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After another day  identifying all the unidentified Solanaceae in both the herbarium of the Instituto and the Universidad Nacional de Cuyo, we went in search of Solanum juncalense, a species we had been looking for on previous field trips in the Mendoza area.

 

I had accumulated much locality information for this solanum in the herbaria – we have very few collections of this species in the Museum’s collections, so my work in the collections here in Mendoza has really helped my understanding of its distribution and variation. One of the localities was in the department of Tunuyán, up the valley from where Claudio’s parents had a farm. We had intended to spend the day there anyway, so went in search of Solanum juncalense – the last chance to find it!

 

Today was the first Sunday of a long holiday, and everyone was out with tents camping or barbeques having a Sunday asado in the countryside. We headed up the valley, on a road that crossed several streams – a bit worrying, as it had rained every day and the arroyos grow quickly and become impassable. We carried on past a guardia post where we had to leave our names to a confluence of two valleys – one of the localities I had found in the herbarium yesterday.

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The valley is called Cajón de los Arenales, and is the jumping off place for the ascent of the mountain at its head

 

And there it was….  at the side of the road, right where we parked the car was Solanum juncalense in full flower. The botany gods were smiling on us for sure…..  everywhere else we had been looking for this we had looked in vain, but there it was!

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Solanum juncalense is a member of the Morelloid clade Tiina and I are currently working on, and an endemic to this part of Argentina and adjacent Chile (although I think the one Chilean collection is actually from the Argentine side of the border!). It is a relative of Solanum sinuatiexcisum, which we collected high up in the northern Andes of Argentina last year

 

Solanum juncalense is a member of a species complex that I thought I understood before I saw the material here in Argentine herbaria. Previous taxonomic treatments distinguished the species by length of hairs (tiny to extremely tiny!!) and colour of flowers; I thought I had found another difference when I was in Córdoba, but looking at the many herbarium sheets of these plants in Mendoza I am now thinking this is all a cline – variation from north to south that is continuous, and not several species at all!

 

In addition, these plants we found sometimes had white flowers and sometimes purple (more commonly purple…  but both colours were there!). So maybe I am more confused now than I was before, but maybe not, at least now I know what to look for….. If I am right and this is all just continuous variation, then the correct name will be Solanum echegarayi, published a few years before Solanum juncalense.

 

The size of the plant had also been important in previous treatments, and plants were described as annuals. But how wrong….  these plants all grow from deep underground rhizomes (underground stems) and shoots grow up from buds along the stem to reach the surface, a bit like a potato grows from the eyes on the tuber. One of the rhizomes we dug up was about 1 centimetre in diameter and very corky. The snow is very deep in this area in winter and the plants die back to survive from Another example of why field work is so important – these sorts of characteristics are just not apparent from herbarium specimens, and are often not noted down on labels.

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Several different 'plants' of Solanum juncalense are sprouting from this rhizome – if a collector just pulled at the above-ground stem it would seem it was an annual plant!

 

I would have liked to dig some more and see if all the plants in one area were connected, but we needed to get back before the arroyo began to flood (we could see it raining up higher). In addition all the plants we found were growing in the loose soil of ant nests; the ants were not at all happy with us disturbing them and they both bit and stung. Apologies to my hymenopterist colleagues for not collecting them, all I could think of was to get them off me!

 

What a find though for my last day in Argentina – this time. This is an amazingly diverse and fascinating country, with many endemic species and genera of Solanaceae. I have great colleagues here in Argentina – Gloria and Franco in Córdoba and Iris in Mendoza – so I am sure I will be back….. but this has been a wonderful field trip, topped off by a great find and some new discoveries about the plant!

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Iris Peralta and her husband Claudio Galmarini in Cajón de los Arenales

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When we arrived in Las Leñas late at night it had been raining and there was no mobile signal – in the morning it was restored and we received several worried calls from Mendoza, there had been landslides in the mountains on the road to Chile and since we hadn’t been heard from people were concerned! We had been blithely unaware, but decided to watch the weather as we collected.

 

From Las Leñas we were headed for the Valle Hermosa – beautiful valley – a place right near the border with Chile. This area is where the plane crash about which the movie “Alive” was made – the survivors were not far from civilisation in Argentina, but thought they were closer to Chile and walked for days in the high Andes. The mountains are beautiful, but dangerous. We left our things in the hotel, and told them we would be back at noon or so to collect them and carry on back to Mendoza….

