Meeting report

Bryological symposium

Dr Hugh McAllister of Ness Botanic Gardens, the local organizer, found us a splendid place to stay in Burton Manor, a large house on the Wirral converted into a conference centre. Ness Gardens, the venue for the meeting on Saturday, was a short car ride away, and members returned to Burton Manor in the evening for the Centenary Dinner. Sincere thanks to both Hugh and Dr Rachel Janes, also of Ness Gardens, for their efforts in organising this centenary AGM. My thanks also to the speak ers for providing an entertaining and interesting selection of talks, particularly those who were called upon to contribute at short notice.

Nick Hodgetts

Dr Dennis Brown and Julian Smith (University of Bristol): The Wormery.

A series of experiments to study the decomposition of 2 cm apical segments of Rhytidiadelphus squarrosus were described. A glass frame covered with netting was used in place of the traditional net bag and moss segments were placed directly on a lawn soil surface, after the grass had been removed. Segment losses were attributed to worms. Plastic drainpipes driven into the ground, with or without added worms, supported this suggestion. Drainpipes, partly filled with soil and containing a single worm (the wormery), were used under controlled laboratory conditions to test worm preferences for mosses held above the soil surface by supporting them through holes in a plastic dish. These showed that worms more readily consumed oven-baked moss apices more than either boiled or live green tips or brown bases and showed a stronger preference for oven-baked apices when soaked in extra nutrients obtained from homogenized fresh apices. Worms were most selective when the soil contained high percentages of leaf litter as an alternative food source, or when the soil or moss was wettest. The apparatus is a simple and convenient way of testing the role of worms in early stages of moss decomposition.

Dr John Edmondson (Liverpool Museum): Museum bryophyte collections: their scientific and cultural value.

The bryophyte collections at Liverpool Museum were briefly described, with special reference to the historically important collections of Sir James Edward Smith, John Forbes Royle and the Liverpool Botanic Garden herbarium, which was founded in 1799. In order to maximize the scientific value of the collections and to increase the efficiency of the loans service, considerable effort is now being made to document them on computer. Liverpool Museum is also committing more resources to maintaining the stability of the specimens and their labels through appropriate conservation treatments and improved storage. The cultural value of such collections was also discussed, referring to the educational value of these records of the past activities of bryologists and the insights they give into the social milieu in which the collections were first made. Some thoughts were shared on the new uses of preserved bryological collections, including their value as sources of DNA samples, for chemical screening, paleoclimatology, ethnobryology and pollution monitoring. Lastly, the point was made that the value of collections could be greatly enhanced through specialist input from taxonomic experts and other users.

Dr Mike Le Duc (University of Liverpool, Ness Gardens): Bryophytes and bracken control.

Bracken, Pteridium aquilinum (L.) Kuhn, is a very serious weed in the uplands and marginal land of the UK. Dense monocultural stands are known to infest around 1.6% of the total land area, with a similar amount present as sparse cover. As bracken has a large underground rhizome system its elimination is impracticable.

In steep and undulating terrain the only effective method for bracken control is by aerial spraying with the herbicide asulam. This licensed process is increasingly widely used in the uplands, with about 6000 ha being sprayed in 1990.

The impact of asulam treatment on the vegetation of upland and marginal land is not well known, especially in the longer term. Asulam itself has a narrow spectrum of activity; it is known to damage only ferns, some docks and a small number of grasses. Asulam’s effect on bryophytes is not known. Moreover, once sprayed the vegetation undergoes a post-treatment succession, the direction of which is influenced by a number of factors, some natural such as climate, others site- or management-specific, for example grazing pressure (Pakeman, Le Duc & Marrs, in press).

