NorthernPatagonia

This is a report on the Alpine Garden Society trip to northern Patagonia in November and December 2005. Although there have been previous AGS trips to the Argentinean Lake District (see Erskine 1994), no AGS trip had previously been as far north in Argentina as the southern volcanic rim of the Andes at Cavihue and Copahue. We visited a wide range of climatic and ecological areas and habitats during the trip, and as a result we saw nearly 500 species of flowering plants and ferns (including fern allies). Not all these plants are strictly alpine plants (some are very tall trees!). Our list is not complete as we made no serious effort to identify grasses, sedges, or rushes in the steppe. The lists for the alpine sites are thought to be fairly complete as we attempted to identify all vascular plants present at these sites.

Patagonia is a remarkable area because of its vast size, its emptiness, its remoteness, its climatic extremes, its geological and topographical diversity, and its remarkable flora and fauna. In this section we summarise some of the main features of the Patagonian environment as a background for understanding the distributions and ecological behaviour of the plants we saw. Volcan Copahue

Patagonia, including Tierra del Fuego, is a huge territory more than 900,000 square kilometres located between 39° and 55° South. The topography is dominated in the west and south by the rugged Andean mountain chain, and in the east by dissected plateaux giving way to low, flat or gently undulating plains. This topography largely reflects the tectonic structure of the area, dominated by subduction of the Pacific oceanic crustal plate beneath the South American continent and active strike-slip faulting between plate fragments. Granitic intrusions and metamorphic rocks underlie much of the mountainous terrain, forming spectacular peaks in some areas. Late Mesozoic and early Tertiary sedimentary and volcanic rocks create a more tabular relief in the plateaux that decline eastwards. Throughout the 1.6+ million years of the Pleistocene, the western slopes of the Patagonian Andes have been periodically buried beneath massive ice-fields. In contrast to the spectacular glacial scenery superimposed on the structurally controlled topography in the west, the legacy from glaciation to the east is more subtle, where vast amounts of glacial and glaciofluvial deposits form rolling terrain composed of morainic ridges and mounds. These merge into immense plains of outwash gravel that extend to the Atlantic (McEwan et al. 1997).

The regional climate of Patagonia is strongly affected by the westerly storm tracks coupled with precipitation induced by the high western flanks of the Andean Cordillera. This produces a strong west-east gradient with annual precipitation of 4000-7000 mm falling on the western slopes of the Cordillera at 50°S, whereas less than 800 mm fall on the eastern side in Argentina due to a strong rain-shadow effect.

In addition to rainfall and temperature, wind is a major factor in the climate of Patagonia with the 'Roaring Forties' and the 'Furious Fifties'. As Coronato (1993) noted, "in few parts of the world is the climate of a region and its life so determined by a single meteorological element, as is the climate of Patagonia by the constancy and strength of the wind". Wind chill in Patagonia reduces the mean annual temperature perception by 4.2°C.

The vegetation patterns of Patagonia are closely related to the temperature and precipitation gradients. High winds and high rainfall (2000-5000 mm yr^-1) extending along the west coast as far north as 48°S result in extensive areas of Magellanic moorland of bog communities and dwarf-shrub heaths. Where precipitation is between 800-4000 m yr^-1 a temperate rainforest dominated by evergreen Nothofagus spp. (N. dombeyi in the north, N. betuloides in the south) occurs. In areas of lower precipitation the deciduous Nothofagus pumilio is often dominant. Deciduous forests of N. pumilio and N. antarctica occur along the eastern flanks of the Andean Cordillera up to an altitude of about 500 m where the precipitation is between 600 and 800 mm yr^-1. Forest vegetation gives way eastwards as precipitation falls below 400 mm yr^-1 to steppe grassland and shrub vegetation, dominated by tussock grasses and spiny shrubs. The dryness of the region is exacerbated by the combination of high evaporation and persistent strong westerly winds.

Further details of the environment as well as an account of the prehistory and ethnography of Patagonia are given in McEwan et al. (1997), Bolzón and Bolzón (2005), and Correa (1969-1999).

