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Meetings of the BBS - 2001

 

SPRING MEETING 2001

Tenerife, Canary Islands, 16-23 February

Photographs of the Tenerife Meeting

The archipelagos of northern Macaronesia (The Azores, Madeira and Canary Islands) have a fascinating and diverse flora, with habitats ranging from warm semi-deserts to wet evergreen broadleaved forests. With greater accessibility their bryophyte flora has become increasingly well-known in recent decades, but there is still more to discover.

The opportunity for the BBS to visit Tenerife, the largest of the Canary Islands, was due to Roy Perry’s generous offer to organise a week’s meeting from 16-23 February 2001. On a fairly large and diverse island such as Tenerife, Roy had the difficult task of packing a suitable programme of excursions into just six days of field work. This he did admirably well: we ranged widely over the island and visited a truly remarkable series of habitats.

Our base for the meeting was the tourist resort of Los Christianos, perhaps not the most obvious choice for a bryological meeting, but with plenty of accommodation and easy access to the road network. The participants in the meeting, in addition to Roy and Hilary Perry, were John Blackburn, Tom Blockeel, Gerard Dirkse, Uwe and Elena Drehwald, Gert and Elisabeth Mogensen, David Rycroft, Jonathan Sleath and Tony (A.J.E.) Smith. We were also joined on several days by Ana Losada-Lima of La Laguna University.

SATURDAY 17 FEBRUARY

Barranco del Infierno

Our first venue required only a short drive from Los Christianos to the village of Adeje and the Barranco del Infierno, at 300-600 m altitude. Barrancos in the Canary Islands are ravines and gorges of various sizes. The Barranco del Infierno is particularly grand and impressive; it is approached by a path along steep slopes with xerophytic vegetation characteristic of the lowland parts of southern Tenerife. We set out without Gerard Dirkse, whose arrival in Tenerife had been delayed by flight problems. The first part of the path, on south-facing slopes fully exposed to the sun, was devoid of bryophytes, but provided an excellent opportunity to become familiar with some remarkable flowering plants. Among these were the cactus-like clumps of cardon (Euphorbia canariensis), with its succulent columnar stems reaching a height of two metres or more, and the shrubby Euphorbia obtusifolia, Plocama pendula and Ceballosia (Messerschmidia) fruticosa. Even the convolvulus (C. floridus) and dock (Rumex lunaria) formed shrubs, and there was a strange scrambling asclepiadaceous plant Periploca laevigata. The first bryophytes found were mainly on slopes sheltered from the full effects of the sun. They included Crossidium crassinerve, C. squamiferum, Riccia gougetiana, and a Tortula which may be T. brevissima but raises questions about the separation of this species from T. muralis. A small water channel leading from higher parts of the ravine contained Philonotis rigida. After about 30 minutes walk, the path descends to the bed of the ravine and the walls begin to close in. A few isolated specimens of the famous dragon tree (Dracaena draco) could be seen high on the crags above. Along the bed of the ravine there were stands of the Canary willow (Salix canariensis), and we made our first acquaintance with the magnificent Canary bellflower (Canarina canariensis) with its large pendent orange bells. There were some further bryophytes: Grimmia laevigata on a boulder, Timmiella barbuloides c.fr. in the stream bed, and Frullania ericoides on a bank of soft rock. Tom collected an odd moss from the muddy path, which proved to be Chenia leptophylla. We were to see this species several times again during the week. It is evidently a fairly common weedy species on the island.

This barranco is one of the few places in southern Tenerife where there is running water for much of the year. The stream is a small one and it eventually peters out, but at the head of the ravine it forms a high waterfall which bars further progress. This is the type locality for the moss Platyhypnidium torrenticola, originally described in the genus Gradsteinia but now known to be related to Rhynchostegium (Platyhypnidium) riparioides. Having P. torrenticola in mind, we looked at the aquatic mosses in the stream at various points, and R. riparioides was present. When we reached the head of the ravine, there was some confusion about the precise whereabouts of the type locality for P. torrenticola. Some of us investigated a dripping cliff and found a small spiky pleurocarpous moss which turned out to be Rhynchostegiella teneriffae. A little further along, the rest of the party found the main waterfall and in it a large sheet of pleurocarpous mosses, accessible only by wading into the large pool below. Jonathan did the noble thing, waded in, and was rewarded with P. torrenticola. Subsequently it turned out that a moss collected by Tom from a small waterfall further down the stream was also P. torrenticola, so there is more than one population of the species.

During the walk back to Adeje we finally met Gerard Dirkse. Gerard’s knowledge of the local bryophyte flora was to prove invaluable to us during the meeting.

Arona

Our next stop was a brief visit to a small barranco at 600 m near the village of Arona. As this was a shallow, open barranco, the xerophytic flora was rather different from that at Adeje. It was not long before we found a fine patch of Gigaspermum mouretii on thin soil on a ledge, and there were a number of small Pottiaceae, including Tortula atrovirens (a species found in many subsequent localities), T. perlimbata (usually regarded as synonymous with T. solmsii), Didymodon australasiae, and further specimens of the moss resembling T. brevissima. Among the flowering plants, the strange Ceropegeia fusca (Asclepiadaceae) attracted attention.

Ifonche

The final venue for the day was another xerophytic site, but this time at a higher altitude (1040 m) at the edge of Canary pine (Pinus canariensis) forest near Ifonche. There is a shallow barranco here, the upper part of Barranco del Rey, with open pine woodland nearby. Some of us searched the barranco, which proved to be an excellent place for thallose liverworts and small Pottiaceae. Among the former, Exormotheca pustulosa and Targionia hypophylla were found on soil on a ledge, and Oxymitra incrassata, Riccia nigrella and the very hairy R. trichocarpa in the barranco bed. The Pottiaceae included Timmiella barbuloides, Tortula ampliretis, T. cuneifolia and a good quantity of Crossidium geheebii. Under the pine trees there were extensive sheets of Gongylanthus ericetorum. Pleurochaete squarrosa and Acaulon muticum s.l. were also found.

SUNDAY 18 FEBRUARY

Las Cañadas: Boca de Tauce

No visit to Tenerife is complete without a trip to Mt Teide and the Las Cañadas National Park. The Park occupies a large caldera, the floor of which lies at about 2000 m altitude. The rim of the caldera is incomplete, but in places reaches over 2500 m high. In the centre the cone of Mt Teide rises to 3715 m, much the highest point in the Canaries and indeed Macaronesia. The caldera is a subalpine volcanic desert. There are some relatively recent lava flows dating from the 18th century. Bryophytes occur primarily on hard rocks on north-facing slopes, in sheltered places, and in the few gullies where seepages and trickles of water emerge.

We approached the caldera via Vilaflor and through open forests of Canary pine. These forests on the south-facing slopes of Tenerife are very dry, and have only a sparse ground vegetation. The effects of past forest fires can be seen in places. Canary pine is unusual in being fire-resistant; the shoots sprout back again from the burnt trunks and branches.

Our first stop was at Boca de Tauce to examine the rocky slopes at 2050-2100 m on the approach to Mont. Gangarro. We hoped to see the endemic Grimmia curviseta here, with its distinctive gymnostomous capsules, and were delighted to find it almost immediately. Grimmia indeed was the most prominent genus on the rocks and boulders: we also saw G. laevigata, G. ovalis and a sterile species of the G. montana complex. Other mosses on the rocks included Syntrichia virescens, Schistidium flaccidum, Orthotrichum rupestre and, in deep crevices, Fabronia pusilla.

Barranco de los Riachuelos

While the rest of us were searching these rocks, Roy had a rendezvous at the visitor centre a little way along the road at the parador. There he discovered that as today was a Sunday there would be a manifestación (demonstration) on the road through the caldera. This has become a regular event each week; the demonstrations are in protest by hunters against the proposed elimination of mouflon from the park. The mouflon were introduced in the 1970s but have had a damaging effect on the native vegetation, which evolved in the absence of grazing ungulates. This meant a rapid change of plans for the day, and put an end to our own intended bryological manifestation at El Portillo on the other side of the Park. After some discussion, we decided to visit a barranco on the north side of the caldera wall, at the Fuente de los Riachuelos (2000-2100 m alt.). The Fuente is a spring giving rise to a small stream in the barranco, a rare phenomenon in the caldera. Initially we headed into the wrong barranco, and to find the spring some of us crossed over into the next ravine. The stream was duly found, and in it beds of sharp-leaved Carex paniculata subsp. calderae. There were a few bryophytes in and near the stream. Brachymenium notarisii with capsules was by a little waterfall, and there were some sterile Bryums. A trickling rock face had Rhynchostegium riparioides. Unexpectedly, in an excavated tunnel (dug for water catchment) we found Aulacomnium androgynum and Leptobryum pyriforme in quantity. The Aulacomnium was also found in a natural habitat among the roots of a small stand of Salix canariensis. Philonotis fontana was in another seepage area.

Vilaflor

In the early afternoon, after confirming that the road past the Mt Teide telerifico was indeed blocked, we made our way back down to Vilaflor. Tom was keen to search for xerophytes in the low-lying barrancos in the south-west of the island, and it was unlikely that we would have any further opportunities on subsequent days. We made a short stop just above Vilaflor during our descent, to look at the Barranco del Chorillo, a dry barranco in pine forest at 1450 m. Here we found good fruiting material of Fabronia pusilla in rock crevices, and a patch of Frullania on a rock face nearby. The latter was at first taken for F. ericoides, but it has a large stylus and appears to be a form of F. dilatata with spreading to subsquarrose dorsal lobes.

Barranco near El Guincho

The south-west part of Tenerife is being rapidly developed and the low-lying barrancos are under increasing threat. We visited one just off the autopista 1 km west-north-west of El Guincho, at 150 m alt. It was a bit squalid, with dumps of rubbish, but the flora was fascinating. Gerard almost immediately located Goniomitrium seroi on thin soil on the rock ledges. There were good quantities present, but frustratingly all of it was sterile. G. seroi has rhizoidal tubers, and their presence was later confirmed under the microscope. In one place the Goniomitrium was associated with Riccia trabutiana. Another interesting find was Crossidium davidai, which mimics and is easily passed over as tiny Tortula atrovirens. Under the little roadbridge across the barranco, there was some damp soil with nice rosettes of Riccia crystallina. On the same damp soil there was Tortula bogosica, associated with a tiny and as yet unidentified pottiaceous moss with distinctive lingulate leaves.

This was not Roy’s lucky day. Having already had to re-think the programme because of the manifestación in the National Park, he ended the day with a double puncture caused by a broken road edge on the way back from the barranco. Fortunately it was not far from the airport, and the necessary repairs were eventually accomplished.

MONDAY 19 FEBRUARY

El Pijaral

On this day we made the first of two trips to the Anaga peninsula. After two days in xerophytic habitats, the vegetation in this north-east corner of Tenerife was strikingly different. The peninsula is rugged and the mountains rise to an irregular crest with peaks exceeding 900 m. Cloud forming on the north-west side of the peninsula swirls over the summit ridges. The tops of the hills therefore are moist and humid, and support some fine areas of laurel forest (laurisilva). The laurisilva is evergreen woodland formed by several superficially similar trees from many genera in various plant families, including species of Ilex, Prunus, Heberdenia, Laurus, Persea, Ocotea and Picconia. Viburnum tinus subsp. rigidum is also widespread. At the upper edges of the forest, and especially on the ridges, tree heather becomes prominent, often accompanied by Myrica faya.

