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Meetings of the BBS - 1961

 

Annual Meeting 1961

Lewes, 6-11 April

The Society held its Spring meeting in Sussex this year, a county which had not previously been visited by the Society for an extended field meeting. Lewes was the centre from 6 to 11 April from which the daily car journeys were made to areas selected by Dr Rose and Mr Wallace to whom all who attended will wish to express their thanks for undertaking the initial organization, with the assistance of Mrs Paton, and for leading the party over some of these areas during the week. As was to be expected there are very few new records to report from such a well-worked county, but for those members not well acquainted with the chalk of the south-east there were many interesting plants to be seen and quite a number also on the sands and clays of the Weald.

On 6 April the chalk hills west of Lewes were visited and such characteristic calcicoles as Fissidens cristatus, Encalypta streptocarpa, Weissia microstoma, Neckera crispa, Entodon orthocarpus, Cirriphyllum crassinervium, and Campylium protensum were seen. Pottia davalliana, Phascum floerkeanum, Barbula unguiculata var. cuspidatum*, Pleurochaete squarrosa, Pohlia delicatula, Eucladium verticillatum and Plagiothecium denticulatum were also recorded on this excursion in addition to an interesting specialized flora on chalk pebbles in shaded situations consisting of Fissidens minutulus, Seligeria paucifolia, S. calcarea and Tortella inflexa. Leiocolea turbinata was fruiting freely on the damp chalky clay beside shaded paths. The spongey bark of elder branches provided a habitat for numerous bryophytes including Zygodon viridissimus var. occidentalis.

* = New v.c. record throughout.

The morning of the second day, 7 April, was spent at the sandrocks west of Uckfield where fruiting Orthodontium lineare was seen in great quantity. On these rocks also there was Campylopus brevipilus, C. fragilis, Diphyscium foliosum, Pohlia annotina var. decipiens, Lepidozia sylvatica, Calypogeia neesiana var. meylanii, Barbilophozia attenuata, Mylia anomala and Cephalozia connivens. Campylopus introflexus agg. and Rhodobryum roseum were in the heath on top of the sandrocks. In the adjoining woodland there was Rhynchostegiella pallidirostra and Scleropodium caespitosum. Roadside banks revealed fruiting Reboulia hemispherica and Bartramia pomiformis which are both rare in the south-east. In the afternoon a part of Ashdown Forest near Fairwarp was examined. The valley of a small stream, which had escaped the destructive effect of numerous heath fires, contained a very interesting flora including Sphagnum subsecundum var. auriculatum, Campylostelium saxicola, Hyocomium flagellare (c.fr.), Isopterygium elegans (c.fr.), Calypogeia arguta and Scapania undulata var. dentata. Sphagnum molle was collected on the damp heath.

Under Mr Wallace's leadership the party assembled at the foot of Chanctonbury Hill on the Saturday and worked the slopes and top of this well-known landmark. Leptodon smithii was found on several elm trees near the meeting place and they also provided the habitat for Tortula laevipila var. laevipiliformis. The exposed roots of trees and their bases in the various pieces of woodland bore a rich bryophyte flora including Isothecium striatulum, Cirriphyllum crassinervium (c.fr.), Eurhynchium murale, Rhynchostegiella pallidirostra and Plagiothecium curvifolium. Higher up the trees on trunks and branches Lejeunea ulicina was abundant; Zygodon viridissimus var. occidentalis, Cryphaea heteromalla (c.fr.), and Radula complanata were found on several species of tree. Mr Townsend found a form of Dicranoweissia cirrata with large gemmae at the leaf-base. Other interesting plants on the chalk were Tortella inflexa in fruit, Trichostomum sinuosum and Thuidium philiberti. Dr Watson repeated a discovery he made two years ago further west along the same escarpment by finding Nowellia curvifolia on a rotting log. The return to Lewes was made via Sullington Warren on the Lower Greensand where Campylopus introflexus agg. was present in some quantity and Miss Lobley found Orthodontium lineare* in a rabbit burrow. Dicranum spurium was still to be seen and growing amongst the various Sphagna in the wetter areas there was Lepidozia setacea, Cephalozia macrostachya and C. connivens.

