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Meetings of the BBS - 1985

 

Spring Field Meeting 1985

Chichester 18 - 23 April

For southern England, Sussex is extremely rich in its bryophytes. The promise of a varied programme of trips with a wide range of species to be seen and most attractive countryside, prompted nearly 50 members to attend all or part of the meeting. Sites to be visited were restricted to the western part of the county (v.c. 13) which reduced the amount of daily travelling to a minimum. The meeting was based on Bishop Otter College in Chichester where we were housed in student accommodation which we had to ourselves for the majority of the week. The food was excellent, although the ingeniously designed plastic packaging for the packed lunches proved quite a test for all but the most mechanically minded members.

Despite the fact that the area is comparatively well recorded, 8 new records for West Sussex were found and we added more than 75 plants to the 10 km squares we visited. Indeed, the meeting was set off to a good start when George Bloom discovered Marchantia alpestris* lurking in the grounds of Bishop Otter College on the day before the organized trips began.

[* = New vice-county record]

18 April. In the morning Dr Francis Rose led the party to the Nature Reserve on Heyshott Down. This is an area of chalk grassland, scrub and mixed woodland on the steep north-facing scarp of the South Downs which includes some interesting overgrown quarry works. The sparsely wooded grassland areas yielded Rhodobryum roseum and Hylocomium brevirostre, while Racomitrium lanuginosum was seen on more exposed areas. The search for Antitrichia curtipendula, which had been recorded near the top of the slope many years ago, proved fruitless, but the quarry site compensated for this with a rich bryophyte flora including Pleurochaete squarrosa and Entodon concinnus. Several members looked rather pink on the backs of their necks after the unaccustomed sunshine.

The afternoon's site was Ambersham Common. This is an area of heathland on the Folkestone Beds of the Lower Greensand, much frequented, as it turned out, by adders. Braving the zoological guardians of the site, we found quantities of Dicranum spurium, which was as splendid as had been promised, and several Sphagna including S. magellanicum. Perhaps the richest finds were among the hepatics with Cladopodiella francisci, Kurzia sylvatica and Calypogeia sphagnicola as well as Jean Paton's two vice-county records, Calypogeia neesiana* and Lophozia ventricosa var. silvicola*.

19 April. Rewell Wood and the associated gravel pit were the venue in the morning. We were disappointed not to re-find Atrichum angustatum in the wood or Ditrichum pusillum and Funaria fascicularis in the pit, but nevertheless it was a successful morning. The gravel pit, in which we were treated to a demonstration of motor-cycle scrambling, was particularly good for Fossombronias with both F. husnotii and F. incurva in some quantity as well as Lophozia bicrenata, L. excisa, Bryum bornholmense, B. sauteri, and B. gemmiferum. What with the motor cycles and Martha Newton on the lookout for potential speakers at the AGM, members found they had to keep their wits about them.

A quick sortie across the A27 to the reported site of a number of Nicholson's old records proved disappointing, but spirits were rapidly raised by the main venue for the afternoon, the Sussex Trust for Nature Conservation's reserve at Hurston Warren. This had been billed as one of the best bogs in West Sussex and it lived up to its reputation with another two vice-county records from Jean Paton (Drepanocladus fluitans var. falcatus* and Riccardia latifrons*) as well as ten species of Sphagnum, Cephalozia macrostachya, Calypogeia sphagnicola, Cephaloziella hampeana and Aulacomnium palustre with sporophytes.

20 April. The weather turned against us on the Saturday with drizzle and low temperatures. The morning we spent in Verdley Wood which is an extensive area of deciduous woodland, largely coppiced, on steep rocky slopes of the Lower Greensand Hythe beds. Several of the tree bases supported Plagiothecium latebricola while Bazzania trilobata and Kurzia sylvatica were also found in the coppice wood. Flushes yielded Marsupella emarginata while one or two rocks in the valley bottom were colonized by Heterocladium heteropterum.

Northpark Copse, the afternoon's site, has Dicranum as its speciality: six are recorded. We managed to locate five, including D. flagellare, but failed to spot D. tauricum on that occasion. Other interesting finds included Martha Newton's discovery of Pellia neesiana*, Hookeria lucens, Trichocolea tomentella and Barbilophozia attenuata.

