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Meetings of the BBS - 1970

 

Annual Meeting 1970

Beddgelert 1-8 April

The Annual Meeting (1-8 April) was held at Beddgelert, Caernarvonshire, and was attended by about 30 members amongst whom we were pleased to welcome Professor Hisatsugu Ando of the University of Hiroshima, Japan. The meeting was planned with special reference to south-west Caernarvonshire, a previously bryologically neglected area, but was marred by cold weather. Few new county records were found as east Caernarvonshire has been well worked.

The first two days of the meeting were spent on the Lleyn peninsula (v.-c. 49). On 2 April members visited Yr Eifl (The Rivals). On these mountains the very acid Calluna heath with granite outcrops produced little of interest except Grimmia elongata. Near the stream Nant Gwrtheyrn were seen Archidium alternifolium, Mnium seligeri* (damp soil in woodland, A.C.C.), Epipterygium tozeri, Philonotis rigida, Cephaloziella pearsonii, Frullania fragilifolia, F. germana and Jubula hutchinsiae and, on a cliff path near derelict buildings at Forth y Nant, Fossombronia incurva* (J.A.P.) and Marsupella funckii. On a peaty bank in a wood nearby at Gallt y Bwlch, Aulacomnium androgynum* and Plagiothecium ruthei* were found (M.F.V.C.). In the afternoon some members visited Sarn Meyllteyrn (Leptodon smithii); the banks of the Afon Horon near Nanhoron, where finds included Hygroamblystegium fluviatile, Cololejeunea minutissima* (on ivy stems, J.A.P.) and Metzgeria fruticulosa; and a wet heath, unfortunately being ploughed up, at Cwmistir near Groesffordd (Campylopus brevipilus and Hypnum imponens).

[* new vice-county record.]

On 3 April Cors Geirch, a rich fen near Bodfuan, was visited. Those who waded the muddy approach were rewarded with Campylium elodes c.fr., Camptothecium nitens, Mnium pseudopunctatum, Bryum neodamense* (R.R.), Moerckia flotoviana, Preissia quadrata and, on tussocks, Riccardia latifrons* (E. R. B. L) and Cephalozia bicuspidata var. lammersiana* (J.A.P.). In a nearby grass field Bryum micro-erythrocarpum* was found (A.C.C.) and in boggy ground above the fen Mnium rugicum* (J.A.), In the afternoon some members visited sand-dunes at Abersoch, where finds included Bryum donianum, Eurhynchium megapolitanum* (J.A.P. et al.), Thuidium philibertii and Riccardia incurvata; coastal cliffs at Llanbedrog (Bryum alpinum c.fr., Philonotis rigida and Ulota drummondii); a wooded gorge and sandy cliffs near Treheli, Porth Nigel (Heterocladium heteropterum var. flaccidum and Brachythecium mildeanum); Moelwyn Mawr (Desmatodon convolutus and Frullania fragilifolia); and a fallow field at Mynydd Mawr near Aberdaron, where Ephemerum serratum var. minutissimum* was found (B.J.O.).

On 4 April a visit was paid to Moel-yr-Ogof where outcrops of basic volcanic rocks support a rich flora. Because of the cold weather little of interest was found and a number of members preferred low-lying areas. One of the most interesting of these was Ceunant Llenyrch, a wooded ravine near Maentwrog (v.-c. 48), where finds included Hylocomium umbratum c.fr., Orthodontium lineare, Ulota drummondii, Aphanolejeunea microscopica, Drepanolejeunea hamatifolia, Harpalejeunea ovata, Douinia ovata, Jamesoniella autumnalis, Sphenolobus helleranus, Riccardia palmata and Cryptothallus mirabilis* (under Sphagnum recurvum in Betula scrub, J.G.D.). In wooded valleys above Llyn Gwynant (v.-c. 49) Gymnostomum calcareum, Tetraphis browniana and Jubula hutchinsiae were found.

At the Annual General Meeting, which was held at the headquarters hotel in the evening, Professor P. W, Richards was elected an Honorary Member of the Society and Dr D. H. Dalby was elected Honorary Secretary in place of Mr E. C. Wallace who retires after more than 20 years' service to the Society.

