A Northumberland Alpine Gardener's Diary
This entry: 02 June 2017 by John Richards
Primulas and other alpines from the Alpi Orobie
The Alpi Orobie
The where? Well, in our dotage your diarist and Mrs diarist have decided to eschew the well-worn alpine tracks and to branch out a bit into areas about which rather little is written, at least about alpine plants in English. Sometimes this is proving a modest success (as regards our March foray to Evia), and other times we have drawn a relative blank (for instance our October trip to north-eastern Greece), which did not stop us having a really good time, and enjoying excellent birding!
So it was that for a full fortnight (May 11th-25th) we took advantage of the total dearth of Shows to disappear to the central Italian Alps. The Alpi Orobie, also known as the Bergamasque Alps, lie between the Italian Lake District (Como and Maggiore) to the west, and the Dolomites and Lake Garda to the east. Like most of Italy's alpine areas it lies within a salient towards southern Swizerland, between Bergamo to the south and Sondrio to the north. It is a rather wild and underpopulated region with relatively few roads, a poorly developed ski industry, spectacular vertiginous scenery, and only one road pass, the Passo S. Marco (2028 m) which was closed during our visit. Thus, we missed one target, the very local Androsace brevis on M. Ponteranica, which would have been under snow.
Clearly it had been a curious spring. Lower down, all the spring flowers were well through flower (Helleborus niger, Hepatica nobilis, Erica herbaca, Scilla bifolia, Crocus vernus, Petasites albus, Primula vulgaris etc). However, there was a good deal of snow down to about 1800m, so that most alpines had scarcely started, and Primula elatior, Crocus vernus, Soldanella alpina and Anemone nemorosa were still at their best. Apparently it had been a dry snowless winter, and then there had been heavy late snowfalls in the early spring. On the whole we had good weather, but with cold nights which tended to warm up during our stay.
We spent six nights in each of two villages, Branzi (Villa Chiara) south of the horrid resort of Foppolo in the west, and Borno (Albergo Venturelli), north of Brento in the east. Both hotels, the large villages, and their surrounding areas were delightful, and we would especially recommend Villa Chiara with its stunning view of a 300m waterfall.
Often, when choosing an area to visit, I have only one or two initial goals, which I then have faith will lead to other delightful targets. So it was that my first idea was to see the relatively recently discovered Primula albenensis in the wild. This was originally described in the early 1990's from M. Alben which is in the SW Orobie, north off S. Pellegrino, famed for its water. Here it is quite a trek, and most sites are I believe relatively inaccessible, so that it did not appeal to our ageing limbs. However, intelligence had reached me that it has even more recently been discovered some distance to the north-west, to the south-west of Cassiglio, in a much more accessible spot. This is quite a lowland site at not much more than 1000m and we were told that late April was the best time for flowering. As always, the time of our visit was a compromise as I felt that such a date would be far too early for most other plants, or indeed for comfortable weather. Also, we had hoped for Androsace brevis too. As it was we fell right between two stools of course. Although we went straight to the Primula albenensis on our first full day in the area (May 13th), and thanks to excellent directions walked straight to the plant, it was over flower and boasted only some withered petals.
At these sites anyway (we found three populations) the plant lives under overhangs, caves even, in a steep limestone valley. It reminded me irresistably of another primula from much less accessible parts of a far-away land, P. caveana (section Cordifoliae) from great altitudes in the central Himalaya, which also lives under overhangs. If I show you this picture of the latter (by David and Margaret Thorne) you will see what I mean.
The next picture is of P. albenensis again.
Remarkable, isn't it? Here it seems is a superb example of convergent evolution. Two unrelated primulas (they link to opposite ends of this vast genus) have come to resemble one another very closely (far more closely than either resembles its closest relatives) while occupying very similar niches, albeit at very different altitudes, at opposite ends of the globe.
One more photo, to show one of the populations and to demonstrate the habitat.
Before we move on, let me also recommend the little road that winds up to the village of Ornica, north of the main valley. This is all limestone country and the cliffs are covered with Saxifraga mutata, S. caesia, Gentiana clusii, Pinguicula alpina, Globularia meridionalis, Polygala chamaebuxus, Rhododendron hirsutum, Cyclamen purpurascens, Phyteuma charmelii, Primula glaucescens (over flower) and much else. A special plant here, and in the side valley which runs south just west of Cassiglio, is the chasmophyte Campanula petraea. This had yet to produce its lemon heads, but this very local plant has beautiful rosettes.
