BBS > Activities > Meetings and Workshops > Previous > 1982
Meetings of the BBS - 1982
Okehampton, 14-21 April
The Spring Meeting was held at Okehampton, north Devon (v.-c. 4) from 14 to 21 April. The northern half of Devon has been much less well explored and less well mapped than the southern. It was thought, correctly, that Okehampton being on the northern edge of Dartmoor would be in reach of a wide enough range of habitats to produce a varied flora and to attract a good attendance so that some useful mapping might be done. Well over thirty members attended the meeting and we were especially fortunate in the weather, enjoying almost continuous sunshine and having not a single drop of rain fall upon us, most remarkable when centred on a town with an annual rainfall of between 45 and 50 inches.
15 April. The Meeting started with a gentle introduction to Dartmoor. A short journey to Belstone, a couple of miles south-east of Okehampton, was followed by a walk a short way up the East Okement River. Flushes on the side of the valley had Cephalozia pleniceps and Pellia neesiana. Nardia compressa was in the river and *Plagiochila spinulosa on a tree by it. Other noteworthy finds were *Leucobryum juniperoideum, *Marsupella sphacelata and Bryum bornholmense. After lunch the party went a couple of miles east to examine some old copper mine workings at South Zeal. A good deal of Cephaloziella material was there. Most of it was, as so often, C. divaricata; but small quantities of C. stellulifera and C. nicholsonii were also found. After this most of us strayed into south Devon (v.-c. 3) and had a look at the heathland to the north of Buttern Hill, south of Throwleigh. A fairly long list of specie s included nothing rarer than Splachnum ampullaceum and Fontinalis antipyretica var. gracilis.
[* = New vice-county record]
16 April. As a contrast to Dartmoor there was a long drive to the north coast. The principal stop was at the wooded cliffs to the east of Clovelly. The flora here was not very rich. Fissidens celticus, present in some quantity was the best find. F. curnowii, Plagiochila punctata, P. spinulosa and Nowellia curvifolia were also seen. After lunch we split up, visiting different localities round the coast to the west. Hartland Point yielded Frullania microphylla and Pottia crinita. Hartland Quay had a richer flora, including fruiting Archidium alternifolium, Tortula canescens, Pottia starkeana var. brachyodus, Scleropodium illecebrum and Cololejeunea minutissima. Welcombe Mouth also proved profitable, yielding Fissidens celticus, Desmatodon convolutus, Bryum gemmiparum and Scleropodium caespitosum.
17 April. Back again to Dartmoor, this time up the West Okement River and to Black Tor Copse, one of the famous Dartmoor high level oakwoods. This is fascinating ecologically but only moderately rich in bryophyte species. The Society visited it in 1966 on the Tavistock meeting (Trans. B. B. S. 5, 426). Lophocolea fragrans was a noteworthy addition to the flora of the wood. The West Okement valley proved quite rewarding, with Rhynchostegium alopecuroides, Isothecium holtii, *Marsupella aquatica and Diplophyllum obtusifolium. Lower down the valley Heldon Quarry produced several calcicoles uncommon in the district: Aloina aloides, *Gymnostomum aeruginosum, Tortella tortuosa, Anomodon viticulosus, Camptothecium lutescens.
18 April. Being Sunday this was the traditional "free day", presumably to allow members to go to church. Our devotions did not impede our fieldwork. Some members went to Lydford Gorge, previously visited on the Tavistock meeting. Most of the species seen then (though not Fissidens celticus) were refound, but there were no significant additions. Sourton Quarry, to the north of Lydford, had *Barbula reflexa, *Eurhynchium swartzii. var. rigidum and Bryum flaccidum. The valley of the River Torridge at Beaford Bridge, some fifteen miles north of Okehampton, was worth visiting just for the spring flowers. Bryophytes seen included *Barbula nicholsonii, Pohlia lutescens, Bryum sauteri and Orthotrichum rivulare. One member drove to Bolt Tail, on the South Devon coast, visited by the Society from Totnes in 1950. Species seen this time but not in 1950 included Weissia perssonii, Eurhynchium speciosum, Bryum dunense and Cololejeunea minutissima.
19 April. Again no formal excursions were planned, in the hope that members would disperse and map some of the less well worked 10 kilometer squares. Those who visited the Torridge yesterday tried the Taw today and found many of the same species. Cinclidotus mucronatus was at Lapford, Pohlia lutescens there and near Bondleigh - whatever did we overlook this as until fifteen years ago? Bryum donianum was found at South Tawton, *B. dunense and Fissidens celticus at Spreytonwood. Those who visited some of the ground in the upper part of the Teign valley, west of Chagford (v.-c. 3) were rewarded by the only Orthodontium lineare seen on the meeting as well as Isothecium holtii and many plants seen on other days.