Argentinean botanists have divided the flora and vegetation of Argentina into 8 dominions and 17 provinces (Cabrera 1994, Bolzón and Bolzón 2005). Within Patagonia 4 dominions and 7 provinces or eco-regions occur (Bolzón and Bolzón 2005). These provinces have a distinctive climate and support characteristic species and vegetation types (Cabrera 1994).

The AGS tour was in four provinces, namely Provincia del Monte, Provincia Patagónica, Provincia Subantártica, and Provincia Altoandina. The features of these provinces are as follows:

Map of route

Plant identifications

Thanks to the 7 parts and 8 volumes of Flora Patagonica (Correa 1969-1989), plant identification is relatively straightforward, assuming you can manage some botanical Spanish. The illustrations for each species are generally very good and invaluable. Problems occur in identifying Calceolaria, some rosulate Viola, some Rhodophiala and Tristagma species, and certain cacti and orchids.

Identification of cacti and orchids was helped with reference not only to Flora Patagonica but also to the small booklets by Kiesling and Ferrari (2005) and Freuler (2003), respectively. Identification of forest trees and shrubs was greatly aided by Hoffman (1982). Arce and Gonzalez (2000) was invaluable in identifying spiny shrubs that all look alike in the Provincia del Monte.

Identification of a third species of Tristagma (seen in small quantity at La Hoya this year and last year and in considerable quantity on the lower slopes of Cerro Chapelco this year) was made using Hoffman et al. (1998) and herbarium material in Amsterdam as T. sessile. This species is well illustrated on Plate 504 in the AGS Encyclopaedia of Alpines Volume Two (Beckett 1993-94) but labelled as T. patagonicum! What we consider to be real T. patagonicum is well illustrated by Peter Erskine on p.312 in the AGS Special Issue on South America (1994, volume 62, number 3).

Identification of Rhodophiala seems to be relatively straightforward. Plants with pale yellow flowers, some maroon blotches on the base of the petals, and with fully developed leaves appear to be R. elwesii. At the railway crossing in the steppe east of Esquel (December 2) we saw a more delicate plant with flowers a sharp lemon yellow-green colour and with leaves not fully developed. This appears to be R. mendocina mentioned in Flora Patagonica as likely to occur in the region but is not listed as a member of the Patagonian flora. There are no problems as far as we know with R. andicola. At the base of Cordon del Cajon Chico (where we parked in 2004) there was this year a spectacular narrow red flowered Rhodophiala. This appears to be R. andina (Hoffman et al. 1998), again not listed in Flora Patagonica.

More serious problems arise with the rosulate Viola and with Calceolaria. To summarise much discussion and correspondence between Peter Erskine, John Watson, Martin and Anna Sheader, and ourselves, we believe the situation for rosulate Viola is as follows:

Our name Flora Patagonica name

Viola dasyphylla                         Viola dasyphylla
Viola coronifera                          Viola coronifera
Viola cotyledon                          Viola cotyledon
Viola sacculus                            Viola sacculus
Viola columnaris                         Viola columnaris in part
Viola petraea                             Viola columnaris in part
Viola escondidaensis                   Not listed
Viola vulcanica                           Viola pseudovulcanica
Viola Bariloche 'Shanty Town'       ? form of Viola columnaris or V. petraea

Our reasons for distinguishing V. petraea on Sierra Ventana (and also Cerro Catedral in 2004) are that it closely resembles the original description in 1925 of V. petraea. The northern plants at Cordon del Cajon Chico and in the Caviahue-Copahue areas closely match the original description in 1916 of V. columnaris. Flora Patagonica combined the two taxa. We revert here to the two original taxa, whereas Peter Erskine (personal communication) considers them all part of a very variable Viola columnaris complex. More detailed work is clearly needed to resolve this problem. V. escondidaensis is not listed in Flora Patagonica. It is discussed at length by Watson (1994b). Viola vulcanica is illustrated on p.337 in Watson (1994b) but like Flora Patagonica, it is incorrectly called Viola congesta. It is correctly labelled on Plate 539 in the AGS Encyclopaedia of Alpines Volume Two (Beckett 1993-94).