On 5 April one party visited Anglesey (v.-c. 52). In coastal woodland on the south side of Traeth Dulas, north-west of Llanallgo, finds by J.A.P. and A.C.C. included Dicranella staphylina, Funaria fascicularis, Orthotrichum pulchellum, Metzgeria fruticulosa* (on a hazel branch), Lejeunea lamacerina var. azorica* (on shaded rocks) and Plagiochila asplenioides var. major* (on a bank). On mine waste or adjacent peaty soil at the copper-mined Parys Mountain, so named after Robert Parys in the fifteenth century, J.A.P. and A.C.C. found Bryum ruderale*, Cephaloziella stellulifera*, Calypogeia muellerana* and Lophozia bicrenata*. Aberffraw sand-dunes produced Petalophyllum ralfsii, Southbya tophacea c.fr. (see p. 328), Solenostoma sphaerocarpoidea and Cephaloziella hampeana* (dune slack, J.A.P. & A.C.C.).

It had been hoped to work the Moelwyni near Blaenau Ffestiniog (v.-c. 48) on 6 April but because of snow the excursion was limited to Llyn Stwlan, access to which was given by the Central Electricity Generating Board. The terrain is composed of hard slaty acidic Ordovician rocks and produced Acrocladium sarmentosum, Philonotis caespitosa, Sphagnum girgensohnii, Barbilophozia barbata, Scapania subalpina, S. uliginosa and Plectocolea obovata. After lunch some members visited the wooded valley of the Afon Goedal above Rhyd-y-Sarn (Leucobryum glaucum and L. juniperoideum (Brid.) C. Muell., both c.fr.); the gorge of the Afon Cynfal near Pont Tal-y-Bont (the water was badly polluted but in and by the river were Atrichum crispum, Isothecium holtii and Heterocladium heteropterum c.fr.); a second ravine of the same river about 2 miles north of Ffestiniog (Encalypta ciliata); and Portmeirion (Campylopus polytrichoides, Isopterygium elegans c.fr. and Frullania microphylla).

The final excursion on 7 April was to Morfa Harlech, an extensive area of sand-dunes. In the past a number of interesting species have been recorded but on this occasion the most notable finds were Amblystegium varium, Campylium polygamum, Moerckia flotoviana and Riccardia incurvata. In the afternoon members visited some of the Merionethshire valleys including Cwm Bychan where a number of species recorded on previous visits (see Rep. Br. bryol. Soc. 2, 325-6 and Trans. Br. bryol. Soc. 4, 888-92) were seen; the Llandecwyn/Bryn Bwbach valley (Atrichum crispum, Coscinodon cribrosus, Fissidens celticus, Grimmia doniana var. arenaria, Leuco bryum glaucum c.fr., Philonotis capillaris, Pohlia bulbifera, Calypogeia sphagnicola, Cephaloziella subdentata and Cryptothallus mirabilis); and Cwm Croesor (Cynodontium polycarpum).

Although south-west Caernarvonshire proved somewhat dull bryologically compared with Snowdonia, much useful recording was carried out for the mapping scheme.

A. J. E. SMITH

 

Summer Meeting 1970

Sligo, 2-16 September

The summer meeting was held in Sligo from 2 to 16 September. The number attending averaged about six at any one time. This was disappointingly small but we were glad to welcome Dr and Frau E. Hegewald from Dortmund.

3 September. The first excursion was to Knocknarea, a hill to the west of Sligo (v.-c. H. 28). Approaching from the northeast side, the party struggled through rocky Corylus scrub to open heathy ground. Here J.A. found Dicranum bonjeanii* and Tritomaria exsectiformis was seen among Calluna. On limestone outcrops near the top of the hill Marchesinia mackaii, Scapania aequiloba, Gymnostomum calcareum and Orthothecium intricatum were noted. The descent was made by way of a forestry road where J.A. recorded Dicranella schreberana*. A short visit was then made to the sand-dunes at Strandhill where Dichodontium pellucidum var. fagimontanum, Entodon concinnus and Thuidium abietinum were seen.

On 4 September it was decided to take a look at the northern end of the Ox Mountains. Loch Minnaun was reached by way of boggy moorland and the steep acid outcrops of Knockalongy, above the lake, were worked. Although bryologically the area was distinctly dull, three new records were made for v.-c. H. 28. D.M.S. found Riccardia multifida* and a small amount of Anthelia julacea* and Diphyscium foliosum* was collected by J.A.