Notice the superficial similarity between Campanula petraea and Primula albenensis! (the campanula has very hairy leaves however). The whole of this area proved very good for butterflies, not only British rarities such as Chequered Skipper and Duke of Burgundy, but exotics like Twin-spot fritillary and Lesser Marbled Fritillary. Here is Chequered Skipper, now restricted to a handful of sites in th west Highlands.
Time to move on, as we did. Exploring the road up to a small ski centre at San Simone, we encountered the first of a number of sites for Primula hirsuta. This widespread species typically grows on wet shaded rocks of an acidic reaction, and here it seemed to be growing on a mica-schist (the whole area is extremely complex geologically with limestone, conglomerates, marbles, schists, gneisses and some very dull and slabby slates; on the whole the limestones and schists were the most interesting).
Note than in Primula hirsuta the flower stalks are characteristically shorter than the leaves, at least in flower, and the leaf-margins are whitish, not reddish. We also found populations further up our acidic valley from Branzi, above Carone, and the day we tried to drive up the San Marco Pass. On the latter occasion, the road was barred at 1860 m, apparently because of snow on the north side of the pass. This was disappointing as we wanted to drive to the summit which was apparently free of snow, but were not allowed. Instead we took a lovely walk westwards on the south side of M. Ponteranica. Not much was flowering yet, but there was a lot of Primula hirsuta.
Let us move on, as we did, to the area near our second stop at Borno, a district where there are two localised primulas. These both grow on the Passo Croce Domini where we visited them while we were staying at Lake Garda in 2010 (reported in this diary, number 152). On that occasion, we struggled through drifts of snow on our 4 km walk to Cornone Biana. Primula glaucescens was in good condition, better than this year, so I shall not repeat myself with that species. This time we not only enjoyed a much easier drive (we were staying only some 20 km to the west), but a straightforward and enjoyable walk. In 2010 it came on to rain, so that Primula daonensis was bedraggled and in poor condition. This year we suffered no more than heckling at the Cornone from a student field-trip, although whether the subject was Brexit or football we have yet to discover. Here it is, growing with Antennaria dioica and Loisleuria procumbens.
In the next (better) photos you can see the reddish fringe of quite long glandular hairs which characterise the rather narrow unlobed leaves typical of thios species.
At this station, Primula daonensis grows amongst grass on level ground at an exposed site, so it is dwarf and the stem does not exceed the leaves. This is, I believe, rather unusual. A few days earlier we had essayed up the Vivione Pass, east of Schilpario. This is a very narrow pass with long stretches lacking any passing places. We were lucky during a mid-May midweek to encountered virtually no traffic going either up not down. Woe betide us if we had! However, fortune favours the brave as my mother (still!) says, and this turned out to be a quite exceptional day.
On both sides of the pass, acidic cliffs border the road with considerable populations of P. daonensis in a much longer-stemmed cliff-dwelling form, P. hirsuta, and in both areas, a considerable majority of P. x seriana. More on the latter in a minute. First, here is P. daonensis again.
Here is a smaller plant of P. daonensis from Vivione.
Here is a typical plant of P. hirsuta from the same area. Note the shorter stems, wider leaves with a pale margin.
And here are some typical, vigorous plants of the hybrid P. x seriana, growing with both parents. At best, this hybrid seems to be very rare. According to Smith, Burrow and Lowe, which is my 'Bible' for European primulas, it had only ever been collected once, by Kellerer, at the eastern end of the Orobie Alps, which is exactly where we were. It is not, I think in cultivation. I have examined the leaf-hairs microscopically, and these definitely confirm the identification. The hairs of P. hirsuta and P. daonensis are very different and these are exactly intermediate. Interestingly, they look very like those of P. villosa, which is not known from this area of the Alps at all. You will also note the intermediate forms of leaves, stem length and flower shape and colour.
There was much more to be seen on the Vivione Pass, as illustrated by the Polygala chamaebuxus in the last photo. However, the star turn was undoubtedly Fritillaria burnatii which occurs in countless thousands in the meadows at about 1600 m on the west side of the pass. These are worth any effort to go to see, one of the great floral spectacles. I shall close with a series of pictures. By the way, it was common on the Passo Croce Domini this year too!