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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Underground Birds’ Nests!

This afternoon I was very lucky to be able to fit in a short trip to an undisclosed site in Ashdown Forest to see a very rare plant: the Bird’s-nest Orchid. I have been asked to keep the precise location a secret as there are only two individual plants flowering at the moment and I believe there might be some collectors keen to get their hands on them. Luckily Ashdown Forest is a huge place and these orchids are incredibly easy to miss.

I first learnt about these orchids being present at Ashdown Forest – one of the largest areas of woodland and more importantly open heathland in the South East – on the Sussex Botanical Recording Society website. There is a new ‘Latest Sightings’ feature on the website and I have been lucky enough to post a ‘Latest Sighting’ on there already, on the Krauss’s Clubmoss. You can read the orchid latest sighting here and my clubmoss latest sighting here.

The beech woodland where the plant was growing was very nice except there was very little diversity of ground flora. I think this may be due to the very large population of deer, particularly the Fallow Deer, which have over-grazed the area. However, there were some nice patches of late-flowering Bluebells as well as Ground Ivy, Germander Speedwell and not-yet-flowering Wood-Sorrel. In fact I saw a couple of female Fallow Deer while we were there, although they were very shy and were gone before I could see more than their heads with their sensitive ears standing up rigidly, on high alert. Deer were hunted in Ashdown Forest in the past so they must have learnt to be very wary of humans even now when deer-hunting has been discontinued.

There were some very large and beautiful Beech trees in the woodland that seemed to support a plethora of life. In one tiny patch of about 3 square centimetres there were no less than 5 adult Athous haemorrhoidalis, a common beetle whose larvae feed on tree roots. I also watched my first Spotted Flycatcher of the year flycatching from the mighty limbs of a particularly grand Beech tree.

We carried on down the road, checking every beech clump on the left side of the road to see if we could spot the easily-missed orchids. Surely we were supposed to be looking on the left side of the road? My dad agreed and we continued, starting to lose hope. We soon reached a point which was surely much farther than the directions had intended. Where were they? We must have missed them. We gloomily trod back up to the car, disappointed that we hadn’t seen these special plants. My eyes drifted over to the side of the road we hadn’t been looking at, where I stopped suddenly. I stood staring at two beige plants with disbelief. We had found the two Bird’s-nest Orchids! They were looking exactly as they had in the photo on the latest sightings page on the SBRS website which was taken 8 days before. Here are some photos and a very short mini-documentary:

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3 West Sussex firsts in one summer!

This summer has been a productive one, with my first three vice-county firsts all being found in my garden. I find out whether a species is a vice-county first or not by emailing the Sussex Biodiversity Record Centre, who are really kind and give me all the information I need. These are the three species:

Orius laevigatus – I came across quite a few of these small bugs on various bushes in my garden including Yew and our Buddleja. They may be small, but they are also predatory, and will feed on small invertebrates like bug nymphs and so on. There are 12 records in the Sussex Biodiversity Record Centre database for this species, but believe it or not they are all from East Sussex! Most of the records are concentrated around nature reserves like Rye Harbour, so I’m really pleased to have found it in the garden!

Entomobrya nivalis – Entomobrya nivalis is a species of springtail, which are tiny invertebrates you can sometimes find hopping around among leaf litter. However, this is quite a conspicuous species and is covered in stiff bristles and has greyish mottling all over. This time there are only 9 records in the Sussex Biodiversity Record Centre database, but again they are all in East Sussex!

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Entomobrya nivalis

Now, I’ve saved the best for last – Bright Four-spined Legionnaire (Chorisops nagatomii) – The Bright Four-spined Legionnaire is a fly with not only a great name but is quite colourful too. It has a yellow abdomen with black stripes running horizontally across it as well as a beautiful iridescent blue-green thorax. I was very surprised to find it on my kitchen window while I was having lunch, and even more so to find out that there are only records for Sussex and neither of them in West Sussex!

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Bright Four-spined Legionnaire (Chorisops nagatomii)