Begonia in the herbarium
Herbaria are essentially plant libraries, collections of specimens used for identification and classification of plants. Restricted to private collections before the 19th century, herbaria began to emerge as national institutes during the Victorian era. During this golden age of botanical discoveries, the colonial expansion of European nations allowed naturalists to discover and classify exotic species, keeping type specimens as morphological references for botanists and taxonomists.
Since the end of the 20th century and the start of the genomic era, herbarium specimens have become an invaluable biological resource for genomic studies. Reflecting the genetic diversity of their populations at a certain point in time and space, they are unique biological markers to assess the evolution of plant population genetics, biogeography, and ecology through time.
My ESR11 project is focusing on the genetic evolution of Begonia populations over time, using herbarium specimens. The first batch of specimens analyzed in this study belongs to the species B. socotrana and B. samhaensis, which are endemic to the Socotra archipelago located on the east coast of Yemen. B. samhaensis has been described by M. Hughes & A.G. Miller in 2002 and a specimen is available for sampling in the Royal Botanical Garden of Edinburgh herbarium. B. socotrana on the other hand has been described much earlier in 1880 by Isaac Bayley Balfour during a British Association expedition to the island of Socotra. Since, different expeditions have collected this species in different geographical locations and at different times: Dr. Balfour (1880), Mr. & Ms Bent (1897), A.G. Miller (1989), and M. Thulin & A.N. Gifri (1994).
In order to accurately trace the evolution of the B. socotrana populations over time, different European institutes have been contacted to include the most diversified specimen samples from these expeditions. So far, the Uppsala Museum of Evolution and the Royal Botanic Gardens, Kew have kindly granted several specimens from areas as diverse as the limestone Reiged plateau on the North coast of the island, the Mugadrihon pass, and the Hajhir mountains. These precious historical samples will be included in a genome-wide analysis batch with more recently collected B. socotrana plants and used to model the evolution of Begonia populations on the island from the 19th century up to modern times.