Viola dasyphylla	Viola vulcanica	Viola columnaris

Viola cotyledon	Viola sacculus	Viola coronifera

Calceolaria is equally frustrating but the work of Christine Ehrhart (2000) on Chilean Calceolaria helps to resolve some of the mess in Flora Patagonica's account. She, correctly we feel, brings together into Calceolaria polyrhiza the small and very variable C. lanceolata, C. polyrrhiza, and C. prichardii. Her C. polyrhiza is thus a variable species with great variation in flower shape, spotting, and size. As regards the other Calceolaria we saw, the situation appears to be as follows:

Our names, following Ehrhart (2000) Flora Patagonica and/or 2004 names

C. corymbosa ssp. corymbosa               C. volkmannii (incorrect determination)
C. corymbosa< ssp. montana                  C. mollisima
C. crenatiflora                                   C. crenatiflora
C. tenella                                             C. tenella
C. laguna-blancae (not in Chile)              C. laguna-blancae
C. biflora                                             Not seen in 2004, C. biflora
C. germainii                                         C. germainii
C. borsinii (not in Chile)                         Not seen in 2004, C. borsinii

Species Lists and Illustrations

These are the lists of all the flowering plants and ferns that we saw and recorded. The localities visited are grouped into the main provinces and habitats visited – steppe, forest, and alpine. The plants are grouped by families (in alphabetical order) within Pteridophyta, Gymnospermae, Angiospermae Dicotyledoneae, and Angiospermae Monocotyledoneae. We have added some short diagnostic notes for each species as a help to identifying photographs taken during the trip.

The lists make no attempt at being complete for introduced weeds and aliens or for grasses, sedges, or rushes in steppe or forest habitats. The lists for alpine areas are thought to be moderately complete, given the time of year we visited these areas and the large amounts of snow persisting this year. Any introduced species is marked by an asterisk in the notes column and in the text.

Taxonomy and nomenclature follow, as far as possible, Flora Patagonica (Correa 1969-1999) with some updates from Ezcurra and Briori (2005) and Ehrhart (2000).

Localities visited

Click on the locality for a species list. A photo gallery of the places and plants seen can be found here.

1. Steppe and Monte shrub areas – Provincia del Monte and Provincia Patagónica

29 November – Dry shrub-dominated vegetation of the Provincia del Monte on the northern part of the Valdes Peninsula. Particular highlights of the day, other than the superb fauna, were the cacti Maihueniopsis darwinii var. hickenii and Gymnocalycium gibbosum, the abundance of Grindelia chiloensis and Hoffmannseggia trifoliata, the small Malvaceae Lecanophora ameghinoi, the range of spiny shrubs in different families all looking identical (e.g. Larrea, Lycium, Retarilla, Schinus), the attractive Atriplex lampa bushes, and several spiny composite cushions of Chuquiraga erinacea, C. avellandedae, and Brachyclados megalanthus. A total of 47 species was noted.

30 November – We drove 600 km westward with eight botanical stops. We started in the warm low-altitu Maihuenia patagonica de Monte scrub and as we travelled westwards and gained altitude we moved into the Provincia Patagónica with its widespread steppe. The first three stops (55, 60, 130 m elevation) were all in the Provincia del Monte and we saw some very elegant plants including the yellow-flowered olive-relative shrub Menodora robusta, several look-a-like spiny shrubs like Prosopis alpateco, Prosopidastrum globosum, Larrea nitida, and Cyclolepis genistoides, the orange Chuquiraga avellandedae, the spectacular low bush of Cassia (=Senna) aphylla, masses of Hoffmanseggia trifoliata along the roadside, the pale form of Perezia recurvata ssp. beckii, the tall Junellia ligustrina, and good forms of Nassauvia glomerulosa and Nardophyllum obtusifolium. After lunch (180 m) where we saw Pterocactus kuntzei and Neoporteria straussiana on river cliffs, we stopped to admire fine stands of Salix humboldtiana on river alluvium at 210 m, and found the smaller, dark leaved Grindelia tehuelches. Roadside rock outcrops at 350 m supported bushes of Frankenia patagonica and below there was the diminutive succulent composite Duseniella patagonica. Above 600 m we started to encounter species-rich steppe with Junellia thymifolia, J. connatibracteata, J. tonini, Glandularia macrospermum, Adesmia guttulifera, A. campestris (= A. volkmanii), A. cabrerae, Arjona tuberosa, Maihuenia patagonica, Maihueniopsis darwinii, Pterocactus araucanus, Acantholippia seriphiodes, and bushy Senecio filaginoides. A total of 69 species was recorded.