5 September. As the weather looked fairly promising we went to Gleniff (v.-c, H. 28). This corrie, which is not marked on the ½ in. O.S. map, lies south of Clogh about 3 miles east of Benbulbin. It is famous for the many rarities found on its limestone ledges and cliffs, notably Barbula reflexa var. robusta, Gymnostomum recurvirostrum var. insigne, Seligeria oelandica, Dicranella grevilleana and, among short turf on the lower slopes, Timmia norvegica. All these species were seen, also Amblyodon dealbatus, Seligeria trifaria, Orthothecium rufescens, O. intricatum and Amblystegiella sprucei. E.H. recorded Seligeria recurvata* from the limestone cliffs and J.A. found Dicranella rufescens* on mud by the waterfall.

6 September. The morning looked like being wet so it was decided to keep to low sheltered ground and Slish Wood, on the southern side of Lough Gill (v.-c. H. 28) was chosen. Although the bryophytes here were quite luxurious the species seen were disappointingly commonplace. Porella pinnata was plentiful on lakeside boulders and Hypnum lindbergii was seen on the forestry track. After lunch work had to be abandoned because of heavy rain.

7 September was spent in Glenade (v.-c. H. 29), mostly among the fantastic pillars and crags of Peakadaw. Although the only new record was of Fossombronia pusilla*, found by J.A. on a bank by the track below Peakadaw, many interesting species were seen, including Adelanthus decipiens, Bazzania tricrenata, Cololejeunea calcarea, Riccardia palmata, Herberta adunca, Seligeria pusilla, S. recurvata, S. trifaria, Gymnostomum recurvirostrum var. insigne, Mnium orthorhynchum and Trichostomum crispulum var. elatum. Thuidium delicatulum was noted on the way down and Splachnum ampullaceum was seen by a ditch. On the return journey along the track through Glenade an old quarry was visited, the floor of which was carpeted with Barbula reflexa, some of which bore fruit. A short stop was made at Glencar Waterfall on the way back but conditions were too wet to bryologize profitably.

On 8 September a visit was made to the north-facing limestone rocks and cliffs of calcareous shale at Aghadunvane, south-west of Lough Melvin (v.-c. H. 29). The approach was made by way of boggy fields, where Mnium seligeri was seen, and a wooded ravine in which Nowellia curvifolia was found on a rotten log. At first glance the area appeared unpromising but perseverance and some scrambling rewarded us with Barbula reflexa var. robusta (in small quantity and of poor quality), Gymnostomum recurvirostrum var. insigne and Seligeria oelandica. It was noted that although there was an abundance of young fruit on the Seligeria, mature capsules were very rare whereas in Gleniff they were plentiful. Other interesting species seen were Riccardia palmata, Herberta adunca, Dicranella grevilleana, Orthothecium rufescens and O. intricatum. On the way back to Sligo J.A. et al. made a detour through the Glenaniff valley where Tortula ruralis* was recorded from the roof of one of the many derelict dwellings seen en route. On a track south of Kinlough J.A. found Phascum cuspidatum*.

9 September. The morning being very wet and windy it was mainly passed in driving to Lough Carra (v.-c. H. 26). On the way Cinclidotus fontinaloides was seen growing luxuriously on an asbestos roof ! The first stop was at Keel Bridge, 3 miles north of Ballinrobe. Here, in trying conditions of wind and rain, the party bryologized until lunch time. The principal feature of this area was the abundance of Tortella densa growing on limestone pavement. D.M.S. found Pellia endiviifolia* in a wet depression. Scorpidium scorpioides was abundant in flushed ground and J.A. recorded Dicranella schreberana* , Barbula revoluta* and Brachythecium glareosum* from the side of a track. After lunch the weather improved and a move was made to the shore of L. Carra, near Partry House. Here Riccia sorocarpa* was plentiful, mixed with a little R. beyrichiana and J.A. recorded Phascum cuspidatum* and Pohlia wahlenbergii* We then went north to explore the peninsula north-east of Partry. In wet fields on the way to the lough Acrocladium giganteum and Mnium seligeri were seen, but Corylus scrub and dry limestone near the shore did not yield anything of interest. In the evening Mr and Mrs Perry joined the party.

