“Trés rare”, a very rare fern in the Basque Country in the 19th century. This is what the botanists who had found the first specimens in their articles said. It was in the mountains of Biriatou that the botanist Zeiller was the first to discover it (1885). And he vomited telling the other botanists that there was more there. Thus, at the few years (1898), M. Botanist Michel Gandoger announced a discovery in the journal Bulletin of the Société Botanique de France. He found in Jaizkibel a fern called Trichomanes radicans, today known as Vandenboschia speciosa: Pasaia and Hondarribia. As pointed out at the beginning of the article, Gipuzkoa was not the territory that attracted a priori these botanists. For this reason, he says that he was visited rarely compared to “exotic” territories such as Andalusia.

Once they opened the way, they found the fern in other places: In 1904, M. Daguin, who was a professor of the Liceo de Baiona, and Zeiller himself, in the Laxia basin, in the Txaenia canyon and in Bidarrai.

Reading these old documents there are references that do not lose their relevance. In fact, the descriptions that ancient botanists make about the places where the fern was found give us many clues about the land of the plant and about the conditions that still need to live today.

There's also life in dark valleys.

The articles written by botanists often speak of deep valleys, canyons or caves. In fact, the fern of Vandenboschia speciosa needs to survive the conditions that occur in the subtropical areas: high humidity and temperatures not very variable. And these conditions are met, in our case, in those areas: in the closed valleys of the Atlantic side.

This relíctic species, the largest in the past, has today found its refuge in the deep valleys surrounded by forests, where the rainforest makes it difficult to escape the river's moisture. In these places, frost is difficult to cover the canyons adjacent to the river and small caves between stones, and temperatures are more stable throughout the year. It is here where the fern finds its corner, in the area closest to the subtropical conditions. Adding to these characteristics is the tendency of fern to soils of high acidity.

The fern populations of Vandenboschia speciosa in the Basque Country should be carefully preserved. The best fern areas in Europe are in the Azores, Madeira and the Canary Islands, where the climate is very favourable to frost. In continental Europe, however, fern is limited to the coast. It has been found in several coastal areas of Britain and Britain, always non-continuously. Within Europe, it has only been located in certain areas. Coming down from the Basque Country, the situation is not much better.

Translucent fern

The darkness, the holes in the rocks at the edge of the deep streams, is their place. In the darkness that will withstand very few plants, you will have to perform photosynthesis by acquiring a few rays of light to survive. As if it were little a subtropical condition plant that grows in the dark, the singularity of its leaf or forehead is also evident. In fact, they are made up of a single cellular layer, translucent. This point of transparency will give reason to the botanist who chose to call beautiful. In this sense “speciosum”, which is special.

The fern wanted to live in hiding but…

The attempts to search for fern that have been carried out in the Basque Country in recent decades have borne fruit and new specimens have been found in places previously unknown or where it was believed to be scarce. In areas where in-depth sampling has been carried out, such as Jaizkibel and Urumea, the number of known specimens has increased 10 times in the last decade. But all of this has a reason: at the beginning of this century local scientists discovered the biggest secret of fern until then unknown in the Basque Country:Gametófita phase of Vandenboschia speciosa.

If the fern wanted to live in hiding, it is no longer of any use. Although it was known that all ferns could have two phases throughout their life cycle, two different bodies, in the Basque Country only the “fern” phase of the Vandenboschia speciosa, the sporophyte, was known. However, there is another phase in which fern looks totally different: the gametophyte phase. At this stage, the fern resembles the moss, it is more difficult to recognize, it is smaller and, as if it were not enough, it often hides inside the darker holes of the river bank, making it almost invisible.

However, from the first day when the gametophyte phase was discovered in the Basque Country, it was seen that from there the fern could be found in more places. In fact, in Euskal Herria, unlike many other places, fern can be found in the two phases of its life cycle, as if it had two different bodies, and both can also use different dwellings, which is a great advantage for the survival of fern. Knowing the gametophyte phase of fern opened a new way for the botanists of the Basque Country. Since then, the team of the Society of Sciences Aranzadi dedicated to the research of the speciosa Vandenboschia has located Garo in unknown places. Every year it still appears somewhere not seen before.

Due to all this complexity, and taking advantage of the excellent research opportunity offered by the rivers of the Basque Country, the team of Dr. Victor Suárez from the University of Granada moved to Jaizkibel and Urumea in 2012 to collect samples of European genetic research on this fern. In their own words, local populations will be of great importance in research.

Vulnerable if you don't look after the riverside forests

This protected species in Europe has also been threatened. In Ireland, for example, he was about to disappear because collectors picked them up for their own herbalists. In the Basque Country, however, the threats have changed. The stems of riverside forests caused by the hardest forestry plants or in a whole basin can cause damage, as they take away protection and make them more vulnerable to frost. The modelling work carried out in the Urumea basin also does not provide for a good future for the species. And climate change can be a hard enemy to a species that needs high humidity and stable temperatures.

If we want this extravagance that nature has given us to continue among us, the best prevention is for the forests on the riverbank to remain well, or to recover. Those of us who work in the search for this plant, on the other hand, will continue to await the results of genetic research in Europe, without losing the opportunity to skate their eyes on the wet walls of the dark and steep streams in search of new specimens.