2 December – We spent this day exploring the steppe east of Esquel where we followed RP12 down to where the steppe started to have Sisyrinchium macrocarpum affinities with the Provincia del Monte at about 675 m elevation (42°42.8'S, 070°46.074'W). Many interesting and attractive plants were seen at the stops (745-810 m) prior to the Railway Crossing where we had lunch. Before lunch, plants of particular note included Corynabutilon bicolor, Oxalis nahuelhuapensis, Junellia minutifolia, Anemone multifida, Sisyrinchium macrocarpum, S. patagonicum, Scutellaria numulariaefolia, Nassauvia glomerulosa, N. axillaris, Gunnera magellanica, Mulinum microphyllum, Pozoa coriacea, Tetraglochin caespitosum, T. alatum, and Tropaeolum incuisum. At the railway crossing (745 m) (42°47.771'S, 070°57.315'W), many interesting plants were also found inclding Rhodophiala mendocina, Anarthrophyllum rigidum, Stillingia patagonica, Jaborosa exerta, Austrocactus patagonicus, Melosperma andicola, Oxalis compacta, and Montiopsis gayana.

As we drove further east, the vegetation became even drier with abundant Ephedra ochreata, E. chilensis, Junellia micrantha, Senecio filaginoides, Haplopappus pectinatus, Hoffmannseggia trifoliata, Lycium chilense, Chuquiraga aurea, C. avellandedae, Cyclolepis genistoides, Nassauvia ulicina, Pterocactus araucana, Tetraglochin acanthocarpus, Loasa bergii, and Lathyrus magellanicus.

On the return to Esquel we had a final stop where Oreopolus glacialis was in particularly good form. This stop produced several interesting plants including Ephedra frustillata, Olsynium junceum, Sisyrinchium iridifolium ssp. valdivianum, Leuceria achillaefolia, and Armeria maritima ssp. andina.

After short stops to admire Buddleja nappii (985 m), Mimulus glabratus, Pratia repens, Nastanthus patagonicus, Satureja darwinii, and Junellia succulentifolia (990 m), Anarthrophyllum stigulipetatum (one bush in flower at 1060 m elevation) with Haplopappus prunelliodes, H. glutinosus, Rhodophiala mendocina, and a small blue Adesmia, as yet not positively identified (? Astragalus vagus), and Junellia mulinoides and Maihuenia patagonica (945 m), we reached our final destination east of Pilcaniyeu at 41° 07.340'S, 070° 42.478W.

Here, at 1000 m elevation, there is a good colony of Viola escondidaensis (almost certainly) with white fleshy rhizomatous runners, along with Junellia micrantha, J. minutifolia, J. mulinoides, Hypochoeris incana, Ephedra frustillata, Nassauvia lagascae, N. glomerulosa, N. juniperina, Azorella trifurcata, and Colobanthus lycopodioides on rock outcrops nearby.

6 December – We visited the outskirts of Bariloche at Pampa da Hueneles (41° 10.465'S, 071° 19.45'W) to see a rosulate Viola that may be a form of V. columnaris or V. petraea or a new taxon. Growing with it were Quinchamalium chilense, Pozoa coriacea, Oreopolus glacialis, Anenome multifida, and Mulinum microphyllum. Oxalis adenophylla

7 December – We returned to the small area of steppe near the airport to admire magnificent Oxalis adenophylla in full flower, along with Calandrinia caespitosa (orange), Chloraea magellanica, Ophioglossum crotalophoroides, Arenaria serpens, Geum magellanicum, and Plagiobotrys corymbosa. We saw 38 species in total.