20 April. On this, the last day, we went to Fingle Bridge, on the Teign (v.-c. 3). This beautiful wooded valley was visited by the Society on both the Totnes and the Tavistock meetings. We were pleased to see many of the rarities previously recorded, including Porella pinnata, Jubula hutchinsiae and fruiting Grimmia montana, and to find a few less expected plants - Cephaloziella turneri, Cynodontium bruntonii, Leucobryum juniperoideum and Zygodon baumgartneri.
It is always a little arbitrary deciding which species to pick out for mention. Many not mentioned at all in this account because they were seen in too many localities would be decidedly noteworthy in most parts of the country: Metzgeria temperata, M. fruticulosa, Saccogyna viticulosa, Atrichum crispum, Schistostega pennata, Epipterygium tozeri.
While those who hankered after the fleshpots of South Devon may have found the bryology a little disappointing, nearly 350 species and varieties were seen on the meeting, including many south- western ones of limited distribution in the British Isles. Not many new county records were made, that of Marsupella sphacelata, not known previously south of Brecon, being the only extension of range. The contribution to the mapping scheme was more substantial, about 1650 records being made in 14 squares. All those that participated in the meeting owe a debt of gratitude to Dr. Michael Proctor for all that he did to organise it and make it so successful.
A. C. CRUNDWELL
Penrith, 29 July-3 August
About 25 members (including, as one was heard to remark, "a whole... galaxy of talent") attended this meeting, the majority throughout the week but a few attracted only by the Borrowdale excursion. We were pleased to welcome Lillian Franck from West Germany, on her second B. B. S. meeting this year. The sites explored during the week were in vice-counties 69 (Westmorland) and 70 (Cumberland).
29 July. The Moor House National Nature Reserve 35/73 (69) was approached by a long track ascending to an altitude of about 700m. Here a band of limestone, some of the highest in England, was exposed in places and Silverband mine, once worked for galena but now reworked for barytes, was an obvious feature on the landscape. In a shallow grassy gully with loose limestone rubble, Plagiobryum zieri, fruiting Bryum pallens, Racomitrium canescens var. ericoides, Mnium marginatum and Scapania aspera were found together with other commonly occurring calcicolous species such as Tortella tortuosa and Ctenidium molluscum.
The beck south of Middle Tongue was examined where some of the prominent species included Drepanocladus exannulatus, D. revolvens, Hygrohypnum ochraceum, Scapania undulata, S. uliginosa, S. scandica, Leiocolea alpestris and Calypogeia trichomanis were also present. Alan Crundwell found Bryum elegans and Schistidium trichodon, Eustace Jones found Marsupella sprucei and Jean Paton refound Barbilophozia lycopodioides. Whilst lunching at the top of the beck we were hailed by a victim of the 'Pennine Way undefined' who had lost his way in the mist which, unfortunately obscured the views.
We then continued to the north-east of Little Dun Fell. In the environs of a basic flush we came upon a conspicuous stand of Oncophorus virens which still retained some of its noticeably strumose capsules and several patches of Meesia uliginosa, some of them fruiting. Amongst some material picked up by Martin Crundall, Jean Paton discovered *Harpanthus flotovianus (new to England) which was growing well in a limited area. Other species seen were Rhizomnium pseudopunctatum, Splachnum sphaericum, Mylia taylori and two other interesting plants peculiar to this area, the pink Sedum villosum and the grass Alopecurus alpinus.
[* New vice-county record]
Finally we visited the rocky outcrop of Green Castle via the grassy slopes where the yellow Saxifraga hirculus grows. Here we saw Seligeria recurvata, Philonotis calcarea, wiry mats of Pseudoleskeella catenulata var. catenulata and fruiting Amblyodon dealbatus. Joan Appleyard found Cratoneuron commutatum var. virescens whilst Alan Crundwell found Tortella fragilis.