Anaga is a long drive from Los Christianos, but the journey is speeded by the autopista. Our route was via San Andres to El Bailadero. Tom’s car load, arriving with time to spare, stopped at 450 m on the way up to El Bailadero and found Exormotheca pustulosa, Mannia androgyna and Campylopus pilifer near the roadside.

The main excursion was to El Pijaral, a little to the north-east of El Bailadero. There is a path around the north-west side of the hill, through wet laurel forest at about 760 m. The entry point on the summit ridge leads through mixed woodland with Erica scoparia subsp. platycodon. We were immediately able to appreciate many of the characteristic epiphytic bryophytes, some of them in pendent masses; Neckera intermedia and Porella canariensis were abundant, and other species included N. cephalonica, Leptodon longisetus, Leucodon canariensis and Frullania teneriffae. In places there were masses of Plagiochila bifaria and a second Plagiochila resembling P. spinulosa but recently identified by David Rycroft and his collaborators as P. stricta. There were large Sonchus species (S. acaulis and S. congestus) along the way. As we moved into more sheltered parts of the forest, the canopy became more closed. The pathside banks supported numerous species: Atrichum angustatum, Fissidens serrulatus, F. curvatus (F. algarvicus), Eurhynchium meridionale, Rhynchostegiella trichophylla, Andoa berthelotiana, Telaranea nematodes, Jungermannia hyalina, Lophocolea fragrans and Lejeunea eckloniana. On tree boles there were some familiar Atlantic liverworts, including Plagiochila punctata and P. exigua, and also the moss Dicranum scottianum. A wet bank by the path had both Tetrastichium fontanum and T. virens growing in close proximity. A gully with a small stream was wet enough for Jubula hutchinsiae, and also had Heteroscyphus denticulatus. The tiny Aphanolejeunea sintenisii grew here as an epiphyte on other bryophytes (including Thamnobryum and Porella) and on fronds of Killarney fern (Trichomanes speciosum).

Further along we passed a steep crag with sheets of Radula jonesii. It also supported Myurium hochstetteri and small amounts of Marchesinia mackaii and Acanthocoleus aberrans. More familiar to most of us, but very rare on Tenerife, was Racomitrium aquaticum. Gerard was able to demonstrate Plagiochila virginica (P. dubia) on tree roots nearby. Eventually the path climbed back over the summit ridge through tall Erica, with Lepidozia cupressina in the ground flora. The very humid conditions on the ridge were demonstrated by the presence of epiphyllous liverworts. The commonest of these were Drepanolejeunea hamatifolia and Microlejeunea ulicina, but there were several others, including Colura calyptrifolia, Cololejeunea minutissima and Aphanolejeunea microscopica.

Chinobre

We moved from El Pijaral further along the peninsula to the recreation area ‘La Ensillada’ west of Chinobre. Ana directed us to a path through Erica scoparia woodland (at 810 m) where she had previously seen several Riccias. The visit was intended to be short one, but the path held our attention for over an hour. The Riccias were found, and included R. nigrella. Phaeoceros bulbiculosus was plentiful. Among the mosses were Anomobryum julaceum, Philonotis rigida with capsules, and Bryoerythrophyllum inaequalifolium with abundant axillary gemmae. Gerard found a few stems of Chenia leptophylla, and this prompted a close and prolonged scrutiny of the bare soil. Eventually we found further good material close to our starting point!

Mont. Paso: Barranco de la Iglesia

In the late afternoon we had time for a short visit to the upper parts of the Barranco de la Iglesia at about 850 m. This is an area of little-visited laurel forest on the steep slopes of Mont. Paso. Gerard and Tom disappeared quickly into the forest and eventually found a gully at the base of a large crag. The vegetation was dense and progress difficult. Additional species to those seen at El Pijaral included Homalia lusitanica on a boulder, Asterella africana growing with Jubula in a wet crevice in the gully, and Anthoceros caucasicus at the base of the crag. Filmy fern (Hymenophyllum tunbrigense) was present. A very interesting find on a moist lightly shaded rock near the base of the crag was Rhamphidium purpuratum, growing with Epipterygium tozeri. Higher up the gully there was some very robust Plagiochila exigua on rock, and Ulota calvescens on a twig. Meanwhile David found further material of Plagiochila stricta.

TUESDAY 20 FEBRUARY

Montaña de la Hoya

The fourth day of the meeting took us to the opposite side of Tenerife, in the vicinity of Santiago del Teide. We visited two very different habitats. The first locality was Montaña de la Hoya, a little to the south of Las Manchas, at an altitude of 1080-1100 m. We investigated the open rocky north-west-facing slope of the montaña, which was covered with a fine growth of the shrubby Euphorbia atropurpurea (in full flower) and Retama raetam. The bryophyte flora had a Mediterranean feel. There were large quantities of Riccia gougetiana and R. lamellosa, partly dried out but partly (in the shade of some of the larger crags) in moist, fresh condition, and then very distinctive. Riccia nigrella, R. crozalsii and Gongylanthus ericetorum were also found. The mosses included Cheilothela chloropus, Tortula cuneifolia, Crossidium squamiferum, Brachymenium notarisii, Bartramia stricta and Anacolia webbii. Gerard found a few stems of Syntrichia bolanderi at the edge of a path. By late morning, when we left the site, the sun had coaxed into flower the beautiful crocus-like blooms of Romulea grandiscapa.

Monte del Agua

The central ridge of Tenerife descends to the north-west corner of the island and terminates in the Teno Peninsula. From Montaña de la Hoya we drove north through Santiago del Teide across this ridge to our second venue, Monte del Agua, just west of Erjos del Tanque, at 1000-1050 m. Here there is a very fine tract of laurel forest on north-facing slopes. An earth road, winding but level, leads through the forest. The approach took us past a rock cutting with Ptychomitrium nigricans and Anacolia webbii. There was some Chenia leptophylla by the track. The laurel forest at this site is much drier than on the Anaga peninsula, and the undergrowth is less dense. Many of the characteristic laurisilva epiphytes were present, including Neckera intermedia, N. cephalonica, Leptodon longisetus, Frullania polysticta and Porella canariensis, and there were additional ones, including Cryphaea heteromalla, Pterogonium gracile and Ptychomitrium nigricans. The banks by the road were interesting, with Fossombronia angulosa, Cephaloziella turneri, Rhabdoweisia fugax, large quantities of Scapania compacta, and bewildering forms of Scleropodium tourettii. The forest road was also interesting; some of the characteristic species were now becoming very familiar, including Phaeoceros bulbiculosus, Riccia nigrella and Bryoerythrophyllum inaequalifolium. In the interior of the forest the bryophytes, especially the liverworts, were less prominent than at El Pijaral. They included Sematophyllum substrumulosum on a stump, Rhynchostegiella trichophylla on stones, and Cololejeunea schaeferi epiphytic on Porella on small rock outcrops. Gerard, Tom and David were keen to find Plagiochila virginica, previously recorded from here by Gerard. After prolonged searching they eventually found small amounts of it on the roots of laurel trees in a dry gully. During the search they also found Lophocolea fragrans, Homalia webbiana and Isothecium algarvicum. After such an excellent day the walk back to the cars in the late afternoon, to the sound of laurel pigeons taking flight in the forest, was very gratifying. An added bonus was a clump of the green-flowered orchid Gennaria diphylla on the roadside bank.

WEDNESDAY 21 FEBRUARY

Aguamansa

The Orotava valley penetrates the northern slopes of Mt Teide and the central ridge of Tenerife. In this area the effects of temperature inversion are particularly dramatic. The moisture-laden prevailing winds form cloud banks on the north- to north-west-facing slopes. They ascend the mountainside but are trapped by an upper layer of hot dry air. The road from Mt Teide into the Orotava valley overlooks the sea of cloud below, and the views are spectacular. The cloud banks also give this part of Tenerife a very different climate from the southern part.

We spent most of the day near Aguamansa, following the path above Los Organos, from the recreation area of ‘La Caldera’ to Roque de El Topo, at 1200-1400 m. The slopes are steep and are covered with Pinus canariensis forest and some Erica-Myrica woodland. The forest is much more humid than on the southern slopes of Mt Teide, and some of the trees are draped in pendent lichens. Initially we investigated the tracksides. Anacolia webbii occurred in remarkable abundance, and capsules were found. On and by the path we also noted Riccia crozalsii, Cephaloziella turneri, Funaria convexa, Entosthodon obtusus, Syntrichia bolanderi (with capsules), Bryum canariense, B. donianum and Anomobryum julaceum, as well as some of the common ruderal species seen on previous days. The path soon reaches steep woodland and crags. At one point there is a huge chasm in the rocks, on the floor of which was a stand of the strange rosaceous shrub Bencomia. We gradually accumulated a good list of bryophytes: Mannia androgyna, Fissidens curvatus (F. algarvicus), Syntrichia princeps, Tortula ampliretis, Anoectangium aestivum, Grimmia lisae, G. decipiens, Hedwigia ciliata, Leptodon smithii (on rock), Antitrichia californica and Isothecium algarvicum. There was a fine group of Orchis canariensis on a forest bank. At one point, in dense mist, we encountered a handrail at the side of the path. It was only when the mist cleared briefly that we realised we had just traversed a precipitous and vertiginous crag! The reward was Amphidium tortuosum (A. curvipes) in a damp cleft, and a fine stand of Antitrichia curtipendula, which we could compare with the A. californica found previously.

Roque Acebe

Our second venue of the day was at Roque Acebe, along the road from La Esperanza to El Portillo. It is at 2000 m, near the upper reaches of the pine forest, and is a known site for Andreaea heinemannii, indeed the only known locality for the genus on Tenerife. Roy had refound the Andreaea (originally recorded by Per Størmer in the 1950s) on a previous visit, but conditions had been poor and Roy was concerned that only small quantities might be present. In fact, we found it plentifully, at two nearby places on opposite sides of the road. This was a good place for Grimmiaceae, with (among others) Racomitrium heterostichum, Grimmia ovalis, G. curviseta, G. laevigata, G. montana, Schistidium flaccidum and S. confertum. Tortula inermis was also seen.

From Roque Acebe, we drove a few kilometres westwards for a roadside stop by some overhanging cinder depositions, at 2050 m, just west-north-west of Montaña de la Negrita. In the unusual habitat inside the overhang Leptobryum pyriforme and Funaria hygrometrica were plentiful, and there was a little Syntrichia bolanderi and some quantities of an unidentified concave-leaved Bryum.

THURSDAY 22 FEBRUARY

Llano de los Viejos

For the final excursion of the meeting, we returned to the Anaga peninsula and the laurel forests. We made a brief stop at Llano de los Viejos, at 780-800 m, north-east of Las Mercedes. This is now a recreation area, and the site is therefore disturbed and defaced by litter. Nevertheless there were some interesting bryophytes, including Chenia leptophylla (predictably) in the car park, Homalia webbiana and Fissidens taxifolius subsp. pallidicaulis. Both Lejeunea flava and L. canariensis were found near the bases of laurel trees.

