Source: Adastra 2014, published by the Sussex Biodiversity Record Centre, February 2015
2014 was another very good year for bryophyte recording in Sussex with several new species for the county, the re-finding of numerous ‘old’ records, and even a new species for Britain (and that’s in addition to the two we had last year). Sussex has always been ‘on the map’ in terms of bryophyte recording and it’s still one of the more important counties in England for mosses and liverworts. That’s not to say we have an abundance of rarities – indeed the more interesting plants often take a lot of searching for – but they are often there for the patient observer to find.
At the beginning of the year the author was involved in a survey of all the sandstone outcrops in the Ardingly area; the outcrops around Wakehurst Place are justifiably famous and some of the rarest liverworts in our county are to be found there. The rocks in adjoining woodland are well maintained too, with brambles and Rhododendron kept under control. The gardens themselves are also exceptional for bryophytes and the gardeners have an enlightened view when it comes to weeding. Two species of hornwort grow in one part of the gardens in profusion, but these are generally very uncommon in Sussex. Even better for lovers of leafy liverworts, the tops of some of the sandstone rocks by one of the streams have an abundance of Jungermannia hyalina in one of its few extant sites in the county. Nearby Paddockhurst has an abundance of the rare liverwort Tritomaria exsectiformis, and still has the same small colony of Dicranodontium denudatum that Francis Rose found in 1969 – there is probably only one other site for that now in Sussex. In the same general area, sandrocks at Philpots near West Hoathly have an abundance of Dicranum scottianum amongst many other special plants. There is optimism that these rock outcrops will continue to remain one of the highlights of Sussex well into the future as long as maintenance, funded by Natural England, continues to keep the Rhododendron at bay.
Ashburnham Place was visited twice in the year, it was another site well known to Francis Rose and has a diverse range of habitats. In April, a large colony of the rare Sphaerocarpos texanus was discovered growing in an earth border by a wall; it is one of our most extraordinary liverworts with inflated ‘balloons’ each with a tiny apical pore for spore dispersal. The two species of Sphaerocarpos have an eastern distribution in Britain with Norfolk being their stronghold. In the same border was Entosthodon fascicularis, a decidedly scarce moss. Ashburnham is one of the few places in Sussex where a list of over 100 species in a day is easy to achieve; the gardens and woodland are well looked after.
The author organised a five-day meeting for the British Bryological Society in April; this was centred in Rolvenden, Kent, but more than half of the meetings were in East Sussex. On one of these Sam Bosanquet spotted an Orthotrichum he couldn’t identify – Sam is one of the country’s experts for this genus. Its true identity remained uncertain until one of the world’s experts, Francisco Lara, was shown a specimen of the moss during a specialist course later in the year and he immediately recognised it as Orthotrichum rogeri: new to Britain. This was found on an Oak tree on Ashdown Forest, in an otherwise unremarkable patch of open woodland. There are many similar spots in the county and several other species of Orthotrichum, either never seen in this country or not seen for a very long time, could well be present. Anyone interested in searching for them would be well advised to get the latest published volume in the Spanish flora (Flora Briofitica Iberica), which covers the genus in exceptional detail although it should be noted that the text is in Spanish.
A big achievement this year, masterminded by Penny Green, was to transfer to computer all of Rod Stern’s records. The site record cards had never been digitised before and Bob Foreman, aided by several SxBRC volunteers, managed to get it all into one Excel file. This was then checked against the cards by this author. There are nearly 9,500 records in that dataset and it covers large parts of West Sussex and numerous places in East Sussex. Rod has been thanked for the recording, for keeping the cards and for making them available for this exercise. Although the data had been included at the 10km grid square level in the Atlas that Howard Matcham produced with Rod and Francis Rose, this is the first time that localised records have been available for many sites.
Ashdown Forest has occupied much of the author’s time during 2014. It was well known to William Nicholson who lived in Lewes and was active in the early part of the last century. Several species that he considered to be frequent have declined and there have regrettably been a few losses. Many changes in the bryophyte flora of the area can be attributed to reduction in grazing and consequent tree growth which the Conservators work hard to control. Atmospheric pollution is a more insidious factor causing grasses such as Molinia to thrive, often at the expense of species of Sphagnum. Against this trend, Sphagnum molle was once considered to be rare on the Forest but is now known to be widespread there. There are 17 types of Sphagnum on Ashdown Forest, quite remarkable for south-east England; it is highly unlikely that any more will be added now. The one that most people want to see is S. magellanicum, a beautiful deep wine-red in colour. There are only a few places to see this, but a couple of new patches were discovered this year. One of the best finds in 2014 was Scapania curta in Hindleap Warren, which adjoins the public land at Ashdown Forest; it is one of several species that Jean Paton used to find quite regularly in the 1950’s but which have either got rarer, or perhaps we have not got quite the same keen eyes as that remarkable lady.