30 July. The River Eden flows through pleasant country to the east and north of Penrith, characterised by attractive villages built of the local Permian sandstone. At Eden Gorge 35/5242 (70) the river passes through a deep cutting which is well wooded with Sessile Oak, Elm, Ash and Alder. Blasia pusilla with its curious stellate gemmae, was found on the side of the sandy track down to the river, and Sphagnum quinquefarium on the bracken and heather fringed banks beside it. On the damp shaded sandstone crags we saw Cynodontium bruntonii, Dicranodontium denudatum, Mnium stellare, Orthodontium lineare, Saccogyna viticulosa, Jungermannia paroica, Calypogeia integristipula, Cephalozia lunulifolia and at their base, some Lunularia cruciata with female inflorescences. Fallen rocks close to the river were covered with Dichodontium pellucidum and Barbula cylindrica. *Bryum flaccidum occurred on trees by the river, B. klinggraeffii on silt, Fissidens crassipes, Fontinalis antipyretica, F. squamosa and abundant Cinclidotus fontinaloides on rocks in the river. As on several other days the weather was warm and humid and this induced our aquatic member, Rod Stern, to take to the water.
After lunch, most of us visited the delightful Nunnery Walks (admission 25p) on the opposite side of the river where the Croglin Water plunges over waterfalls in a narrow, wooded, sandstone ravine. Here, in the permanently damp atmosphere a few metres above the surging water, there was an extensive growth of Harpanthus scutatus on steeply sloping sandstone alongside the path. On damp rocks close to the stream there were Hygrobiella laxifolia, Plectocolea obovata, Lejeunea lamacerina, L. patens, Fissidens pusillus var. pusillus, a tall shade form of Cynodontium bruntonii, Hyocomium armoricum, Hygrohypnum ochraceum and Thamnobryum alopecurum. Dicranum majus and Plagiothecium undulatum were both fruiting well nearby and Alan Crundwell found Leucobryum juniperoideum on soil under Beeches.
Meanwhile, Joan Appleyard, Tony Smith and Harold Whitehouse did some recording in the vicinity of Old Wythes Wood north of Greystoke and foundOrthotrichum stramineum by the roadside.
Later on we all joined up to explore an area of limestone grassland, woodland with limestone outcrops and a stretch of limestone pavement in Greystoke Park 35/4231 (70). The habitats were rather dry with the usual calcicole species. Ditrichum flexicaule was common and robust, Isothecium myurum occurred on vertical limestone and Rhytidiadelphus loreus on the top of a limestone wall under trees. Several tufts of Breutelia chrysocoma were found on a grass-covered boulder, Cololejeunea calcarea in a sheltered crevice and Frullania fragilifolia on a tree trunk. Joan Appleyard discovered Bryum pseudotriquetrum in an odd habitat on the limestone pavement. By then, the enervating weather had reduced enthusiasm and we returned to the cars, pausing only to discuss a peculiar Oak tree with almost lobeless leaves.
31 July. Tarn Sike and Sunbiggin Tarn 35/6707 (69) lie in undulating country among limestone hills at about 300 m altitude north-east of Tebay. On Tarn Moor between them the moorland slopes downwards and grades into calcareous fen with a small, deep but sluggish stream running through it and stands of Schoenus nigricans. Archidium alternifolium and Pseudephemerum nitidum were growing between some of the tussocks on the peaty moorland. Odontoschisma sphagni was found amongst Sphagnum capillifolium and Cephaloziella rubella and C. subdentata on decaying Sphagnum. Gradually, the common moorland species became interspersed with and then replaced by those preferring more marshy and calcareous conditions such as Drepanocladus revolvens, Scorpidium scorpioides, Calliergon giganteum, C. sarmentosum and Philonotis calcarea. There were also scattered patches of Splachnum ampullaceum, erect and prostrate forms of Leiocolea bantriensis, the latter form associated with Moerckia hibernica found by Gordon Prothero. Two late flowers of Primula farinosa also excited attention.
On the margin of Sunbiggin Tarn Cinclidium stygium was refound together with Plagiomnium elatum. Dicranella schreberana, Bryum ruderale and B. klinggraeffii all occurred on grassland nearby and a limestone wall was liberally strewn with Tortula intermedia and Orthotrichum cupulatum.
After lunch a visit was made to Smardale Nature Reserve 35/7308 (69) via a narrow lane flanked by Giant Bellflower. The warden, Ron Baines, met us here and escorted us along a disused railway track overgrown with Willows, overtaking a hedgehog and passing under a viaduct of the Skipton to Carlisle railway. At the edge of the path some of the Pyrola minor was still in flower and further along there were Fragrant Orchids, Helleborines and Melancholy Thistle. In one place Stone Bramble was fruiting and Herb Paris was common on the wooded banks below the track. The dark brown Scotch Argus butterflies were another attractive feature of this site. Close attention to the moist track revealed *Haplomitrium hookeri, Fossombronia incurva, F. wondraczekii, Lophozia excisa, Scapania scandica, S. irrigua, Bryum microerythrocarpum and Hypnum lindbergii. Eucladium verticillatum and Jungermannia atrovirens occurred in damp rocky places. Metzgeria pubescens, Lejeunea cavifolia and Porella cordaeana were found on tree trunks down near Scandal Beck, Marchantia polymorpha, M. alpestris and Orthotrichum rivulare on stones in and near the beck, and *Plagiochila britannica on a nearby wall.