Pista de las Hiedras

The main venue for the day was the laurel forest along Pista de las Hiedras to the west of Mont. Taborno. This pista is an earth road at 870 m. Initially, at the western end of the pista, the laurel forest was relatively dry, and we concentrated on the road edges and banks. We found many of the ruderal species that we had seen on previous days, but also saw Corsinia coriandrina for the first time during the meeting; Riccia crozalsii was also present. Further along we found a superb colony of Asterella africana in a damp hollow. There were some attractive flowering plants too, including Geranium canariense and purple cinerarias belonging to the genus Pericallis.

As we progressed along the pista the laurel forest became more varied, and there were some wet gullies. In these gullies were Heteroscyphus denticulatus, Plagiochila stricta, Jubula hutchinsiae, Fissidens coacervatus, Tetrastichium fontanum, Thamnobryum maderense, Rhynchostegiella macilenta, and a few clumps of Killarney fern (Trichomanes speciosum). Epiphytes in the laurel forest included Plagiochila bifaria, P. virginica (on the roots and bases of the trees), Frullania microphylla, Radula carringtonii, Marchesinia mackaii (also found covering an old concrete cistern) and Cololejeunea schaeferi. The upper parts of the gullies led to the summit ridge and some wet Erica-Myrica forest. In spite of the exotic trees, these woods had something of the feel of a western British oakwood, with clumps of Luzula (here L. canariensis), masses of Hypnum (much of it H. uncinulatum), Dicranum scottianum, Isothecium myosuroides, Scapania gracilis and Polytrichum formosum. Ulota calvescens was found in small quantity on Erica.

POSTSCRIPT

In all respects the meeting was a great success. At the time of writing not all of our specimens have been identified and some taxonomic problems remain. We were able to add new localities for several rare bryophytes on Tenerife (e.g. Rhamphidium purpuratum, Crossidium davidai and Tortula bogosica). We are particularly grateful to Roy for the time and trouble he took in organising the meeting and obtaining the necessary permissions. He managed the logistics of the meeting impeccably. We are also very grateful to Ana Losada-Lima for her support and assistance, and for joining us on several excursions.

TOM BLOCKEEL

 

SUMMER MEETING 2001

First Week : Lanarkshire

This meeting was originally planned as an exploration of Renfrewshire (VC 76) and Lanarkshire (VC 77), both relatively under-recorded areas. Due to the uncertainties caused by the foot-and-mouth outbreak, the meeting was seriously threatened, but with the reduction in restrictions by mid-summer, and the fact that the Skye meeting was still on, it was decided to compromise by having a shortened meeting based in Lanark. The location serves as useful stopping-off point for travellers from the south, and provides a good introduction to the Scottish flora.

The setting proved to be very convenient for exploring some of the rich woodlands associated with the Clyde Valley and also the upland landscape to the south. Three BBS members (Richard Fisk, Mark Pool and Sam Bosanquet) travelled up for the meeting and stayed at the base hotel together with myself; two others (David Rycroft and David Long) joined us for some of the days. All localities visited were in VC 77.

WEDNESDAY 1 AUGUST

Lower Nethan Gorge (NS8246)

The first session was gentle, as most of the participants had had long drives that morning; the four ‘residents’ were joined by David Rycroft. The wooded valley is a National Nature Reserve (NNR) owned by the Scottish Wildlife Trust, and is situated to the north-west of Lanark. The valley sides are steep, with a number of rock outcrops, and the riverbed is rocky. A good range of woodland species was found, including Neckera complanata, Homalia trichomanoides and Isothecium alopecuroides, with Amblystegium tenax by the water’s edge. Some of the rock exposures were dry and provided little of interest (although Seligeria recurvata was noteworthy). One of the more interesting epiphytic finds was Orthotrichum stramineum* by Mark. Access further up the riverbed was impeded by recent landslips, so we cut up to the path along the valley top; near here Sam found Riccardia palmata on a rotting log in deep shade. A microscope session after supper allowed comparison of Fissidens viridulus* and F. pusillus, collected from soil and inundated rocks respectively.

The short visit (afternoon only) resulted in nearly 100 records, and had more time been available to explore the upper valley the total would have undoubtedly increased. All in all though, it was an enjoyable start to the meeting.

THURSDAY 2 AUGUST

Culter Waterhead (NT0327 – NT0425)

The hills around Culter Water rise to 600 m and provide an ideal introduction to Scottish bryology. Under a threatening sky, David Long joined the four ‘residents’ and gave expert guidance throughout the day. After a typical BBS start examining the roadside and dam walls (Orthotrichum cupulatum, O. anomalum, Didymodon rigidulus, and Racomitrium elongatum* found on roadside gravel by David), we headed to some mud near one of the reservoir’s inflow burns. A mat of Dicranella rufescens and Archidium alternifolium* was interspersed with Fossombronia incurva, F. wondraczekii*, Riccia sorocarpa*, Pohlia flexuosa*, Ephemerum serratum var. serratum* and Climacium dendroides.

From the reservoir we climbed Snow Gill with the intention of reaching the blanket bog above in time for lunch. Base-rich flushes with Philonotis calcarea, Drepanocladus revolvens*, D. cossonii*, Dicranum bonjeanii and Leiocolea bantriensis* provided attractive features. The sides of the burn produced Scapania subalpina and lots of Anomobryum julaceum, and fine gravels or clays above supported Diphyscium foliosum* and Entosthodon obtusus*. Other finds included Bryoerythrophyllum ferruginascens*, Hedwigia stellata* and, on boulder scree, Grimmia donniana. The various Sphagnum species included S. teres and convincing S. russowii, with tattered notches to its stem leaves, but the ‘convincing’ S. warnstorfii, growing in a basic flush, later proved to be S. capillifolium.

During lunch we discussed the Splachnaceae and Sam promptly found Tetraplodon mnioides on a dead hare within five metres of where we were sitting, A relatively rich area of blanket bog, with frequent Sphagnum magellanicum and both Mylia species, produced several notable finds, including Hypnum imponens* and, more surprisingly, Dicranodontium denudatum*. Further east a small peaty bank supported Kurzia trichoclados*, and nearby David found Anastrophyllum minutum and Riccardia latifrons.

The burn we selected for our descent lay in a different tetrad and had a few rock outcrops and basic flushes. It produced more remarkable finds for the day. Bryum weigelii, with strongly decurrent leaves, was found in a flush, but of most note were rocky outcrops. Records here included fruiting Arctoa fulvella*, Gymnomitrion obtusum, Scapania aequiloba*, Jungermannia paroica*, Lejeunea lamacerina*, Fissidens osmundoides, Plagiobryum zieri* and Andreaea alpina, whilst a low waterfall supported fruiting Hygrohypnum eugyrium*.

The day was enjoyed by all and proved far more rewarding than any of us could have expected. A total of nearly 200 species was recorded, including over 20 new vice-county records!

FRIDAY 3 AUGUST

Near Shotts (NS8761)

After the rich pickings of the previous day, the final day commenced with fruitless searches for two rarities. Buxbaumia aphylla has been recorded from several pit bings (spoil heaps) near Shotts (east of Glasgow). David Long pointed out likely Buxbaumia habitat (the peatier areas on the bing sides where Calluna and Cladonia species were abundant), but unfortunately the moss appears to have gone from these bings. As compensation, finds included Blasia pusilla, Leiocolea turbinata and Calypogeia neesiana. A good area of raised bog, adjacent to the first bing, was searched for Sphagnum pulchrum, recorded some ten years previously by Keith Watson. The area was searched but the species was not refound (some recent severe fires may have taken their toll). However, a good range of typical bog species was seen, including Calypogeia sphagnicola* and Cladopodiella fluitans*.

Cleghorn Glen (NS8845)

The afternoon was more rewarding. We headed to another valley woodland, Cleghorn Glen NNR, just north of Lanark, where a good range of woodland species were noted, including Mnium stellare, Plagiothecium curvifolium*, Zygodon viridissimus var. stirtonii*, Z. rupestris, Neckera crispa*, Fissidens crassipes and Metzgeria conjugata*. The final species list reached 90.

POSTSCRIPT

We were all agreed that the short excursion had been most enjoyable. Most importantly, a very good range of species had been found, including some 30 new vice-county records! There are still plenty of upland burns and mires and deep, wooded valleys to be explored in the area. Hopefully, future excursions can be arranged in the area, and bryologists travelling north may decide to stop off and sample some of the delights and discover more new records in this attractive part of Scotland.

KEITH WATSON

Second Week : Skye

The week in Skye was split into two halves, the first based at the Toravaig Hotel on the Sleat Peninsula and the second at the Taigh Ailean Hotel in Portnalong. A total of 20 members attended the meeting: Frank Bentley (Saturday-Wednesday), John Blackburn, Tom Blockeel (Monday and Thursday), Sam Bosanquet (Saturday-Wednesday), Richard Fisk, Nick Hodgetts (local secretary), Frank Lammiman, Mark Lawley, David Long (Monday and Thursday), Sandra McLean (Saturday-Wednesday), Pete Martin, Sean O’Leary, Roy Perry, Mark Pool, Christine Rieser, Martin Robinson (Wednesday-Friday), Gordon Rothero (Sunday-Monday), Graeme Smith, Phil Stanley and Keith Watson (Saturday-Monday). We were also pleased to welcome Sid Clark, the photographer from the Royal Botanic Garden in Edinburgh who was accompanying David Long on a trip to photograph bryophytes, and Stephen Varwell and Alex Turner, two members of staff from the Portree office of Scottish Natural Heritage (SNH).

All excursions were in VC 104 (North Ebudes). In the following account, tetrads are indicated in the standard fashion, i.e. labelled A-N, P-Z within each 10-km square, with A being in the SW corner of the square and Z in the NE corner.

SUNDAY 5 AUGUST

Mudalach (NG72M, NG72S)

Roy and Phil decided to record on forestry tracks in the extensive afforested area west of Kyleakin while the rest of us went on to Mudalach itself (which is apparently not known by this name to the locals). Once we’d left the forestry track, the initial going was rough, and we had to pick our way over deep tussocks of Molinia on land ploughed for tree planting. A path eventually appeared beneath the pylons after a few hundred metres. As it turned out, this difficult route was unnecessary, since a path went round through the trees and would have led us to the same destination. We went back that way! At last we left the conifers and the woodland became more natural, with mainly birchwood in the swampy valley bottom leading to the beach at the head of Loch na Béiste, the rather open and young woodland continuing along the southern side of the loch. The swampy woodland had some interest, with much Sphagnum and masses of Frullania and Ulota, including U. drummondii. Heathy and rocky banks supported many typical western woodland species, including Hylocomium umbratum, Ptilium crista-castrensis, Lepidozia pearsonii and Kurzia trichoclados. Keith delighted many of us by finding a solitary Bog Orchid (Hammarbya paludosa) in a flush in an open area, with Lesser Twayblades (Listera cordata) lurking under the heather nearby. Sphagnum warnstorfii and S. molle also occurred in the flushes. Sam found two colonies of Leptoscyphus cuneifolius on birch trees and also recorded Cololejeunea minutissima. Many of the more widespread western and Atlantic species were also found, including Harpalejeunea molleri, Harpanthus scutatus and Plagiochila killarniensis (or P. bifaria as we must now call it).

