Two generations of botanists end titanic task: Describing the 6,120 plants of Spain and Portugal

A plant of the grass family native to the Americas that was introduced in parts of Spain, Muhlenbergia schreberi, is the very last entry in a vast botanical inventory that was 39 years in the making and required the efforts of two generations of experts.

The description of this particular species was the final touch on the comprehensive catalog’s 25th volume, which went to print this past summer. The project, known as Proyecto Flora ibérica, has been hailed by specialists as the greatest milestone in the classification of the region’s biodiversity since the days of the illustrious 19th-century botanist Heinrich Moritz Willkomm, who led plant-collecting expeditions in Spain and Portugal.

The first volume of Flora ibérica was published in 1986. Almost four decades later, the plant encyclopedia lists 6,120 species, of which 22% are endemic, meaning they do not grow in any other part of the world. This figure represents around half of all the plants in Europe, underscoring how the relevance of the project extends well beyond Spain and Portugal’s borders.

Yet so far, there have been no public celebrations, no presentations, not even an official announcement. Carlos Aedo, a researcher at Madrid’s Royal Botanical Garden and coordinator of the final phase of the project, said that to 21st-century Spanish science, the impact of classifying species is “irrelevant.”

The titanic task required input from no fewer than 255 authors from 72 institutions in 14 countries, including 27 Spanish and seven Portuguese universities. “Making this possible required two generations of botanists,” said Aedo, who joined the enterprise as an intern at age 30 and ended up as its coordinator.

The project lists all the vascular plants (those with water-carrying tissues such as roots, leaves and stems, as opposed to non-vascular plants like mosses) in the Iberian peninsula. The inventory extends to mainland Spain and Portugal, the microstate of Andorra and Spain’s Balearic Islands. It did not take islands in the Atlantic Ocean – including Spain’s Canaries and Portugal’s Madeira – into account because of their completely different biodiversity.

The number of endemic species in the Iberian peninsula is much higher than in other parts of Europe. “In Germany, you can count them on the fingers of your hands,” noted Aedo. “Iberian flora is very rich, as it is across the Mediterranean. In terms of diversity it is similar to Greece and Italy, and a bit below Turkey.” Aedo explained that glacial periods in northern Europe killed off a lot of plant life there when the ground was covered with ice.

With the advent of the digital era, work became easier. At first, researchers would mail one another photocopies; each author’s work had to be physically sent to a scientific editor who in turn ran it by a team of 50 advisors before having a secretary do a final proofread. These days, the volumes are available online on the digital library of Madrid’s Royal Botanical Garden.

Another challenge was deciding on the proper name of each plant, considering that the same word is colloquially used for many different species depending on the region. The word aulaga, for instance, is used across Spain to mean 25 different species.

Too big for one lifetime

The driving force behind an initiative that began in 1982 was the biologist Santiago Castroviejo, former director of Madrid’s Royal Botanical Garden, who died in 2009 at the age of 63 without seeing his project completed. Of the two other main figures behind Flora ibérica, Pedro Montserrat passed away in 2017 as he was about to turn 99. Only the Portuguese botanist Jorge Paiva, who at age 88 continues to send in corrections, has lived to see the 25 volumes in print.

The reason for drawing up an inventory of all the plants on the Iberian peninsula was the fact that, until now, Spain was one of the very few European countries lacking such a list. In fact, in 1982 the main reference book for Spanish plant scholars was still Prodromus Florae Hispanicae, written in Latin in the 1800s by the German botanist Willkomm and his Danish counterpart Johan Martin Christian Lange.

“Although the heyday for Spanish botanists was the 18th century, at that time they were focusing more on the plants of the Americas,” said Aedo. “Later there was an attempt by [Mariano] Lagasca in the early 19th century, but he was forced into exile in London because of his political activity as a liberal, and another project by [Pius] Font i Quer in the 20th century, after the [Spanish] Civil War, did not come to pass either.”

Finding new species

Despite the staggering figures, the register is not final: the plant world is in a constant state of flux and new species are emerging even as others become extinct. There were even times when botanists found plants that did not match any existing records. This was the case with an asparagus plant from the southeastern Spanish region of Murcia, which was named Asparagus macrorrhizus, and grows exclusively in the few surviving sandbanks between the buildings of La Manga and San Javier near the Mar Menor, a saltwater lagoon that has made world headlines because of its life-killing pollution levels. During their endeavor, scientists have discovered other new species such as Gadoria falukei, which only grows in rocky terrain in the mountains of Gador (Almería), or Primula subpyrenaica, discovered in the Pyrenees.

What is not known cannot be protected, hence the importance of these types of tallies. The effort will help with land management, but also support research by scientists and scholars. Yet participants complain their work is not being valued. “This doesn’t happen everywhere. In the US, when a researcher who has spent 10 years collecting plants in Bolivia returns, he gets named head of the herbarium at the Missouri Botanical Garden,” said Aedo. “Any scientist wishing to survive in Spain needs to obsessively publish articles in high-impact magazines, while other structural projects are considered irrelevant. It’s the end of an era.”