A corner of County Kerry in a Kentish Cave

Saturday saw me attending another excellent field trip run by the South-East group of the British Bryological Society. This time we were headed to a private site just inside Kent called Hungershall Rocks. The sandstone at Hungershall Rocks is part of a large number of these outcrops stretching across the Weald from Tunbridge Wells to Ardingly and all along the ridge there are sites with a wealth of rare bryological flora.

Hungershall Rocks is a private site just outside Tunbridge Wells near High Rocks which we were lucky to get access to. Plenty of excellent bryologists have visited the site in the past and the records stretch back over more than 150 years. It has been interesting to see how the bryological flora of the site has developed over such a long time, with new species being discovered but equally species that were here in the past being lost from the site.

The rocks themselves are mainly under tree cover, however some are more exposed. Some patches are dripping wet due to the clay within the rocks and others bone dry. There are a plethora of nooks, crannies, ledges and some caves too. This wide range of rock features leads to a very diverse set of mosses and liverworts that can be found on these rocks.

It wasn’t only mosses and liverworts that were in abundance either. There were many different vascular plant species inhabiting the rocks, especially ferns. One of the best finds of the day was this beautiful, eye-catching and impressive-looking plant:

DSCN2127

It’s stunning, isn’t it?

It wasn’t too easy to get to. It was growing on the wall of a small cave, where very little sunlight penetrated. There was only really room for one person inside the cave and that person had to be in a crouched, uncomfortable position. So why was this rather underwhelming (to be honest) plant worth such an effort to get to?

It is Trichomanes speciosum, the Killarney Fern. Killarney is a small town in Ireland’s County Kerry, the county where half of Ireland’s known populations of this fern are found. As you can see from the map below, this species has a predominantly Western distribution in the UK and is quite unusual in the East, being recorded in only a handful of sites in the South-East:

Killarney Fern

NBN Gateway map for Trichomanes speciosum

You might be thinking that it doesn’t look like a normal fern usually does and you’d be forgiven for thinking so because this is not the most commonly seen fern life-stage. The life-cycles of ferns are very complex and unusual and this is a seldom noticed part of it.

The green felty stuff that you can see in the image are the rhizoids of the gametophyte (also known as the prothallus), the gametophyte being the life-stage before the recognisable adult sporophytes that we most commonly come across; the rhizoids being filaments attached to the gametophyte which conduct water.

On the undersides of the fronds of adult ferns there are small, usually brown, sporangia which contain spores. These spores are released and when a suitable site is found, they grow into a gametophyte like the one shown in the image. The word gametophyte comes from the word gamete – the male and female reproductive cells (the ova and the sperm cells) that they produce.

The gametophyte features an archegonium and an antheridium. The archegonium is the female reproductive organ, which contains a single ovum. The antheridium is the male reproductive organ, which releases lots of sperm. The sperm swims through a thin film of moisture and into a nearby archegonium where the ovum is waiting to be fertilised.

Once the ovum has been fertilised, it becomes a zygote and later an embryo. The embryonic fern relies on the prothallus (gametophyte) from which it grows for its water and nutrients. Soon the embryonic plant grows into a sporophyte (the large leafy plant we most regularly recognise as a fern) and the prothallus dies.

That is fern reproduction explained as simply as I could (I can only just understand some of it myself) and there is a lot more to it. This link explains fern reproduction in much more detail, however as a warning there is certainly a lot of scientific jargon used: http://www.sas.upenn.edu/~joyellen/fernreproduction.html

The following diagram is a representation of the fern life cycle, from the same website:

Fern_life_cycle2copy

So, that felty green stuff on the wall of a cave might not look like much. However clearly there is a lot of interesting information and a very complex life-cycle behind it.

Advertisements

2000 and beyond!

As many of you know, I have been keeping a pan-species list for a year and a half. A pan-species list (or PSL) is a list of all species that you have seen within either the UK or Britain and Ireland. My main target, that I set in the new year, was to get to 2000 species by year-end, which was always going to be a big challenge for me. I started the year on around 1300 species and retrospectively I am very pleased at the number of species I added during the course of the year.

Just a couple of weeks ago I was on the home straight. I needed just 29 species for me to reach the magical number however I was in the last, and generally toughest month due to the lack of many invertebrates. However, I had a field trip planned which would hopefully get me all the way.

On a cold Sunday morning I met several other bryologists (bryology is the study of bryophytes – mosses and liverworts)/naturalists in a car park in the Lewes district of Sussex. We were at Chailey Commons for a meeting of the South East group of the British Bryological Society.