21 April. The northern part of West Sussex has much Weald Clay and Sunday's visits were to two Forestry Commission woods on the clay near Plaistow. The first was Kingspark Wood, well known to entomologists as one of the best butterfly sites in southern England, and also a good area for the Violet Helleborine. Part of it is now an SSSI. The main interest at the site is along the rides and tracks; the party examined these as well as the stream valleys. Three Scapanias were seen: S. irrigua, S. nemorea and S. undulata, as well as Amblystegium varium and Hypnum lindbergii. Martha Newton found Pellia neesiana again. Altogether, more than 80 species were recorded.

A similar number of species were seen in the afternoon at Hog Wood, where the party was allowed as far as the vice-county boundary but not across into 'Jack Gardiner's territory' in Surrey! Hog Wood had rather more water than Kingspark Wood, and more broadleaved trees as well, with associated epiphytes. Interesting finds included Calliergon cordifolium, Fissidens exilis, Rhytidiadelphus loreus and the woodland form of Ctenidium molluscum. On the trees the bryophyte flora included Radula complanata, Orthotrichum lyellii, O. affine, O. pulchellum and O. stramineum; Martin Corley found Lejeunea lamacerina.

22 April. Monday morning was spent on Climping Beach and Littlehampton sand dunes. The party made its way via the rather derelict boat mooring area at the estuary of the River Avon, where Pottia heimii was found, and across the Golf Course, to the astonishment of several players. Bryum inclinatum was not seen, but Rhynchostegium megapolitanum was on the dunes and both Aloina aloides and Zygodon conoideus were discovered as we made our way to some impressive large elder trees. With military precision, members were ferried back to their setting- off point and thence to Arundel where Leptodon smithii was found on trees overlooking the car park at the Wildlife Reserve. After lunch we made a circuit of Swanbourne Lake in Arundel Park. Cephaloziella baumgartneri was there, but only in tiny scraps, the colony having been much reduced from former glory by ivy invasion of the site. Other interesting species included Eurhynchium swar tzii var. rigidum, Fissidens incurvus, F. limbatus and Tortella inflexa. A couple of members later admitted to rounding the afternoon off with a cream tea in a local cafe.

23 April. The morning of the last day was spent in Duncton Chalkpit, a six-acre reserve managed by the Sussex Trust for Nature Conservation. The site includes an old limekiln (with Gyroweisia tenuis and Tortula marginata) as well as bare chalk and scrub. Eighty species were recorded in an hour and a half, including Seligeria calcarea on the quarry face and S. paucifolia on detached pieces of chalk with Tortella inflexa and Fissidens pusillus var. tenuifolius. Nowellia curvifolia was seen in shaded places and Chris Preston and Angela Newton found more Leptodon smithii on an ash tree. As the party was about to move on, Eustace Jones appeared with Platygyrium repens - only the second record for v.c. 13, it having been found by Rod Stern for the first time in another locality earlier in the year. A short stop in a narrow lane at Barlavington with steep Upper Greensand banks enabled the party to see Rhynchostegiella curviseta and luxuriant Eurhynchium schleicheri.

After lunch the party was joined at Iping Common by Miss Anne Griffiths, the ecologist from West Sussex County Council. She explained their management policy for this local nature reserve whereby heather is maintained at the expense of invading Scots Pine which has eliminated so much heathland in south-east England. Several species of Sphagnum were seen on the wetter ground, together with the usual hepatic associates. Apart from Drepanocladus exannulatus var. rotae (in its second v.c. 13 locality), all the plants had been recorded earlier in the week, but those who had missed the first couple of days were able to see Campylopus brevipilus, Drepanocladus fluitans var. falcatus, Dicranum spurium and Lophozia ventricosa var. silvicola.

At nearby Chithurst, the party bade farewell to West Sussex with a flourish -Targionia hypophylla in its only v.c. 13 locality, growing on a stone wall with Reboulia hemisphaerica.

All in all, it was a most successful meeting which was thoroughly enjoyable both bryologically and socially. This was in no small part due to the excellent organization by the local secretary, Rod Stern. Shepherding so many wilful and unruly bryologists about is no mean task and we were all most grateful to Rod for his friendly and efficient leadership. I am also very grateful for his help in preparing this account of the meeting.

GILES CLARKE


Summer Meeting 1985

Lenggries, Bavaria, 28 July-4 August

Nine members plus families and several German bryologists accepted Professor Duell's invitation to join the excursion in the Bavarian Alps, and included Dana Bergstrom (Australia) George Bloom and wife, Joan Gutteridge and husband, Martin Godfrey, Barbara Murray (Alaska), Brian O'Shea, Roy Perry and family, Michael Proctor and John Port.