1 August. Following the established practice, groups of members dispersed in different directions on this free day, which was hot, humid and, for some people, wet for about two hours around mid-day. At Crowdundle Beck 35/6430 (69 & 70) one group found Atrichum crispum. Dicranella rufescens, Rhynchostegium murale, Fissidens pusillus var. pusillus, Schistidium alpicola var. rivulare, Grimmia trichodon, Orthotrichum lyellii, and, on a sandy bank, Gyroweisia tenuis. They also confirmed that a bryophyte desert exists at the place marked Meikle Awfell in the same 10 km square. At Udford on the River Eamont they found Metzgeria fruticulosa growing in some quantity on Elder bushes.
A second group went to the northern end of Bassenthwaite Lake 35/2031 (70) where they found Amblystegium varium, Philonotis caespitosa and Ephemerum serratum var. serratum on the western side. On the eastern side, on a very gently shelving beach amongst sparse Phragmites, there was a remarkable and intricate carpet of bryophytes which included *Jungermannia hyalina, Scapania undulata, abundant Amblystegium tenax, Philonotis fontana and Plagiomnium rostratum.
Another car load exploring v.-c. 70 to the west of Penrith, saw Pylaisia polyantha growing on Elder in fen carr south of Newton Reigny, and fruiting Calliergon cuspidatum. They then recorded in two sites in opposite corners of square 35/32, at Low Bridgend and east of the disused Troutbeck Station.
Harold Whitehouse and Chris Preston explored the area east of Carlisle (70). In a sandpit at Moss Nook 35/5054 they found some puzzling plants which they eventually realized were prothalli of Equisetum arvense.
2 August. The morning was spent in Great Wood 35/2721 (70), which lies alongside Derwent Water and belongs to the National Trust. On the ground under the trees there was an abundance of common woodland species, Nowellia curvifolia covered many of the rotting logs and Frullania tamarisci was a prominent epiphyte (to which forestry workers can become allergic). Other species included Rhabdoweisia crispata, Bazzania trilobata, Saccogyna viticulosa, Scapania scandica and Plagiochila spinulosa. Unfortunately, despite their proximity to the species-rich area of Lodore Cascade, the Great Wood crags and the stream to the south proved to be relatively disappointing. On returning to the car park several members ill-advisedly lunching on the wrong side of the fence found themselves obliged to share it with a remarkably persistent horse.
At Seatoller in Borrowdale 35/21 (70) in the afternoon the combination of a damp climate and well wooded hillside with acidic and basic rocks produced a more interesting array of bryophytes such as Thuidium delicatulum, Rhabdoweisia crenulata, Tritomaria exsectiformis, Lophozia longidens, Barbilophozia atlantica, Radula voluta, Jamesoniella autumnalis, Anastrepta orcadensis and Lepidozia pinnata. Filmy Fern was common in places.
Joan Appleyard and Tony Smith had decided instead to do some recording in an area to the west of Penrith. At Raven Crags, Mungrisedale 35/3630 (70) they were rewarded by the discovery of *Grimmia anodon in only its second known site in England.
3 August. Cliburn Moss 35/5725 (69) is a peaty area well colonised by Pine and Willow. In recent times deep drainage ditches have been cut and the ground is drying out. Sphagnum imbricatum once grew here but was not refound. S. magellanicum, Hypnum imponens, *Cephaloziella elachista and Chiloscyphus pallescens were seen in and near the remains of the central bog. Many of the hollows left by peat cutting were filled with luxuriant Calliergon giganteum, Pellia neesiana was abundant in places, Campylium polygamum and Rhizomnium pseudopunctatum were also noted. Riccia glauca and Fossombronia foveolata were seen on the track as we left the site.
Most of us spent the last afternoon in the rocky sessile oakwoods of Naddle Low Forest beside Haweswater 35/5015 (69). Here the bryophytes were plentiful and sometimes luxuriant, for example, Bazzania trilobata, Mylia taylori, Barbilophozia attenuata, Tritomaria quinquedentata with perianths and fruiting Lophozia incisa intermingled with robust Calypogeia neesiana. Other plants, some of which had not been seen previously during the week, included Bartramia hallerana, Dicranum fuscescens, Hypnum callichroum, Plagiothecium laetum, Racomitrium aquaticum, Ptilium crista-castrensis, Bazzania tricrenata, Lepidozia pearsonii and Riccardia palmata. At the end of another hot sunny day, several members attempted to cool off by paddling in Haweswater Beck.
