With over 2050 known species, Begonia is one of the largest plant genera. Since most begonias are small weeds, a begonia taller than a human is a very unusual sight. However, the newly discovered Begonia giganticaulis is one of the few exceptions.
In 2019, Dr. Daike Tian and his colleagues initiated a field survey on wild begonias in Tibet, China. On September 10, 2020, when Dr. Tian saw a huge begonia in full bloom during surveys in the county of Mêdog, he got instantly excited. After checking its flowers, he was confident it represented a new species.
Dr. Daike Tian with an individual of Begonia giganticaulis. Photo by Qing-Gong Mao The research team measures the height of a Begonia giganticaulis individual at its collection site. Photo by Qing-Gong Mao
From a small population with a few dozens of individuals, Dr. Tian collected two of the tallest ones to measure them and prepare specimens necessary for further study. One of them was 3.6 meters tall, the thickest part of its ground stem close to 12 cm in diameter. To measure it correctly, he had to ask the driver to stand on top of the vehicle. In order to carry them back to Shanghai and prepare dry specimens, Dr. Tian had to cut each plant into four sections.
To date, this plant is the tallest begonia recorded in the whole of Asia.
Begonia giganticaulis, recently described as a new species in the peer-reviewed journal PhytoKeys, grows on slopes under forests along streams at elevation of 450–1400 m. It is fragmentally distributed in southern Tibet, which was one of the reasons that its conservation status was assigned to Endangered according to the IUCN Red List Categories and Criteria.
After being dried at a herbarium and mounted on a large board, the dried specimen was measured at 3.1 m tall and 2.5 m wide. To our knowledge, this is the world’s largest specimen of a Begonia species. In October 2020, the visitors who saw it at the first Chinese begonia show in Shanghai Chenshan Botanical Garden were shocked by its huge size.
Currently, the staff of Chenshan Herbarium is applying for Guinness World Records for this specimen.
Tian D-K, Wang W-G, Dong L-N, Xiao Y, Zheng M-M, Ge B-J (2021) A new species (Begonia giganticaulis) of Begoniaceae from southern Xizang (Tibet) of China. PhytoKeys 187: 189-205.https://doi.org/10.3897/phytokeys.187.75854