Dr Rose took the party to Fairlight Glen on 10 April which is the locus classicus in south-east England for Fissidens rivularis and Dumortiera hirsuta which still seemed to be holding their own in spite of some evidence of pollution of a side stream. Epipterygium tozeri was fruiting well on a pathside bank and Dichodontium pellucidum, Hookeria lucens and Eucladium verticillatum were on wet rocks by the stream. In the afternoon some members were shown a very rich piece of country towards the eastern boundary of Sussex in Marline Wood where a stream runs over a series of terraces formed of Ashdown Sand. Here we were shown an impressive quantity of fruiting Tetraphis browniana and another station for Fissidens rivularis which was also in fruit. Other plants present in this valley were Fissidens adianthoides, Trichostomum tenuirostre, Hookeria lucens, Heterocladium heteropterum and the var. flaccidum, Metzgeria conjugata, and Solenostoma pumilum with perianths. Another group visited Bingletts Wood and saw Dichodontium pellucidum, Hookeria lucens, Heterocladium heteropterum, Rhytidiadelphus loreus, Hyocomium flagellare and Saccogyna viticulosa. Yet another group visited Bedgebury Forest in Kent where they saw Atrichum angustatum, A. tenellum, Polytrichum nanum (c.fr.), Pohlia rothii*, Bryum bicolor and Lophozia incisa.

On the last day a reduced party went to Abbott's Wood north of Eastbourne where Polytrichum nanum and P. aloides were both fruiting and in addition Pleuridium subulatum, Hylocomium brevirostre, Fossombronia pusilla (c.fr.), Lophozia capitata*, Nardia scalaris and Cephaloziella rubella were amongst the more interesting plants. The meeting was blessed by fair weather and all those present were grateful to the organizers for arranging such a varied programme which proved interesting in spite of the inclusion of some well-worked ground. I would like to thank all those who kindly supplied me with lists of their findings.

P. J. WANSTALL

 

Autumn Meeting 1961

Dumfries, 2-9 September

The autumn meeting was held at Dumfries from 2 to 9 September, sixteen members attending throughout the week. This was the first time that the B.B.S. had met in S.W. Scotland and it was unfortunate that the weather did not co-operate in the welcome. Luckily most of the members had seen Scotland in happier mood and were not unduly daunted. Ample transport was available and each of the cars was able to have a rest day, while the members circulated daily among the others.

On Sunday 3 September the venue was in the east of Dumfriesshire (v.c. 72) and the party assembled at Gilnockie Bridge in Eskdale. The cars then moved on up the Ewes Water to Mosspeeble. The day's main search was directed to the two gullies, Birkshaw Linn and Bloodycleuch Linn, at the north end of Arkleton Hill, where streams flowed over and between low cliffs of calcareous Upper Old Red sandstone. Here, on a previous occasion, Distichium inclinatum, Amblystegiella sprucei and Leiocolea heterocolpos had been found, but this time only the last was seen. On the west side of the hill there are several small corrie-like hollows, containing outcrops of similar rock. Some members of the party proceeded towards one of these, Rowantree Cove, but as the upper ground was mist covered, it seems improbable that the cove was fully explored. The two linns unite at their foot and run as Mosspeeble Burn in a ravine through Silurian rock of the non-calcareous (graptolitic) facies of Wenlock time. Most of the party had a good look at the sandstone of the two gullies and some visited the lower ravine. A long list of the species seen could be compiled, as mapping cards were used, but the following selection gives an idea of the bryophytic flora. Sphagna were well represented by palustre, magellanicum, compactum, squarrosum, recurvum, tenellum, contortum, subsecundum vars. inundatum and auriculatum, fimbriatum, girgensohnii, robustum, capillaceum, quinquefarium and plumulosum. Other mosses seen were fruiting Polytrichum alpestre, Fissidens minutulus, F. osmundoides, Ditrichum flexicaule, Seligeria doniana, S. recurvata, abundant Dicranella varia, D. subulata, Dicranum scottianum, Encalypta ciliata, Tortula subulata var. subulata and var. graeffii*, Gymnostomum aeruginosum, G. recurvirostrum fruiting, Gyroweissia tenuis, Anoectangium compactum, a very narrow leaved form of Trichostomum crispulum, Weissia rutilans*, W. microstoma*, Tetraphis browniana, Leptobryum pyriforme, Pohlia cruda, P. rothii, P. annotina var. decipiens, P. proligera*, Bryum pallens fruiting, Mnium seligeri*, fruiting Breutelia chrysocoma, Thuidium philibertii, Hygrohypnum eugyrium, Eurhynchium swartzii var. rigidum*, and Plagiothecium succulentum. The hepatics included Pellia neesiana *, Ptilidium ciliare, Blepharostoma trichophyllum, Calypogeia neesiana var. neesiana*, C. muelleriana*, C. arguta, Lophozia alpestris, Leiocolea badensis, L. muelleri, L. bantriensis, Tritomaria exsectiformis, Sphenolobus minutus, Anastrepta orcadensis, Plectocolea paroica*, Nardia geoscyphus*, Plagiochila spinulosa, Chiloscyphus pallescens*, Scapania umbrosa, Lejeunea patens*, and L. lamacerina*.