11 December – We had a short stop on the drive from San Martin de los Andes to Moqueque to admire the spectacular shows of Eschscholzia californica, and found Sisyrinchium cuspidatum. At our lunch stop we admired Rhodophiala elwesii, Collomia linearis, Clarkia tenella, Gayophytum micranthum, Adesmia parviflora (yellow), and at the tyre-puncture stop Viola arvensis (*) and Navarretia involucrata.

On arriving at Moqueque, botany quickly resumed just outside the hotel with Haplopappus prunelloides, Pozoa vulcanica, Anagallis alternifolia, Ranunculus flagelliformis, Adesmia parviflora (yellow and blue), Gaultheria pumila, Chloraea magellanica, and, most excitingly, Viola cotyledon, all growing at 1135 m elevation. A total of 72 species was noted for this day.

13 December –Our last botanical stop in the steppe habitat within Provincia Patagónica was between Pino Hachado and Loncopue on RN22/21 to admire the spectacular large mats of Argylia bustillosii on the roadside banks growing with Fabiana imbricata and Haplopappus pectinatus.

Altogether, 272 species were seen in the Provincia del Monte and Provincia Patagónica.

2. Forest areas – Provincia Subantártica Gavilea odoratissima

3 December – We drove north from Esquel through the Los Alerces National Park. Initially we drove west through lightly wooded slopes with fine Austrocedrus chilensis and Maytenus boaria. Although Mutisa spinosa was present, it was largely dead and only a few flowering specimens were found, along with the climber Eccremocarpus scaber. Embothrium coccineum was in flower but not at its best. Shortly after entering the Park we had a good orchid stop with abundant Gavilea odoratissima in good flower, and also G. lutea (going over), Chloraea magellanica, C. philippi (in bud), Codonorchis lessonii, and G. araucana (not good). Other plants of note included Luma apiculata (cold by the lake), Lomatia hirsuta in flower, Calceolaria crenatiflora, Mutisia decurrens (not in flower), Viola maculata, and Gunnera tinctoria. We admired magnificent Araucaria araucana (males and females) and Fitzroya cupressoides at the Park's headquarters. On the drive to Bariloche we stopped at wet rocks by the road at 830 m above Lago Guillermo to admire Calceolaria tenella, along with C. crenatiflora, Gunnera tinctoria, and Geranium magellanicum. A total of 81 species was noted.

5 December – Because of the huge amount of snow on Cerro Catedral and Peter Erskine's note at Lago Gutierrez about conditions on Catedral, we decided to cancel a visit to Cerro Catedral. Instead we took the boat across Lago Nahuel Huapi to Puerto Blest and Rio Cantaros. The boat dropped us at Rio Cantaros and we walked around to Puerto Blest.

The temperate rainforest (800-850 m elevation) is dominated by Nothofagus dombeyi, N. pumilio, Fitzroya cupressoides, Podocarpus nubigena, and Saxe-Gothaea conspicua. A range of shrubs, many not in flower, were seen including Azara lanceolata, Luzuriaga marginata, Lomatia ferruginea, and the low-growing Nertera granadensis. There were several species of Hymenophyllum filmy fern, a luxuriance of the tall Dendroligotrichum dendroides moss on the forest floor, and large wefts of the long white lichen Protousnea poeppigii, with obtuse-branched angles and apothecia on the main branches only (Krog 1976). Rock outcrops by the boat quay near Bariloche were full of orchid interest with Chloraea chica, C. cylindrostachya, Gavilea australis, G. araucana, G. lutea, and G. patagonica, along with wonderful Calceolaria crenatiflora on cliffs. A total of 76 species was recorded that day.

6 December – To reach El Mirador del Nirihuau and Sierra Ventana, we walked through Nothofagus pumilio forests with Misodendron oblongum, Berberis serrato-dentata, Valeriana clarioniifolia, Ourisia poeppigii, and Polystichum andidum to reach the tree-line at 1530 m. 34 species were noted.

7 December – As we approached Villa La Angostura, we stopped to admire Buddleja globosa growing at the edge of Nothofagus pumilio forest. Other plants of note include Luma apiculata, Oxalis valdiviensis, and Mimulus glabratus. Fifteen species were seen.