28 July. The party was very efficiently gathered up by Dr Duell and Roy, from various flights into Munich, and transferred to the hotel at Lenggries, an hour or so to the south, and at a height of about 700m. After a meal, no time was lost getting into the field, and the afternoon was spent in a pleasant amble up a side valley out of the village, past trees bearing a good growth of fruiting Orthotrichum obtusifolium.

29 July. The local geology is almost entirely limestone, though the leaching effect of a mountain climate with high rainfall is very evident in the forest flora, rich in familiar acid-woodland species. On Monday morning a visit had been arranged to the nearby Arzbach valley, where it was pointed out that much of what had been dismissed as Eurhynchium striatum was in fact E. angustirete. Antitrichia curtipendula was frequent, and others such as Lescuraea plicata, Pterigynandrum filiforme, Moerckia hibernica, Tayloria serrata, Paraleucobryum longifolium, Bazzania flaccida and Bryum schleicheri var. latifolium were seen. One plant of Buxbaumia viridis was on the trunk of a trackside tree, but collection was forbidden, so this is evidently a rarity. An introduction was also made to two non-British species, Brotherella lorentziana (Sematophyllaceae) and a conspicuous yellow-green Barbula, B. crocea.

Fine shows of Campanula cochlearifolia and C. scheuchzeri diverted attention from bryophytes, and for those of more sinister intent, Atropa belladonna was available, though not yet in berry.

30 July. The following day's choice of another valley, the Steinbachtal, SE of Bad Tölz, was dictated by the weather, which threatened rain. The flora here reconfirmed the basic nature of the area with Scapania aequiloba, Isopterygiopsis muelleriana, Orthothecium intricatum, and Schistidium trichodon on limestone boulders. The beautiful Ptilium crista-castrensis was plentiful under foot and Ptilidium pulcherrimum was found on a conifer.

31 July. Wednesday morning looked more hopeful, but by the time the cable-car reached the top of Lenggries' local mountain, the Brauneck, at 1500m, the clouds had gathered and a sudden storm later in the morning had the party rapidly struggling into waterproofs. This is the zone of the high alpines including Lescuraea incurvata, Tayloria serrata, T. froehlichiana, Geheebia gigantea, Campylopus schimperi, Brachythecium reflexurn, Campylium halleri, Cratoneuron decipiens, and the red hair- pointed Tortula, T. norvegica.

The flowering plants were again a distraction with Aster alpinus, Dryas octopetala and Pinguicula alpina particularly in evidence, and the character separating Gentiana pannonica from G. purpurea was examined at length to produce a verdict in favour of the former.

1 Aug. Next day's visit to the Kreuzeck, near Garmisch-Partenkirchen, involved a long winding route for the drivers. By cable car again, this time up to 1700m - not for us to be trusted in the helicopter ferrying loads of beer up to the cafe at the upper station. The memorable finds included Ctenidium procerrimum, Cirriphyllum cirrosum, Hypnum bambergeri, Pohlia wahlenbergii var. glacialis, and Polytrichum longisetum, besides Marchantia alpestris. Again the alpine flora was in good flower, with Campanula barbata, Gentiana bavarica, Tozzia alpina, and the orange form of Saxifraga aizoides.

A return to valley level brought a complete change of habitat, to an area of boulder-strewn woodland by the Eibsee where the noteworthy species included Anastrophyllum michauxii, A. hellerianum, Bartramia halleriana, Mylia taylori, Sphenolobus minutus, and two Bazzanias, B. trilobata and B. tricrenata, both abundant. All were in fine condition following a lunch-time downpour.

2 Aug. On Friday the day was divided between two sharply contrasting venues. In the morning, a National Nature Reserve, the Sindelsbachfilz, a large area of calcareous fen where among other Sphagna, S. magellanicum, was conspicuous, and Polytrichum strictum and Dicranum undulatum were to be seen in quantity. Here too the sundews, Drosera rotundifolia and D. obovata, were both closely examined.

After lunch it was off to a different Steinbachtal, E. of Bichi, different too in flora. A wooded valley where the first group of trees examined yielded Anomodon longifolius and A. attenuatus, Amblystegium subtile c.fr., Pseudoleskeella nervosa and generously fruiting Leucodon sciuroides on an elm. Later Dicranum viride and Frullania jackii were recorded, the latter having underleaves reminiscent of Calypogeia neesiana. Other notable finds included Encalypta streptocarpa with sporophytes and Entodon schleicheri.