A research project, funded by the Ministry of Agriculture, Fisheries and Food, was instigated to address this problem. It was undertaken, jointly, by the Institute of Terrestrial Ecology (ITE), Monks Wood, and the University of Liverpool Environmental and Horticultural Research Station, Ness Botanic Gardens. The project co-ordinator (Robin Pakeman, ITE) and I shared the field work and, with the assistance of several students, we carried out a major survey in the summers of 1994 and 1995. With agreement from local managers we visited 117 sites, mostly heath and acid grassland, from Skye to Exmoor, the Lleyn Peninsula to the North York Moors. At each site transects were laid across the sprayed areas and 1-m quadrats were employed to assess the cover of vegetation . We used the chronosequence, or space-for-time substitution, approach and were thus able to estimate the course of events over a period of zero to 19 years after spraying.

A total of 75 bryophyte species were found in this study, 60 of which were mosses. The latter included the common heathland species Dicranum scoparium; but Polytrichum formosum, usually a woodland species, was more common than another member of the heathland community, P. commune. Several Campylopus species were found, including C. pyriformis and C. introflexus most commonly. C. subulatus was present at only a few sites, mainly in NW England and N Wales. Leptodontium flexifolium was also rare, being found only in NW England. The weft-forming pleurocarps, Pseudoscleropodium purum, Rhytidiadelphus squarrosus (the most commonly occurring of the mosses) and Pleurozium schreberi were all very common, as was Hypnum jutlandicum, seemingly quite adapted to surviving amongst thick bracken litter. Eurhynchium praelongum and Hylocomium splendens were both fairly frequent, notably at sites in the Southern Uplands and NW and NE England. Of the liverworts Calypogeia fissa, Barbilophozia floerkei, Lophocolea bidentata and Ptilidium ciliare were the most common. However liverwort recording was uneven and the data are not considered further here.

When sprayed and unsprayed sites were compared it was found that the frequencies of occurrence of the most common mosses were greater in the sprayed sites (Table). However when tested statistically it was found that only Dicranum scoparium, Campylopus introflexus and Pleurozium schreberi, perhaps the most shade-intolerant members of the group, showed a significantly greater frequency after spraying. None of the species tested statistically (Table) were less frequent on sprayed sites.

Species	Unsprayed	Sprayed
Polytrichum formosum	13	20
Dicranum scoparium *	27	54
Campylopus pyriformis	20	22
Campylopus introflexus **	7	47
Pseudoscleropodium purum	20	39
Eurhynchium praelongum	13	14
Hypnum jutlandicum	40	62
Rhytidiadelphus squarrosus	60	66
Pleurozium schreberi *	13	40
Hylocomium splendens	13	20

Table. Relative frequency (%) of occurrence of the commoner species of moss on bracken-infested land. Comparison of sites sprayed with asulam (n = 101) with unsprayed sites (n= 15). Species showing distributions statistically (G-statistic) dependent on spraying are indi cated by: *, p < 0.05; **, p < 0.01.

Many other factors could be responsible for determining species composition in a complex environment. To investigate this we used canonical correspondence analysis (CCA), a multivariate ordination technique that automatically relates, by regression analysis, ordination axes to measured environmental variables (ter Braak, 1986). In this way it was possible to assess the relative importance of a set of environmental variables, including elapsed-time since spraying, in determining species composition.

We found that the two most important variables influencing plant species composition were those determining geographical location, namely national grid easting and northing. The sequence of importance of the other variables was: distance of the site from the sea; altitude; amount of non-bracken litter present (a variable influenced by the general type of vegetation present); amount of animal excrement present (an indicator of the grazing pressure); elapsed-time since spraying. Two other variables were statistically significant, but less important in the model: site slope, and the amount of bracken litter present. The latter is a complex indicator of the vigour of the original bracken infestation and rates of litter breakdown and dispersal.

Using the CCA ordination scores for the ten common mosses on the vector of elapsed-time since spraying it was possible to elicit two main types of response to the spraying event. The first type was a continuing increase in abundance for some time following spraying. This behaviour was shown by Polytrichum formosum, Dicranum scoparium, Campylopus pyriformis, C. introflexus, Eurhynchium praelongum and Hypnum jutlandicum. The other group (Pseudoscleropodium purum, Rhytidiadelphus squarrosus, Pleurozium schreberi and Hylocomium splendens) was found to show an initial increase in abundance, immediately after spraying, and then gradually decline.