By the loch the going became very steep and rather too difficult and dangerous for some of the party, so they stopped to have lunch and then worked their way slowly back, bryologising all the way. Radula aquilegia and Lophocolea fragrans were found on wet rocks just above high-water mark.

Gordon led the more tenacious forward party further round, reaching as far as the eastern tetrad of Mudalach, and was rewarded with further species, such as Colura calyptrifolia, Harpalejeunea molleri and Cololejeunea calcarea. Acrobolbus wilsonii, recorded here previously by Ben Averis, was unfortunately not refound. A colony of Trichostomum hibernicum was found a little further up the hillside.

MONDAY 6 AUGUST

Ben Aslak (NG71P, NH71U)

A large party met on the road through Glen Arroch near the bealach, and drove to the end of a long forestry track, courtesy of Forest Enterprise, who had lent us the key to the padlocked gate. The target for the day was the long cliff on the north side of Ben Aslak, known to be rich in Atlantic bryophytes. As soon as we got out of the cars (having spent some minutes turning them round for a quick exit later!) Tetraplodon mnioides was spotted on the gravel of the track.

To begin with, we climbed steadily over boggy acid ground typical of Skye, with plenty of Sphagnum, Campylopus atrovirens and Pleurozia purpurea, but little else to detain us. However, Frank and Christine continued to record in this area, adding Ditrichum heteromallum and several species of Sphagnum and Scapania to the day’s list.

The first crags encountered were mainly acidic, with Gymnomitrion obtusum, G. crenulatum, Douinia ovata, Hedwigia stellata, etc. Further on, contouring round towards the north-facing cliffs, we encountered some distinctly base-rich flushes with Calliergon sarmentosum, Scorpidium scorpioides and even a little C. trifarium.

The crags just east of these flushes were quite strongly base-rich, with Antitrichia curtipendula and Anoectangium aestivum. The cliffs became richer and richer as we went east, with Herbertus aduncus subsp. hutchinsiae in huge cushions and lots of Bazzania tricrenata and Plagiochila carringtonii. Mastigophora woodsii, Herbertus stramineus and Dicranodontium uncinatum were also present. Gordon found a number of colonies of Campylopus setifolius, and went into monitoring mode, marking and photographing them. A fair amount of Paraleptodontium recurvifolium was also found, mainly as scattered shoots among other bryophytes on the ledges. Gordon and Sam found Trichostomum hibernicum in flushes.

Further species were added as we progressed along the cliffs, including several montane calcicoles, such as Ctenidium molluscum var. condensatum, Plagiothecium denticulatum var. obtusifolium and Isopterygiopsis muelleriana. Ditrichum zonatum, Arctoa fulvella and Marsupella adusta were found in high rock crevices. Meanwhile Tom, David and Sid had walked over the top of the hill to reach a section of the cliffs further east, adding Hypnum hamulosum, Orthothecium rufescens, Amphidium lapponicum, Scapania ornithopodioides and Bazzania pearsonii to the list. The summit ridge was also not without interest, and David recorded Campylopus gracilis.

Kinloch Lodge (NG71C)

Some of us stopped at the woods at Kinloch Lodge on the way back to the headquarters hotel to see Plagiochila atlantica. The known colony was duly refound and then Gordon found a much more extensive ‘new’ colony near the path! Several other typical Atlantic woodland species were also seen, but this was really just a flying visit at the end of the day and no systematic recording was done.

TUESDAY 7 AUGUST

Soay (NG41)

The group split on this day, with some opting to visit the Torridonian sandstone island of Soay off the west coast of Skye, and the rest visiting Durness limestone sites in the Strath Suardal area. After the first group (the majority) arrived at Elgol, David immediately found Myurium hochstetteri behind the sheds at the jetty while waiting for the boat. The rest of us visited it later in the afternoon.

We climbed (over another boat, which was being painted) into the Kaylee Jane, operated from Soay by Gordon the boatman, and had a pleasant 20-minute trip to the island, with Manx shearwaters skimming the waves nearby along with the odd arctic skua. We disembarked in two groups via a small landing craft.

On arrival we decided to split into two groups, one covering the smaller but higher north-eastern half of the island, the other the slightly larger but lower south-western half. Both groups also recorded to some extent in the narrow central glen connecting the two halves. Here the ground is much more sheltered, with some development of woodland. The only occupied houses on the island are in this central area.

The north-eastern party soon found an excellent bog with Sphagnum austinii, S. fuscum, S. subsecundum* and Cladopodiella fluitans, and continued on to the wooded northern side. This had good oceanic communities, with Aphanolejeunea microscopica, Colura calyptrifolia, Drepanolejeunea hamatifolia, Harpalejeunea molleri, Plagiochila killarniensis and Hylocomium umbratum. David found Lophozia obtusa on a bank, and Sam recorded Tritomaria exsecta on rotting wood. Other species here included Herbertus aduncus subsp. hutchinsiae, Ptilium crista-castrensis, Dicranodontium uncinatum and Dicranum scottianum. Mark Lawley nobly split from the party to record the most remote tetrad on the northern tip of the island and found plenty of interest, including Anastrophyllum minutum, Weissia perssonii and, on the way there, Lophozia longidens* on a birch.

The second party went through woodland in the central glen, and then on to sandstone ravines on the north coast and back over moorland. They found a similar selection of Atlantic species in the central glen to that found by the north-eastern group. Cephalozia catenulata was found twice on peaty banks. More Sphagnum fuscum was found in the boggy moorland in the centre of the south-western part, and S. molle was also recorded. A single colony of S. strictum was located after considerable searching. Although widespread in VC 104, this species is by no means common. Mark Pool found Riccardia latifrons.

The large amount of Harpanthus scutatus, generally rather a rare species on Skye, seems to be a feature of the island: it was found in abundance on sheltered rocks in a number of places. Just before leaving, Mark Pool found Ulota hutchinsiae near the point of embarkation.

Strath Suardal (NG62)

The other group, consisting of John, Richard, Frank and Christine, explored the Durness limestone in the Suardal area near Torrin. Most of the characteristic calcicoles were seen, and Colura calyptrifolia was found on rocks in a stream. The party also visited the magnificent colonies of Campylopus shawii growing in flushes at Camas Malag near Torrin; one carload of the Soay party also made a detour to see these on the way back to the hotel. Roy and Phil also visited this area, finding Orthothecium intricatum on the south-west slopes of Strath Suardal. Sphagnum skyense was searched for at its type locality but not refound. The locality has now been visited by a number of bryologists over the years but the plant has not been seen since the type collection in 1987.

WEDNESDAY 8 AUGUST

Sligachan area (NG42)

The plan was to have a relatively easy day after the exertions of the last three days. We started in the bogs behind the Sligachan Hotel, but did not reach the best ground. Indeed, the morning was a little disappointing, with little of note except Cladopodiella fluitans and Sphagnum strictum to be found on the bog, the latter recorded by Roy. Sphagnum molle was also collected, and Mark Lawley found Hedwigia ciliata var. ciliata* on a rock nearby. Frank found some Sphagnum pulchrum, but we missed the principal site for this species. Pipewort (Eriocaulon aquaticum) was the main excitement, growing in some of the lochans in the bog. We had an early and leisurely lunch in the sunshine outside the Sligachan Hotel and refound Glyphomitrium daviesii where Mark Pool had seen it ten years before. Campylopus shawii was also seen growing in flushes near the river, although it was relatively poor material compared with the magnificent colonies at Torrin. Mark Lawley collected Fossombronia foveolata from the riverside.

Allt Grillan (NG43A, NG43F)

Those of us who were making our way towards Portnalong for the second part of the week stopped near the turn-off to Carbost to survey the Allt Grillan, a small ravine woodland with some base-rich exposures that SNH had asked us to visit. It is a Site of Special Scientific Interest for its vascular plant communities but was unknown for bryophytes. It turned out to be a superb little ravine with most of the typical Atlantic Lejeuneaceae (including Drepanolejeunea hamatifolia, Harpalejeunea molleri and Aphanolejeunea microscopica), Cololejeunea calcarea, Radula aquilegia, Ulota calvescens (on hazel), U. drummondii, and magnificent hanging brackets of Metzgeria leptoneura. Three small colonies of Radula voluta were seen on damp rocks by the stream, rather miserable-looking material but here growing at the most northerly site yet discovered for this species. More than 120 species were recorded in total.

THURSDAY 9 AUGUST

Sgurr a’Mhadaidh Ruaidh (NG45U)

Perhaps the most spectacular day of the meeting was spent right in the middle of the Trotternish Ridge. Sgurr a’Mhadaidh Ruaidh is less well-known than the Storr or the Quiraing but its bryophyte flora is at least as good as either. We had to drive down a long rough track from Lealt to reach the site, past (or through) such obstacles as a flock of sheep being sheared, rocks and deep puddles, but all the cars made it. The whole day was then spent exploring the cliffs and coires above. The loose basalt rock of the area is highly treacherous, and there were times when I feared for the safety of the party as we scrambled up the steep scree and felt it slipping from beneath our feet. Fortunately there were no casualties and we soon found some of the area’s characteristic bryophytes, which include many arctic-alpine species growing here at a relatively low altitude. These included Encalypta alpina, E. ciliata, E. rhaptocarpa, Amphidium lapponicum, Myurella julacea, Hypnum hamulosum, Tortula subulata var. graeffii, Mnium thomsonii, Eremonotus myriocarpus, Jungermannia borealis, Molendoa warburgii, Plagiothecium cavifolium, Eurhynchium pulchellum var. diversifolium, Isopterygiopsis muelleriana, Anthelia juratzkana, Didymodon icmadophilus, Bryoerythrophyllum caledonicum, and several independent finds of Timmia norvegica. Anoectangium aestivum was seen with capsules, rather a rare sight.

Atlantic species were well represented among the rocks, with Mastigophora woodsii, Metzgeria leptoneura, Glyphomitrium daviesii, Scapania ornithopodioides and Dicranodontium uncinatum. Jungermannia subelliptica and Plagiochila britannica were also found. Perhaps the ‘star find’ of the day was Bryum arcticum*, found by Tom in a rock crevice high on the cliffs, the first British record of this rare species since the 1960s. A number of specimens collected from the site remain to be determined. Unknown to us, Hamatocaulis vernicosus was lurking in the wet ground near Loch Cuithir, waiting to be found by Sandy Payne later in the year!

The vascular plants were good too. There was more Alpine Saxifrage (Saxifraga nivalis) here than most of us had ever seen, and Moonwort (Botrychium lunaria) on the grassy slopes near the track was another bonus. Sean found a small stand of Alpine Woodsia (Woodsia alpina), which caused quite a stir.

Sam, who had left us by this time, had visited the Storr earlier in the week and come up with two sites for Scapania gymnostomophila, as well as S. aequiloba and Eremonotus myriocarpus.

