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Rediscovery of Swertia dilatata var. pilosa after 140 years

Published online by Cambridge University Press:  25 March 2024

Sunit Singh
Affiliation:
Department of Botany & Microbiology, HNB Garhwal University, Srinagar (Garhwal), Uttarakhand, India
J. P. Mehta
Affiliation:
Department of Botany & Microbiology, HNB Garhwal University, Srinagar (Garhwal), Uttarakhand, India
Amber Srivastava*
Affiliation:
Botanical Survey of India, Northern Regional Centre, Dehradun, Uttarakhand, India
Sushil Kumar Singh
Affiliation:
Botanical Survey of India, Northern Regional Centre, Dehradun, Uttarakhand, India

Abstract

Type
Conservation News
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence CC BY 4.0.
Copyright
Copyright © The Author(s), 2024. Published by Cambridge University Press on behalf of Fauna & Flora International

In India, the genus Swertia L. of the family Gentianaceae is represented by 36 species and 10 varieties, distributed mainly in temperate and alpine Himalayan regions but with a few species in the Western Ghats. The genus is highly valued for its medicinal importance and most of the species are known by the common names chirayita or chiroto. Swertia chirayita is a highly exploited species facing severe threats. With similar morphological appearance in their vegetative state, most of the allied species are also exploited from the wild and are thus threatened. Because of their complex taxonomy, limited data are available on the distribution of allied species, and only eight have been assessed for the IUCN Red List.

Swertia dilatata, which is closely allied to Swertia purpurascens and Swertia paniculata, is differentiated mainly on the basis of dilated stamen filaments. It was first described by C.B. Clarke from Nepal in 1883 along with a variety, S. dilatata var. pilosa. The two varieties can be differentiated by the greenish yellow corolla and glabrous leaf and calyx of S. dilatata var. dilatata and pale to purplish pink corolla and hairy leaf and calyx of S. dilatata var. pilosa. Variety dilatata is common, reported from the eastern Himalayas of India, Nepal, China and Myanmar, but variety pilosa has not been recorded since the type collection.

Swertia dilatata var. pilosa, showing (a) habit, (b) leaf, (c) flower bud, (d) flower, (e) corolla, (f) calyx, (g) stigma and (h) stamen.

In October 2023, during a field trip to the East Pindar range in Badrinath Forest division of Chamoli district, Uttarakhand, India, we collected a specimen of Swertia from the Deval region. We identified it as S. dilatata var. pilosa, the first record of this variety after 140 years and the first record in India. The specimen has been deposited in the herbarium of HNB Garhwal University, Srinagar (GUH).

We observed that unlike other species of the genus, S. dilatata var. pilosa is uncommon. We found only a few individuals, growing in semi-shaded localities of evergreen forest of Cupressus torulosa D. Don ex Lamb. We currently consider this variety to be Data Deficient but we are working on a full assessment for the IUCN Red List.