Some areas of treated brackenlands in the North York Moors support this result for the alien Campylopus introflexus. A dense mat of the moss appears to be obstructing the establishment of other species. However our model suggests that after about nine years the problem may ease as the moss begins to decline in abundance. Colonies of C. pyriformis, on the other hand, tend to break up quite soon to provide establishment sites for Calluna vulgaris.

The disappearance of the weft-forming pleurocarps through time is thought to be associated with grazing pressure, which inevitably increases after the removal of the bracken canopy. However, the disturbance created by stock is very effective in dispersing thick mats of bracken litter. The process can often lead to the presence of bare ground, thus aiding the establishment of Campylopus species.

In conclusion, the process of spraying with asulam for bracken control does not, in itself, affect the distribution of the commoner mosses seriously, although the abundance of some may increase. However the post-treatment succession, which is affected by a number of other environmental variables, both physical and biotic, can interact to alter the bryophyte flora.

References

Pakeman RJ, Le Duc MG, Marrs RH. (in press). Moorland vegetation succession after the control of bracken with asulam. Agriculture, Ecosystems and Environment.

ter Braak CJF. 1986. Canonical correspondence analysis: a new eigenvector technique for multivariate direct gradient analysis. Vegetatio 67: 69-77.

Mr Brian O’Shea (London): The BBS and the Internet.

The BBS now has its own ‘Home Page’ on the Internet’s World Wide Web (WWW), hosted on the Edinburgh Royal Botanic Garden computer. The Internet is a way of connecting you and your computer to the computers of others, and these can be public or private, acad emic, commercial, personal, national government, or indeed any data resource that people want to make publicly available. If you are a private individual wanting access to the Internet, you will need a device called a modem to connect your computer via a telephone link to an Internet service provider (ISP). If you are connecting via your organisation, this part will not be visible to you: all you will be aware of is that the Internet link is there, usually on your local network (organisations may be ISPs them selves, or may take their service from an ISP using a permanent data link rather than a dial up service). The ISPs are connected into a global network which includes mechanisms for routing messages, maintaining addresses of all nodes on the network etc. Each node has a universal resource locator (URL) that indicates country (unless the USA when this is omitted), type of organisation and node name within that type of organisation. For instance my own node name is ‘oshea.demon.co.uk’ indicating that I get my service via an ISP called demon, which is a commercial organisation in the UK. The Royal Botanic Garden at Edinburgh has a node name ‘rbge.org.uk’, indicating that it is a non-commercial organisation. In practice URLs are not as simple as this, but the principle of the hierarchical address still applies. The URL for the BBS Home Page is:

http://www.rbge.org.uk/bbs

There are some organisations that provide an Internet service in a slightly different way, such as Compuserve. They have a self-contained network of their own which provides various internal facilities, but also have gateways out of the network into the Internet itself.

The Internet provides a number of facilities, but some of these are increasingly being subsumed within WWW, so the majority of people on the Internet now use three main facilities: email, newsgroups and WWW. Email (electronic mail) operates in a similar way to ordinary mail. You compose letters ‘off-line’ (i.e. you don’t need to be connected to the Internet mail service) and then when complete ‘send’ them, which means that a link is made to the network and they are dispatched. Mail to you arrives in the same way: whenever the link to the Internet is open, mail for you can be received. If like me you are a personal subscriber to the Internet, this means that when you have letters to send, you connect to the network by clicking an icon on the screen (which initiates the dialling to my ISP), and then as soon as the connection is made all your mail is sent and any for you is received. You can then disconnect, after probably only a few seconds of phone use, and look at your received mail. If you are using an organisat ional machine, without the need for dialling up for connection, mail is sent and received constantly.