FRIDAY 10 AUGUST

Rubha Hunish (NG47C, NG47D)

Our final day, with a considerably reduced number of participants, was spent at the extreme northern tip of Skye, where we hoped to see some more Myurium. It turned out to be a spectacular day from a scenic point of view. The weather was lovely, and the views from the top of the cliffs and from the extreme tip of the peninsula over to the Outer Isles, with gannets dive-bombing in the foreground, were truly magical. As for the bryophytes, we found a number of things on the walk in. A bog in the narrow glen below Meall Tuath had a variety of Sphagnum species and Cephalozia pleniceps, and the open moorland contained Splachnum ampullaceum with very strongly toothed leaves (one member was convinced he had discovered a new species!), the distinctive Campylopus atrovirens var. falcatus and much Glyphomitrium daviesii on the rocks. Grimmia funalis also grew on rocks in the area. Earlier in the week David and Sid had visited the site and found Hedwigia ciliata var. ciliata* on exposed rocks at the top of the cliffs but this was not refound.

There was some nice vegetated boulder scree on one of the cliffs above the peninsula, with much Colura calyptrifolia on the heather stems. An extensive mass of Myurium hochstetteri was found growing in a gully in the cliff above the scree, and there were smaller colonies scattered elsewhere. The peninsula itself was rather dull, being too windblown by salt-laden gusts to have much in the way of bryophytes. There was some species-poor bog in the middle of the peninsula, where some of us puzzled over a thalloid liverwort for some time before concluding that it was nothing more than atypical Pellia epiphylla. Indeed, many of the bryophytes here looked odd, presumably because of the saline influence. ‘Interesting’-looking Sphagna all turned out to be S. subnitens, S. flexuosum or S. inundatum, and scruffy pleurocarps were Campylium stellatum var. protensum, Warnstorfia fluitans and W. exannulata. Much of the Campylopus in the area was C. brevipilus. The rocks above the shore had little except for Ulota phyllantha and Schistidium maritimum, but small colonies of Weissia perssonii and Tortella flavovirens were also found.

Archidium alternifolium was seen on bare ground by the path back to the cars.

OTHER LOCALITIES

In addition to the arranged sites, most members managed to visit the well-known Acrobolbus wilsonii site near Broadford at one time or other during the week, with Roy finding a new stand of Acrobolbus there. A number of other sites not on the official programme were also visited, notably by David and Sid (who were after photographs), Roy and Phil (who were based in Portree for the week and so often went their own way), and Frank and Christine (who did some useful ‘extracurricular’ recording in Tokavaig Wood and Glen Brittle). David had more Sphagnum subsecundum from the Black Lochs south-east of Skulamus, and several members also visited this site independently to see S. pulchrum. Perhaps the most astonishing record of the week was Dicranum subporodictyon*, found by David on wet sloping rocks at Eas a’Bhradain (the Robbers’ Falls). This is a well-known tourist spot and bryologists must have passed it by many times without being aware of the Dicranum!

The week was most enjoyable - even the local secretary started to enjoy it after about Wednesday! - and the weather was remarkable for Skye in August, with a significant amount of rain falling only on Monday. The clouds gathered again the day after the meeting closed and the following week was dreadful! Many useful records were made, which will contribute significantly towards an eventual tetrad Flora of Skye, and several taxa new to the vice-county were found. There are still a number of specimens that have so far defied identification, some of which may turn out to be interesting.

ACKNOWLEDGEMENTS

I would particularly like to thank Stephen Varwell and Alex Turner (the local SNH officers at the Portree office) for all their help in arranging access permission and providing much useful information, John Birks for providing information on Soay, Duncan Geddes for granting permission to visit the island, and Gordon the boatman for taking us there. Thanks are also due to the proprietors and staff of the Toravaig Hotel and the Taigh Ailean Hotel for their excellent service and hospitality.

NICK HODGETTS

 

AGM AND SYMPOSIUM MEETING 2001, CARDIFF

FIELD EXCURSION TO WYNDCLIFF AND GREAT BARNET’S WOODS



JAN KUCERA (UNIVERSITY OF SOUTH BOHEMIA, CZECH REPUBLIC): TAXONOMIC PROBLEMS AND FINDINGS IN THE EUROPEAN SPECIES OF DIDYMODON, PARTICULARLY THE D. RIGIDULUS GROUP

The genus Didymodon in its present concept (Zander, 1993) is a moderately large genus (ca 120 species) within the largest moss family (the Pottiaceae). The delimitation of the genus has been subject to considerable recent changes, following the revolutionary concepts of Saito (1975), in which emphasis was for the first time given to gametophyte characters.

The European members of the informal Didymodon rigidulus group comprise the taxa described as D. rigidulus Hedw., Grimmia andreaeoides Limpr. (=D. rigidulus subsp. andreaeoides (Limpr.) Wijk & Margad.), D. glaucus Ryan, Eucladium verbanum W.E. Nicholson & Dixon (=D. verbanus (W.E. Nicholson & Dixon) Loeske), Tortula acuta Brid. (=Didymodon acutus (Brid.) K. Saito), D. validus Limpr., Barbula icmadophila Schimp. ex Müll. Hal., and B. mamillosa Crundw. These taxa were subjected to a complex taxonomic treatment in the course of my PhD studies. The taxonomic methods involved herbarium study, statistical evaluation of quantitative characters, and isozyme analyses.

From the eight intensively studied taxa in the D. rigidulus group, three were discovered not to have a close relationship with D. rigidulus. They are D. glaucus, D. verbanus and Grimmia andreaeoides; the latter was found to be conspecific with the North American D. subandreaeoides (Kindb.) R.H. Zander. Both D. glaucus and D. subandreaeoides merit specific status. Their differences from D. rigidulus are well illustrated by a number of qualitative and quantitative characters, including species-specific zymogram patterns in some isozyme systems. D. verbanus is also specifically distinct from D. rigidulus, but its relationship to D. glaucus has not been fully elucidated. Both taxa are to a great extent distinct in some qualitative and quantitative characters, but they could merely be geographically segregated male and female populations of the same taxon. On the other hand, several other explanations are possible, and so it seems appropriate to distinguish D. verbanus as a species, until more information is available.

D. mamillosus was found to fall within the range of variation of D. rigidulus in all of its characters. D. validus is the taxon with the closest relationship to D. rigidulus, based on the shared qualitative characters (occasional presence of axillary gemmae and identical leaf costa anatomy), and forms transitional to D. rigidulus occur in the centre of its distribution. Plants which are not fully developed are also extremely difficult to distinguish from D. acutus.

D. acutus is regarded as specifically distinct from D. rigidulus. Its distribution is suspected not to extend substantially beyond the European subcontinent, and difficulties in distinguishing this taxon from D. rigidulus in America seem to be caused by the occurrence of other minor taxa of the D. rigidulus group, similar but not identical to D. acutus.

D. icmadophilus is also undoubtedly specifically distinct from D. rigidulus, as shown by the presence of species-specific patterns in several isozyme systems. Mixed stands of the two species have also been found. There are obvious sporophyte differences but fertile material of D. icmadophilus has been found very rarely. No stable distinguishing gametophyte characters could be found during my studies. Barbula abbreviatifolia was shown to be a synonym of D. icmadophilus.

Studies indicated the possible existence of another taxon, extremely closely related to D. rigidulus, in the western Mediterranean area, but the variability of this taxon has to be studied with respect to other Holarctic taxa close to D. cordatus Jur. and D. rigidulus.

Despite my studies, several taxonomic problems remain in both the D. rigidulus group and several other informal groups. Molecular studies are needed to clarify the status of D. validus with respect to D. rigidulus and D. acutus. The same applies to the distinction between D. icmadophilus and D. acutus; between D. verbanus and D. glaucus; between D. insulanus (De Not.) M.O. Hill, D. bistratosus Hébr. & R.B. Pierrot, and D. vinealis (Brid.) R.H. Zander; and between D. maximus (Syed & Crundw.) M.O. Hill and D. giganteus (Funck) Jur. One or two additional taxa may still remain to be described within the D. rigidulus group in the Mediterranean area, particularly with respect to D. cordatus. Several little-known taxa have to be newly evaluated, e.g. D. incrassatus (Lindb.) Broth., D. lamyanus (Schimp.) Thér., and D. tomaculosus (Blockeel) M.F.V. Corley. The types have to be located for several ‘forgotten’ taxa, such as D. barbulae Wibel ex Roem., D. barbuloides Lib. ex Marchal, D. camusii Husn., D. soaresii Luisier, and D. tenellus R. Hedw. ex Brid.; it is anticipated that they will be synonymised with other European taxa.

References

Saito K. 1975. A monograph of Japanese Pottiaceae (Musci). Journal of the Hattori Botanical Laboratory 39: 373-537.

Zander RH. 1993. Genera of Pottiaceae: mosses of harsh environments. Bulletin of the Buffalo Society of Natural Sciences 32: 1-378.



JONATHAN SLEATH (HEREFORD): BBS FIELD EXCURSION TO TENERIFE, 2001

A dozen or so bryologists met on the island of Tenerife in February 2001 for a week in the field, organised ably by Roy and Hilary Perry. The meeting was most successful; a great variety of fascinating habitats was visited and we saw many interesting plants, including a good number of Macaronesian endemics. A slide presentation was given to illustrate some of the species seen and localities visited. An account of the meeting has been written for the Bulletin by Tom Blockeel (see pp 3-11 of this issue).



DR DAVID S. RYCROFT (UNIVERSITY OF GLASGOW): PLAGIOCHILA IN EUROPE (AND BEYOND)

This paper reports progress in the three years since the 1998 BBS Loughborough meeting . It looks at aspects of Plagiochila in Britain, Europe and Macaronesia, but, as the title implies, it is also necessary to take account of the situation further afield. The topics covered include evidence relating to the presence in Macaronesia of Pbifaria (Sw.) Lindenb., Pdubia Lindenb. & Gottsche and Pspinulosa (Dicks.) Dumort., to the synonymy of Pkillarniensis Pearson and Pbifaria, and to the systematic position of Patlantica F. Rose. Much of the work has involved others (who are cited along the way) and I wish to acknowledge particularly close collaboration with Jochen Heinrichs (Göttingen), much facilitated by the tremendous benefits of electronic mail.

Madeira

A Plagiochila from Madeira mentioned at the 1998 Loughborough meeting (Drehwald 960277, initially identified as Pkillarniensis) was found in two locations during a holiday in 1999, and has been determined as the Neotropical P. retrorsa Gottsche, along with material from Costa Rica that had been the subject of a chemical investigation . The discovery that the Southern Appalachian endemic P. sharpii H.L. Blomq. is synonymous extends the Central American and Macaronesian distribution.

A different Madeiran Plagiochila is likely to be mistaken for P. spinulosa, but has features (including more teeth, a smooth cuticle and a chemical profile with a large amount of 4-hydroxy-3´-methoxybibenzyl) that distinguish it. So far, no existing name has been found. This taxon may be found readily on the northern side of Madeira; it occurs less frequently than P. bifaria but apparently much more frequently than P. retrorsa.

