The genus Swertia L. is represented by nearly 168 species occurring mainly in temperate and alpine regions. In India, the genus is represented by 36 species, mainly distributed in the Himalayan region, and with few a species occurring in the Western Ghats. Nine species are endemic to India and have been recorded in only a few locations or have a restricted range.

Swertia wattii C.B. Clarke is a micro-endemic species reported from only a single locality. It was described by C.B. Clarke in 1889 on the basis of collections in October 1885 from Jakpho hill (also known as Mount Japfu) in the Naga hills of Nagaland state. Because of the lack of details available for this species it has sometimes been erroneously merged with the closely related Swertia paniculata Wall.

Swertia wattii flowering on Japfu hill in the Naga hills of Nagaland state. Photo: A. Srivastava.

While working on the revision of genus Swertia L. in India, author AS surveyed localities in the Naga hills lying in Manipur and Nagaland states during 19 September–3 October 2023. On Japfu hill AS located a small population of S. wattii (LWG 119225) on a hill top at 3,024 m and on the adjoining slopes of Dzukou valley at 2,600 m. This is the first record of the species since 1885. The species is locally common on open hill slopes where it grows amidst the native dwarf bamboo Sinarundinaria rolloana (Gamble) C.S.Chao & Renvoize. We recorded the species in a total of 11 locations on Japfu hill and the adjoining Dzukou hills.

The main threat to the species is seasonal forest fires caused by anthropogenic factors, but it is also exploited for medicinal use, with the decoction used as a febrifuge. Our observations indicate that S. wattii is endemic to a narrow geographical area. A single stochastic event or any change in land use could result in a major depletion of the population.

This is communication number CSIR-NBRI_MS/2024/03/09 of the Council of Scientific and Industrial Research–National Botanical Research Institute.