[* = New v.c. record]

4 September was spent visiting a number of lowland localities of varying types. Not everybody reached Nunland Hill (v.c.73), but those who did were soon well down in a stubble field with some success. Their finds included Ditrichum cylindricum*, Pseudephemerum nitidum. Ephemerum serratum var. serratum and var. minutissimum*, Bryum erythrocarpum and Eurhynchium megapolitanum*, this last being exciting as an inland station of a moss with very few Scottish records. Hepatics seen were Anthoceros punctatus, A. laevis*, Fossombronia pusilla, F. wondraczekii and Cephaloziella starkei.

The excursion reunited at the Grove (v.c.73), where mixed deciduous woodland with old elders and a humid atmosphere produced a number of epiphytes, such as Tortula laevipila and T. papillosa on a roadside ash and Metzgeria fruticulosa, fruiting Zygodon conoideus, the Orthotricha affine, striatum, lyellii, pulchellum, and Diaphanum, and Cryphaea heteromalla, also Rhytidiadelphus squarrosus five feet up an elder. Plagiothecium curvifolium* was seen here. The best find was Dicranum flagellare* on rotten stumps, the second Scottish vice-county record. Some members meanwhile had looked at a Carex paniculata and willow swamp where they found Climacium dendroides with immature fruit (totally immersed when visited later in the autumn), Mnium rugicum* and M. seligeri*. The whole party now settled to their sandwiches together in a space by the wood.

After lunch about half the company proceeded direct to a wooded Permian sandstone ravine on the Carron Water near Enoch (v.c.72), while the others visited an islet in the Cluden Water (v.c.73) to see Orthotrichum rivulare on water-washed willows; Chiloscyphus pallescens* was also encountered here. The Carron Water habitats were more overgrown than when last surveyed but Barbula unguiculata var. cuspidata* and Thuidium philibertii were seen on a roadside bank, and in the gorge the party recorded fruiting Dicranella rufescens, Tetraphis browniana, Bryum inclinatum, Bartramia ithyphylla and Hypnum cupressiforme var. mamillatum among the mosses while the hepatics included Metzgeria fruticulosa*, Calypogeia neesiana var. meylanii*, C. muelleriana, plentiful Plectocolea paroica, Harpanthus scutatus, Cephaloziella starkei and Cephalozia bicuspidata var. lammersiana.

5 September dawned dismal and with a dubious forecast. Moffatdale (v.c. 72) was overcast on arrival and the weather degenerated into a downpour, which made visual aids a doubtful advantage. However those who stayed until the time arranged for departure found conditions improved. This area of U-shaped valleys set in a Silurian setting of shales and greywackes has base-rich pockets and is probably the best known part of Dumfriesshire bryologically. The members split into two main groups. One party visited the Grey Mare's Tail waterfall ravine. They noted there Lophozia alpestris, Scapania subalpina, Radula lindbergiana and Frullania fragilifolia among other hepatics. Mosses included Brachydontium trichodes, Rhabdoweissia crenulata*, Arctoa fulvella fruiting, Gymnostomum aeruginosum, G. recurvirostrum, Anoectangium compactum, Trichostomum brachydontium, Pohlia annotina, P. delicatula and Plagiobryum zierii. This party then moved on to Raking Gill near the head of the dale and there they recorded Lophozia bicrenata, Solenostoma triste, S. cordifolium, Plagiochila spinulosa with perianths, P. punctata, Dicranoweissia cirrata, Encalypta streptocarpa, fruiting Plagiothecium denticulatum and the var. obtusifolium*.

