Checklist of Orchids of Kottavasal Hills in Achancoil Forests, southern Western Ghats, (Kollam, Kerala), India

Jose Mathew 1 & K.V. George 2

1 School of Environmental Sciences, M.G University, Kottayam, Kerala 686560, India

2Department of Botany, CMS College, Kottayam, Kerala 686001, India

1 polachirayan@yahoo.co.in (corresponding author), 2 kvgeorge58@yahoo.in

doi: http://dx.doi.org/10.11609/JoTT.o3859.7691-6

Editor: Pankaj Kumar, Kadoorie Farm and Botanic Garden, Tai Po, Hong Kong. Date of publication: 26 August 2015 (online & print)

Manuscript details: Ms # o3859 | Received 21 November 2013 | Final received 05 May 2015 | Finally accepted 30 July 2015

Citation: Mathew, J. & K.V. George (2015). Checklist of Orchids of Kottavasal Hills in Achancoil Forests, Southern Western Ghats, (Kollam, Kerala), India . Journal of Threatened Taxa 7(10): 7691–7696; http://dx.doi.org/10.11609/JoTT.o3859.7691-6

Copyright: © Mathew & George 2015. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

Funding: None.

Competing interests: The authors declare no competing interests.

Acknowledgements: The authors are thankful to the Director, School of Environmental Sciences, M.G. University, Kottayam, Kerala for suggestions and encouragement. The first author benefited greatly from discussions with the reviewers.

Abstract: The orchidaceous plant treasures in the Kottavasal Hills of Achancoil Shear Zone of the southern Western Ghats, situated in Kerala and a part of Agasthyamalai Biosphere Reserve, have not been subjected to a detailed floristic investigation. Field surveys were conducted during the period 2009–2012 and 53 orchid taxa were collected and documented. The present study points out that the orchid flora of Achancoil Shear Zone tends to have an affinity to the remnants of the Mozambique belt.

Keywords: Achancoil, orchids, southern Western Ghats.

Achancoil is a shear zone (ASZ) that lies between the Madurai granulite block and Trivandrum khondalitic block. It is the continuum of the Mozambic belt of pan African orogeny, passing through Madagascar to Sri Lanka. The rock type and its genesis show the affinity of AKSZ to the remnants of the Mozambic belt, especially Sri Lanka (Rajesh et al. 1998). Biological linkages in between these geographical segments have great significance and hence worthy to be subjected to detailed investigation. The Kottavasal Hills are the highest hill ranges in the ASZ (Fig. 1).

Orchidaceae is one of the largest families of flowering plants in the world (Atwood 1986) with many species locally restricted and are generally rare (Benavides et al. 2005). Orchids comprise five subfamilies and approximately 870 genera and 30,000 species (Dressler 1993; Chen et al. 2009; Govaerts et al. 2009). Verma & Lavania (2014) reported 1414 orchid taxa under 186 genera from India; 265 taxa are found in Kerala comprising 108 terrestrials including six mycoheterotrophs and 157 epiphytic species distributed along different forest types (Sasidharan 2013). Orchid flora is one of the important components of tropical montane rainforests and grasslands like that of Achancoil for which there is no available literature.

This study deals with the enumeration of orchid flora of the seasonally inundated tropical montane forests and grasslands of Kottavasal in the ASZ of the southern Western Ghats. Endemic orchids have also been marked.

Methods

The study area is situated in Agasthyamalai Biosphere Reserve of Kerala, a part of the southern Western Ghats, about 40km east of Punalur and 30km west of Shenkottai, Tamil Nadu, within 09003’11”–09005’36”N & 77010’14”–77013’09”E. The study area includes 12km2 of the tropical montane evergreen forest to grasslands. The altitudinal range varies from 751–1500 m. The survey for orchids was conducted during 2009–2012 and voucher specimens were collected to verify the taxonomy and distribution of each species using various publications (Fischer 1928; Sasidharan & Sivarajan 1996; Ramachandran & Nair 1988). Herbarium studies were also conducted to confirm the identity of each species at Kerala Forest Research Institute (KFRI), Jawaharlal Nehru Tropical Botanical Garden and Research Institute (JNTBGRI) and Calicut University (CALI). The occurrence and distribution of listed species were verified and analyzed with the help of standard publications (Ahmedullah & Nayar 1986; Gopalan & Henry 2000; Sasidharan 2013). The voucher specimens were deposited in the School of Environmental Sciences Herbarium, Mahatma Gandhi University, Kottayam, Kerala.

