The genus Cyananthus Wall. ex Benth. (Campanulaceae) comprises c. 20 species and exhibits a typical Sino–Himalayan distribution. Most Cyananthus species are prominent components of alpine meadows at high altitudes in this region. In India, the genus is represented by nine taxa distributed mainly in the Himalaya.
On 20 September 2025, we collected a noteworthy plant at an altitude of 3,600 m, c. 1 km from Chuna Valley near Mago village in Tawang district, Arunachal Pradesh. Voucher specimens were deposited at the Central National Herbarium (CAL; collection numbers SL, MD and SSD 101402). The plant was growing on alpine grassy and rocky slopes, with 3–7 mature and a few immature individuals. We identified it as Cyananthus hookeri C.B. Clarke, characterized by dwarf caespitose densely villous stems; rhombic or ovate, alternate pubescent leaves with crenate or entire margins; solitary, terminal flowers subtended by a whorl-like aggregation of 3–5 leaves; calyx densely hirsute outside with long stiff hairs; corolla purple-blue, outside glabrous, inside densely villous at throat; lobes narrowly obovate or oblong, apex often with brown-yellow villous hairs, style extending above corolla throat, and stigma 4-fid.
Cyananthus hookeri was described from Wallanchoon, eastern Nepal, in 1912. It occurs throughout the eastern Himalayas, in Bhutan, China, India and Tibet, but with a restricted distribution. We searched Indian and other herbaria and located only two collections from India, from Sikkim in 1867, at 3,657 m, by Sir J. D. Hooker, at herbaria K (K000814099) and P (P00650044). Our new collection is thus the first in India for 158 years and the first in Arunachal Pradesh.
We observed < 50 mature individuals, and therefore we recommend the species to be categorized as Endangered nationally in India, based on IUCN criteria B1ab(iv,v); i.e. extent of occurence < 5,000 km2 (B1), limited to less than five locations (a) and a continuing decline inferred (b) in number of locations or subpopulations (iv) and number of mature individuals (v). This reflects the extinction risk faced by C. hookeri in India and will help to mobilize resources for appropriate conservation action.
Cyananthus hookeri in flower in Chuna Valley, Tawang district, Arunachal Pradesh, India.
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