Newsgroups allow you to participate in discussion groups of specific interest to you, and all members of the group (which may be thousands) receive all contributions. There may be a number of ‘threads’ within the discussion group any of which you can follow or contribute to. The link to the Internet operates in a similar way to email. There is a specific one for bryology called ‘Bryonet’. The World Wide Web (WWW) is the aspect of the Internet which has fuelled the exponential growth we are now seeing. WWW is a way of looking at information other people have made available on their computers as specially formatted documents that can contain pictures, sound, animations or video, and can be interactive. They are viewed using a computer program called a ‘browser’ , such as Netscape or Microsoft Internet Explorer. There are two aspects that make this a much more powerful tool than it sounds. Firstly, the documents are ‘hypertext’ – that is, it is possible for a document author to highlight parts of the document that link you to more information on that subject. That link can be to elsewhere in the same document or to another document anywhere in the world, and the way that the WWW works means that the time to access a document on the same computer may not be significan tly faster than accessing a document at the other side of the world. Potentially this makes each document like a page of an infinite encyclopaedia, and hence the term ‘surfing the Internet’. Secondly, the documents are indexed via vast ‘search engines’ that constantly keep up to date with what’s where, so you can search for ‘bryology’, and come back with thousands of ‘hits’. As it will search for words in combination, this is usually the best way to find restaurants in Rochdale, the weather in Wales, mosses in Madeira, cinemas in Seattle or whatever else it is you want to search for.

The BBS Home Page (so called because it is where the BBS lives on the Internet) is intended to be both a shop window for the society and an information resource for both members and anyone else who is interested. The first page of a WWW site is usually a welcome screen of some sort, which says who you are and provides links to the documents that are available on the site. David Long is the ‘editor’ of the BBS site, appointed by Council, and although the initial launch of the BBS site was limited to documents that were easily available in computer format, David is now seeking views on how the site should develop.

Although it was possible to show samples of WWW documents on the overhead projector, we were fortunate that Ness Botanic Garden very generously provided two computers linked to WWW for our use during the meeting, so we were able to demonstrate both the BBS site as well as links to the American Bryological and Lichenological site and other sites of bryological interest.

R.D. Porley (English Nature): The Darwin Initiative bryological expedition to Uganda.

The Tropical Bryology Group last had a bryological expedition to Africa in 1991, when seven members went to Mulanje Mountain, Malawi. That expedition was largely self-financed. Progress has been steady with naming the collections and publishing the results. However, to maintain and develop the groups’ expertise in tropical bryology, particularly in the field, it was decided to return to Africa. It was agreed that this time we would need to seek funding for the expedition, and we submitted a proposal to the Darwin Initiative in late 1994. This is a fund established by the UK government following the Earth Summit in Rio de Janeiro in 1992. Its purpose is to support the development of an integrated strategy for the deployment of UK scientific, industrial and managerial expertise to assist developing countries implement the Convention on Biological Diversity.

We were delighted to learn that the proposal had been successful and that we had secured funding to enable a three year project to go ahead. The project was to study and document the bryoflora of montane rain forests in Uganda. The present political stability in Uganda, the dearth of published bryological data for the country, the pressing priority to document the biodiversity in one of the richest parts of Africa, and to contribute to the effective conservation of the rain forests convinced us that Uganda was the country to go to. Furthermore, Uganda represents something of a gap in our knowledge of the bryoflora of East Africa, with Tanzania, Kenya, Burundi, Rwanda and eastern Zaire being relatively better known.

There are five key objectives of the project:

• to make as complete an inventory as possible of the bryophytes of Bwindi Impenetrable National Park, Rwenzori National Park and other montane forests in western Uganda.
• to compare the bryophyte floras of these areas both with each other and with other East African forests.
• to identify centres of bryological diversity as a contribution to their effective conservation.
• to communicate the bryological importance of the study areas to specialists and administrative authorities.
• to facilitate the study of bryophytes in Uganda by providing bryological literature and training for local botanists, and donating a set of named vouchers to the herbarium of Makerere University.

