The endemic flora of the Arera and the Alben

The Park explains the richness of the flora with the variety of habitats and with the glaciations, which isolated plant populations and favoured the formation of new species. The Club Aquile Rampanti, which has documented the species along the normal route up the Arera, adds the most quoted hypothesis: some Prealpine areas, including the Pizzo Arera, were not covered by ice and acted as refuges for species that vanished elsewhere, on a limestone-dolomite substrate and with a wetter climate than the main Alpine ridge.

The result is a mosaic of scree, ledges, cliffs and stony pastures in which different species occupy very narrow niches. According to the Club Aquile Rampanti, Primula albenensis and Linaria tonzigii are the only two strict endemics of the province of Bergamo; the Park notes that the Linaria is known from very few sites between the Arera and the Presolana.

Linaria tonzigii, the Bergamo toadflax, was described by Fausto Lona in 1949 and dedicated to the Milanese botanist Sergio Tonzig (Acta Plantarum). It is a plant 6-10 centimetres tall, with stems woody at the base that creep among the stones, leaves in threes and yellow flowers 21-25 millimetres long with a 10-11 millimetre spur; it flowers from late June to mid-July and ripens its seeds between July and August, but spreads mainly by lengthening its stems through the debris. It grows only on unstable carbonate scree between 1,600 and 2,400 metres, in four groups: Monte Cavallo-Pegherolo, Cima di Menna, Pizzo Arera and Monte Ferrante (Lombardy Region).

Galium montis-arerae, the Pizzo Arera bedstraw, was described in 1957 by Merxmüller and Ehrendorfer and has the Arera as its type locality (Acta Plantarum, Wikipedia). It has square stems, fleshy leaves in whorls of six to eight and a panicle of yellow flowers; it lives only between Monte Pegherolo and the Concarena. Along the Sentiero dei Fiori the Club Aquile Rampanti reports it on the scree of the first stretch, a short distance from the Capanna 2000.

Primula albenensis was noticed in 1988 by Enrico Banfi and Renato Ferlinghetti on the slopes of Monte Alben and described as a new species in 1993 in the journal Webbia. It is a low, entirely mealy plant, with flowers from purplish pink to violet; it grows in cracks in limestone-dolomite cliffs, usually shaded and facing north, between 670 and 2,000 metres, and flowers from April to June: on the Alben its sites lie above 1,150 metres and flower later (Club Aquile Rampanti). Besides the Alben it grows in the Aralalta group and the Val d'Ancogno; in 2023 Banfi and Ferlinghetti described Primula × chignolensis, a hybrid with Primula auricula found above Chignolo d'Oneta and on the Alben ridge.

Other species the Club Aquile Rampanti observed in late July between the Capanna 2000, the summit and the Mandrone include Campanula raineri, the archduke's bellflower, in rock cracks; Primula glaucescens, the Lombardy primrose, which flowers as soon as the snow melts; Silene elisabethae in the dry meadows above the hut; Allium insubricum, abundant between the hut and the Passo Gabbia; Minuartia grignensis on the overhanging walls before the Mandrone; and Saxifraga vandellii, which flowers in June.

The reference route is the Sentiero dei Fiori, the loop CAI Bergamo builds from a stretch of trail 244, trail 218 from the Mandrone to the Passo Branchino and trail 222 for the return, graded E and marked with panels on the area's natural features: according to the Orobie Park it stays between 1,821 and 2,078 metres, and the hut's page on the regional portal reckons about 3 hours. The Club Aquile Rampanti advises going at least as far as the Mandrone scree, about three quarters of an hour from the Capanna 2000: the first stretch crosses dry meadows with Allium insubricum and Campanula raineri, goes over the Passo Gabbia and drops below a line of overhangs to the debris where Linaria tonzigii grows. The full circuit of the Arera is a different matter: it stays on trail 244 and crosses the Forcola di Valmora, is graded EE, and since 31 May 2026 the CAI has reported some chain anchors detached below the col.

To walk up to the Capanna 2000, Flora Alpina Bergamasca suggests trail 221 from Zambla instead of the road: it is the Sentiero FAB dell'Arera, described in a 2015 booklet produced with the municipality of Oltre il Colle and later merged into the book «I sentieri dei fiori dell'Arera» (EQUA, 2018, 144 pages). Primula albenensis, on the other hand, is to be looked for on the cliffs of the Alben, from April to June.

Scree and ledges are the very habitat of these plants: look at them from the path. The Region observes that walking on scree is not in itself the main threat to the Linaria, which likes mobile debris, but lists picking in the most accessible spots among the risks; the provincial description of the SAC calls for regulating the growing flow of visitors, botanists included, on the Sentiero dei Fiori.

In Lombardy regional law 10 of 2008 divides protected flora into two lists, 663 species in all: on list C1 picking is forbidden, on list C2 you may pick at most six specimens, branches or fronds per person per day; for woodland fruits such as bilberries, strawberries and raspberries the limit is one kilogram per person per day (Flora Alpina Bergamasca).

List C1, approved by regional resolution 8/11102 of 2010, includes all species of primrose, saxifrage, rock-jasmine and gentian, except the spotted gentian, which is on list C2, and also Linaria tonzigii, Galium montis-arerae, Campanula raineri, Physoplexis comosa, Allium insubricum, Silene elisabethae, Minuartia grignensis, Viola comollia and edelweiss. Linaria tonzigii is also listed in Annex II of the European Habitats Directive. The practical rule given by Flora Alpina Bergamasca is the simplest: do not pick any flower.

The Orobie Bergamasche Regional Park was established by regional law 56 of 15 September 1989 and Oltre il Colle is one of its municipalities (Parks.it). Around the village there are two Special Areas of Conservation managed by the Park: IT2060009 Val Nossana – Cima di Grem, 3,369 hectares from the slopes of the Pizzo Arera to the Cime di Belloro, and IT2060008 Valle Parina, 2,225 hectares from the Cima di Menna to the mouth of the Parina (Province of Bergamo).

Viola comollia, often listed among the rarest flowers of the Orobie, is not one to look for here: it grows on siliceous scree and rubble (Acta Plantarum), while the Arera and the Alben are limestone.