The other party chose Blackhope as their objective, Nether Coomb Craig, Upper Coomb Craig, Upper Toor Gill and Hartfell Craig, all being visited by different members. Nether Coomb Craig yielded the Sphagna recurvum, contortum, subsecundum var. inundatum and auriculatum, robustum and plumulosum, the Andreaeas alpina, rupestris and rothii, Oligotrichum hercynicum, Brachydontium trichodes, fruiting Blindia acuta, fruiting Dicranella squarrosa, Rhabdoweissia denticulata, fruiting Dichodontium pellucidum, Campylopus fragilis, C. flexuosus, C. atrovirens, Tortella tortuosa, Trichostomum tenuirostre, Weissia controversa, Grimmia doniana, fruiting Anomobryum filiforme, Bartramia ithyphylla, Breutelia chrysocoma, Ptychomitrium polyphyllum, Fontinalis antipyretica, Drepanocladus revolvens, Scorpidium scorpioides, Isothecium myosuroides var. brachythecioides*, fruiting Isopterygium pulchellum and Ctenidium molluscum var. robustum*. Among hepatics were Anthelia julacea, Ptilidium ciliare, Anastrepta orcadensis, Marsupella ustulata*, Gymnomitrion concinnatum, Plagiochila punctata and Lejeunea cavifolia*. These long list are representative of Blackhope bryophytes. Plants added from the other ground looked at included fruiting Diphyscium foliosum, Dicranum falcatum, Rhabdoweissia fugax, Amphidium lapponicum, Grimmia stricta, Drepanocladus fluitans, Plagiothecium denticulatum var. obtusifolium, and P. succulentum, Pellia fabbroniana, Lophozia alpestris, and Gymnomitrion crenulatum*

On their return to Dumfries part of the excursion stopped at Ae Bridge over Ae Water (v.c.72) and there they found Marchantia polymorpha var. aquatica* Metzgeria conjugata, Leiocolea muelleri, Tritomaria exsectiformis and Nowellia curvifolia. A further halt was made at Locharbriggs quarries (v.c. 72) where Riccia sorocarpa, Fossombronia pusilla, Lophozia ventricosa var. silvicola*, and L. excisa, Cephaloziella hampeana, C. starkei and Scapania irrigua were recorded.

6 September was devoted to Scottish Carboniferous Limestone outcrops in Dumfriesshire (v.c.72). First stop was Kelhead limeworks (long disused and the main seams flooded); the waste heaps are fairly well leached but the hollows were damp. The most interesting plants seen were Thuidium philibertii, Campylium protensum* and Drepanocladus aduncus. The party then moved on to Blackwoodridge near Eaglesfield where there are some undisturbed rock faces. Here Fissidens viridulus, Aloina aloides, Barbula trifaria*, Bryum argenteum var. lanatum*, Zygodon viridissimus var. occidentalis (on elder tree) the Orthotricha striatum, affine and pulchellum, Amblystegium juratzkanum* and Leiocolea turbinata were seen. The third locality visited was Penton Linns on Liddel Water, which here forms the boundary between Dumfriesshire and Cumberland. Upon arrival the party took lunch on a rather uncomfortable rock sloping into the river. Subsequently only the Dumfriesshire side was charted, though it took a nice eye to see that some of the water-loving Fissidens were natives of the right country. Here the limestone exposure is good and the following plants were seen, Fissidens minutulus, F. crassipes*, F. rufulus*, F. cristatus, Distichium capillaceum, the Seligerias doniana, pusilla, and recurvata, Barbula spadicea, B. trifaria, Encalypta streptocarpa, Gyroweissia tenuis fruiting, Eucladium verticillatum*, Trichostomum crispulum, T. brachydontium, Grimmia apocarpa, G. alpicola var. alpicola*, and var. rivularis, Bryum bicolor, Mnium marginatum, M. stellare, M. longirostrum, Orthotrichum anomalum, O. cupulatum var. nudum*, Homalia trichomanoides, Leskea polycarpa fruiting, Anomodon viticulosus, Cirriphyllum crassinervium, Rhynchostegiella teesdalei, Marchantia polymorpha var. aquatica, Metzgeria pubescens, Blepharostoma trichophyllum, Bazzania trilobata, Leiocolea turbinata, L. muelleri, Sphenolobus minutus, Solenostoma atrovirens var. sphaerocarpoidea, Lophocolea heterophylla, Chiloscyphus pallescens, Cephaloziella hampeana, Cephalozia bicuspidata, Scapania aequiloba*, Porella laevigata, P. platyphylla, Lejeunea cavifolia, L. lamacerina, L. ulicina, and Cololejeunea calcarea.