8 December – To reach Cero Bayo with the car park at 1050 m, the refugio at the tree-line at 1505 m, and the summit at 1795 m, we walked (or drove!) through extensive Nothofagus pumilio forest, with Gaultheria phillyreaefolia, Viola magellanica, Ovidia andina, Berberis darwinii, B. linearifolia, Fragaria chiloensis, Blechnum microphyllum, B. chilense, B. penna-marina, Polystichum chilense, P. andidum, and Rumohra adiantiformis. A total of 51 species was recorded.

9 December – We walked up managed ski-slopes through Nothofagus pumilio forest on the lower slopes of Cerro Chapelco from 1250 m to the tree-line at 1745 m. Very little of interest was seen other than Berberis montana and B. serrato-dentata, and the Mutisia spinosa

sheer abundance of the large wispy white lichen Protousnea magellanica growing on the trees, with apothecia on the main and secondary branches (Krog 1976). Protousnea is confined to Nothofagus forests in Chile and Patagonia, but it also occurs on rocks in heathlands in Tierra del Fuego and on the Falkland Islands (Krog 1976). On the drive to San Martin de los Andes, we stopped at roadside cliffs (670 m) with an abundance of Mutisia spinosa var. spinosa and M. spinosa var. pulchella. It is a matter of opinion if these two varieties warrant separate taxonomic status – we doubt it! The total number of species found was 19.

11 December – A few (14) woodland plants were recorded from Araucaria araucana forests as we drove to Moqueque (e.g. Senecio fistulosus, Mimulus bridgesii, Chloraea magellanica, Calceolaria crenatiflora).

13 December – Again, a few (11) woodland plants were noted in the magnificent Araucaria araucana forests (1335 m) along the drive from Moqueque to Pino Hachada. These included Senecio portalesianus. There was a superb slope pink with Oxalis adenophylla within the forest.

A total of 161 species was seen in Provincia Subantártica. Many more are probably present but botanising in high temperate rainforest is not easy and many woodland shrubs are difficult to distinguish and identify.

3. Alpine areas – Provincia Altoandina

We visited eight mountains and found a large number of species (247) despite the late season.

1 December – La Hoya. This is a small ski-centre overlooking Esquel. We parked at the ski-centre at 1200 m and walked up to 1860 m. A huge amount of snow remained in the basin. A good range of species (61) was seen including Caltha appendiculata, Hamadryas kingii, Ourisia poeppigii, Oxalis erythrorhiza, and Viola sacculus (rather poor compared to 2004). The prize of the mountain is, of course, Ranunculus semiverticillatus in both white- and pink-flowered forms. In the same screes we saw Tristagma sessile, seen again in abundance on Cerro Chapelco.

6 December – Mirador del Nirihuau. Despite pessimistic reports from Peter Erskine that this area was poor on his visit on 1 December 2005, Valeriana moyanoi we decided to visit it in the absence of any other nearby mountain that was not buried by snow. Our efforts were rewarded because after walking from Refugion Neumeyer at 1290 m through Nothofagus pumilio woodland, we passed the tree-line at 1530 m and reached the summit at 1600 m. We saw a total of 70 alpine species, including Viola petraea, Nassauvia lagascae, Olsynium junceum, Nastanthus patagonicus, Barneoudia major (not in flower), Tristagma nivale, T. patagonicum, Moschopsis subandina, Polygala salasiana, Mulinum echinus, M. microphyllum, M. leptacanthum, Valeriana carnosa, the spectacular pink 'pen-wiper' type Valeriana moyanoi, and magnificent Oreopolus glacialis. A nice range of blue legumes was seen, with Adesmia parviflora the smallest, then, in increasing size, Astragalus nivicola, A. palenae, and finally Lathyrus magellanicus.

8 December Cero Bayo. We struggled in snow and wind to get to the summit at 1795 m. Few plants of note were found except Ourisia alpina and Valeriana phillippiana. This mountain is probably not worth re-visiting except much later in the season. We recorded a total of 55 species despite the poor conditions.