10 September was spent on the coast between Pollyarry and Bundoran. This was a wise decision as inland the hills were misty and windswept all day but near the sea we enjoyed continuous sunshine. The first stop, on the Pollyarry cliffs, was bryologically dull so the party soon moved on to the sand-dunes behind Bunduff Strand, south of Muilaghmore (v.c. H. 28). Here Barbula reflexa, Campylopus introflexus, Distichium inclinatum, Entodon concinnus, Lophozia excisa and Scapania compacta were seen. J.A. found Bryum donianum* on a wall by the road. The cliffs west of Tullaghan (v.-c. H. 29) were the next stop. Grimmia maritima and Ptychomitrium polyphyllum grew on stone walls, Pottia heimii* was found by J.A. on a bank, and boggy ground provided a few more species for the record card, notably Campylopus introflexus c.fr. which was present over a wide area and spreading rapidly, following the course of water seepage. On a bridge at Largydonnell, E.H. found Grimmia trichophylla*. That evening Mrs Paton arrived.

On 11 September members met at Lough Key but the weather having improved, it was decided to explore the Bricklieve Mountains (v.-c. H. 28), known locally as Carrowkeel. This change of plan caused rather a late start and in addition some confusion arose from the non-existence of a small lake marked on the map. The party worked northwards along the west ridge where J.A.P. recorded Sphenolobus minutus* from peaty ground among rocks. We then descended into the west valley where Calypogeia sphagnicola* was recorded from a bog by J.A.P. who also found Lepidozia sylvatica* on a peaty slope. J.A. recorded Mnium rugicum* from marshy ground and J.A.P. made the interesting find of Metzgeria fruticulosa c.fr. in a wet thicket. Other species seen included Lepidozia pinnata, Marchesinia mackaii, Tritomaria exsectiformis, Cephaloziella hampeana and Dicranum scottianum. On the return journey some members stopped at an old quarry near Derry, on Lough Arrow, where J.A.P. found Petalophyllum ralfsii*. Unfortunately Mr Synnott had to leave that evening.

On 12 September further ground in the Benbulbin area (v.-c. H. 28) was chosen for exploration, namely, the corrie to the north-east. Most members saw Polytrichum aurantiacum* c.fr. on the boggy moorland leading to the corrie. The terrain was very like that of Gleniff and all the rarities of Gleniff were found. In addition J.A.P. collected Plectocolea subelliptica* from a bit of sandy limestone. In the afternoon we climbed to the summit plateau and walked over moorland and peat hags to King's Mountain. On the way, Splachnum ovatum and Tetraplodon mnioides were seen; J.A.P. recorded Lepidozia pearsonii* and Scapania scandica* and J.A. added Cephaloziella starkii*. On the way back to Sligo some members visited woodland at Lissadell House, north of Drumcliff, where J.A.P. found Bryum rubens*.

On 13 September numbers were further depleted by the departure of Mr Wallace. Again the weather was poor so it was decided to go to the deciduous woodland around Templehouse Lake, south of Coolaney (v.c. H. 28). An abundance of Riccia glauca* was spotted by J.A.P. on the roadside verge where the cars were parked. Riccardia palmata, R. latifrons and Nowellia curvifolia were seen on rotting logs in the wood. In the afternoon a variety of habitats in the vicinity of the Owenaher River, south-west of Cloonacool, was worked. Pohlia bulbifera* was found by J.A.P. on the bank of the river and J.A. recorded Bryum alpinum var. viride* from boulders. Plectocolea subelliptica, Solenostoma triste, Sphagnum magellanicum, Splachnum ampullaceum, Fissidens osmundoides and Dicranum scottianum were some of the species seen in boggy ground and among rocks. Several people then went to a roadside quarry near Masshill. This visit proved very fruitful as J.A.P. recorded Fossombronia incurva*, Haplomitrium hookeri*, Lophozia bicrenata*, Plectocolea hyalina*, Riccia warnstorfii* and Dicranella crispa*. J.A. added Pellia neesiana*, Archidium alternifolium* and Pohlia rothii*. Fossombronia incurva was also seen by A.R.P. near Easky Lough, Ox Mountains.