Results and Conclusion

During the present study, 53 orchid species belonging to 38 genera were recorded (Table 1). Among these orchids, 30 species (57%) were epiphytes, 17 (32%) were terrestrials and 6 (11%) were lithophytes. The present explorations resulted in the enumeration of 50 Asiatic elements. Among these, 15 species (28%) are considered endemic to India, viz.: Anoectochilus elatus, Brachycorythis iantha, Bulbophyllum tremulum, Coelogyne nervosa, Conchidium filiforme, C. microchilos, Dendrobium georgei, D. kallarense, Eria pauciflora, E. mysorensis, H. longicornu, Luisia macrantha, Trias bonaccordensis, T. stocksii and Vanilla wightiana; 15 taxa (28%) are Indo-Sri Lankan; and 11 taxa (21%) are Indo-Malayan elements. Indo-Chinese, Indo-Myanmar and Indo-Nepal elements contribute a single taxon representation (2% each). Four taxa (7.5%) in the orchid flora of Kottavasal Hills were enlisted from three or more provinces of Asia. Of the remaining, five species (10 %) were treated as Afro-Asian, Australasian and Pantropical elements (Table 1).

Endemicity of the orchids in the Kottavasal Hills throws light on the significance of biogeography of ASZ (Images 1–14). It is assumed that the invasion of African elements to the peninsular Indian region and migration of Indian endemics to Sri Lanka might have occurred along with the splitting of the Mozambic belt (Mathew 2015). Calanthe sylvatica present in the foothills of Kottavasal, is widespread from Africa, through Madagascar, Indochina to Sri Lanka (Sasidhran 2013). Besides that, the moderate rate (28%) of Indo-Sri Lankan orchids in ASZ validates the above hypothesis.

References

Ahmedullah, M. & M.P. Nair (1986). Endemic Plants of the Indian Region, Peninsular India - Volume I. Botanical survey of India, Calcutta, 262pp.

Atwood, J.T. (1986). The size of the Orchidaceae and the systematic distribution of epiphytic orchids. Selbyana 9: 171–186.

Benavides, A,M., A.J. Duque, J.F. Duivenvoorden, A. Vasco & R. Callejas (2005). A first quantitative census of vascular epiphytes in rain forests of Colombian Amazonia. Biodiversity and Conservation 14(3): 739–758; http://dx.doi.org/10.1007/s10531-004-3920-9

Chen, X.Q., Z.J. Liu, G.H. Zhu, K.Y. Lang, Z.H. Ji, Y.B. Luo, X.B. Jin, P.J. Cribb, J.J. Wood, S.W. Gale, P. Ormerod, J.J. Vermeulen, H.P. Wood, D. Clayton & A. Bell (2009). Orchidaceae, pp. 1-506. In: Wu, Z.Y., P.H. Raven & D.Y. Hong (eds.). Flora of China. Science Press, Beijing and Missouri Botanical Garden Press, St. Louis.

Govaerts, R., M.A. Campacci, D.H. Baptista, P.J. Cribb, A. George, K. Kreutz & J.J. Wood (2009) World checklist of Orchidaceae. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/monocots/ [accessed on 02 February 2015; 18:42 HT].

Dressler, R.L. (1993). Phylogeny and Classification of The Orchid Family. Dioscorides Press, Portland, 314pp.

Fischer, C.E.C. (1928). Orchidaceae, 1399–1478. In: Gamble, J.S. (ed.). Flora of Presidency of Madras. West, Newman and Adlard, London.

Gopalan, R. & A.N. Henry (2000). Endemic plants of India: CAMP for the strict endemics of Agasthyamalai Hills, Southern Western Ghats. Bishen Singh Mahendra Pal Singh, Dehra Dun, 476pp.

Mathew, J. (2015). Floristic and ethnobotanical studies of Achankovil Forests, Western Ghats, Kerala. PhD Thesis. School of Environmental Sciences, Mahatma Gandhi University, XIV+800pp.

Rajesh, H.M., M. Santosh & M. Yoshida (1998). Dextral Pan-African shear along the southwestern edge of the Achancoil shear belt, South India: constraints on Gondwana reconstructions: a discussion. The Journal of Geology 106: 105–114.

Ramachandran, V.S. & V.J. Nair (1988). Flora of Cannanore. Botanical Survey of India, Calcutta, 599pp.

Sasidharan, N. & V.V. Sivarajan (1996). Flowering Plants of Thrissur Forests. Scientific Publishers, Jodhpur, 579pp.

Sasidharan, N. (2013). Flowering Plants of Kerala: CD-ROM ver 2.0. Kerala Forest Research Institute, Peechi, Kerala.

Verma, D. & S. Lavania (2014). Addition to the Orchid Flora of Meghalaya, India. Richardiana 15: 105–114.