At the southern end of Haweswater the Appleyard/Smith splinter-group found Archidium alternifolium in quantity, Fossombronia wondraczekii and Pohlia bulbifera on the lake margin.
The programme for the week included visits to a pleasing variety of carefully chosen sites. A lot of useful work was done for the mapping scheme and some very interesting plants were seen. We are all most grateful to Philip Taylor of Kendal who organised the meeting so efficiently and for being so friendly and helpful throughout the week. We are also grateful to Rod Corner of Penrith (who, alas was not with us) for helping Philip prepare the programme, and to Bob Walker of Kendal and Jeremy Roberts of Wetheral whose knowledge of localities was so useful to us.
M. L. CRUNDALL
AGM & Symposium, 25 September, 1982
The paper-reading meeting on the weekend of Sept 25-26 in Ancaster Hall, University of Nottingham, attracted an attendance of nearly fifty members and friends, including two from overseas. They heard a series of well-presented papers covering a particularly wide range of bryological topics. Thus, the proceedings opened with a more detailed account of the chromosomes of certain members of the Brachytheciaceae than any so far available. Another paper, drawing Phylogenetic conclusions from biochemical data, was presented in such a way that even those of us who may be bewildered by chemical formulae were able to appreciate the fine points of the persuasive new arguments put forward. Yet another engrossing talk took the form of a guide to classical bryological literature and stimulated an awareness of the development of the art of illustration. It was a theme related to that of another speaker who involved his audience in an interesting exercise designed to estimate the ext ent to which photography can substitute for bryophyte collecting. The remaining papers, however, were all concerned with various aspects of reproduction and development. One concentrated attention on problems of reproductive behaviour in mosses, while another probed the influence of light on the development of liverwort setae and archegoniophores and the third, using electron microscope techniques, investigated the role of microtubules in bryophyte spermatogenesis. Summaries of these papers are given below.
Dr. S. V. McADAM (Aberdeen) "Karyotype variation in the Brachytheciaceae: a pattern of relationships."
The work embodied in this paper is to be published in the Journal of Bryology.
Mr. C.C.J. MILLER, Prof. J.G. DUCKETT (Queen Mary College, London) and Z. B. CAROTHERS (Illinois): "Experimental studies of spermatogenesis in bryophytes."
The highly differentiated spermatozoids of bryophytes are excellent vehicles for investigating many fundamental problems of cell biology including the manner of growth of microtubules and their precise role in subcellular shaping processes. Using antitubulin raised against porcine brain tubulin immuno-cytochemical tests on Sphagnum and Polytrichum provide the first direct evidence that the cytoskeletal band of microtubules, or spline is composed of tubulin. Intense fluorescence from the lamellar strata of the multilayered structure (MLS) strengthens the notion that these are a highly structured microtubule organising centre (MTOC) as does the substructural modification of the lamellae by griseofulvin, an inhibitor considered by some to affect MTOCs.
Having thus established the basic chemistry of the spline the microtubule inhibitor colchicine was used to determine the direction of assembly of the tubules. The occurrence of late spermatids of Pellia with a normal MLS and flagellar bases at the anterior end but grossly distorted nuclei lacking a spline indicate that the microtubules assemble at their posterior ends. Since the elongation of the spline precedes that of the nucleus, growth of its microtubules cannot be the force generating system responsible for shaping the gametes. More likely the spline acts as a cytoskeletal alignment system. Bundles of microfilaments adjacent to the spline (revealed for the first time in plant spermatids (Petalophyllum) by new fixation procedures) are by far the most likely candidate for the force-generating elements.
Spermatozoids of Marsupella and Sphagnum have been fractionated by treatment with non- ionic detergent and sonication. The nucleus is readily separable from the spline in Marsupella but remains attached much more firmly in Sphagnum. High resolution electron microscopy of negatively stained preparations reveals that the firmer adherence in Sphagnum is associated with more highly decorated tubules than those of the spline in Marsupella. A sheath of 30nm filaments is unique to the spermatozoids of Sphagnum and underlines the separation of the genus from all other groups of bryophytes.
Dr. D. H. LEWIS and Dr. A. CHRISTIE (Sheffield): "The phylogeny of leafy liverworts in relation to their success as land plants."
