Talk 25th January and field trip 8th February 2025.
‘An introduction to Bryophytes’ was the theme of two events. First was a talk by Marion Rayner. This was followed by an excursion to look at Bryophytes with Marion and Alan Rayner.
The Talk
The talk covered the essential details of what bryophytes are (and what they are not). It showed why they are important, their growth forms, and their reproduction. Marion then turned to review the sort of habitats to find them in, and hence where bryologists like to visit.
Attendees also heard about a surprising aspect of bryophytes, poikilohydry. This ability to survive repeated cycles of wetting and desiccation is described as a ‘bryophyte superpower’!
Marion illustrated some of the challenges of ‘mossing on The Levels, but also she showed the pleasure when a special species is found.
Alan deployed a water spray bottle to ensure the specimens on display remained hydrated. Many of them, Marion mentioned in the talk, and everyone could examine them with hand lenses.
The Walk
The weather for the excursion was initially cold and very grey. This was perfect for the bryophytes but certainly not 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, on the branches of an Elder bush here we saw cushions of mainly acrocarpous epiphytes. These were principally Lewinskya affinis (Wood Bristle-moss) and, the beautiful Orthotrichum pulchellum (Elegant Bristle-moss). This species has neat capsules bearing dark tipped calyptrae that resemble ballerina skirts. We found one distinctive pleurocarp Cryphaea heteromalla (Lateral Cryphaea), 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 assuredly an excellent place to see a variety of leafy liverworts. These ranged in size, firstly, the large brownish growths of Frullania dilatata (Dilated Scalewort). Secondly, green Radula complanata (Even Scalewort) with its brown dehiscing capsules, and finally, Myriocoleopsis minutissima (Minute Pouncewort) bearing distinctive five-sided perianths. Here, too, the group was able to experience the aromatic Lophocolea heterophylla (Variable-leaved Crestwort) on some rotting wood. We also discovered two thallose liverworts here: Metzgeria furcata (Forked Veilwort) and M. consanguinea (Whiskered Veilwort).
Metzgeria consanguinea
The Sweet Track
As we moved towards the woodland along the Sweet Track, first we found mosses typical of woodland. Mnium hornum (Swan’s-neck Thyme-moss), some of which had developing capsules, and pale green Eurhynchium striatum (Common Striated Feather-moss). This has slightly plicate (pleated) leaves, which we observed with hand lenses. Subsequently, we came across dark green clumps of Polytrichum formosum (Bank Haircap), which looked 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). Eventually we began retracing our steps towards the Avalon Marshes Centre. We stopped for one final species growing in the track: Plagiomnium affine (Many-fruited Thyme-moss) with its 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, but we will come back for more.
Marion Rayner
9.2.2025