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The high Andes in central Argentina are very dry, above about 2500 metres elevation there is little or no vegetation; in winter these slopes will be completely snow-covered

 

As we drove up the valley, it was apparent that the rains had fallen and the vegetation was greener than I had seen for a long time. Patagonia had been so dry, but here it was almost lush, as dry deserts go. Crossing a small stream on the road, we found the first excitement of the day – Schizanthus grahamii – a plant I knew well from gardens but had never seen in the wild before. It was all over the banks of the stream, and individual plants varied a lot in flower colour, from pale to very deep pink.

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The flowers of Schizanthus (sometimes called butterfly flower or poor-man’s orchid) are highly asymmetrical, with one large upper petal usually a different colour than the rest; in this species the upper petal is orange and the side petals pink

 

The pass into Valle Hermosa is at about 2700 metres elevation, and the view is spectacular. The valley is glacial in origin, and has been further sculpted by the rivers that run through it. We got someone to take our photo at the top with the valley behind! This valley is famous for its fly fishing, people come from all over to fish in the rivers; our photo was taken by the guide who was taking a presenter from a Brazilian fishing TV channel around the region.

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The Mendoza team, from left to right Iris Peralta, me, Gualberto Salazar and Pablo Molina – Gualberto and I are leaning apart to show the lake!

 

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Fishing streams in Valle Hermosa

 

The bottom of the valley is flat and rocky, again with the sand beneath, a perfect habitat for the Portulacaceae Iris was searching. She had collected there before, so this trip was really not to find new things for her, but for her to show Pablo how to collect and recognise these tiny little plants. And they were tiny and hard to find!

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This is an annual species of Montiopsis that was growing in places where water had been standing but now dried out, on very loose sandy soil. The flowers were less than a millimetre in diameter – minute!

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The flowers of these purslanes only open at midday – once they are open they are pretty easy to see, this species Montiopsis gilliesii (named for Gillies the Scottish botanist!) has bright pink flowers that are held flat against the ground, when the fruits begin the develop the stem stands erect and they are held up high. Who says plants don’t behave!!

 

We stopped to have lunch at the lake overlooked by Cerro Torrecillos (little towers, what a good name!), but they wanted to charge us 10 pesos to sit there, so on we went. By this time the skies were getting dark and we began to hear thunder from the mountains to the west.

 

Bearing in mind that there had been landslides we decided to return ….... first stopping at the pass to collect the purslanes that were now in full flower. The clouds billowed, and the thunder rolled – there was definitely a storm on the way! The extraordinary thing was that people in city cars were attempting the descent into the valley – let’s hope they didn’t end up stuck there! The road was definitely not for city cars……

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Iris, Gualberto and Pablo racing around on the pass collecting as the storm rolled in

 

We got back to where we had left our things at 5 pm (a bit later than the noon we predicted!!) gathered all together and headed down the valley. We stopped at the Pozo de Animas, where we found another mixed population of tobaccos, this time Nicotiana linearis and Nicotiana corymbosa; the latter species we had also seen high up in the mountains – it has a huge distributional range and grows in many different vegetation types.

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The Pozo de Animas (Well of Souls) is a natural feature of this karstic landscape formed by the collapse of rock above an underground cave created by water eating away the limestone. The hole is perfectly circular and the water is VERY deep

 

We arrived back in Mendoza at 11:30 pm, and discovered why everyone was a bit worried about us up in the mountains! The landslides near Uspallata, where we had been a few days before, were huge and had blocked the road to Chile in at least six places. One slide was almost a kilometre across and several metres deep – the clean-up was predicted to take days…..  fortunately no one was hurt, but hundreds of people were trapped. We had been lucky to go up the road in full sun and to see the mountains in all their glory before these unusual rains set in!

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After a day of working the in herbarium in IADIZA ( Instituto Argentino de Investigaciones de las Zonas Aridas), where Iris works, we set off again to look for wild tobaccos, cacti and purslanes in the valleys leading to the high mountains in the more southern part of the province of Mendoza.

 

We made an early start, as we had far to go and little time! Iris and I were accompanied by Pablo Molina, her student who will be studying the phylogeny of cacti and purslanes, and Gualberto Salazar, who was driving, but was a dab hand at botany as well. Driving south from Mendoza to join my old friend Ruta 40 again we saw to the west the Cordillera, here called the “Chain of Silver” for the high snowy peaks that are always snow-covered.