7 September. The excursion planned for this day was to the north-facing crags above Loch Dungeon in the Kells hills (v.c. 73). The rock here is of Ordovician age and, lying close to the large granite intrusion north of Loch Dee, it has been in part metamorphosed by contact. Base-rich pockets are relatively few and the party probably never saw them. Asplenium viride was not reported and Anoectangium not on the lists. Pleurozia is here near its southern limit in Great Britain and the Marsupella and Gymnomitrion genera are well represented. Marsupella ustulata*, emarginata and aquatica, Gymnomitrion obtusum and crenulatum were all seen and M. alpina also occurs. Sphagna recorded included palustre, papillosum, compactum, recurvum, tenellum, cuspidatum, subsecundum vars. subsecundum, inundatum and auriculatum, capillaceum and plumulosum. Other bryophytes encountered were representative of the local flora and included Andreaea alpina, A. rupestris, Oligotrichum hercynicum, Diphyscium foliosum, Fissidens adianthoides, Dicranum blyttii, Campylopus flexuosus, C. setifolius, Grimmia doniana, G, torquata, Tetraplodon mnioides and Acrocladium stramineum among the mosses and Ptilidium ciliare, Lepidozia setacea, Calypogeia muelleriana*, C. fissa, C. arguta, Lophozia alpestris, L. incisa, Barbilophozia floerkei, B. attenuata, Solenostoma pumilum, S. cordifolium, Mylia taylori, Cephaloziella pearsonii, Scapania curta, S. gracilis and S. nemorosa.

Meanwhile the lure of the fabulous Black Burn near Newcastleton in Roxburghshire (v.c. 80) had seduced a carload of our members, though this had been made up to us by the accession for the day of our Bibliographer and a Nature Conservancy presence. A list from the Black Burn is characteristic of its flora, which is noteworthy for the many tiny species growing on the limestone there. On the wet moorland between the road and the burn Mylia taylori, M. anomala, Cephalozia connivens, C. macrostachya with perianths and Splachnum ampullaceum were noted. The other bryophytes recorded were the mosses Polytrichum alpestre, P. formosum*, Fissidens minutulus, Ditrichum cylindricum, D. heteromallum, Brachydontium trichodes, the Seligerias doniana, pusilla and recurvata, Dicranella rufescens, Dicranodontium asperulum, Gyroweissia tenuis and Tetraphis browniana, also the hepatics Blasia pusilla, Plectocolea paroica and Harpanthus scutatus. Everybody concluded the day's proceedings with conversation over coffee at Mainsriddle.

8 September. Some members of the excursion were leaving for home today, but all went to Maidenbower Craigs (of Permian sandstone, v.c. 72) near Dumfries to search for Paraleucobryum longifolium for which, with Grimmia patens, there exists an old record in this locality. Although the main object was not achieved, a little G. patens was seen and other mosses were Rhabdoweissia denticulata, Cynodontium bruntonii, Gyroweissia tenuis, Eucladium verticillatum, Amblystegium compactum* (an exciting find), Rhynchostegiella pallidirostra, R. tenella and Plagiothecium sylvaticum*. Hepatics included Reboulia hemisphaerica*, Marchesinia mackaii*, and Lejeunea lamacerina. A nearby field of stubble provided Ditrichum cylindricum, Ephemerum serratum, Anthoceros punctatus*, A. laevis, Riccia warnstorfii*, and Fossombronia pusilla. We now said farewell to the Northumbrians who, with other members, visited parts of the Lochar Moss (v.c.72) where they saw the Sphagna palustre, magellanicum in some quantity, papillosum, compactum, recurvum, tenellum, cuspidatum, capillaceum, and plumulosum, Fossombronia pusilla, F. wondraczekii, Lepidozia setacea, Calypogeia fissa, Mylia taylori, M. anomala, Cephaloziella starkei, Cephalozia connivens, Odontoschisma sphagni, Pseudephemerum nitidum, Tetraplodon mnioides fruiting, Pohlia annotina and Acrocladium stramineum.