On 14 September an excursion was made to the eastern border of Leitrim (v.-c. H. 29). The north-facing cliffs and hill slopes of Glenfarne, near Belcoo, were worked in the morning. Here J.A.P. found Pohlia annotina*, Calypogeia neesiana var. neesiana* and Cephalozia media* and E.H. found Tetraplodon mnioides*. Most members saw Dicranodontium asperulum* among boulders and Dicranum scottianum c.fr. was frequent on rocks. J.A. recorded Bartramia pomiformis* from a dry rock face and Solenostoma sphaerocarpum* from boulders in a stream. By the stream, J.A.P. collected Atrichum crispum*. After lunch the party split up, some going to look at the summit plateau while others went south-east into Cavan (v.-c. H. 30), below Englishman's House. Descending by way of some old workings, J.A. collected Dicranella rufescens* on the muddy slopes and J.A.P. found Cephalozia leucantha* and Tritomaria quinquedentata* among boulder scree, where Lepidozia pinnata and Bazzania tricrenata were also seen. In a flush below the crags, further records were made, namely, Pellia neesiana* and Drepanocladus exannulatus var. exannulatus* by J.A.P. and Mnium pseudopunctatum* and M. rugicum* by J.A.

On 15 September J.A.P. went to Gleniff but as everyone else had been there, they elected to investigate the eastern slopes of Benbo, south-west of Manorhamilton (v,-c, H, 29). Here E.H. recorded Nardia compressa* from boulders in a stream. Other species seen included Lejeunea lamacerina var. azorica, Solenostoma pumila, Lepidozia pearsonii and Archidium alternifolium. In the afternoon a visit was paid to the slopes of Crockauns, south of Glencar Lake. The boggy ground and small streams of the lower ground were mostly acid. Here Blasia pusilla and Dicranella rufescens were seen and J.A. recorded Bryum bornholmense*. On and among the limestone higher up grew Orthothecium rufescens, Neckera crispa, Distichium inclinatum and Lejeunea patens. Dichodontium pellucidum var. flavescens was seen in a stream. J.A.P. recorded Fossombronia wondraczekii* from a small marsh north of Dromahair (v.-c, H, 29). At Cormac Keagh's Hole (v,-c. H, 28), on the north side of Benbulbin J.A.P. also found Cephalozia leucantha* on a boggy slope and Bryum capillare var. elegans* (new to Ireland) on calcareous boulders.

Although given better weather more high ground would have been worked, with the resulting benefits of a greater number of alpine species, a valuable contribution was made to the mapping scheme as 20 cards were filled in, although some of the lists were short. Twenty-nine hepatic and 34 moss records were made. We would like to thank Mr Synott for his help and general support on the meeting.

J. APPLEYARD

 

Autumn Meeting 1970

Sheffield, 24-25 October

A week-end meeting was held on 24 and 25 October in the Department of Botany, Sheffield University, by kind permission of Professor A. J. Willis. About 50 members assembled on the Saturday when the President, Mr A. J. Pettifer, introduced six speakers, summaries of whose papers are given below.

Dr J. O. RIELEY: 'The effect of canopy and bryophyte layer on the amount and chemical composition of the precipitation in a sessile oakwood.'

The phytosociology of the North Wales oakwoods was described as a basis for delimiting areas for productivity and nutrient studies which could be compared with data for other associations. Chemical analyses (calcium, magnesium, potassium and sodium) for a 52-week period, based on a statistical sampling procedure, were presented, together with data on seasonal variation, and the total input of the four elements available to the bryophytes. The results of regression analyses were described. The non-parametric 'sign test' was used to detect changes in the amounts of water and the four elements in precipitation as it passed through the Quercus canopy and the bryophyte ground layer during a 20-week period. It was found that potassium was leached from the tree crowns into the throughfall, that potassium and calcium were removed from the throughfall by the bryophyte layer and that magnesium and sodium were leached out of the bryophyte layer.

Mr H. THOMAS: 'Variation in the sward structure of Mnium hornum.'