9 December – Again our activities on Cerro Chapelco were severely limited by the enormous amount of snow on the slopes below the ridge. The highest point reached was 1810 m and there was nothing in flower. The highlights for the day were Ranunculus semiverticillatus in good flower below the main screes, wonderful mixed stands of Tristagma patagonicum, T. sessile, and T. nivale in recently melted-out areas, Viola dasyphylla (some good patches were found with patience), good Draba gilliesii and Onuris graminifolia, a good clutch of Nassauvia (N. lagascae, N. pygmaea, N. revoluta, N. argyrophylla), and Silene cuspidata. The stunning views of Volcan Lanin justified the effort to get above the trees. Only 67 species were noted. Oreopolus glacialis

10 December – We got an early start to give us a full day on Cerro Colohuincul. We parked at the east end of Lake Curruhue Chico at 1035 m, passed the krummholz of Nothofagus pumilio at 1750 m, and saw Viola coronifera from 1770 m to 1850 m. Besides V. coronifera and V. dasyphylla (locally very fine), we saw a good range of alpines including Valeriana boelckii, V. carnosa, V. moyanoi, V. phillippiana, Ourisia fragrans, Nassauvia darwinii, N. revoluta, N. lagascae, N. aculeata, N. pygmaea, Adesmia parviflora, Silene cuspidata, Azorella monanthos acting as a 'nurse' plant for Viola dasyphylla (see Nunez et al. 1999, Arroyo et al. 2003 for details), Tristagma patagonicum, T. nivale, Oxalis adenophylla, Plantago barbata, and Oreopolus glacialis. The vegetation on the exposed ridge showed clear 'vegetation stripes' parallel to the predominant wind direction, as first described from the Cairngorms by A.S. Watt and E.W. Jones in the late 1940s. Viola coronifera showed a tendency to grow amongst rocks or large stones that may provide some shelter from the full wind force, in other words it appears to favour sheltered areas on very exposed ridges.

On the way down, Rhodophiala elwesii, Chloraea cylindrostachya, C. speciosa, Gavilea lutea, and Embothrium coccineum were all admired. Mutisia oligodon was seen but not in flower. A total of 117 species was recorded.

12 December – We drove to 1795 m up the slopes of the volcanic hill of Volcan Batea Mahuida. The summit plateau (1965 m) provides magnificent views of seven snow-capped volcanoes. In addition the flora is good with superb Viola cotyledon, Valeriana boelckii, V. phillippiana, Ourisia fragrans, Oreopolus glacialis, Nassauvia lagascae, and Anemone multifida. A pleasant surprise find on the screes by Ian and Carole Bainbridge was Chaetanthera villosa, unfortunately not in flower. A total of 90 species was noted.

13 December – We drove to the top of the pass between Moqueque and Pino Hachada and divided into four groups to explore the mountains around. A fantastic number of species (113) was recorded, including many 'stars' such as Viola dasyphylla, Patosia clandestine, Primula magellanica, Pinguicula chilensis, Anagallis alterniflora, Calandrina affinis (white), C. caespitosa, C. colchaguensis, Mimulus cupreus, and Oxalis adenophylla. Everyone seemed to enjoy doing some basic plant-hunting in groups; just like a Botanical Society of the British Isles field-day!

14 December – Our last field day was devoted to Cordon del Cajon Chico (summit 2248 m) near Caviahue. This mountain was explored last year and found to have several botanical riches. We parked at 1760 m and approached the mountain from the east side via a sheep path. A range of good plants were seen on the way up including Glandularia araucana, Calandrinia affinis (white), Calceolaria polyrhiza C. corymbosa, Cassia arnottiana, Nierembergia aristata, and Valeriana ,boelckii. At about 2065 m on a south-facing volcanic scree, Jaborosa volkmannii was found in some quantity. What is written about it in Ward's (2004) book on The Plant Hunter's Garden in the chapter 'Beware the Jaborosa, my son!' about John Watson and Anita Flores de Watson is fun. "Jaborosa was at once a gratifying and delightful plant, a plant they had chased for years". The Watson catalogue says "What to say of a plant whose every part shouts class, and which can manufacture from volcano dust a perfume to upstage any female habituée of the Ritz?" The genus name is derived from the Arabic jaborose, used for the name of the closely related Mandragora, the mandrake.

