Talk 25th January and field trip 8th February 2025.
‘An introduction to Bryophytes’ was the theme of two events: a talk by Marion Rayner and then an excursion to look at Bryophytes with Marion and Alan Rayner.
The talk covered the essential details of what bryophytes are (and what they are not), why they are important, their growth forms and reproduction before turning to review the sort of habitats to find them- and hence where bryologists like to visit.
Attendees also heard about a surprising aspect of bryophytes -poikilohydry- the ability to survive repeated cycles of wetting and desiccation which was described as a ‘bryophyte superpower’!
Some of the challenges of ‘mossing on The Levels’ were illustrated but also the pleasure when a special species is found.
A water spray bottle was deployed to ensure the specimens, many of which had been mentioned in the talk, remained hydrated so that everyone could examine them with hand lenses at the end of the talk.
The weather for the excursion was cold and very grey which was perfect for the bryophytes but less comfortable for the group of 13 who set off to Shapwick Heath Sweet Track.
Near the interpretation panel a grassy area quickly produced four common pleurocarps: Calliergonella cuspidata (Pointed Spear-moss), Rhytidiadelphus squarrosus (Springy Turf-moss), Kindbergia praelonga (Common Feather-moss) and Brachythecium rutabulum (Rough-stalked Feather-moss). In contrast the branches of an Elder bush here were festooned with cushions of mainly acrocarpous epiphytes- principally Lewinskya affinis (Wood Bristle-moss) but also the beautiful Orthotrichum pulchellum (Elegant Bristle-moss) with it’s neat capsules bearing dark tipped calyptrae that resemble ballerina skirts. One distinctive pleurocarp Cryphaea heteromalla (Lateral Cryphaea) was found on a branch. It has two forms of growth – the small worm-like branches precede larger side branches bearing cigar shaped capsules.
The boardwalk through a wet area with Willows provided an opportunity to play ‘epiphyte bingo’ as there were a variety of mosses and liverworts to tick off from our list of epiphytes. This humid area was a good place to see a variety of leafy liverworts. These ranged in size from the large brownish growths of Frullania dilatata (Dilated Scalewort) and green Radula complanata (Even Scalewort) with its brown dehiscing capsules, down to the tiny Myriocoleopsis minutissima (Minute Pouncewort) bearing distinctive five-sided perianths. Here too the group were able to experience the aromatic Lophocolea heterophylla (Variable-leaved Crestwort) on some rotting wood. Thallose liverworts were represented by Metzgeria furcata (Forked Veilwort) and M. consanguinea (Whiskered Veilwort).
Metzgeria consanguinea
As we moved towards the woodland along the Sweet Track we found mosses typical of woodland. Mnium hornum (Swan’s-neck Thyme-moss) some of which was developing capsules, and pale green Eurhynchium striatum (Common Striated Feather-moss). This has slightly plicate (pleated) leaves which we tried to observe with hand lenses. Dark green clumps of Polytrichum formosum (Bank Haircap) looking robust in contrast to the more delicate species encountered here. Finally we hurried to the end of the Sweet Track to appreciate the luxurious yellow-green growths of Thuidium tamariscinum (Common Tamarisk-moss) before retracing out steps towards the Avalon Marshes Centre stopping for one final species growing in the track: Plagiomnium affine (Many-fruited Thyme-moss) with it’s large round leaves spaced along the stem.
As an introduction to the beautiful world of bryophytes this was a good range of species to have encountered!
Marion Rayner
9.2.2025