Our first stop on our outing was the short acidic grassland immediately next to the car park. There were a few common grassland species here, including the very familiar Rhytidiadelphus squarrosusor Springy Turf-moss. This species is not only confined to acidic grassland like this but can also be found almost anywhere with short grass. For example it out-competes the grass in our lawn in some places! Once you have seen this species regularly it becomes quite distinctive, it is medium to large sized (for a moss!) with a red stem. It has very short, thin leaves on the stem as well as slightly larger pointed leaves on the short branches and at the apex.

dscn9834

Springy Turf-moss (Rhytidiadelphus squarrosus)

Another species found in this short grassland was Kindbergia praelonga, or Common Feather-moss. This is another largish moss which, as its name suggests, resembles a feather. Unlike Rhytidiadelphus squarrosus is completely green, including the stem. It has opposite branches with leaves similar in size to those on the green stem. The branches become shorter, like the tip of a feather.

rscn9844

What I believe to be a frond of Kindbergia praelonga

After examining the grassland, we moved to a small patch of woodland around a quite large but seasonal pond. This pond is one of the few sites outside of the New Forest for Fairy Shrimps, however I needed to have been visiting in summer for a chance to see one of these rare crustaceans.

In this small wood we found a number of common woodland species, including our first liverworts of the outing. The first liverwort I came across was the small but abundant Metzgeria furcata, also known as the Forked Veilwort. This liverwort is very thin and forms small patches on tree trunks with the thalli (the leaves) adpressed to the substrate. It is the most common thallose liverwort and away from the coast, the most frequently encountered Metzgeria species. It also occasionally grows on rocks, although more frequently in the west of Britain where it is generally damper.

Along with that species of Metzgeria we also came across another species of the same genus: Metzgeria fruticulosa, or Bluish Veilwort. This is much less common than M. furcata, and a new species for me. This species is separated from furcata by the gemmae, which is “a small cellular body or bud that can separate to form a new organism”. Metzgeria furcata only produces gemmae rarely in Britain however fruticulosa is almost always gemmiferous, with gemmae located at the tip of the thalli.

We also encountered several patches of the moss Fissidens taxifolius (Common Pocket-moss) on the soil on the steep bank leading down to the pond. The genus Fissidens is a tricky genus for beginners as specimens often need close examination, either in the field with a hand lens or with a microscope. Luckily I was with lots of people much more knowledgeable than myself, so the specimens we found were quickly identified as this species.

dscn8638

A species of Fissidens from the Cotswolds last year

After recording everything that could be found in that small patch of woodland we headed to a habitat I have never explored before: a WW1 trench! There were a number of very interesting bryophyte species in this trench that was used for training in the Great War, including one of the least common bryophytes of the meeting: Aulacomnium androgynumThe common name of this species is Drumsticks, named after the very distinctive reproductive feature, which comprises of a long stalk with a ball of gemmae at the vertex.

A variety of different mosses and liverworts were not the only new species I found in the wartime trench. There were also a range of ferns growing on the muddy bank and luckily a member of the Sussex Botanical Recording Society, Helen Proctor, was on hand to help me identify a few. Most were common species that I had recorded before, however one was a common species that I hadn’t recorded before! This was the Broad Buckler-Fern, Dryopteris dilatata. Distinguishing this species confidently from other species is possible by looking at the brown, papery scales on the stem. If these scales have a dark centre, then they belong to the Broad Buckler-Fern.

After a thorough exploration of the trenches, we moved on to an area of damp heath. Here there were Sphagnums aplenty! Sphagnums are large mosses which love damp, boggy habitats on the edges of streams and other water bodies as well as in bogs and marshes. The genus is quite easy to identify from other mosses due to its size and elongated, upright shape with a thick capitulum, which is a compact head containing new branches. However, identifying Sphagnums to species level is much trickier! For a confident identification one will need good literature, such as the key in the British Bryological Society’s Mosses and Liverworts of Britain and Ireland: a field guide. Fortunately there was also a Sphagnum expert with us who was able to verify what we found. I was quite pleased at the number of Sphagnum species we recorded on the outing: compactum, fallax, capillifolium, papillosum, palustre and fimbriatum. However, this is only a small fraction of the species of Sphagnum in the UK!

While we were examining the Sphagnum one of the members of the field outing flushed a medium-sized, stocky bird from the leaf litter. It flew high in the direction of the road. I stared at it as it flew off with my mouth agape for a fraction of a second, before I exclaimed: Woodcock! These plump wading birds are related to the Snipes, however they are unusual in that they are nocturnal; they often feed away from water (on moist pastures for example) and they roost in woodlands. Woodcock was one of my bogey birds: species that I really should have seen but hadn’t. I have traipsed through many woods in my local area hoping to disturb one from its daytime rest, which is by far the easiest and most common way to spot a Woodcock, without any luck. Therefore I was exceedingly pleased to have finally come across one.

Soon after we flushed the Woodcock, it was time for me to head off. When I arrived back home I counted up the number of new species I had found and I was pleased that I had just made it to 2000, with Woodcock being species number 2000! Now it is time to think of a new target to keep me motivated to find more interesting wildlife. My next PSL target is to reach 3000 species by my 15th birthday in August 2018.