The other party made for the Kirkcudbright (v.c. 73) coast and climbed the lower part of Airdrie Hill to see Grimmia decipiens (on granite). En route they recorded Pohlia rothii*, P. annotina, Funaria obtusa, Riccardia multifida, Calypogeia fissa, C. muelleriana, Lophozia ventricosa var. silvicola*, Cephalozia pleniceps*, and sterile C. loitlesbergeri* (perianths found at later date). From this hill where sandwiches were taken, the party moved to the coast beyond Caulkerbush where going down at Needles Eye, they walked along over the marshland partly salt, which lies at the base of the wooded cliffs or heughs, to the waterfall by Lot's Wife. The rocks here are Silurian of Wenlock age, much altered by the neighbouring granite intrusion. A basic element is present (Cirriphyllum crassinervium occurs), but this characteristic is not fully brought out by the few plants listed on this occasion which included, Grimmia hartmanii, Mnium longirostrum, Orthotricha affine, stramineum and diaphanum, Pellia fabbroniana, Marchesinia mackaii and Lejeunea lamacerina*.

All the members on the excursion were energetic and enthusiastic, often erudite. The number of new records was gratifying and it is to be hoped that the Society will revisit some part of Southern Scotland in the not too distant future. Any losses of men or materials were redeemed and the impression left was of a happy and harmonious week.

H. MILNE-REDHEAD

 

Weekend Meeting 1961

Cambridge, 28-29 October

A week-end meeting was held on 28 and 29 October in the Botany School, Cambridge, by kind permission of Prof. H, Godwin.

The programme on Saturday, 28th, consisted of paper-reading and a conversazione. The President, Miss E. M. Lobley, could not be present and so the task of introducing the four speakers fell to Dr E. F. Warburg.

Summaries of the papers follow:

Dr E. LODGE: 'The Genus Drepanocladus'.
Some of the problems in circumscribing the genus Drepanocladus were briefly considered and then an account was given of transplant experiments which have been carried out on British material of D. fluitans and D. exannulatus. These investigations have shown that the two species are each represented in Britain by two distinct genotypes. Experimental control of the environment, however, has indicated that the two genotypes of each species are extremely plastic. The taxonomic implications of these observations were then considered. The paper concluded with a description of the work of the Finnish bryologist, Tuomikoski, on the Fennoscandian races of D. exannulatus.

Mr D. BRIGGS: 'Experimental Studies in the Genus Dicranum'.
Four species of Dicranum had been studied, D. fuscescens, D. majus, D. scoparium and D. bonjeanii and evidence was presented, from morphological studies, which showed that these were, in fact, good species.

Intra-specific variation within the group was examined and the results of culture experiments were given which indicated that such characters as undulation of the leaf-tip and leaf stance could be modified by altering the external environment and were probably unreliable as key-characters, at species or varietal level. Varieties based on entireness of leaves were also difficult to apply as the variation in serration appeared to be continuous.

The results of cytological investigation into Dicranum populations were also presented. Intra-specific variation in chromosome number was shown to occur in D. fuscescens, D. majus and D. scoparium and also variation in 'small' chromosomes. The chromosome variation did not appear to 'follow' the morphological variation. (Full details of these Dicranum studies will be presented elsewhere.)

Mr J. H. DICKSON: 'Some preliminary observations on the Quaternary Moss Flora of Britain'.
The kinds of fossil mosses found in British Quaternary deposits were indicated by means of slides.

Four deposits were explained in some detail. Two of these, referable to the late glacial period at Low Wray Bay, Windermere (Zone II) and Loch Droma, Wester Ross (Zone I) were dealt with in such a way as to show how fossil moss assemblages can help in reconstructing past environments.

The moss floras of the full-glacial deposits at Colney Heath, Herts, and Broome, Norfolk, were used to demonstrate distributional changes. Thus, Cratoneuron filicinum var. curvicaule, Oncophorus virens, Scorpidium turgescens and Timmia sp., found at Broome, were far outside their present British ranges during the full glacial period.