Tenerife

During the BBS meeting organised by Roy Perry on Tenerife in February 2001, five Plagiochila taxa were observed, of which two were of particular interest. First, Gerard Dirkse demonstrated a taxon that had been determined as P. dubia. This taxon, from the Neotropics, was treated recently by and, following further work, has been synonymised with P. patula (Sw.) Lindenb. . The Neotropical taxon has leaf margins that are long-decurrent ventrally, whereas those of the taxon from Tenerife (and Madeira) are short-decurrent. We now find that the Macaronesian taxon agrees with the type of the North American P. virginica A. Evans; analysis of internal transcribed spacer (ITS) sequence variation of nuclear ribosomal (nr) DNA supports assignment to sect. Contiguae Carl .

The second Plagiochila has been regarded as Pspinulosa, but it has characteristics that distinguish it from that taxon as it is known in the British Isles: the odour of the crushed leaves is more spicy, the leaf insertion is more vertical, and the leaf cuticle is rougher. In addition, the shady, tending to dank, habitat where it was to be found, associated with species such as Trichomanes speciosum Willd. and Heteroscyphus denticulatus (Mitt.) Schiffn., was atypical of the haunts of Pspinulosa in the British Isles. The monoterpenes responsible for the odour are principally ocimenes (mainly alloocimene and neoalloocimene), compounds named after Ocimum basilicum L. (sweet basil). In contrast, the principal monoterpene in Pspinulosa is b -phellandrene . Ocimenes have not been reported previously from Plagiochila, but we have observed them in extracts of Pstricta Lindenb. from Costa Rica and Ecuador. The chemical profiles of these extracts were also similar to those from the Tenerife taxon with respect to the other components (including 9,10-dihydrophenanthrenes). Morphological comparison confirmed that the Tenerife taxon is Pstricta. Preliminary phylogenetic analysis of ITS sequence variation of nrDNA shows that examples of Pstricta from the Neotropics and Tenerife are closer to each other than they are to Pspinulosa .

In other systems, such as those of Mentha species, it is generally thought that a single enzyme is responsible for converting the precursor molecule (geranyl pyrophosphate) to a monoterpene product. If this scheme also applies to liverwort systems, then observation of a different monoterpene in Pstricta compared to Pspinulosa suggests the presence of a different enzyme, rather than switching off of part of a pathway so that one product builds up at the expense of another that would normally be formed further down the pathway.

Azores

At the time we were finishing work on Pretrorsa, we heard from Rosalina Gabriel of a Plagiochila that had been collected by Dias on Pico in 1992 and noticed by Sjögren in the herbarium AZU in 1999. Although the chemical profile was similar to that of Pretrorsa, the leaf cuticle was rough, and the plant matched the types of Ppapillifolia Steph., Pdeciduifolia Steph. and Psolmsii Steph., all collected by Herzog at Comarapa, Bolivia, in 1911; a further synonym is Pverruculosa R.M. Schust. . P. papillifolia can therefore be added to the Macaronesian flora.

Recently, the Azorean endemic Pallorgei Herzog & Perss. was found to be synonymous with the Neotropical Plongispina Lindenb. & Gottsche . It has been established that the blue colour of the stem tips of this species (at least in the Neotropics) is caused by the presence of oil bodies that contain 1,4-dimethylazulene, the blue compound that also occurs in the oil bodies of Calypogeia azurea Stotler & Crotz.

British Isles (and Europe)

Evidence that Pnorvegica H.H. Blom & Holten and Pporelloides (Torrey ex Nees) Lindenb. are very close genetically has been provided by Cronberg , who observed no difference in isozyme banding patterns between the two taxa; in contrast, Pasplenioides (L. emend. Taylor) Dumort. showed several differences. Pnorvegica should be placed in sect. Plagiochila.

The plagiochilines (T and U) that we reported from Scottish material of Pcarringtonii (Balfour) Grolle suggested a systematic position close to sect. Plagiochila. We have now observed the same two plagiochilines in extracts of subsp. lobuchensis (leg. D.G. Long) from Sikkim and Nepal; the close relationship of the two taxa is supported.

Three years ago there was no chemical evidence to support the synonymy of P. killarniensis and P. bifaria . Now, however, there is: a specimen from Ecuador (collected in 2001, Holz EC-01-416, GOET) that is close morphologically (teste Heinrichs) to the type of P. bifaria from Jamaica has a very similar chemical profile to that of a specimen (Rycroft 00051) from the type locality of P. killarniensis, above the Torc Cascade. The methoxyl region of the proton NMR spectra illustrates vividly that the ratios of three of the characteristic compounds (methyl everninate, killarniensolide and methyl 6-methoxy-2-methyl-3,4-methylenedioxybenzoate) in the two extracts are extremely similar to each other and to those published .

In 1975, Eustace Jones and Francis Rose presented an exhibit entitled ‘The mystery of Plagiochila ambagiosa solved’ at the BBS Conversazione in Reading; a long-standing taxonomic problem had indeed been solved, but the systematic mystery remained. Our chemical studies of Patlantica showed that the chemical profile was dominated by plagiochiline C, and that a new bicyclogermacrenol derivative, that we named ‘atlanticol’, was present as a minor constituent . In connection with other work, we examined the extract of a specimen of Paerea Taylor from Costa Rica and observed an extremely similar chemical profile; not only was plagiochiline C dominant but atlanticol, the compound hitherto unique to Patlantica, was also present. Paerea, the type species of Plagiochila sect. Bursatae Carl, is one of the few members of the Plagiochilaceae that are characterised by the presence of leaf surface waxes . The obvious investigation was undertaken, and waxes were duly observed on leaves of Patlantica using scanning electron microscopy . Our results indicate that Patlantica has close relatives in sect. Bursatae of the Neotropics.

Conclusion

Five taxa (Ppapillifolia, Pretrorsa, Pstricta, Pvirginica, and the Madeiran indet.) have been added to the recorded Plagiochila flora of Macaronesia since 1999, and one, Pdubia, has been deleted. The position with respect to Pspinulosa requires further investigation. There are now several species linking the Plagiochila floras of the Neotropics and Europe (including Macaronesia).

The recent check-list of hepatics for Europe and Macaronesia includes 14 Plagiochila species in seven sections, four being those of Carl . Ten of these species, in five sections, occur in the British Isles. Now, only one year on, the species tally is 16. Chemically, there is a division between those that contain 2,3-secoaromadendrane sesquiterpenoids and those that produce aromatic (in the chemical sense, i.e. benzenoid) compounds. The chemical division accommodates the morphologically-derived sections: sect. Plagiochila (P. asplenioides, P. britannica, P. porelloides; P. arctica and P. norvegica are included here but have not been studied chemically), sect. Carringtoniae Inoue (P. carringtonii), sect. Bursatae (P. atlantica), and sect. Contiguae (P. virginica) have 2,3-secoaromadendranes; sect. Arrectae Carl (P. bifaria, P. punctata, P. retrorsa, P. spinulosa, P. stricta), sect. Bidentes Carl (P. exigua (Taylor) Taylor and, tentatively, P. papillifolia), and sect. Glaucescentes (P. longispina) have aromatic compounds. Analysis of ITS sequence variation in nrDNA is proving to be a useful tool in understanding these relationships.

References

Anton H, Kraut L, Mues R, Morales Z MI. 1997. Phenanthrenes and bibenzyls from a Plagiochila species. Phytochemistry 46: 1069-1075.

Blomquist HL. 1940. Another new species of Plagiochila from the Southern Appalachian Mountains. Bryologist 43: 89-95.

Carl H. 1931. Die Arttypen und die systematische Gliederung der Gattung Plagiochila Dum. Annales Bryologici, Supplementary Volume 2: 1-170.

Cronberg N. 2000. No difference in isozyme banding patterns between Plagiochila porelloides and P. norvegica. Lindbergia 25: 17-19.

Grolle R, Long DG. 2000. An annotated check-list of the Hepaticae and Anthocerotae of Europe and Macaronesia. Journal of Bryology 22: 103-140.

Heinrichs J, Anton H, Gradstein SR, Mues R. 2000a. Systematics of Plagiochila sect. Glaucescentes Carl (Hepaticae) from tropical America: a morphological and chemotaxonomical approach. Plant Systematics and Evolution 220: 115-138.

Heinrichs J, Anton H, Gradstein SR, Mues R, Holz I. 2000b. Surface wax, a new taxonomic feature in Plagiochilaceae. Plant Systematics and Evolution 225: 225-233.

Heinrichs J, Anton H, Holz I, Gradstein SR. 2000c. On the blue stem colour in Plagiochila longispina Lindenb. & Gottsche (Plagiochilaceae). Cryptogamie, Bryologie 21: 109-111.

Heinrichs J, Gradstein SR. 2000. A revision of Plagiochila sect. Crispatae and sect. Hypnoides (Hepaticae) in the Neotropics. I. Plagiochila disticha, P. montagnei and P. raddiana. Nova Hedwigia 70: 161-184.

Heinrichs J, Grolle R, Drehwald U. 1998. The conspecificity of Plagiochila killarniensis Pearson and P. bifaria (Sw.) Lindenb. (Hepaticae). Journal of Bryology 20: 495-497.

Heinrichs J, Pröschold T, Renker C, Groth H, Rycroft DS. In press-a. Plagiochila virginica A. Evans rather than P. dubia Lindenb. & Gottsche occurs in Macaronesia; placement in sect. Contiguae Carl is supported by ITS sequences of nuclear ribosomal DNA. Plant Systematics and Evolution.

Heinrichs J, Rycroft DS. 2001. Leaf surface waxes and lipophilic secondary metabolites place the endemic European liverwort Plagiochila atlantica F. Rose in the Neotropical Plagiochila sect. Bursatae Carl. Cryptogamie, Bryologie 22: 95-103.

Heinrichs J, Rycroft DS, Groth H, Cole WJ. In press-b. Morphological and phytochemical studies of Plagiochila papillifolia Steph., a Neotropical liverwort new to Europe. Journal of Bryology.

Rycroft DS. 1999. A chemist's view of liverworts: NMR fingerprinting and chemotype classification of British Plagiochilae. Bulletin of the British Bryological Society 72: 50-54.

Rycroft DS, Cole WJ. 1998. Atlanticol, an epoxybicyclogermacrenol from the liverwort Plagiochila atlantica F. Rose. Phytochemistry 49: 1641-1644.

Rycroft DS, Cole WJ, Aslam N, Lamont YM, Gabriel R. 1999a. Killarniensolide, methyl orsellinates and 9,10-dihydrophenanthrenes from the liverwort Plagiochila killarniensis from Scotland and the Azores. Phytochemistry 50: 1167-1173.

Rycroft DS, Cole WJ, Heinrichs J, Groth H, Renker C, Pröschold T. In preparation. Phytochemical, molecular and morphological evidence for the occurrence of the Neotropical liverwort Plagiochila stricta in the Canary Islands, new to Macaronesia.

Rycroft DS, Cole WJ, Lamont YM. 1999b. Plagiochilines T and U, 2,3-secoaromadendranes from the liverwort Plagiochila carringtonii from Scotland. Phytochemistry 51: 663-667.

Rycroft DS, Heinrichs J, Cole WJ, Anton H. 2001. A phytochemical and morphological study of the liverwort Plagiochila retrorsa Gottsche, new to Europe. Journal of Bryology 23: 23-34.



