An ashy folder is opened to reveal a grass specimen, brown in colour after preservation, glued on to thick paper and neatly labelled. Taking a leaf from this folder reveals a lot about the botanic wealth of India. “This is Hubbardia heptaneuron, a grass that was found in the spray zone of Jog Falls in Karnataka. It became extinct in those parts after the waterfall dried up temporarily due to the setting up of a Linganamakki reservoir,” explains V. Pandurangan, director of Jawaharlal Nehru Tropical Botanic Garden and Research Institute (JNTBGRI). Situated inside the JNTBGRI near Palode, Thiruvananthapuram, the herbarium with a collection of more than 38,000 specimens of plants from common trees to endemic orchids, housed inside the plant systematics and evolutionary science department building, is the crown jewel of the institute. Plant systematics and evolutionary science department | Photo Credit: Aswin V.N. Pandurangan explains the significance of a herbarium in one line: “If a plant species specimen is not in a herbarium, then it doesn’t exist as far as researchers are concerned.” A herbarium is a botanical repository that keeps chemically treated and pressed plant samples for reference purposes. In short, it is a museum of plants. “The entire field of plant taxonomy, the science of naming plant species, is built around herbariums and, without it a scientific study of plants cannot be done,” says Pandurangan. A repository of plant species found across a large region is extremely important for researchers as everyone may not be able go on the field to collect a sample for study. Instead, they can use the sample in herbariums for research. Founded in 1979 by A. Abraham, first director of the institute, the herbarium used to be housed in a building near the main office near the entrance. “During the time of the British Raj, University College in Thiruvananthapuram was an active centre of plant taxonomy and they had a good collection there. That was shifted to our herbarium when it started functioning,” says Pandurangan. In 2006, the new building was inaugurated and the herbarium was shifted to its current location. Garcinia imberti, Kokum specimen collected by T.S. Bourdilon in 1895 | Photo Credit: Aswin V.N. Although the term ‘plant museum’ might sound fancy, herbariums are closer to libraries than conventional museums. Plant samples dried and glued onto thick handmade paper are kept in files and stored inside large metallic cupboards based on the families they belong to. “The paper is special and will last for decades. A label containing what is known as the passport information is glued alongside the plant in which the taxonomy of the specimen, location and date of collection, name of the collector and special characteristics of the specimen would be recorded,” explains the director. The information on the passport card is what gives future botanists information on how to identify and where to look for a species. If multiple discoveries of the same species are made, then there is a chance of them being named differently by the discoverers. Along with the internationally approved name of the species and the name of the researcher who fixed it, all the different names provided to it by past botanists will also be recorded in the files to avoid future confusion and for study purposes. Paphiopedilum druryi, orchid variety endemic to Agasthyamala region | Photo Credit: Aswin V.N. This systematic process is especially important in the case of plants that have not been recorded in the wild in a long time. For instance, although discovered more than a 100 years ago, Paphiopedilum druryi, an orchid species found in only the Agasthyamala region, was believed to be extinct. “Since the samples collected in the 1800s were kept in herbariums, botanists knew where to look for it and that is how it was rediscovered. Whenever a researcher finds something that we don’t have in our collection, we check with other herbariums like the one at Kew Gardens in London, one of the biggest in the world, as they would have samples of all Indian plant species discovered during the colonial era,” says Panduragan. Botanists would only go about naming it as a new species, following the rules of International Code of Botanical Nomenclature, if they are not able to find a match for the specimen at any of the herbariums around the world. A sample of new species collected will also be sent, usually on request, to other herbariums like Kew Gardens. “Likewise, if we don’t have a species in our collection, we can request for a sample from other herbariums where they might have multiple samples,” he adds. British botanists of the colonial era also made sure that samples of whatever they collected were kept in herbariums in India as well. “If at some point these species become extinct, then these samples can be used for study purposes. These old samples would also help in understanding what changes the species have undergone since the time it was collected,” he says. The biggest challenge the herbarium staff face is pest control. Insects might damage folders, paper and sample specimens. To avoid that, cupboards are treated with pesticides twice every year. “These chemicals are carcinogenic. So we are trying to phase them out by shifting to a deep-freezing pest killing method. The folders are frozen in a three-way process up to -40 degree Celsius, which would destroy even the eggs of the pests,” says G. Rajkumar, head of the department. As the next step forward, the institute is in the process of digitising the collection. When it is finished, researchers would be able to access the herbarium collection via the Internet from anywhere around the world. Pandurangan says, “At one point, many of these species would only be found in herbariums. So, at the end of the day, what we are doing is preserving knowledge and a valuable gene pool of plants for future generations.”

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