Six UK members of the Tropical Bryology Group, Jeff Bates, Nick Hodgetts, Howard Matcham, Ron Porley, Robin Stevenson and Martin Wigginton left England on 19 January, 1996. We were joined in Kampala by Stephen Byarujali and Berna Nakityo of Makerere University.

Uganda is about the same size as the UK although 25% of the country is water (Lake Victoria, Albert, Edward, George, Kyoga and The Nile). It is situated on the equator on the Central African Plateau with most of the land over 1000 m above sea level. The Rwenzori, Ptolemy’s fabled Mountains of the Moon, forms the western border with Zaire, and Mt. Elgon rises above the plains over to the east on the Kenyan border.

Bwindi Impenetrable National Park, the main study site in year one, is located in the south west corner of Uganda at the end of the western arm of the Great Rift Valley. It covers some 321 km and varies in altitude from 1160 m to 2600 m. It is of one of the few forests in East Africa to show an intact altitudinal zonation from lowland forest type, through sub-montane to montane. The known flora and fauna of Bwindi is impressive: there are over 1000 vascular plants, possibly a greater number of trees than in any other East African forest, there are several endemic trees and many central African trees reach their eastern limits here. It is the best forest for primates in East Africa, supporting about half the global population of mountain gorilla. In addition there are chimpanzees, black and white colobus and several Cercopithecus species, 58% of African montane birds, also occur in Bwindi, including the spectacular Rwenzori turaco. Bwindi is an important Nile catchment area and is vital for watershed protection (facilitated by the large bryophyte biomass acting as a slow release sponge).

The drive from Kampala to Bwindi, which took us across the equator, was about 400 km. It seemed to be twice as far though because of the rather ancient Landrover (probably from the old Colonial days) which we had the use of. Howard was voted to be our main driver and it was no easy task. However, despite the bonnet having to be raised far too frequently, it did eventually get us there (and back). Daily sorties on foot were made into Bwindi forest from Ruhiija, our base for the first half of the trip, and then from our base at Buhoma, which took us further north.

Bryophytes were collected from as wide a range of habitats as possible; particular attention was paid to twigs and branches laying on the forest floor as this was the only way to sample the canopy. Typical plants found in this situation were Mastigophora diclados, Chandonanthus hirtellus and Macromitrium spp. The forest floor, on bare exposed earth banks, could also be rewarding, with Telaranea nematodes and two ecostate Fissidens species, F. bryum and F. usambaricus, all previously unreported for Uganda. However, trees proved to be amongst the most productive of the habitats for bryophytes, supporting diverse range of epiphytes and epiphylls.Plagiochila squamulosa was particularly prominent, together withPilotrichum sp., Calyptothecium hoehnelii, Porothamnium spp., Syrrhopodon gaudichaudii and, more rarely, Prionodon sp. More familiar plants were also present, such as Pterogonium gracile and Leptodon smithii. Buhoma was noticeably more humid than Ruhiija and correspondingly richer in bryophytes. Epiphylls were encountered in some quantity, including the distinctive Radula flaccida and Caudalejeunea sp. Other notable plants from this area, and not so far recorded for Uganda, include Distichophyllum rigidicaule, Homaliodendron piniforme, Syrrhopodon gardneri and Frullania diptera.

In addition to the general collecting, Jeff Bates was keen to undertake an ecological study or two. The main study involved investigating bryophyte diversity and species ranges in relation to altitude. Five plots, 25 x 25 m, were delimited at points along an altitudinal gradient and all bryophyte species recorded noting whether on trees , rotting wood, rock, on leaves and so on. Observations on stand structure, vascular flora and topography were also made. Alongside this study was an investigation of epiphyte communities. In each of the plots mentioned above, five mature trees were selected and the epiphyte community sampled by a 25 x 10 cm quadrat attached to the trunk at about chest height. This was repeated at a number of aspects on each tree to characterize any variation in the community. One of the plots was set up in high altitude bamboo forest; bryophytes were present on the stems particularly around the rough nodes.