Compared with the check list of Jones (1956), the new census catalogue of British hepatics (Corley & Hill, 1981), based on the classification of Grolle (1976), arranges British leafy liverworts into substantially more families and into a different sequence. With regard to British families, the scheme of Schuster (1979) has approximately the same number as that of Grolle but the order in which families are listed is essentially its reverse. Owing to the inherent problems of inferring phylogenetic relationships from linear lists, a representation for leafy liverworts similar in style to that of Dahlgren (1977) for angiosperms was constructed based on the distribution of 4 kinds of soluble carbohydrate - sucrose, sedoheptulose, and six- and seven- carbon sugar alcohols. The scheme supported the phylogenetic arrangement of Schuster (1966 and 1972) and implies a progressive evolutionary loss of the capacity to accumulate free sedoheptulose, heptitols and hexitols. These are abu ndant in genera, such as Herberta and Bazzania, considered by him to be primitive and absent in genera such as Porella considered by him to be advanced.
These conclusions were examined in relation to the hypothesis that the essential role of boron in plants concerns synthesis of lignin and that possession of sugar alcohols, which complex borate, precludes the development of this capacity (Lewis, 1980). It was argued that development of a lignified vascular tissue as an adaptation to life on land could therefore not have occurred in primitive leafy liverworts but that, in more advanced groups which lack sugar alcohols, this may now be possible. The presence of brittonins, methoxylated aromatic compounds, in Frullania (Asakawa, Tanikawa & Aratani, 1976), a genus in which hexitols are absent or in low concentrations, could support this hypothesis if their biosynthesis involves a boron-dependent metabolism related to that proposed for precursors of lignin. These speculations highlight the necessity to study the boron-requirement of bryophytes in general. None appear to have been made.
Prof. J. G. DUCKETT (Queen Mary College, London): "Does photography render the collection of bryophytes unnecessary?".
Although the most serious threat to the British Bryophyte flora is the rapid loss of natural and semi-natural habitats (H. J. B. Birks, Bull. Br. bryol. Soc. 1982, 39, 17-18) potential dangers from collecting should also be considered. In contrast to the situation with groups of organisms such as birds or vascular plants which may, with practice, be identified in the field, the acquisition of bryological competence depends on regular collecting. The healthy state of the British Bryological Society, and our detailed knowledge of the bryophyte flora, owes much to the tradition of field excursions and collecting. Paradoxically collecting may also serve the interests of conservation. Preservation of mosses and liverworts whose value is cultural, scientific-educational and aesthetic-recreational (Birks, l.c. 1982) rather than of direct economic importance, depends heavily on the efforts and information provided by active bryologists. Any extensive ban on colle cting would be marked by a dangerous decline of interest in bryophytes.
It is axiomatic that beginners must collect virtually everything in order to become familiar with the flora. Ultimately however every experienced bryologist must carefully examine his or her need for collecting, particularly when rare and/or endangered species are involved. The following table is a highly subjective attempt to categorize how I, as a fairly active bryologist with some 20 years experience in the field, identify British bryophytes.
It is clear from the table that approximately 25% of the flora MUST be collected for identification. This chiefly includes taxa whose recognition depends on characters such as peristome structure, spore morphology or cell sizes. The subdivision of each category into "common" species and those where collecting may be harmful focuses attention on the fact that there are a large number of species where it is difficult to justify repeated gatherings just to fill one's herbarium. However, multiple packets of some uncommon species can prove extremely valuable providing that the collecting has been done carefully. For example a packet containing plants with a range of morphology, sex organs and sporophytes provides basic information on reproductive biology.
The habits of bryologists in the field may be far more damaging to the flora than the actual removal of material for herbarium specimen. Devastation of Sphagnum lawns in the search for Cryptothallus is a particularly horrendous example. Some plants may be replanted after cursory examination with a hand lens, whilst others are doomed (e.g. Lejeuneaceae closely adhering to rock faces and tufts of saxicolous Grimmiaceae on dry rocks). Whereas there is little or no risk in collecting from arable fields where survival depends on the spore or gemma bank, removal of spring annuals from shallow soils overlying limestone may also destroy a habitat plus the spore reservoir which has taken many many years to form. These examples illustrate why bryologists must always be sensitive to the nature of any habitat they are exploring. On balance the value of collecting bryophytes far outweighs the potential dangers so long as each individual exercises restraint and common sense.
Members were invited to attempt the identification of 30 hepatics and 50 mosses from colour slides. The results, which perhaps provide the most telling answer to the question posed in the title of this paper, are as follows:-
Prof. ELIZABETH G. CUTTER (Manchester): "Growth and response to light of archegoniophores and setae of liverworts."
