Fieldwork and old-fashioned sleuthing are combining to unravel mysteries of the plant world. Now, B2K has been conquered: not a mountain, but a milestone in the study of biodiversity for partner scientists in Asia, the Americas and Edinburgh. Research into new plant collections and historic records has broken through the barrier of 2000 Begonia species known to science.

Notably once described as a “repulsive” bedding plant by gardening guru Monty Don, the Begonia is one of the world’s largest flowering plant genera and much is still to be learned about its evolution and distribution in the wild. With the race underway to catalogue life of Earth in the face of the biodiversity crisis, rigorous fieldwork is key to research. In recent weeks, however, scientists at the Royal Botanic Garden Edinburgh (RBGE) and their international partners have also capitalised on some traditional detective work in unravelling secrets of new and lost species.

Dr Mark Hughes, a tropical botanist focussing on this mega-diverse genus, explained the significance of breaching the B2K landmark: “Keeping track of species names is fundamental to plant biodiversity accounting,” he said. “To record the 2000^th species of Begonia is a major accomplishment in a long-term project which not only involves cultivating and recording species new to science but also poring over historic records for others that have been missed or misidentified over the generations.

“While Herbarium and Archive records here, at RBGE, and at our partner organisations around the world are significant, there are challenges in streamlining the various banks of information. In particular, many of the older species’ names were published in rare journals. These and their associated specimens need to be traced and verified as part of our wider research. With improvements in technology and information sharing, and a more coordinated approach, we are now seeing real dividends.”

The last decade has witnessed substantial progress in Begonia studies, with between 50 and 100 species being added each year. They have included species that are striking to the eye, fragile, bizarre, critically endangered and even the smallest ever found. A flurry of new species in the first weeks of 2021 has taken numbers of known species beyond the 2000 barrier.

One of these finds has significant backstory, Dr Hughes revealed: “During an expedition to North Sumatra, Indonesia, in late 2018, colleagues from Bogor Botanical Gardens, Java, found an unusual Begonia in the forests near Lake Toba. Since then, we have been undertaking a joint investigation and, from going into the Archives and examining careful and meticulous records dating back to 1822, we are now in no doubt, we have Begonia fasciculata. Not a new species, but one that has not been recorded as living for nearly 200 years.

“This species was described as new to science by the indefatigable William Jack, a polymath who graduated from Aberdeen University at the age of 16. Jack had a photographic memory for plants. He worked in Sumatra with Stamford Raffles, the founder of colonial Singapore, and commandeered a printing press from missionaries to produce an account of the plant species he collected in 1822.

“Shortly after his work was printed, Jack died of a fever, probably malaria. Then, the ship chartered to convey his plant collections to England, ballasted with gunpowder, caught fire and the living material was atomised off the south coast of Sumatra. Many of the species Jack described have not been recorded growing anywhere since. Fortunately, his records still exist and – after much scrutinising - confirmed what we suspected; this is not a new but a rediscovered species.”

While B2K marks an impressive milestone, the work is far from over and it is anticipated at least another 500 species in the dense and diverse forests of New Guinea and Borneo will eventually be described as new to science. Each of these needs to be studied closely and given a name. Only then, can they have a conservation status and scientists start the lengthy process of properly understanding them, their relevance within their natural habitats and relationship with other living entities.

Find out more about our Begonia research programme.