3 Aug. By popular request, the final day in the field demanded a return to the Brauneck. A wider ranging route was followed, to Hinterer-Kirchstein and Propstenwand, and ended by a return via the Arzbach valley, where our drivers were waiting. Many plants seen had been met earlier in the week, for example Hylocomium pyrenaicum, Meesia uliginosa and Cololejeunea calcarea, but there were new finds, including Mnium thomsonii, Myurella Julacea, Cirriphyllum tenuinerve and Paraleucobryum sauteri. The sight of Michael stalking mountain goats for a photographic close-up will be long remembered. The long day provided a fitting close to a meeting much enjoyed by both German and 'British' sections of the group.

Thanks must go first to Professor Duell and our German hosts for the first class arrangements made on our behalf; to our hard-worked drivers; and by no means least to Roy for his handling of the British end of the organisation.

J. PORT


 

AGM & Symposium Meeting 1985

Cardiff, 21-22 September

The meeting proved to be one of exceptional interest and one that was well attended. It was further distinguished by the presence of two overseas members, both of whom had agreed at short notice to contribute very informative papers before an audience of over sixty members in the palatial National Museum of Wales. Meeting as we were in the Museum and, later, in the Herbarium, it was highly appropriate that we should hear a detailed account of the activities of a herbarium in the United States of America, but the programme also covered a wide range of other aspects of bryology. An initial look at the effects of successive glaciations on the development of the British bryophyte flora was particularly pertinent to the topic of another speaker concerned with the taxonomy of Tortula in the southern hemisphere. Adaptation to environmental factors, but of quite a different kind, were also considered by those speakers who demonstrated on the one hand the physiological response of Sphagnum to nitrogen and, on the other, the nature and extent of the Greek bryophyte flora. There was also a paper which gave us the unusual opportunity not only to learn more about the hornworts, but also to do so in the context of their developmental morphology. It was a challenge to our President to draw these diverse subjects together but this he did in his presidential address. Summaries of these papers follow.


Mr M. F. V. CORLEY (Faringdon, Oxon.): "The bryophyte flora of the British Isles during and after the Ice Age."

The present distribution of any species of bryophyte is a product of its dispersal mechanism and its reactions to ecological and climatic conditions, both now and in the past. The effects of historical factors on species distribution are considered here.

Conditions in Britain at the height of the last glaciation were extreme, with a considerable part of the country under ice sheets and the remainder experiencing a severe climate. Yet sub- fossil evidence and comparison with peri-glacial areas in Greenland indicate that many bryophyte species were present.

With the retreat of the ice, some of these species became extinct; many arctic-alpine species migrated northwards and up the mountains. Species of warmer climates invaded the southern parts of Britain and spread northwards. At first open habitats were plentiful and wetlands far more extensive than they are today. Calcareous soils were also more widespread than they are now. A number of fenland bryophytes are known to have been common at that time.

Changes in sea level following the melting of the ice sheets flooded land bridges to outlying islands, including Ireland, and eventually cut off the whole of Britain from mainland Europe, making colonisation by additional species more difficult. Soon afterwards, in the Atlantic period, higher rainfall and warm conditions caused forest cover to reach its greatest extent; at the same time moorland areas developed extensive peat cover. This period was optimal for the spread of species of warm shady habitats which reached their greatest extension, and have become more restricted since, often becoming confined to western coastal districts. It was also critical for fen species, with increasing acidification of fens from peat drainage water, and for species of open habitats, which were severely restricted at this time, which may explain many anomalous distributions, where species were confined to a few sites and have not spread extensively since.

Following the Atlantic period, lower temperatures and the increasing activities of man have progressively diminished the area of forest. Many species distributions are at least partly influenced by man. Indeed the greatest factor changing distributions at present is the effect of man in altering habitats.


Dr M. R. CROSBY (Missouri Botanical Garden): "The I. M. S.: a muscological data base."


Dr J. A. LEE (University of Manchester): "Nitrogen as an ecological factor in bryophyte communities."

For many bryophyte species nitrogen deposition from the atmosphere represents the major source of combined nitrogen for growth. Ammonia is assimilated via the glutamine synthetase-glutamate synthase pathway, and nitrate-nitrogen enters this pathway following reduction to ammonia. The enzymes of nitrate reduction, nitrate and nitrite reductase, are substrate inducible and their activity can be used to assess nitrate utilization by bryophytes.