BRIAN O’SHEA (LONDON): SEMATOPHYLLACEAE: A TROPICAL MOSS FAMILY WITH SPECIES IN BRITAIN

The Sematophyllaceae contain three British species (one discovered only recently), all of which are treated in the British Isles as belonging to the genus Sematophyllum. This paper focuses on the significance of the two species known since bryological research started in the British Isles (S. demissum and S. micans), and where they fit within the family.

Although the Sematophyllaceae are predominantly found in the tropics, where they can be very common, there are a number of essentially temperate species, which on the whole - as with the British plants - are rather rare. It is a family that poses a lot of taxonomic problems, particularly in the area of genus and family delimitations, and the relation of the genera in Sematophyllaceae s.l. with the rest of the Hypnales. Molecular studies indicate that diversification in the Hypnales occurred comparatively rapidly, probably associated with the spread of trees in the early Tertiary; because of the speed of change, there is very little morphological or molecular evidence indicating how taxa are related. In addition, the majority of the extant species are probably very recent and actively evolving, so there has been little time for distinctive characters to appear and be differentiated.

The level of diversity in mosses measured by the number of described species is significantly skewed in the tropics, where many species were described at a time when the tropics were seen as an area of boundless fecundity and diversity, and almost every new collection was described as a new species. Taxonomic work in the tropics has been constantly hindered by the sheer volume of work in examining hundreds of type specimens to find the few that are good species. Ireland (1992) boldly reduced the Latin American Isopterygium species from 92 to eight in his revision of the genus, and suggested there might be further reductions to come. Similar reduction might occur when the 64 African species of Sematophyllum are revised; 59 of them are endemic, and 40 occur in only one country, many of them known from only one collection. O’Shea (1997) estimated that the number of moss taxa recognised in sub-Saharan Africa might reduce by 57%.

S. micans has been seen as a bit of an oddment for some time. In America it has traditionally been placed in Hygrohypnum because of the leaf shape, semi-aquatic habitat and somewhat inflated leaf cells, whereas in Europe it has been put in Sematophyllum because of the inflated, coloured alar cells. In fact it has a poor resemblance to either genus, as it differs from Hygrohypnum in its lack of a central strand, decurrent leaves, short-cylindric capsules with round-pored stomata (Hygrohypnum has oval-pored stomata) and short-rostrate opercula, and from Sematophyllum in its atypical alar cells, decurrent leaves and quite different sporophyte. Buck (1997) created a new genus for it: Schofieldiella, which he placed in the Hylocomiaceae. Although it doesn’t look like a Hylocomium, Buck listed the following similarities: relatively strongly toothed, decurrent branch leaves, relatively strong double costa, short-cylindric capsules, and round-pored stomata. He aligned it to the genus Leptocladiella in the Hylocomiaceae, which he thought showed striking similarities, including the fact that it has species as small as S. micans, although S. micans lacks the sympodial growth form. Tan & Jia (1999) took a different approach and opted for the genus Hageniella in the Sematophyllaceae. They maintained that the differences from more typical sematophylloid plants is within a permissible range; the only problem is the decurrent leaves, but they point out that these are only slightly more decurrent than the type species of Hageniella. The conclusion from this is not entirely clear. It may be that we have found the right genus, but there may be more debate about whether the genus is in the correct family. S. micans remains an interesting but puzzling plant.

S. demissum also presents taxonomic difficulties. H.N. Dixon, apart from being the author of three editions of the Student’s Handbook of British Mosses and being the first BBS President in 1923, was also one of the most prolific authors of new species this century. Although he never went to the tropics, from the first few years of the 20th century he took an interest in what were called ‘exotic’ mosses. I don’t think anyone has calculated how many species he described before his death in 1944, but it was well over a thousand, and they were from all over the world. One of his interests was the Sematophyllaceae, and he spent some time looking at a group in Sematophyllum called the ‘caespitosum group’. Species in this group are most easily characterised by their leaf shape and the very short cells towards the leaf apex. Dixon published his findings in 1920, and made 58 species synonyms of S. caespitosum (now known as S. subpinnatum) on the basis that it was a very plastic taxon that grew in a wide variety of habitats and the variation was environmentally determined. In many ways this was quite revolutionary, as the tradition had been that anything slightly different was described as a new species (and Dixon himself followed this practice in much of his work). The interest in this for us is that S. demissum (and S. adnatum, recently found naturalised in Italy, via imported American trees) share similarities with this group, although they were not dealt with by Dixon, presumably because they weren’t tropical. Dixon spent two pages trying to define his concept of S. caespitosum, but he found it extremely difficult to characterise. He certainly gave up on the idea of defining varieties, as the variation was so great in all directions, with so little correlation between characters. A look at American moss Floras will indicate the similarity of S. caespitosum/subpinnatum and S. demissum. Buck (1998) considered that European S. demissum might be the same as S. adnatum, although American S. demissum is not the same and should be called S. carolinianum. Looking at collections elsewhere in the range of S. demissum, the plants in Hong Kong and Japan look similar to ours, but so does the Japanese S. robustulum. Whilst we are normally quite sure about how our species are delimited in Britain, here we have found a weakness that needs to be tackled, so perhaps this throws it back to bryologists in the BBS. What is S. demissum? Is it a good species, or is it a synonym of something else, e.g. is it the same taxon as S. adnatum? There are plenty of challenges left in the Sematophyllaceae - even in Europe.

Buck WR. 1997. Schofieldiella (Hylocomiaceae), a new genus for an old species. Journal of the Hattori Botanical Laboratory 82: 39-46.

Buck WR. 1998. Pleurocarpous mosses of the West Indies. Memoirs of the New York Botanical Garden 82: 1-400.

Dixon HN. 1920. Rhaphidostegium caespitosum (Sw.) and its affinities. Journal of Botany 58: 81-89.

Ireland RR. 1992. The moss genus Isopterygium (Hypnaceae) in Latin America. Tropical Bryology 6: 111-132.

O’Shea BJ. 1997. The mosses of sub-Saharan Africa. 1. A review of taxonomic progress. Journal of Bryology 19: 509-513.

Tan BC, Jia Y. 1999. A preliminary revision of Chinese Sematophyllaceae. Journal of the Hattori Botanical Laboratory 86: 1-70.



ROD STERN (CHICHESTER): BRYOLOGY OF SOUTH WILTSHIRE

Historically, Wiltshire has been the least well-known bryologically of all the counties of southern England, and the first records were not published until 1891. South Wiltshire comprises the southern half of the county, the northern boundary of VC 8 being the Kennet and Avon Canal. There are some significant differences from the present administrative boundary.

Large parts of VC 8 are on chalk, some of which is covered with Clay-with-Flints. Other important geological formations include the Upper Greensand (which gives rise to relatively acid soils), Jurassic limestones in the west, and Tertiaries in the south-east with acid sands and gravels.

Wiltshire is less wooded than most other counties in southern England, but there are extensive areas of woodland in the west on some large estates. Some of the more interesting bryophytes in ancient woodlands (i.e. woodlands since at least 1600 AD) include Hylocomium brevirostre, Rhytidiadelphus loreus, Herzogiella seligeri, Plagiothecium latebricola and Trichocolea tomentella.

There is much arable land on the chalk, as well as unimproved grassland. The latter is particularly extensive on the Ministry of Defence lands, the largest being Salisbury Plain Training Area which occupies about one-fifth of the vice-county. Generally, the chalk grassland is not very interesting bryologically as the grass is too long for bryophytes, but some closely grazed areas have characteristic mosses, such as Weissia species (including W. sterilis), Rhodobryum roseum and Thuidium abietinum subsp. hystricosum, while bare chalky patches may have Microbryum rectum, M. curvicolle, M. floerkeanum, Acaulon muticum and Ephemerum recurvifolium.

The south-east part of VC 8 in or near the New Forest (much now being in Hampshire) has wet and dry heathland with Dicranum spurium, Splachnum ampullaceum, Calliergon stramineum, Hypnum imponens, Campylopus brevipilus, Cladopodiella fluitans, C. francisci, Cephalozia macrostachya, Ptilidium ciliare and many other bryophytes of interest, including fifteen Sphagnum species.

The main bryologists in VC 8 in the first half of the 20th century were C.P. Hurst in the north-east and the Dunston brothers in the south-west. After 1950, much useful recording was done by Jean Paton, Joan Appleyard, Ted Wallace and Francis Rose. The BBS had its spring meeting in 1989 based at Salisbury, and it became clear that much of VC 8 was still poorly known bryologically. A relatively intensive survey was carried out over a period of eight years until 1999. Distribution maps were prepared on a 10-km square basis with the intention of producing a bryophyte flora of the vice-county.



ANGELA E. NEWTON (NATURAL HISTORY MUSEUM, LONDON): PHYLOGENETICS, MOLECULAR DATA AND THE BRYOLOGIST IN THE FIELD

Papers describing research using phylogenetic methods and molecular data are now widespread in many of the bryological journals, but how relevant are these methods, and the results obtained using them, to the bryologist in the field? It is of course impossible (at present) to use DNA to identify a plant in the field, just as it is impossible for most people to use scanning electron microscopy to look at spore walls to identify a plant. However, just as scanning electron microscopy permits an understanding of relationships that can be relevant to the bryologist in the field, so do phylogenetics and molecular data.

We all know taxa - species and genera - that are rather fickle and cannot be pinned down to a genus or a family, so that circumscriptions keep changing and taxa keep hopping about and turning up in different places in different classifications. One example is the plant that I learnt as Isopterygium elegans (Brid.) Lindb., previously Plagiothecium elegans Brid., and now Pseudotaxiphyllum elegans (Brid.) Z. Iwats. The new generic name has been largely accepted in the literature (e.g. Blockeel & Long, 1998), but the family placement has varied. The species has been transferred around in the Plagiotheciaceae, where it is still placed by the taxonomic database at Missouri Botanic Garden (http://mobot.mobot.org/W3T/Search/most.html), but is listed under the Hypnaceae by Buck & Goffinet (2000). In another example, Hypnum lindbergii Mitt. was transferred to Calliergonella in the Amblystegiaceae by Lars Hedenäs in 1990, but this move has not been widely accepted. On a much larger scale, molecular sequence data have shown that the orders Hypnales and Leucodontales (=Isobryales) are not natural - different groups of leucodontalean mosses appear to have evolved independently from the Hypnales. This may be no surprise to many - there are a number of taxa that have been transferred between families or from the Hypnales to the Leucodontales and back again by different authors. Despite accounting for perhaps half of the species of extant mosses worldwide, there is very little hierarchical structure in the pleurocarps when compared to the acrocarpous taxa. Mosses in the Leucodontales are characterised by epiphytic habit and reduced peristomes, features that have frequently been shown to be correlated, and that may reflect repeated parallel evolution from terrestrial plants with complete peristomes.

The first two examples given above both relate to changes based on morphology, and reflect re-assessments of the relationships of small groups of species. Do these changes actually make sense? Are they likely to be modified in the future? Is there any way of determining which changes are reasonable and which don’t really help? Where do these plants really belong? And on the larger scale, are there sub-groups within the pleurocarpous mosses that can be recognised as orders, or at any other level? It is these kinds of question that phylogenetics and molecular data may help us resolve.

