by Kunjani Joshi

Swertia images
Plants named after Swertia
Gentian species used in folk medicine
Ethnobotany of gentians
Endangered gentians
Swertia in Nepalese Himalaya

Nepal, a central segment of Himalayan mountain systems, is rich in species diversity of Swertia due to its transitional location between the Paleoartic and Indo-Malayan realms, and a great variety of physiographical characteristics and abundant diverse ecosystems within a short span of space. The meadow, open forest and scrub ecosystems of the mountainous areas of Eastern, Central and Western Region of the country are the suitable habitats of the species.

 Taxonomy of Swertia  L.

The circumscription of Swertia has been subject to major change ever since its establishment. The identification and systematic arrangement of the species have carried out based only on morphological characteristics. These works show controversy in species and varieties boundaries. Some species are excluded in the respective groups and some are placed as synonyms and some new species added to the family. Recently, Joshi and Joshi (2008) have published the checklist of Swertia. Table 1 presents the 31 species of Swertia with varieties and their distribution in Nepal.

Table  1. Species of Swertia and their distribution in Nepal. Source: Joshi and Joshi (2008)  

Swertia shows wide range of morphological variation within and among the population, resulting a considerable uncertainty about the delimitation of species (Photos 1- 14). Recently, more initiatives have been taken to phylogenetic study of the species on the basis of molecular differences.  Chassot et al. (2001) have studied the DNA sequencing of some Nepalese species of Swertia (S. bimaculata, S. chirayita, S. ciliata, S. cordata, S. aff. pseudohookeri). Similarly, molecular differentiation of  11 Nepalese species: S. angustifolia, S. chirayita, S. ciliata, S. dilatata, S. lurida,, S. macrosperma, S. multicaulis, S. nervosa, S. paniculata, S. pedicillata, and S. racemosa have been investigated by Joshi in 2008 (Joshi and Li, 2008).

Biogeography of Swertia

Swertia species are widely distributed in hills and mountains of the Eastern, Central and Western Regions. Out of 75 districts of the country, Swertia species have documented from 54 districts so far (Fig.1). Such wide distribution of the species of Swertia and other plant communities could also be highlighted with the help of recent evidence of the geological past of the Asian region and migration of species from the neighboring continents. However, as there are no fossil records relating to the Swertia and other species of Gentianaceae in Nepal, it is not possible to discuss the biogeographical distribution from the palynological point of view. But formation of Tibetan Plateau and upliftment of Himalayas and other mountain ranges (Karakoram, Kunlun Shan, Tian Shan, Hengduan mountains) due to collision of Deccan Plate with the southern Laurasia coastline at about 45 million years BP in Eocene times and geobotanical development of the Himalaya might have changed climatic patterns and encounter some important changes with the dispersal and distribution of plants. At present, it is difficult to interpret these issues due to lack of data and information on inter and intraspecies linkages. Priority should be given to integrated study of the taxa and its eco-distribution for a conclusive biogeographic interpretation.

Ethnobotanical value

The rural people rely on some Swertia species for their primary healthcare and treatment of diseases. Recently, Joshi (2008) has documented the medicinal uses of some species of Swertia (Table 2). Among the species, S. chirayita is important for its medicinal properties. Adulteration of chiraito with other low quality species of Swertia and other related species are very common in the trade of chiraito.

Table 2. Ethnomedicinal uses of some species of Swertia, Source: Joshi (2008)

Strategy for Future Actions

Despite the implementation of various activities for the conservation of the species and their habitats, there is still a gap on our knowledge. Therefore, the following strategies have been recommended for sustainable management of plant resources in an environmentally sound way.

1. Formulation of Policy, Action Plan and Programs related to the conservation and sustainable uses of the economic and useful plants, especially Swertia species.
2. Intensive inventory and documentation of the useful species with indigenous uses, knowledge and practices
3. Research on molecular phylogenetics, biogeography and chemical constituents and
4. Implementation of integrated action activities:
      (a) Initiate domestication and cultivation of Swertia species. This will help in providing additional income and benefits to local people contributing to poverty alleviation and sustainable development of the resources.
    (b) Conservation of the species i.e. in-situ and  ex- situ conservation.
    (c) Awareness activities and involvement of local people in the integrated management of habitats and species.

Information by:
Kunjani Joshi, Dept. of Botany, Patan Campus, Tribhuvan University, Nepal,
at present Harvard University Herbaria, Cambridge, MA, USA; Email: kunjanijoshi@hotmail.com

References:

Chassot, P., Nemomissa, S., Yuan, Y.M. and Kupfer, P. 2001. High paraphyly of Swertia L. (Gentianaceae) in the Gentianella-lineage as revealed by nuclear and chloroplast DNA variation. Plant Syst. Evol. 229: 1-21.

Joshi, K. 2008. Swertia L. (Gentianaceae) in Nepal: Ethnobotany and Agenda for sustainable management, Environmental Leaflets 12: 1-6.

Joshi, A.R. and Joshi, K. 2008. Swertia L. (Gentianaceae) in Nepal Himalaya — Checklist, Phytogeography, Ethnobotany and Conservation Status, Environmental Leaflets 12 :357-368.

Joshi, K., and J. Li. 2008. Phylogenetics of Swertia L.( Gentianaceae-Swertiinae) and Molecular Differentiation of Swertia Species in Nepalese Medicinal Herbs. Poster Presentation, Botany 2008 conference, August, Vancouver, Canada. (pdf)

Photos:  ©Kunjani Joshi et al. (Kunjani Joshi, D.P. Rijal and A.R. Joshi)

Note:  The GENTIAN RESEARCH NETWORK does not endorse or encourage the use of gentians or gentian-derived products for any medicinal purposes or as a cure for specific diseases and ailments. The information is listed here for educational purposes only. The health value and safety of any of these plants and products has not been evaluated by us and we do not recommend any of them for medicinal use.

© Kunjani Joshi, 2008