M. hornum occupies a wide range of woodland habitats where sward physiognomy can reflect environmental factors. Under deciduous broad-leaved canopies a bud is produced in autumn at the base of each stem and elongation continues through the winter so that old shoots are overtopped in spring as they fall over and die. There is little increase in sward height. In coniferous woods, whether open deciduous Larix or dense evergreen Picea, swards are less dense and taller. The common factor is the accumulation of needle leaves between the moss shoots. In damp Betula wood on disturbed peat in Somerset M. hornum growing around tree bases forms dense clumps with an annual height increment of ca. 10 mm. In this habitat old shoots remain erect for several years, shading the young shoots and causing them to elongate. With increasing diffuse radiation in winter and spring, data from a wide range of habitats showed a significant increase in density and productivity and a significant decrease in height. Growth experiments confirmed the deduced effects of light and humidity, and furthermore, laboratory studies indicated that dense short swards from relatively dry habitats take two to three times as long to lose half the water held at complete saturation than do taller looser swards from more sheltered situations. Comparisons of the CO2 exchange rates of swards from habitats with differing light climates showed that their compensation points were similar at 0·3-0·4 klux in summer.

Dr D. H. LEWIS: 'A chemotaxonomic classification of some groups of leafy liverworts.'

In the following families, or groups of families, the occurrence of acyclic sugar alcohols (polyols) in the genera so far analysed agrees with the taxonomy: (a) Scapaniaceae (three genera), mannitol; (b) Marsupellaceae (two genera), a hexitol, possibly sorbitol; (c) Lophocoleaceae (sensu K. Müller) (two genera), volemitol and mannitol; (d) Herbertaceae, Ptilidiaceae, Trichocoleaceae, Blepharostomaceae (sensu Müller and R. M. Shuster) (five genera) and Lepidoziaceae (three genera), volemitol with sedoheptulose. This polyol-sugar pair is lacking from Anthelia, Pleuroclada and Hygrobiella, a finding which supports Müller's segregation of these genera from the Ptilidiaceae complex. They are also lacking from the Calypogeiaceae, a family aligned hitherto with the Lepidoziaceae. The Cephaloziaceae and Odontoschismaceae (sensu Müller) (five genera) and the Lophoziaceae/Jungermanniaceae complex (ten genera) contain either mannitol or another hexitol, or both. Further analyses here may be taxonomically useful, particularly since the presence of unidentified polyol-like compounds in Mylia (M. taylori and M. anomala) is akin to the patterns of some of the Jungermanniaceae, in agreement with Arnell and Schuster who separate this genus from the Plagiochilaceae, Harpanthaceae and Lophocoleaceae. The genera of the Harpanthaceae (sensu S. Arnell and Müller) represent the only discord found within a family, Harpanthus having mannitol, Saccogyna having another hexitol, possibly sorbitol, and Geocalyx with no polyols. Those of Plagiochila (volemitol, mannitol and a third one unidentified) are also present in Pedinophyllum and Leptoscyphus (L. cuneifolius (Hook.) Mitt.), suggesting that these genera belong in the Plagiochilaceae.

Mr M. F. V. CORLEY: 'Some taxonomic problems in the genus Campylopus.'

Several of the 12 British species of Campylopus are frequently mis-identified owing to their variability and to the unsatisfactory nature of most keys and descriptions. As a result of cultivating material of several species under uniform conditions, and examining much herbarium material, it has been possible to clear up some of these misunderstandings. Some of the most useful characteristics, notably those of the nerve section, have hitherto been neglected.

It was suggested that C. schimperi should be relegated to a variety of C. subulatus. Cultivation experiments showed that none of the varieties of C. flexuosus are genetically distinct. C. setifolius var. intermedius appears to be no more worthy of recognition than some other forms of the species which are not given varietal rank. It was found that two distinct forms of C. pyriformis occur, the typical form and a robust form growing on tussocks in bogs. It was suggested that the latter should be described as a separate variety.

Dr J. A. LEE and Dr G. R. STEWART: 'Intraspecific differences in desiccation injury in mosses.'

A number of species can be found growing in habitats which are subjected to widely different moisture stresses. Populations of these species from 'wet' and 'dry' sites were desiccated and the degree of desiccation injury assessed by measuring the decline in the rate of photosynthesis and the degree of recovery on remoistening. Populations of Acrocladium cuspidatum and Climacium dendroides from calcareous springs and flushes were less resistant to desiccation than populations from limestone grassland. The 'wet' populations showed a greater decline in photosynthesis and a smaller recovery on moistening than the 'dry' populations. Similarly, Hypnum cupuessiforme var. filiforme from tree bark was less severely affected by desiccation than the typical variety of the species from a woodland boulder. These differences were correlated with the degree of moisture stress in the two habitats.