Observations in the 'unpolluted' environment of Swedish Lapland demonstrated how ombrotrophic Sphagnum species respond to nitrate deposition in natural rain events. Sphagnum fuscum showed a rapid induction of nitrate reductase activity to each rain event, the activity declining at the end of the event as the result of nitrate depletion. Repeated artificial addition of 1 mM nitrate to Sphagnum fuscum plants in the field resulted in progressively less induction of nitrate reductase activity after each addition because at this artificially high concentration the supply of reduced nitrogen was too high for growth requirements. The induction of nitrate reductase activity was progressively inhibited by a product of ammonium assimilation, probably glutamine concentration. These and other observations demonstrated that under 'natural' conditions there is a very close coupling of the metabolism of at least ombrotrophic bryophytes with the nitrogen sup ply in rain events.

During the last century there has been approximately a fourfold increase in atmospheric nitrate deposition as the result of atmospheric pollution. Observations in one of the most grossly polluted regions of Europe, the southern Pennines of England, showed that ombrotrophic Sphagnum species transplanted into the blanket mires showed rapid and massive increases in total tissue nitrogen concentration. These transplants also rapidly lost their ability to respond to nitrate deposition in rain events by induction of nitrate reductase activity. Indigenous southern Pennine Sphagnum cuspidatum plants showed very low nitrate reductase activity and did not respond to rain events. In grossly polluted areas the nitrogen supply from the atmosphere is currently supra-optimal for the growth of ombrotrophic Sphagnum species, since in addition to field observations, the concentration of nitrate and ammonium in rain reduced the growth of these species in laboratory experiments. These observations were discussed in relation to the potential effects of the increased atmospheric nitrogen supply on the ecology of bryophyte communities in general.


Dr P. J. LIGHTOWLERS (Institute of Terrestrial Ecology, Penicuik): "The Systematics of austral Tortula: unravelling southern hemisphere taxa of a temperate genus. "

Tortula is a genus whose species occur mostly in the temperate zones of both hemispheres. Although the north temperate species are well studied, the southern hemisphere species are poorly known and, as with other temperate genera, a study of the southern hemisphere species may tell us more about the phylogeny and origins of the genus as a whole.

My knowledge of southern hemisphere Tortula is the result of a taxonomic revision of the genus on the subantarctic island of South Georgia, a study I was able to extend to cover the entire subantarctic and antarctic regions. Most of the southern hemisphere, particularly southern South America, has a poorly known bryoflora: there are a large number of species described in the literature, many of which careful study will show to be synonymous. So a stable and clear nomenclature has not yet been achieved and, in general, taxonomic revisions like that produced for Tortula (Lightowlers, 1985) are necessary before any southern hemisphere bryophyte species can be properly understood.

Subantarctic Tortula species can readily be divided into hair-pointed and nonhair-pointed groups and it is the latter group which is the most diverse. Eight subantarctic species can be distinguished in this group: T. anderssonii, T. arenae, T. filaris, T. fontana, T. geheebiaeopsis, T. robusta, T. rubra and T. saxicola. Leaf and lamina cell measurements, as well as other characters, clearly separate these species. Many of them have also been grown together under identical conditions and were found to remain distinct.

In contrast to the non-hair-pointed plants, the hair-pointed group is more taxonomically difficult. Four provisional taxa were distinguished but these did not appear to be specifically distinct, a conclusion which was supported by evidence from a Principal Components Analysis. Growth experiments also suggested that at least two of the taxa were unstable in cultivation. All of the hair-pointed material was therefore referred to one species, T. princeps, which must be regarded as polymorphic (at least in the southern hemisphere). One of the four provisional taxa was treated as a separate variety (var. magellanica) but the others were combined with the var. princeps.

The non-hair-pointed species of subantarctic Tortula, with the exception of T. saxicola, have dentate or denticulate, lingulate to oblong leaves and base marginal leaf cells which are elongated, rather like a vestigial border. (One species, T. arenae, has a fully bordered leaf.) Together, these species form a coherent and apparently natural group whose closest relative in the northern hemisphere is T. subulata. Because of its bordered leaves, this species has the same leaf base areolation, it has a similar leaf shape and may have denticulate leaves (in the var. angustata). Since T. subulata is the type species of Tortula, the southern hemisphere plants are referred along with this species to the section Tortula.