Dr J. H. TALLIS: 'Some observations on Sphagnum imbricatum'.
Measurements of leaves of Sphagnum austini Sull. ( S. imbricatum Hornsch. ex Russ.) and of the variety imbricatum Lindb., differing in their lax and compacted growth-forms respectively, show that the two taxa differ significantly in the length:breadth ratio (1·175 ± 0·078 and 1·547 ± 0·114 respectively). Transplant experiments indicate that the two are merely growth forms, controlled by the height of the water-table. Measurements of S. imbricatum leaves preserved in Sub-Atlantic peats from three areas show variation in the length:breadth ratio, suggesting that S. imbricatum may have adopted different growth forms during accelerated and retarded phases of peat formation. The principal theories concerning the behaviour of S. imbricatum in recent peats largely fail to take into account the detailed stratigraphy observable in some bog peats.

Many of the 30 members and guests present contributed to the lively discussion of the papers and Dr E. F. Warburg warmly thanked the speakers.

In the evening a conversazione took place and the following exhibits were presented:
J. H. DICKSON, P. E. BROWN
and P. J. HASTINGS:
' Meesia longiseta Hedw. in Britain'.
S. W. GREENE: 'A Botanical Dryer suitable for Bryophytes'.
P. J. GRUBB: 'Polysety in Polytrichum'.
R. E. LONGTON: 'Polysety'.
Dr F. H. PERRING: 'The preparation of Grid Square Distribution Maps'.
J. H. G. PETERKEN: 'Colour Transparencies of Bryophytes'.
Dr C. D. PIGOTT: 'Distribution Maps of Sphagnum imbricatum and Camptothecium nitens'.
Dr L. B. C. TROTTER: 'Drawings showing the Histology of Mosses'.
Dr S. M. WALTERS: 'W, E. Nicholson's Diaries, and the Nicholson Herbarium'.
Dr H. L. K. WHITEHOUSE: 'Rhizoid tubers in British mosses'.
Dr H. L. K. WHITEHOUSE
and Mrs M. P. WHITEHOUSE:
'A possible association between species of Riccia and the occurrence of Phascum cuspidatum Hedw. var. bivalens Springer'.
Mrs M. P. WHITEHOUSE: 'Stereoscopic colour transparencies of Bryophytes and Bryologists'.

On Sunday, 29th, about 25 members and guests set off by private transport under perfect weather conditions to see some of the rarer bryophytes of the Cambridge district. First, a stop was made at Quy Fen, where a very large patch of Tortula vahliana was seen on a north-east facing clay bank beneath elders and brambles. A stubble field at Horningsea yielded Ephemerum recurvifolium and Bryum klinggraeffii.

Next the party visited the ancient earthwork, the Devils Dyke, where it crosses the A. 45 (Cambridge to Newmarket), to see chalk grassland bryophytes, including Weissia sterilis and Tortella inclinata, Dr E. F. Warburg quickly found Tortella inflexa, a new vice-county record. This species has since proved to be common on chalk lumps on a 3 mile stretch of the Dyke, west of the original locality. It may well be that careful searching will show that the species is common over the greater part of the 10-mile-long Dyke, where there are suitable chalk lumps.

At Lakenheath Warren, in Suffolk, v.c. 26, Eurhynchium pulchellum var. praecox and abundant Rhytidium rugosum were seen. In the adjoining Forestry Commission plantation at Wangford Warren, Dicranum rugosum, originally found by Mr M. Macfarlane, and Rhytidiadelphus loreus, found by Dr H. L. K. Whitehouse, were shown to the party. Much to everyone's astonishment, Mr S. W. Greene discovered a large clump of Ptilium crista-castrensis, a new record for southern England. Shortly afterwards, two further clumps were found. Another new county record was made with the discovery of Odontoschisma denudatum on a rotten pine stump.

Close searching of a fairly small area of the plantation has yielded over 20 localities of Ptilium, a species totally unexpected in this part of Britain. It seems likely that the species has been introduced, and with this in mind, Dr H. L. K. Whitehouse is trying to find the origin of the trees (Scots and Corsican Pine) from the Forestry Commission. Dicranum rugosum has also proved to be common at Wangford.

The discovery of Ptilium brought a fine day's bryologizing to a fitting end.

Thanks are due to the local secretary, Dr H. L. K. Whitehouse, whose careful organization was of great assistance to the meeting which was a success in every way, to the Botany School for providing refreshments, to Dr E. F. Warburg for taking the chair, to Dr J. H. Tallis for speaking at short notice in place of Dr C. H. Gimingham, and to Mr S. W. Greene who has not only acted as programme secretary for three of the week-end meetings so far held, but was responsible for their initiation.

January 1962 JAMES H, DICKSON
 
 
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