Tricky Zygodons! Or are they?

Last Sunday I was able to attend a field trip of the South-East branch of the British Bryological Society, to Duddleswell Valley nestled in the expanse of Ashdown Forest. The key site in this valley is a wooded ghyll, which has been a very popular location for bryologists since at least when the brilliant botanist Francis Rose visited in the mid-1950s.

Once we had waded our way through no less than eight different species of Sphagnum mosses we arrived at this famous ghyll and what greeted us was a steep and slippery slope down to the stream below us. Luckily we all made it down safely and we were able to begin!

We worked our way slowly down the ghyll, finding extreme rarities such as Campylostelium saxicola; admiring huge walls of fruiting Pellia epiphylla and finding ourselves knee-deep in shallow-looking mud. I even managed to put my foot in the middle of the largest colony of Nardia compressa in South-East England!

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A large part of the only colony of Nardia compressa in the South-East

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Nardia compressa

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Campylostelium saxicola

Near the end of our excellent and bryophyte-rich walk we came across a good stand of willow trees with many species that we hadn’t yet encountered that day. These species included a small, inconspicuous tuft of moss, a Zygodon species. There are four regularly occurring Zygodon species in the South-East and they are hard to separate in the field. To be certain of an identification to species level you really need to get out the microscope.

Therefore I took a small part of the moss back with me to work on. I was expecting it to be a tricky task that might take me a while to perfect. What surprised me was that it was quite the opposite!

The features to look at are the gemmae. The gemmae of Zygodons are single cells that detach from the moss in order to reproduce asexually, meaning that the fusion of male and female sex-cells (gametes) is not necessary. When mosses and other organisms reproduce asexually like this it is referred to as fragmentation.

Not knowing how to get the gemmae off the moss and onto the microscope slide to examine, I first tried taking a small stem of the moss and seeing if I could spot any gemmae around it. This was unsuccessful and so for my second attempt I simply tapped the clump of moss onto the slide, added a drop of water and a cover slip. I placed this slide under the microscope and I could immediately see several gemmae under 100x and 400x magnification. That was much easier than I had expected!

Next came the actual identification of the Zygodon. The very helpful Brad Scott had narrowed my moss down to two species, Z. conoideus and Z. viridissimus. He also supplied photos of the gemmae of both conoideus and viridissimus, so all I needed to do was compare the gemmae of my moss with Brad’s excellent photos. It was clear: my moss was definitely Zygodon conoideus!

This experience has certainly shown me that not everything that needs microscopic examination is difficult. Certainly some species require very fiddly work to separate but that is not always the case.

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My photo of a gemma of Zygodon conoideus

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Searching for Sandstone Bryophytes: Part 2

I recently visited Eridge Rocks to look for some more sandstone Bryophytes. Eridge Rocks is a superb site with a line of sandstone cliffs running through the 43 hectare woodland towards the nearby nature reserve Broadwater Warren. The cliffs are very tall and I have never explored a habitat quite like it before. It is known for its incredibly diverse community of lower plants (ferns, mosses, liverworts, lichens etc.)

When I arrived I immediately found a new species to me in the form of a nondescript Bramble in the car park. I took photos so that I could identify it at home and it turned out to be Rubus scaber. New species #1 and my 7th Bramble species ever identified (I recently found a lot along our private road). All Brambles might look similar, but they are subtly different in the spine structure, stem hairiness, stem shape, leaf shape and flower shape.

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Unlike Loder Valley, you don’t have to walk far to reach the site. You can see the rocks before you even reach the car park! The first thing I saw when I got to the rocks wasn’t a Bryophyte but in fact a species of Bamboo! It was a bit out of place, but again I took some photos for it to be identified back home. Several different webpages on Eridge Rocks say that Bamboo is found here, but I’m not sure why. There are only two or three healthy shoots and several scraggly ones. After a bit of internet searching I think they are Pseudosasa japonica. If anyone has any other ideas, please comment.