It was decided that two members, Nick and Ron, accompanied by local trackers, would make an excursion into the interior; a day to walk in, a full day collecting and the third day to walk out. Two memorable nights were spent under canvas deep in the rainforest, all too aware that the tents were pitched across a regularly used elephant track. Luckily for us they didn’t pass this way again, at least while we were there. In this part of the forest, large buttressed trees were common having escaped the deprivations of loggers. Tree-ferns were also a prominent feature of this area, and the moss Rhizofabronia persoonii appeared to be restricted to their fibrous stems. Epiphylls were common, with many representatives of Lejeuneaceae, including Taxilejeunea pulchriflora, Colura tenuicornis and Odontolejeunea lunulata, all unrecorded for Uganda. Several epiphyllous Daltonia spp. were also collected. On our way out of the forest we saw fresh gorilla nests, and it was quite a thought that we had been sleeping just a few hundred metres away from these incredible animals.

The number of published taxa from Uganda prior to our visit is something in the order of 362 mosses and 156 liverworts. Bryology in Uganda dates back to the early 1800s a period when some type specimens were published. Several collections have been made since, for example in the 1920s and 1930s, and with a particular increase in activity in the 1950s and 1960s, just before Independence and the Amin era. A large number of collections reside in the British Museum (Natural History), some named, but many not. Brian O’Shea has started working on these collections. Makerere University also houses a small collection of bryophytes from Uganda, some with familiar collector names, such as Alan Crundwell and Francis Rose. However most of these are also un-named. It is early days yet with the naming of our material, but many species are turning out to be new to Uganda, and for mosses the total is now in excess of 400 and for liverworts over 200.

All those who took part in the expedition had memorable experiences. For me, and I suspect others too, it was to see, at close range, a family of mountain gorillas set against the backdrop of their montane rain forest home.

Finally I would like to say many thanks to Nick Hodgetts and Martin Wigginton who did virtually all the organisation of the expedition, both before we left these shores and in Africa.

Jane Burch (Manchester University): The Leucobryoid leaf.

The leucobryoid leaf is a multistratose leaf, characteristic of ten genera of mosses, and consists of dorsal and ventral layers of hyalocyst cells sandwiching a median layer of chlorocysts. The leaf structure is distinctive, giving the mosses a whitish appearance especially when dry, hence the general term leucobryoid mosses, derived from the widespread genus Leucobryum.

The leucobryoid leaf is quite variable in the details of its structure between genera. For example, in some cases there are additional superficial networks of chlorocysts, and in others additional layers of hyalocysts. Moreover, sporophyte structures such as the peristome, indicate that genera with the leucobryoid leaf are not necessarily closely related. The question arises as to whether the leucobryoid leaf can be regarded as a monophyletic character, or a response to habitat selective pressures that has arisen several times.

In order to investigate this problem, the leucobryoid leaf from a range of mosses was analysed using light microscopy. Each moss was scored according to ten characters relating to the leucobryoid leaf, and possible homologous structures were sought between leucobryoid leaves, and also in non-leucobryoid leaves which might give clues to the phylogeny of these mosses. The data were processed using the cladistic program Henig86 (whose results were largely discounted), and also cluster analysis.

From this study, it appears that the leucobryoid leaf evolved on at least five different occasions:

• Leucophanes is the only genus in which the leucobryoid part of the leaf originated from the lamina. This therefore led to the conclusion that it has a separate evolutionary line, and is the only genus belonging to the Leucophanaceae.
• Octoblepharum, Exodictyon and Arthrocormus remain within the Syrrhopodontales, but in a separate family from Leucophanes.
• Leucobryaceae genera Schistomitrium and Leucobryum (pro parte), have extra strata of hyalocysts, and may have evolved from a Campylopus-type ancestor via a Brothera-type leaf, with the central cells accounting for the increased number of hyalocysts.
• Leucobryaceae genera Cladopodanthus, Ochrobryum and Leucobryum (pro parte), evolved from a Campylopus-type ancestor via a Paraleucobryum-type leaf, with just two hyalocyst strata, sandwiching chlorocysts between them.
• Theriotia represents a separate evolutionary line from an ancestral moss.