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Cordon de Plata in the morning light – the highest peak to the left is Tupungato, almost as tall as Aconcagua, but difficult to access and climb, thus less well-known

 

Accessing the mountains involves driving out to flatter land in the east, then west again into deep valleys where rivers have carved out the mountains and roads can enter. We were heading for the Laguna Sosneado – we thought it might be an old name for the lake now called Laguna Blanca near the town of Sosneado, but no, we were wrong!

 

We stopped in the town to ask and were told exactly how to get there….  forty kilometres in on a dirt road up the Río Atuel, which was bad and then got worse. The valley was broad and rocky and the river must have been pretty impressive in full flood – as it was it was running quite red from rain in the upper reaches. The road was perfectly all right – not bad at all!

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The flat valley bottom of the Río Atuel is composed of sandy gravel – the plants trap the sand as it blows in the wind and small hillocks called “monticolos” are formed

 

We decided to drive straight to the lake, rather than stopping on the way up, as our locality data from the herbarium had cited the lake as a collecting site for several species we were looking for, among them a strange Jaborosa that Gloria and Franco from Córdoba were seeking.

 

The lake was a jewel in the dry vegetation all round – it was fed by small springs and was surrounded by grass. A gaucho 'puesto' or summer station was located at the lake – sheep, goats and horses are brought up the valley to graze in the summer, and then taken down again once the snow begins to fall in the autumn.  What a place to spend the summer!

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Laguna Sosneado – surrounded by rich grass that grows in what are called in Argentina 'vegas' – patches of lush vegetation near the water from springs in the middle of otherwise very dry scrub. The lake was beneath some tall basalt cliffs, evidence of the volcanic past of the region

 

Above us in the mountains we heard thunder and the sky turned black; rain fell, but not much – the show was spectacular though! We looked and looked around the lake and in the hills surrounding it for the Jaborosa and for the tobaccos also cited for the area, but to no avail. As it was really beginning to rain and it was getting late (again – it seems to be the story of this field trip!) we decided to go back down the valley…

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The storm came from the west over the Andes – storms in central Argentina can be very violent and hail often falls, damaging the famous vineyards further to the east. Nearer Mendoza they seed the clouds to prevent hail during these storms.

 

We did, however, see some pretty amazing cacti – this individual plant of the cactus Maihuenopsis was about 2 metres in diameter – from the car the mounds these cacti formed looked like sheep! This particular species was very common at one particular section of the valley – starting at about 1800 metres elevation and higher.

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Pablo was excited to find such large individuals – they were in fruit as well, so he could collect seeds to study their anatomy and structure

 

As we drove down the valley we looked for plants as we descended – as we had driven straight up to the lake, we were looking harder on the way down! Iris spotted what she thought was a wild tobacco – so we stopped. And my goodness, we found just the species we were looking for – Nicotiana linearis and Nicotiana spegazzinii. As part of long-term studies I have been doing with colleagues from Kew and Queen Mary, Laura Kelly has discovered that these two species are possibly of hybrid origin and is interested in studying them further. Once we stopped and began to walk around the ground was covered with Nicotiana linearis – it is a tiny little plant only a few centimetres tall, so not easy to see from the truck driving along.

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The flowers of Nicotiana linearis are held in tight clusters, each flower is less than a centimetre long and is a dirty white colour. The whole plant is covered with sticky hairs – in this place, all covered with sand!

 

Nicotiana spegazzinii was much less common that Nicotiana linearis – we only found a few plants, but what was really exciting was that we found intermediates – the two are not as distinct as it appears from the descriptions in the published literature! This will be a perfect place to return to study these plants in more detail – in the daytime! As usual, the best discoveries are made at the end of the day, when the light is dimming and night is falling….

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Nicotiana spegazzinii has  larger flowers (still only about a centimetre long) that are widely spaced along the stems and although it is sticky, does not have such long hairs as does Nicotiana linearis

 

It really started to rain as we finished up collecting the wild tobaccos – and we headed further south to Las Leñas, where we had reserved a room in a ski resort for the night. The central Andes in Argentina are a big skiing destination – the snow is deep and the scenery spectacular – but these resorts are not much used in the summer, so rooms are cheap! As usual, we arrived at about 10 pm – not late for eating by Argentine standards….  We still had a lot of plant organising to do though, and the next day to plan, back into the Andes up the valley.