The setae of Pellia and other liverworts and the archegoniophore stalks of Conocephalum (and Marchantia) showed a positive response to unilateral light from the blue region of the spectrum. Decapitation did not prevent the response; the regions of perception and response are probably the same. Unilateral light appeared to result in promotion of growth on the darker side, probably with some inhibition on the side towards the light.
Experiments in which the setae were marked with anion exchange resin beads showed that growth was uniform over the entire length, whereas in the archegoniophore stalks much more elongation occurred in the region just below the cap. Elongation involved cell division as well as cell extension, and an intercalary meristem appeared to be present in the upper part of the stalk. Removal of the cap resulted in an 8 to 20-fold decrease in growth in the upper region, suggesting that the cap (possibly the developing embryos) supplies a stimulus to growth of the stalk which bears it.
Mr. C. J. MILES (Reading): "Studies on the reproductive biology of British mosses."
Most moss species produce sporophytes in at least parts of their ranges. However, little is known of the frequency with which gametophytes become established from spores in the field or of the extent of self-fertilisation in monoecious taxa, both matters of considerable significance in terms of the evolutionary mechanisms open to mosses. This is a preliminary report of an investigation into these aspects of the reproductive biology of five mosses, Atrichum undulatum, Bryum argenteum, Grimmia pulvinata, Polytrichum alpestre and Tortula muralis.
Analysis of regular collections from several British populations of each species has confirmed that fertilisation and spore release show seasonal periodicity. Colony development and longevity is being studied by repeated photography of permanent quadrats, while counts of sporophytes in the quadrats have yielded estimates of annual capsule production per m² moss cover ranging from c. 800 in A. undulatum to c. 88,000 in T. muralis. These data, combined with haemacytometer estimates of spore content in individual capsules, indicate that spore output per m² moss cover may range from 116 x 106 in A. undulatum to 38,325 x 106 in T. muralis. Spores of the five species germinate freely on agar and also on natural substrata under laboratory conditions, giving protonemata and eventually shoots.
Spores were trapped at various distances around an isolated, transplanted colony of A. undulatum throughout the 1982 winter dehiscence period using vaseline coated slides. Of the 18,360 spores trapped (0.04% of the estimated total released), approximately 95% were caught on the ground beside the colony with a few caught up to 150 cm distant. Previous observations had also shown the occurrence of numerous spores in and around A. undulatum colonies after dehiscence.
Examination of young shoots of A. undulatum and other species in the field has demonstrated that many arise by vegetative propagation. No naturally occurring shoots had clearly arisen via protonemata from spores, although the origin of many of those examined was obscure. Occasional spores recovered from soil near colonies of A. undulatum had germinated but no protonemata comprising more than 5 cells were seen. Experiments have been conducted to compare establishment of colonies from spores and by regeneration from portions of gametophyte by planting both at field sites. Methods for planting spores include their application in concentrated aqueous suspension, immersion of undehisced but artificially opened capsules near the soil surface, and planting net bags containing spores and substrate into the field substrate. Regeneration of new shoots from gametophyte fragments occurred readily in A. undulatum and B. argenteum on soil and in P. alpestre on Sphagnum. Gametophyte fragments of G. pulvinata and T. muralis placed or glued onto concrete consistently blew away. Only once however has the occurrence of spore germination been confirmed, when protonemata and shoots developed in net bags containing spores of A. undulatum. Spores of P. alpestre recovered from net bags placed in Sphagnum remained viable but ungerminated for up to one year. An attempt is being made to determine when establishment from spores is blocked, by planting out simultaneously freshly sown spores, germinated spores, protonemata and protonemata with shoots, the older stages having been raised in the laboratory.
A study of sex distribution in A. undulatum and T. muralis has shown that although both are monoecious most shoots develop gametangia of only one sex during one reproductive cycle. Of over 100 young sporophytes of both species examined, 76% in A. undulatum and 96% in T. muralis were on shoots without current cycle antheridia. Thus crossing between shoots within colonies clearly occurs frequently in these species. The extent to which individual colonies comprise several clones, thus permitting genetically effective outcrossing is currently being investigated.
The study species thus produce viable spores in profusion and a prevalence of self-fertilisation in the monoecious species cannot be assumed. The results suggest that asexual reproduction may be more important than reproduction by spores in maintaining populations of the study species. Further work is required to show whether sexual reproduction plays some role in population maintenance, or in establishing colonies in new areas.
Mr. M. WALPOLE (Loughborough): "A bibliophile's view of bryological literature."
A brief review was given of a number of important illustrated works relating to the history of bryology. Particular emphasis was given to the important and finely illustrated works of Hedwig together with examples from the often overlooked English literature of the middle 19th century. The importance of published Exsiccatae was also covered and examples of photographs of early bryologists contained in a copy of Braithwaite's "Sphagnaceae Britannicae Exsiccatae" were shown.