Old Roar Ghyll is a very special locality in the middle of Hastings, it has recently been transformed with new walkways replacing what was once a jungle. By the ghyll stream are numerous outcrops of thinly bedded sandstone that is very calcareous. Here can be found both Leiocolea turbinata and Jungermannia atrovirens in one of their very few locations away from the chalk. Rocks by the stream have large quantities of Fissidens rivularis – far more than at nearby Fairlight Glen. Rocks actually in the stream support both Rhynchostegiella curviseta and R. teneriffae, often growing together. Most of these plants are very rare in East Sussex and the ghyll must be considered one of the top bryophyte sites in the area.
In May, Jacqui Hutson took a few of us to a very wet wood in Plumpton Green – at one time this was a mill pond but is now mostly alder carr. The water is decidedly calcareous; however, since the stream feeding it comes from the foot of the downs. Here we found some good patches of Plagiomnium elatum, an extremely rare moss in Sussex, together with Oxyrrhynchium speciosum. Both these are also found in similar woodland near Offham, but there can’t be many such sites. As Fran Southgate has reported before, chalk streams are rare and special places.
Grimmia is often considered a difficult genus, partly because many of them are very rare. Last year I mentioned finding Grimmia ovalis on a roof only a few miles from where I live. In 2014 I was able to add Grimmia laevigata from the same roof – I’ve seen them growing together in Wales so it was very much a targeted search and the owners are very friendly. Grimmia dissimulata has a chequered history in Sussex: Howard Matcham and Rod Stern found it on the church wall at Slinfold, near Horsham, but for some reason the specimen, which would have proved it beyond doubt, vanished. It was thought to have been sent to either the referee for the genus or the national recorder for mosses but neither has any record of having received it. So, even though it was seen, it couldn’t be accepted as new for the county. Fortunately it was found in November growing in some abundance on the roof of the small church at Coolhurst, also near Horsham. The local sandstone from which the roof is made can be very calcareous at times and this is a plant that usually grows on limestone. Racomitrium is a closely related genus and mostly found on siliceous rock on mountains. But in some ways, roofs are not that dissimilar to montane habitats and four species of that genus are recorded from clay tiles on roofs at Balcombe. A visit in December with David Streeter and Sue Rubinstein found two of them, R. affine and R. lanuginosum, as well as large cushions of the very attractive Hedwigia stellata.
Sometimes good discoveries are made during organised field meetings. The BBS Southern Group arranged a visit to Iping Common in the autumn; this was primarily to admire the Sphagnum magellanicum and Mylia anomala that still thrive there, albeit in fairly restricted areas. A more general search on the surrounding damp heathland looked like producing nothing more than huge quantities of very common species, such as Campylopus introflexus, then one of the party, John Norton, spotted something different – a fine stand of the very rare Dicranum polysetum. There are quite a lot of species of Dicranum in Sussex but this is probably the hardest to find. Francis Rose knew of one patch on Graffham Common but it had never been re-found. This time we have a very accurate GPS reading so we can keep an eye on it.
I’ve saved until last what I consider to be the best discovery of the year. Whilst looking at a small chalk pit near Glynde, Sue Rubinstein chanced upon several patches of Gymnostomum viridulum, completely new for Sussex. These plants form very small cushions on bare chalky soil but the oval leaves reflect the light and can appear like tiny green jewels on a damp day. Given its close proximity to Lewes it’s inconceivable that Nicholson would have overlooked it, as he seems to have found everything else in the area. It must, therefore, be a more recent colonist; the nearest place to see it being in a chalk pit on the Isle of Wight. How such colonisations of mosses take place is still largely unknown but insects, wind, birds, people and vehicles have all been suggested as possible dispersal mechanisms, the present species having abundant asexual propagules in the leaf axils just waiting to be spread. The Pottiaceae are an attractive family of mosses, but are often difficult to identify.