Other plants of note included Viola columnaris, Olsynium frigidum, Junellia micrantha (at 2245 m), Berberis copahuensis, an undescribed Senecio species close to S. carbonensis, Calandrina colchaguensis, Chaetanthera villosa, Doniophyton anomalum, Saxifraga magellanica, and Boopis gracilis. After descending we then drove round to the south-east side of the mountain (1670 m) where we had parked last year to see Cassia arnottiana, Viola vulcanica, and to re-find the possible hybrid Rhodophiala swarm. We failed to find the possible hybrid swarm that we had seen in 2004 because of the late season in 2005. Instead we found brilliant red R. andina with long narrow tubular flowers. Hilary Birks investigated the Viola vulcanica and found, to her surprise, that the plants were significantly cooler than the gravel around! A total of 117 species was recorded, the same as on Colohuincal.

We concluded the day and the botanical part of the tour with short stops for fine stands of Tropaeolum incisum and Maihuenia poeppigii, the only 'alpine' cactus we saw, the cactus having been re-found by Ariel D'Angelo in exactly the same place we saw it in 2004.

Towards the end of the tour, all 19 participants were asked to decide on the ten species of plant that had impressed them most and to rank these on a 10-1 scale, with 10 being top favourite and 1 being the tenth favourite.

Nineteen people voted for a total of 58 species. A weighted product score was calculated for each species as the sum of its scores multiplied by the number of votes it received. Nineteen species had a product score greater than 40. AGS members had one tree, one shrub, one orchid, and seven herbs in their top ten, reflecting the wide botanical interests of AGS members. It is also interesting that 58 species were considered as favourites, but 25 of these only received one vote each. The hard work to see Viola coronifera on Cerro Chapelco was perhaps worth the effort (!) according to 10 people's votes, but the clear and overall winner was Ranunculus semiverticillatus (12 votes and a high favourite of these 12).

During the trip with its planned travel of 3500 km across 13° longitude and 5° latitude, we saw a total of 498 species, about 25% of the total Patagonian flora. The richest areas are in the Provincia del Monte and Provincia Patagónica. We botanised in temperate grassland (= Patagonian steppe and scrub), temperate woodland (Austrocedrus), temperate forest (Nothofagus, Araucaria, Fitzroya), and alpine vegetation.

The most striking botanical changes along the east-west gradient (increasing precipitation) are changes in vegetation structure, biomass, and production, leading to high forests where there are 800 mm or more annual rainfall. Highest species richness (numbers of species in 1 m²) probably occurs in the steppe areas near Esquel and Bariloche.

A more subtle gradient is the decrease in the number of alpine plants as one moves south-wards. For the eight mountains we visited, there is an average decrease of about 6 species per 1° latitude increase. There are many possible reasons for such a pattern, including climate, particularly the length of the growing season, habitat area, and evolutionary and ecological history.

There is also an altitudinal gradient in alpine species richness in our data, with a nearly constant decrease in alpine richness of 10 species per 100 m altitude. Again there are many possible reasons. The most compelling one considers the fact that species richness is proportional to area (a basic ecological law) and that the area per 100 m up mountains naturally decreases with altitude. There is thus less area with increasing altitude and hence one would expect fewer species with increasing elevation. Even when this area-effect is allowed for, the unexplained variation in alpine species richness may be a result of mountain isolation and hence dispersal, availability of habitats, area of snow-free ground, historical factors, and chance.

The Patagonian flora is a wonderful mixture of steppe, forest, and alpine plants. The AGS Patagonia 2005 tour was able to see a wide cross-section of this flora. Hopefully by exploring some of the patterns hidden in our species lists, we can contribute to our understanding of alpine plant richness in Patagonia.

We are greatly indebted to Cathy Jenks for her invaluable help and skill in preparing this report; to Peter Erskine for so generously sharing his vast knowledge of the area with us and for organising and leading the reconnaissance trip in November-December 2004; to Marcela Ferreyra for her enormous help and endless enthusiasm in the field and in identifying Patagonian plants; to Hilary Little for her very efficient and effective organisation and management of the tour; to Carole and Ian Bainbridge for providing such an extensive bird and mammal list for the trip; and to all the participants on the tour for their enthusiasm, energy, and endurance.