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I quickly moved on to the Bryophytes on the first rock. The variety really amazed me, I wasn’t familiar with most of the Bryophytes except for the few that I had found a few days earlier at Loder Valley. I quickly got my eye in however, my marked pages once again proving useful. By the end of the walk I saw nearly all of the Bryophytes whose pages I had marked. I was following in the footsteps of the British Bryological Society South-East group, who visited the site 13 months ago. Therefore my account is rather similar to the meeting report compiled by Brad Scott: https://diversionsinnaturalhistory.wordpress.com/2014/12/11/eridge-rocks-east-sussex-vc-14/

On the first rock, I immediately saw Dicranum scottianum, Calypogeia integristipula, Odontoschisma denudatum and Barbilophozia attenuata in one cramped patch. They were all out in the open apart from Odontoschisma denudatum which was annoyingly only to be seen in a small crag on the rock face at that particular section. Dicranum scottianum dominated, with Calypogeia integristipula second in command and spreading out from beneath the tufts of Dicranum scottianumBarbilophozia attenuata was only found in certain small patches but more cooperative than the seemingly shy Odontoschisma denudatum. 

Around the other side of the rock (I should mention that the rocks are ten to twenty metres high and up to thirty metres wide) there was a similar patch. There was an old rotting stump leaning against the rock face near that patch and that was dominated by Barbilophozia attenuata. 

The rest of the rocks had communities very similar to that of the first rock, but different micro-climates offered a slightly different array of species. In the darker areas like small caves or heavily shaded sections, the Cephalozia species (C. connivens and C. bicuspidata) were most prominent whereas in the slightly wetter areas Tetraphis pellucida was more dominant.

It wasn’t just the Bryophytes that were interesting though. I was able to find two very interesting lichens that were mentioned in the meeting report above: Cladonia incrassata and Bunodophoron melanocarpum. Cladonia incrassata was the most common one, with the thalli present on nearly every rock. The fruits were less abundant, but where they were present they were very pretty. Bunodophoron melanocarpum I only found one patch of, but it is my favourite lichen I’ve seen so far. It seems very exotic, a lichen I would’ve expected to see in Western Scotland or Cumbria. As said in the meeting report though, it is quite notable in the South-East.

When I got home I was able to count how many new species I had seen. I was very pleased with a total of 16 species, 12 Bryophytes, 2 lichens and 2 vascular plants.

My family and I haven’t explored a habitat quite like Eridge Rocks before. We even saw Homer Simpson (see below).

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Homer, as bald as ever…

Introduction to Bryophytes

Bryophytes are mosses, liverworts and hornworts, and they are an amazing part of natural history. However, many people don’t know that, so this is why you should become interested in Bryophytes:

  • They are rather unrecorded. It is so easy  just to note the bryophytes you see on a short walk that it is hard to believe how few people actually do it. With a better understanding of them, they will be easier to conserve.
  • They can be found nearly anywhere! On trees, walls, houses, all over the place, even one or two on cars and underwater!
  • There are so many species! There are only 4 species of Hornwort, but you can find 763 species of mosses in the UK and nearly 300 Liverworts. Bryophytes love wet climates so that’s why Britain has about two-thirds of all European species!
  • Unlike some species which can only be studied some parts of the year, Bryophytes can be studied year-round. It is probably even easier to find Bryophytes in winter as they are much less likely to be covered by large plants!

I’ve only found 32 species so far and some can be quite difficult to ID, especially Sphagnums (bog mosses), therefore I recommend buying the British Bryological Society’s Field Guide for UK and Ireland. It can help you identify most of the species you find and has been put together by ‘a team of expert bryologists’. It includes keys, photographs, similar species, colour coding, drawings of key features etc.

It is easy to get started with finding Bryophytes, there isn’t too much equipment involved. The only thing beginners really need is a good hand lens but don’t worry if you don’t have that just yet, many species can be easily identified with the naked eye. I would suggest starting in your own garden, big or small, as there is bound to be many easy species there and is a good way to practise. But most of all: enjoy it!

Dotted Thyme-moss

Dotted Thyme-moss

Urn Haircap, my 32nd species

Urn Haircap, my 32nd species