has only very rarely been found in Oxfordshire, although how much of this is due to a lack of habitat, and how much is due to under-recording, it is hard to say. Further south, in the area of low-lying land in Port Meadow that regularly floods in winter, the mud of the draw-down zone yielded more B. klinggraeffii, and, on returning home, Aphanorrhegma (Physcomitriella) patens was discovered on the edge of a clump of the former species. Again, this is probably somewhat under-recorded, but according to BBS data at least, has not been recorded for the vice-county since the 1980s. (Although it was seen nearby on a track by Wytham Wood in v.c. 22 by Chris Preston in 2007). The draw-down zone of Port Meadow might repay further investigation, as, with its use by geese and other birds, it could be the sort of place that one could turn up Ephemerum cohaerens, a nationally rare moss that occurs in similar habitats, and may be moved around by migrating bird life.

The full list of species seen across all the squares is given below. We hope to see you at a future excursion! The next planned date is the 10th December.

Barbula convoluta var. sardoa
Zygodon viridissimus var. viridissimus
Platyhypnidium riparioides
Lunularia cruciata
Barbula unguiculata
Zygodon conoideus var. conoideus
Rhynchostegium murale
Metzgeria consanguinea
Didymodon nicholsonii
Orthotrichum affine
Rhynchostegium confertum
Metzgeria furcata
Didymodon vinealis
Orthotrichum anomalum
Rhynchostegiella tenella
Porella platyphylla
Didymodon insulanus
Orthotrichum cupulatum
Oxyrrhynchium hians
Frullania dilatata
Didymodon luridus
Orthotrichum diaphanum
Kindbergia praelonga
Didymodon sinuosus
Ulota crispa s.l.
Brachythecium rutabulum
Aphanorrhegma patens
Tortula muralis
Bryum capillare
Homalothecium sericeum
Schistidium apocarpum s.l.
Phascum cuspidatum
Bryum argenteum
Calliergonella cuspidata
Grimmia pulvinata
Syntrichia ruralis var. ruralis
Bryum radiculosum
Hypnum cupressiforme var. cupressiforme
Fissidens taxifolius
Syntrichia montana
Bryum klinggraeffii
Cryphaea heteromalla
Ceratodon purpureus
Syntrichia papillosa
Cratoneuron filicinum
Neckera complanata
Pseudocrossidium hornschuchianum
Syntrichia latifolia
Amblystegium serpens
Thamnobryum alopecurum
Pseudocrossidium revolutum
Cinclidotus fontinaloides
Leskea polycarpa
Anomodon viticulosus