16 February 2001 - 23 February 2001
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.
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.
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.
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
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.
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
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.
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.
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.
Tenerife, Canary Islands