Seasonal differences in the desiccation tolerance of populations of A. cuspidatum have been observed. Populations from the 'wet' sites are more tolerant in winter than in summer. However, the 'dry' site populations are more tolerant during summer than at other seasons. More information on seasonal aspects of desiccation tolerance is required before a more comprehensive picture can be built up.

Some of the metabolic effects of desiccation injury were outlined. In A. cuspidatum there is little evidence for a general inactivation of enzymes. The photosynthetic enzyme glyceraldehyde-3-phosphate dehydrogenase is, however, markedly affected and may be largely responsible for the observed decline in photosynthesis.

Miss A. L. D. SOUTHORN: 'Bryophyte colonization of burnt ground.'

It is apparent from the literature that certain species of bryophytes are found on burnt ground over a wide geographical range, the most notable of these being Funaria hygrometrica, Ceratodon purpureus and Marchantia polymorpha. Field studies at widely distributed sites in England showed that F. hygrometrica was characteristically the most abundant species on recently burnt ground, while C. purpureus together with Bryum argenteum and tuberous species of Bryum, commonly occurred as scattered shoots in the dense growth of F. hygrometrica. Burning resulted in changes in a large number of environmental factors, but the widely held view that changes in edaphic conditions are of primary importance in determining the presence of burnt ground mosses and their subsequent disappearance, was confirmed by field experiments. Culture on inorganic nutrient agar under controlled environmental conditions indicated that growth of F. hygrometrica was related to the level of nitrate nitrogen, provided that levels of other nutrients, particularly phosphorus, were adequate. Some correlation was found between these requirements and conditions in the soil after burning. Addition of inorganic nitrogen and phosphorus and other inorganic nutrients to unburnt soil, however, did not stimulate the growth of F. hygrometrica in the field or in greenhouse conditions. It is possible, therefore, that soluble organic substances, which are present in large quantities in burnt soil, may be important for growth under natural conditions. Alternatively, an inhibitor, which is destroyed during burning, may be present in unburnt soil preventing good growth of F. hygrometrica, although this is unlikely. It was suggested that the rarity with which Marchantia polymorpha was found on burnt sites may be related to the infrequency with which sporophytes were produced. In addition, it may require a moister habitat than the other burnt ground species.

After discussion, the President thanked the speakers, particularly Dr Lewis who had also acted as local secretary for the meeting.

In the evening members were invited to be guests of Professor Willis in the Department of Botany for a conversazione where a number of exhibits were shown. These included:
Mr J. R. COLLMAN: 'Principal components analysis of some herbarium material of the Drepanocladus aduncus group.'
Dr M, C. F. PROCTOR: 'Effects of desiccation on subsequent assimilation by Anomodon viticulosus and Porella platyphylla.'
Mr M. V. FLETCHER: 'Some bryophytes from the southern United States.'
Mr A. A. A. SULEIMAN,
Mr M. GADSDEN and
Dr D. H. LEWIS:
'Carbohydrates and photosynthetic products in leafy liverworts.'

On Sunday a party under the leadership of Dr O. L. Gilbert visited Padley Wood, an oak wood on millstone grit. A considerable number of species was found including Leptodontium flexifolium, Dicranum fuscescens, Bryum violaceum* (bare soil in turf, A.C.C.), Barbilophozia attenuata and Solenostoma crenulatum on boulders, and Atrichum crispum, Hygrohypnum ochraceum, Plagiothecium curvifolium and Hyocomium flagellare near streams.

[* new vice-county record]

A small party went to see the large stands of Discelium nudum which have recently been discovered at Ladybower Reservoir. Other species noted there included Dicranella schreberana, D. rufescens, Pseudephemerum nitidum, Pohlia bulbifera* (on exposed mud-flats, M.F.V.C. and J.A.P.), Bryum tenuisetum, Philonotis capillaris* (sandy slope exposed on shore, J.A.P.) and Scapania scandica* (heathy bank above west end, J.A.P.).

At Cressbrookdale moist, lightly-grazed grassland in the valley was remarkable for the great biomass of bryophytes it supported. A number of more uncommon species including Rhynchostegiella teesdalei, Thuidium recognitum, Porella cordeana and Ptilidium pulcherrimum were found under scrub, while the upper cliffs yielded Seligeria acutifolia var. longiseta and Trichostomum brachydontium var. cophocarpum.

G. C. S. CLARKE

 

 
 
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