T. saxicola, like T. princeps, has entire leaves and areolation at the leaf base in which the quadrate upper-lamina-type cells run down the leaf margin into the basal part of the leaf. Both species thus appear to belong to the section Rurales.

Tortula in the subantarctic is therefore dominated by the non-hair-pointed plants here referred to the section Tortula. This group appears to be mainly mesophytic and probably more primitive than the highly drought-adapted section Rurales. Section Tortula may well have originated in the southern hemisphere with large primitive species like T. robusta, and have given rise to the section Rurales through species like T. anderssonii and T. saxicola. These have morphological features intermediate between those typical of the section Tortula and those of the section Rurales.

Like Tortula, many bryophyte genera may have originated in the southern hemisphere although many may have diversified later in the northern hemisphere. A southern hemisphere origin for many bryophyte taxa is particularly likely as, at one time, most of the land masses formed part of the great southern Gondwanaland continent. Reference

Lightowlers, P. J. (1985). A synoptic flora of South Georgian mosses: Tortula. Bull. Br. Antarct. Surv. 67, 41-77.


Dr C. D. PRESTON (Monks Wood, Huntingdon): "The Greek bryoflora: an English view. "

The first bryophytes recorded from Greece were gathered by John Sibthorp (1785-1796). A second collection was brought from the Ionian Islands by the talented and eccentric philhellene Lord Guildford. Thereafter records accumulated gradually, most based on specimens collected by botanists primarily interested in flowering plants. It was not until the late 1950s, with increased opportunities for travel, that bryologists visited Greece regularly. Despite this recent activity, only 2 areas (Crete and Corfu) can be considered to be reasonably well-known bryologically.

The Greek bryophyte flora is intermediate in size between that of the species-rich countries of NW Europe (e.g. British Isles, Germany) and the much more species-poor Middle Eastern territories (e.g. Cyprus, Iraq, Israel). When the Greek flora is compared to the British, it is found that almost all the leafy liverworts recorded from Greece are also found in Britain but over one-third of the Greek thallose liverworts do not occur here: these include the genera Plagiochasma, Mannia, Athalamia, Corsinia and Oxymitra as well as many species of Riccia.

The potential for fieldwork in Greece was illustrated with reference to the varied habitats on the island of Samothrace in the NE Aegean.


Dr M. C. F. PROCTOR (Exeter University): "Amateurs, professionals and the study of bryophyte distribution."


K. RENZAGLIA (East Tennessee State University): "The structure and development of hornworts."

The anthocerotes are a structurally distinct group of bryophytes which show developmental peculiarities in all phases of their life cycle (Renzaglia 1978). The vegetative gametophyte is a simple thallus which, except for the occurrence of small epidermal cells and large internal cells in Megaceros, is composed of isodiametric cells of equal size. Large, single plastids with well-defined pyrenoids characterise the cells of most hornworts, the notable exception being Megaceros which has internal cells with up to 14 chloroplasts which lack pyrenoids (Renzaglia & Hicks, 1984). In several species of Anthoceros, Notothylas and Dendroceros, schizogenous mucilage cavities develop in the dorsal thallus while ventral mucilage clefts are found in all species. These latter structures are the site of development for the Nostoc colonies characteristic of all hornwort thalli. Scattered mucilage idioblasts, likewise, occur in most species while slime secretion from epidermal cells serves to protect the apical region and developing gametangia.

Apical growth occurs through the activity of either a wedge-shaped (most genera) or a hemidiscoid (Dendroceros) apical cell. The distinct growth form of Dendroceros, i.e., the thickened midrib and monostromatic wings, is attributable to this difference in generative cell shape. Lateral derivatives of either cell type give rise to wing tissue and the outer midrib, while the basal merophytes produce midrib tissue, rhizoids and the gametangia. Branching is a true dichotomy in which two branch apical cells are formed through an equal division of the apical cell.

Gametangia occur in rows and are sunken along the dorsal midline of the thallus. The solitary archegonia develop from an epidermal initial while the endogenous antheridia occur singly or in groups of up to 25 (Anthoceros) and are produced from a subepidermal initial. Spermatozoids, as exemplified by Phaeoceros (Moser, Duckett & Carothers, 1977; Carothers, Moser & Duckett, 1977) and Notothylas (Renzaglia & Carothers, in press), differ from those of other bryophytes in that they possess identical basal bodies which are positioned side-by-side at the anterior end of the gamete. Moreover, a spline aperture, a posterior mitochondrion and a stellate pattern in the basal body, features common in most bryophyte spermatids, are absent in the hornworts.