Both new kinds of data and new ways of analysing data are involved. A very large proportion of the work of recognising and describing species, genera and other taxa has been carried out using morphological and ecological data, with progressive refinements, over at least the last 2000 years. But intractable problems remain, some of which we are not even aware of, that cannot be solved with traditional methods. Morphological characters in mosses are notoriously plastic. For example, costa length and form, cell size and shape, and peristome morphology, may be so variable that they provide little useful information, and arguments have raged about the relative importance of the sporophyte and the gametophyte for understanding higher level relationships. However, many morphological characters may be highly informative, including both traditional characters and ‘new’ characters, such as axillary hairs, pseudoparaphyllia, and the presence or absence of a hyalodermis on the stem. Character analysis, which basically consists of careful scrutiny to determine whether a morphological feature is positionally and structurally ‘the same’ as that in another plant, is a necessary preliminary step. The disadvantages of using morphological data are the variability and plasticity of the characters, the long period of training and experience necessary to understand what is seen down the microscope, and the rather few informative characters found relative to the input of effort (usually no more than one to two characters per taxon). One advantage is that morphological characters may reflect the processes of evolution in a stop/start fashion, with more changes happening at periods of great evolutionary change (the periods we are most interested in reconstructing) and fewer in the long quiet periods between.

Molecular data are derived from several different sources - sequences of DNA bases in nuclear, chloroplast, mitochondrial or ribosomal genes, amino acids in proteins, and structural elements in DNA, such as insertions and deletions (indels) and secondary folding. Chloroplast sequences are most often used by botanists, partly because their use reduces problems from non-plant contaminants. There is now a very large amount of data available, especially for the gene rbcL (which codes for production of the essential photosynthesis enzyme ribulose biphosphate carboxylase), allowing extensive comparative studies to be made. Molecular data are also subject to character analysis, in the form of sequence alignment, with each position in the DNA chain representing a character. One of the advantages of molecular data is that they are not directly affected by the ecological pressures that affect morphology. In addition, molecular data can be easily obtained in a suitable lab, and provide much larger amounts of information - frequently more than ten informative characters per taxon. This makes computer analysis much easier and faster; up to a point, the more comprehensive the sampling of taxa, and the more informative characters per taxon, the easier the analysis. One of the principal disadvantages of molecular data is that they appear to evolve at a more or less constant rate in any given lineage, so that ‘fast’ evolutionary events may be missed, or overwritten by later changes.

Phylogenetic analysis, or more specifically, cladistics, is based on principles laid down by Willi Hennig in the 1960s (Kitching et al., 1998), many of which codify good taxonomic practice that would have been used subconsciously by the better earlier systematists. One example is the nature of the information supplied by different characters. These are referred to as autapomorphies, synapomorphies, plesiomorphies and homoplasies. An autapomorphy is a character state that is unique to a single species (or to a single group), and which allows us to identify the species, but tells us nothing about the relationship of that species to others. For example, Rhytidium rugosum has rugose leaves, which allows us to identify it with ease, but this doesn’t tell us what it is related to. This can also apply at the level of a genus or other group - if a genus has a certain character state, but nothing else does, this tells us nothing about the relationship of the genus to other genera. However, if all descendants of a common ancestor share a character state which does not occur in any other taxa, it does tell us about the membership of the group, and is then termed a synapomorphy. But at a different level, if you are looking at relationships within a subset of the group, the character is not informative. Possession of an articulated peristome is a synapomorphy for the arthrodontous mosses, but within the group this character is plesiomorphic, and, for example, tells us nothing about the relationship of Bryum to Hypnum. (Other details of peristome structure might, however, provide useful information to address this problem.) Finally, character states are referred to as homoplasious if the apparent similarities are superficial and do not reflect a shared evolutionary origin. There are different ways in which this might happen - convergent or parallel evolution, reversal, or misinterpretation on the part of the observer. A character state that is homoplasious will provide incorrect or misleading information about relationships. For example, erect capsules are found in a wide range of taxa, but we don’t think that all species with erect capsules are more closely related to each other than they are to species with inclined capsules.

A large amount of data is used in most phylogenetic studies, and analysis is carried out using various computer programs; PAUP and Hennig 86 have been widely used, but there are many others. The programs use logical or evolutionary models to build and assess cladograms, which are approximations of phylogenetic (or evolutionary) trees. There are two basic types: maximum parsimony (which endeavours to find the cladogram that requires the smallest number of evolutionary changes to explain the data at hand) and maximum likelihood (which estimates the likelihood of finding the data at hand for a given cladogram). Both have advantages and disadvantages, and there is an enormous literature discussing the theoretical and methodological issues. New techniques are being developed all the time, e.g. one of the methods currently being actively explored is Bayesian inference. The end result is a cladogram (often referred to as a tree), or more often a series of cladograms which vary to a greater or lesser extent. Each cladogram represents a different possible arrangement of the data, and they are often treated as estimates of the actual course of evolution. Often such groups of cladograms are summarised as consensus trees, with a ‘strict’ consensus, for example, showing only the groups that are found in all the different cladograms. Jacknife and bootstrap values, and decay indices, are also often shown, providing different assessments of the support for individual groups. The cladograms are hypotheses, our current best estimates of the relationships of the organisms, and as such can never be regarded as ‘true’, but they do provide a tool to further explore and understand relationships.

So how do the results of this work affect the bryologist in the field? Much of the work is still very preliminary, but two different kinds of result can be expected. One is clarification of the relationships of individual problematic taxa, and the second is clarification of the relationships of larger groups, so that families and orders become more natural. There have already been some interesting rearrangements of taxa that previously were very poorly understood, although most of these have concerned species or genera that do not occur in the British Isles. For example, several odd taxa that lack peristomes have been transferred to groups very far from their original placements, but with which they share various other morphological features. One of these is Oedipodium griffithianum, usually placed in the Splachnales, but shown by molecular data to belong near the base of the moss lineage near Andreaea, and therefore primitively lacking a peristome (Newton et al., 2000). The position of Hypnum lindbergii has not yet been clarified, although most molecular studies place it distinct from the Hypnaceae, either near the Hylocomiaceae (Buck et al., 2000) or, supporting Hedenäs (1990), with members of the Amblystegiaceae (unpublished data).

Although some orders and families are well circumscribed and useful, others don’t really help much in placing individual species. The result is that many people learn each genus or species as an individual entity. This takes more time and effort than being able to quickly place any species in the higher levels of the hierarchy, where there are fewer possibilities to consider, and fewer chances of going wrong somewhere in the key. If molecular and phylogenetic studies result in the development of more natural classifications, this should eventually make identification and understanding of genera and species more straightforward.

References

Blockeel TL, Long DG. 1998. A check-list and census catalogue of British and Irish bryophytes. Cardiff: British Bryological Society.

Buck WR, Goffinet B. 2000. Morphology and classification of mosses. In: Shaw AJ, Goffinet B., eds. Bryophyte biology. Cambridge: Cambridge University Press, 71-123.

Buck WR, Goffinet B, Shaw AJ. 2000. Testing morphological concepts of orders of pleurocarpous mosses (Bryophyta) using phylogenetic reconstructions based on trnL-trnF and rps4 sequences. Molecular Phylogenetics and Evolution 16: 180-198.

Hedenäs L. 1990. Taxonomic and nomenclatural notes on the genera Calliergonella and Breidleria. Lindbergia 16: 161-168.

Kitching IJ, Forey PL, Humphries CJ, Williams DM. 1998. Cladistics. The theory and practice of parsimony analysis. Oxford: Oxford University Press.

Newton AE, Cox CJ, Duckett JG, Wheeler JA, Goffinet B, Hedderson TAJ, Mishler BD. 2000. Evolution of the major moss lineages: phylogenetic analyses based on multiple gene sequences and morphology. Bryologist 103: 187-211.


FIELD EXCURSION TO WYNDCLIFF AND GREAT BARNET’S WOODS, 9 SEPTEMBER 2001

The group met in the large Forestry Commission car park below the Wyndcliff quarry (ST59I). After an initial get-together we moved off to the first site close to the car park. Several tiny limestone pebbles were shown to support Seligeria campylopoda, a S. recurvata look-alike listed in the Red Data Book as Data Deficient. There was discussion about the conservation of S. campylopoda, the need to include it in the Monmouthshire local Biodiversity Action Plan, and the importance of keeping the pebbles free from fly-tipped rubbish. At the time, this was one of only two known colonies at the species’ only known extant British site. However, Jonathan Sleath discovered two further small populations on pebbles below the car park.

After we had all enjoyed this tiny rarity, things continued to be ‘data deficient’ as we tried to relocate Ditrichum flexicaule s.s., collected from the Wyndcliff 110 years ago by Binstead and Shoolbred. Various candidates were collected from the quarry floor and taken home for later inspection; unfortunately, all proved to be Dicranella varia. Back in the car park, further interest was provided by some Hypnum lindbergii found by Mark Pool, a new record for the Wye valley, and by some ephemerals, including Dicranella schreberiana and Bryum klinggraeffii, demonstrated on a bank by Mark Hill.

Our descent into the Wye valley below the car park, an area of woodland known as Cave Wood, was accompanied by mutterings about how dry the area was. The leader assured people that there were a few more humid areas and, sure enough, we soon found Trichocolea tomentella on rocks in a small stream. Sharing the rocks were plenty of Fissidens rivularis c.fr., an unusually common species in the Wye valley, Riccardia chamedryfolia and Chiloscyphus polyanthos. In our eagerness to reach the stream we had walked past the best humidity indicator of all - Lophocolea fragrans c.fr. was found by Jean Paton and Tom Blockeel in abundance on a large plane tree by a ruined cottage some 50 metres up the path.

With lunch beckoning we split into several small groups to look for calcicoles. Most groups noted Porella arboris-vitae growing in small quantity on low crags with P. platyphylla, Neckera crispa and Anomodon viticulosus, as well as Taxiphyllum wissgrillii and Eurhynchium crassinervium on small rocks. Sam Bosanquet showed a few people Fissidens gracilifolius on fine limestone scree, and Nick Hodgetts found some Plagiochila britannica. A couple of crags plastered with Marchesinia mackaii were located and, while searching one of these, Graham Motley found a Cololejeunea that was assumed in the field to be C. rossettiana; a little was collected and it proved to be C. calcarea, another new species for the site.

After lunch a slightly smaller group moved to Great Barnet’s Woods (ST59C), a mile west of Chepstow. Sam had found Thuidium recognitum here in early 2000 and hoped to assess the size of the population. Unfortunately, finding the limestone pavement on which the Thuidium grew proved difficult enough and the scarce species was not relocated. Despite this, the group remained in good humour and found several new species for the site. Most notable were Jean’s female Pellia neesiana, growing on a trackside with male P. endiviifolia, and John Blackburn’s Leucobryum juniperoideum on a tree stump. As well as a number of calcicoles, this area of poorly-developed pavement held various locally rare mosses, including Hylocomium brevirostre, at one of its very few Monmouthshire sites, and Rhytidiadelphus loreus.

The chance of seeing unusual species, such as Seligeria campylopoda, Fissidens rivularis and Lophocolea fragrans, merely provided a background to bryologising in the field with many friendly BBS members. I hope everyone had an enjoyable time on their brief visit to Monmouthshire.

SAM BOSANQUET

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