A rare plant species believed to have vanished from scientific records for nearly two centuries has been rediscovered in Arunachal Pradesh, highlighting the region’s remarkable yet still poorly documented biodiversity.
Researchers from the Botanical Survey of India (BSI) have recollected Henckelia monophylla—a unique one-leaved flowering plant—after a gap of 189 years in Lohit district of Arunachal Pradesh. The species was last documented in 1836 by British botanist William Griffith during his explorations in the Mishmee Hills.
The rediscovery was made during a field exploration along the Tezu–Salangam road, where scientists Krishna Chowlu and Simanta Taid located a healthy population of the plant growing in moist, shaded roadside habitats.
What makes Henckelia monophylla particularly striking is its unusual morphology. Mature plants typically produce only a single large leaf, from which a flower stalk emerges—an uncommon feature among flowering plants. The plant bears pinkish-white tubular flowers about 7 cm long, making it visually distinctive in its forest habitat.
Although Griffith collected the plant in the 19th century, no botanist had reported the species again for nearly two centuries, making the latest finding a significant botanical rediscovery.
Griffith, an English surgeon-botanist who later served as Superintendent of the Calcutta Botanic Garden, travelled extensively across India and Southeast Asia in the early 1800s. During an expedition to the remote Mishmee Hills in 1836–37, he collected several plant specimens, including the unusual one-leaved species then classified under the genus Chirita, which has since been placed in the genus Henckelia.
The recent collection has also helped clarify the plant’s taxonomic identity and designate a second-step lectotype specimen, refining its scientific classification.
Despite the encouraging rediscovery, the plant remains highly vulnerable. Researchers recorded just over 500 mature individuals at a single locality, and the species faces threats from landslides and developmental activities in the region.
Based on its extremely restricted population and distribution, scientists have assessed the species as Vulnerable under IUCN criteria.
The rediscovery underscores the rich yet understudied biodiversity of Arunachal Pradesh, particularly in remote areas such as the Mishmee Hills.
Scientists say such findings highlight the urgent need for continued botanical exploration and conservation efforts in the Eastern Himalaya, one of the world’s most important biodiversity hotspots.
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