Developmental features of the sporophyte which emphasise the isolated nature of the group include the longitudinal first division of the zygote, the development of sporogenous tissue from the amphithecium and the continued growth of the sporophyte from a basal meristem. Diversity in mature sporophytes serves as the primary basis for the separation of the 5 or 6 genera in the group. In general, the hornworts are a homogenous plant group which when compared with other land plants show unique morphogenetic and structural features.

References

Carothers, Z. B., Moser, J. W. & Duckett, J. G. (1977). Ultrastructural studies of spermatogenesis in the Anthocerotales. II. The blepharoplast and anterior mitochondrion in Phaeoceros laevis: later development. Amer. J. Bot. 64, 1107-1116.

Moser, J. M., Duckett, J. G. & Carothers, Z. B. (1977). Ultrastructural studies of spermatogenesis in the Anthocerotales. I. The blepharoplast and anterior mitochondrion in Phaeoceros laevis: early development. Amer. J. Bot. 64, 1097-1106.

Renzaglia, K. S. (1978). A comparative morphology and developmental anatomy of Anthocerotophyta. J. Hattori Bot. Lab. 44, 31-90.

Renzaglia, K. S. & Carothers, Z. B. (in press). Ultrastructural studies of spermatogenesis in the Anthocerotales. IV. The blepharoplast and mid-stage spermatid of Notothylas. J. Hattori Bot. Lab.

Renzaglia, K. S. & Hicks, M. (1984). Megaceros in the Southern Appalachians. Assn Southeast. Biol. Bulletin 31, 78-79.


The Annual General Meeting which followed (Minutes in Bulletin 48) was succeeded in the evening by a conversazione and sumptuous buffet generously provided by the National Museum of Wales. A large number of demonstrations were displayed and are listed below. An outstanding feature of this meeting was the opportunity it afforded to examine the public galleries of the Museum, as well as the Herbarium which houses the B. B. S. collections. For this, we are greatly indebted to Mr A. R. Perry, whose efforts on our behalf, coupled with those of his family, were so clearly seen in the success of the meeting.

Mrs J. Appleyard and Dr H. L. K. Whitehouse: Gemmae on Orthotrichum tenellum.
Dr K. Benson-Evans: Regeneration studies in some mosses.
Mrs E. Campbell and Dr K. Benson-Evans: Maturation stages in liverworts, Marchantiales.
Annual maturation cycle in Pellia, Jungermanniales.
Mr A. C. Crundwell: Pohlia proligera and P. annotina in Britain.
Mr L. T. Ellis and Dr S. W. Greene: The BBS Bryohistorical Project.
Dr E.W. Jones: Souvenir de Draguignan.
Miss A.E. Newton: Bryophyte site register for Cambridgeshire.
Miss A.E. Newton and Dr C.D. Preston: Flora of Samothrace.
Mr A.R. Perry: B.B.S. tie.
Some recent bryophyte acquisitions in the National Museum of Wales.
Mr A.R. Perry and Dr H. L. K. Whitehouse: Protonema-gemmae in Scopelophila.
Mr J. Slade and Dr K. Benson-Evans: The effect of light intensity and day length on the production of antheridia.
Mr E.C. Wallace: B.B.S. photographs.
Drs M. P. and H.L.K. Whitehouse: Stereoscopic photographs of Gymnostomum calcareum and species confused with it.

M.E. NEWTON


Field meeting

Sunday 22 September dawned fine and sunny after the deluge of the previous evening and this ensured a good number of members taking part in a day in the field in Glamorgan (v.c. 41). Choosing good bryological sites within easy reach of a city or exit routes for people making homeward journeys later in the day, is not always easy, and had been somewhat problematic in this case. But the three sites visited turned out to be well suited to our requirements, with some interesting finds, including four new vice-county records.

The first locality was Coed-y-bedw, west of Taff's Well, a 40-acre deciduous woodland owned by the Glamorgan Trust for Nature Conservation. Geologically interesting, it embraces the transition zone between Coal Measures in the north and Carboniferous Limestone in the south, and possesses sandstone outcrops and limestone rocks separated by a marshy stream bed. Ninety bryophytes have been recorded and we saw such diverse elements as Sphagnum angustifolium, Rhytidiadelphus loreus, Saccogyna viticulosa, Eurhynchium schleicheri and Dicranum tauricum. But the best new finds were also new vice-county records: Trichocolea tomentella* and Campylium calcareum*.