The Annual General Meeting (Minutes in Bulletin 42) was held afterwards and was followed by a reception given by the University, during which the President thanked Dr. J.O. Rieley for his efforts as local secretary in contributing so much to the success of this meeting. The evening continued with a conversazione and an opportunity to display a large number of exhibits as follows.
26th September, 1982. The weather was cool but otherwise fine for our trip. We assembled at Ancaster Hall at 9.30 a.m. on Sunday morning and set off in convoy for Hilton Gravel pits, a Derbyshire Naturalists' Trust reserve on which almost no previous bryophyte recording had been carried out (i.e. only 9 species). The site provides a contrasting selection of habitats including disturbed ground, grassland, arable land, water, swamp and a small area of very wet fen with incipient Sphagnum bog. We increased the number of species recorded for the site to 52! No surprises were found, but we worked up an appetite for lunch.
In the afternoon we spent two hours wading up to our knees in the very wet peaty surface of Chartley Moss, N.N.R., in Staffordshire. This very interesting basin mire had been visited by the B.B.S. once before in 1973 and the number of species recorded on this visit (19) was disappointingly lower than the previous one (73). We did, however, add one new record, Cladopodiella fluitans, to the list! Most members were more interested in the ecology of the site which has a number of unique features.
Bradford University, 27-28 November
Fourteen members of the B.B.S. attended a two-day taxonomic workshop at the University of Bradford, 27-28 November, 1982. The first day was spent in the laboratory of the School of Environmental Science: the morning session was devoted to the genus Scapania and the afternoon session to small acrocarps of soil, under the direction of Mr. David Long and Mr. Tom Blockeel, respectively.
A short talk was given, which outlined the general features of Scapania, hints for field collection, drying, preparation of specimens for microscopic examination, and described some of the important characters used in distinguishing the British species, namely gemmae, perianths, leaf cuticle, size and shape of leaf lobes, structure of the keel, border development, leaf decurrence and oil-bodies. Herbarium specimens, prepared slides and important literature were provided for reference. Participants then studied specimens of a range of species and identified these using several recent keys.
Small acrocarps should be collected with copious soil in order not to lose any vegetative propagules. Specimens are best wrapped in paper and placed in a box or other container to prevent crushing. If they cannot be examined fresh, they should be dried as soon as possible to avoid fungal infection. The low-power binocular microscope is especially useful in sorting specimens and preparing them for examination under higher power. Whenever possible the opportunity should be taken to search for tubers, particularly in such genera as Bryum where they are of diagnostic value. This may be achieved by placing a stem or two, with soil attached, in a drop of water and cleaning away the soil and debris with a needle or brush, repeating the process one or more times in clean water. For final examination a single stem should be teased apart to minimise the risk of foreign tubers mistakenly being identified with the wrong stem. When present, the tubers are usually readily discernible under the binocular microscope at a magnification of x30 or less.
On the second day a field excursion was held to Broadhead Clough near Mytholmroyd, recently acquired as a Nature reserve by the Yorkshire Naturalists' Trust. The clough is an open bowl-shaped valley running up to the Calderdale moorland near Halifax. Though scenically attractive, with woodland of oak, birch and holly, it has only the impoverished bryophyte flora characteristic of the South Pennine areas which have long endured severe atmospheric pollution. The elimination of epiphytic and rupestral species has allowed limited colonisation of trees and rocks by tolerant opportunists such as Orthodontium lineare and Campylopus paradoxus. Wet habitats have a slightly more diverse flora. Hyocomium armoricum and Nardia compressa were recorded by streams, and Tetradontium brownianum on wet grit rock. Three species of Sphagnum, S. recurvum var. mucronatum, S. fimbriatum and S. palustre, were on wet ground on the woodland floor.
The approach to the Reserve, through pasture-land, gave the opportunity to observe small acrocarps on banks by the track. Some of the species discussed on the previous day were present, though not all could be proved in situ. They included Pleuridium acuminatum (a young state with mature inflorescences), Pseudephemerum nitidum, Weissia rutilans, Pohlia lutescens, Bryum rubens and B. sauteri. Scapania scandica was also present. Some of these species, including the Pohlia, were seen on the banks of the Cragg Brook along with Ditrichum cylindricum, fruiting Dicranella schreberana and Bryum gemmiferum.
We are most grateful to our two speakers, the local secretary (Dr. Mark Seaward), and the University of Bradford for such a useful and enjoyable meeting.