These results support the theory, based on sporophyte structure, that the leucobryoid leaf is polyphyletic, but may highlight potential inconsistencies such as the split within Leucobryum, which require more detailed analysis.

The paper was based on a third-year undergraduate project (supervised by Sean Edwards) at Manchester University. It is important to state that the project represented a feasibilty-study for the investigation into the phylogeny of the leucobryoid leaf, and the brief results given above do not represent a proposed phylogeny, but may be useful as pointers for further research.

Mr Ray Woods (Countryside Council for Wales): The conservation of bryophytes in Wales.

The framework of statutory conservation measures was explained for Wales. There are now over 900 Sites of Special Scientific Interest covering over 207,000 hectares. Whilst few SSSIs have been notified exclusively for bryophytes, most important bryophyte sites have been protected by this mechanism. A recent survey of Brecknock showed that 89% of all the mosses recorded from the vice-county and 90% of the liverworts occurred on SSSIs. In Radnorshire, 84% of mosses and 95% of the liverworts were represented on SSSIs. The relationship of the SSSI system to National Nature Reserves and Local Nature Reserves was then explained.

Such designations will only ever cover a small proportion of the countryside. To promote conservation of important habitats in the wider countryside, a range of agri-environment conservation schemes have been developed. These include the Tir Cymen, Environmentally Sensitive Area (ESA) and Habitat Schemes. All seek to prevent damage to a range of bryophyte-rich habitats, such as woodlands, wetlands, rough grazings and rock outcrops, and operate in discrete areas of Wales. These schemes have now been running long enough to begin to judge their effectiveness. Tir Cymen and the ESAs have so far attracted voluntarily nearly half of the farms which were eligible into the schemes. A Welsh Office review is underway to recommend the best way forward.

Finally, members were alerted to the important developments arising from decisions taken at the World Environmental Summit in Rio de Janiero in 1992. Action Plans have been drafted to encourage the conservation of some of our most threatened bryophytes. It is important that the BBS plays a full part in guiding the development of these plans and the selection of the species. Plans have been, or will be, drafted to conserve a number of bryophyte-rich habitats, such as upland oakwoods.

Field Excursion to Esclusham Mountain, 22 September 1996

The weather was warm and sunny for the excursion to Esclusham Mountain (VC 50), an area of North Welsh moorland which was bryologically unknown. The rock is Millstone Grit, so that most of the land is acid. There are, however, numerous old mines, where the underlying Carboniferous limestone has been extracted and dumped on the surface.

The first thing that caught our eye as we examined some mine spoil was a large quantity of Ditrichum flexicaule* s.s., forming its distinctive dense tussocks. Other calcicoles of interest were Climacium dendroides, Cratoneuron commutatum var. falcatum, Orthotrichum cupulatum, Plagiomnium cuspidatum and Rhodobryum roseum. Ron Porley found Entodon concinnus, which had not been seen in the vice-county since about 1920, when it was found nearby at Minera. Alan Crundwell found Bryum creberrimum.

The calcifuge and calcium-indifferent flora was larger but less remarkable. We found 10 species of Sphagnum, including S. girgensohnii and large quantities of S. russowii. S. capillifolium by contrast was scarce and found by only one participant. Also on wet ground were Calliergon stramineum, Drepanocladus exannulatus and D. fluitans. Racomitrium elongatum and R. ericoides grew on dry ground near the road, and Dichodontium pellucidum (confusingly) on limestone rubble. Liverworts were few, with Barbilophozia floerkei, Ptilidium ciliare and Tritomaria quinquedentata perhaps the most notable.

Although we eventually recorded the quite respectable number of 101 species for the card, we were a little disappointed not to find any lead-mine specialists. These could well exist in the area, perhaps nearer Minera, where there are numerous other mines.

Mark Hill