We drove north and in the grounds of the Miners' Rehabilitation Centre at Talygarn we had lunch during which Harold Whitehouse set to minutely examining some old oolite steps for Leptobarbula berica. Unfortunately he later decided that the plant he was collecting was probably just young Barbula vinealis. However, he and Chris Preston made up for this later by finding at the base of a wall the best material of Trichostomopsis umbrosa* either of them had seen in Britain. We spent the first part of the afternoon in the overgrown boggy woodland surrounding the two lakes at Talygarn. Here the epiphytes are quite lush with such species as Metzgeria fruticulosa in evidence, but we found nothing of great note although Cryphaea heteromalla, a very rare species in this part of the country, was on Sallows and on a sandstone coping stone. Besides these there were good growths of many common woodland species, especially useful for beginners.

Back at the cars the party split into three: those who wished to visit the final locality on the programme; those who thought it time to leave for home; and a third party lured by Harold Whitehouse to Hengrove Wood, Claverton, near Bath (6), to try to re-find Leptobarbula recorded there earlier. They refound the spot, but it was so dark, owing to shading by trees, that they could not see any bryophytes! Meanwhile, back in Glamorgan, the now very select party went to Hensol Forest in the region of Pysgodlyn Mawr (the "Large fishpond") to examine an extensive area of sallow carr. The water level of this oligotrophic pond had recently been raised by a dam in order to create more stable conditions for the fishermen using it, and this was causing a rapid increase in the Sphagnum along one of the shorelines, not only in area, but also, it seems, in species. Here on sallows Tom Blocked detected small amounts of Colura calyptrifolia*, a most unexpected find, with its next nearest known localities being in West Cornwall and Merioneth. We wondered whether other excitements such as Drepanolejeunea hamatifolia might turn up, but we were not that fortunate!

A. R. PERRY


Autumn Meeting 1985

Selborne, Woolwich, 2-3 November

Sixteen attended the workshop from 2-3 November in Selborne in addition to the four members (June Chatfield, Alan Crundwell, Francis Rose and Rod Stern) providing tuition. The subject of the Workshop was the larger, common bryophytes of woodland, and after a general introduction to bryophytes in The Gilbert White Field Studies Centre where we were based, the afternoon of 2 November was spent in the field when we walked to Milking Hanger and Long Copse (an S.S.S.I.), a deep wooded valley of standards and coppice cut into the Upper Greensand. This is a remarkably wet wood for southeast England and there was luxuriant growth of bryophytes. We investigated the trunks of the oak standards and secondary tree layer, the ground layer and the sides of the stream - these habitats yielded a total of 45 species. After a busy afternoon outside, members were able to do justice to the gargantuan meal at Bush House when we relaxed in the evening in a beamed restaurant with a l og fire.

All localities visited are in v.c. 12. Sunday morning, which was cold and frosty, was spent on Selborne Hanger, a steep woodland on the scarp slope of the chalk that is capped by acid clay-with- flints, providing an interesting contrast in the bryophyte flora. Selborne Hanger (also an S.S.S.l.) is managed by the National Trust and their local Warden Chris Webb joined the weekend course. Also with the workshop were John Ockenden, responsible for the East Hampshire Hangers Project and Fay Stranack, Chairman of the Conservation Committee of the Hampshire and Isle of Wight Naturalists' Trust.

The final excursion on the Sunday afternoon was to Hogmoor Inclosure, Whitehill, a mixed woodland and heath on acid sandy soil of the Lower Greensand. Here we found a complete contrast in flora with acid indicators like Pleurozium schreberi, Polytrichum juniperinum and Sphagnum spp. Rhytidiadelphus loreus, a moss typical of old woodland, was an unexpected find in this location. Although away from the official theme of woodland bryophytes, a large slab of concrete put down by the army was well colonised by mosses, especially the smaller acrocarps. Forty seven species were recorded from the Hogmoor Inclosure. This proved an enjoyable meeting and there were requests for further bryological activities in this area. The location of the meeting -Selborne - is known as the home of the Reverend Gilbert White, author of The Natural History of Selborne (1789). White was more of a zoologist than a botanist, but his writings do occasionally refer to mosses and one letter in the book features Polytrichum commune or The Great Golden Maidenhair, which was used for making besom brooms.

JUNE CHATFIELD


 

 
 
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