Pleione 11(1): 116 - 124. 2017. ISSN: 0973-9467 © East Himalayan Society for Spermatophyte

Endemic monocot flora of Darjeeling Himalaya, West Bengal,

Suman Nirola1 and A. P. Das Taxonomy & Environmental Biology Laboratory, Department of Botany, University of North Bengal, Siliguri 734013, West Bengal, India E-mail: [email protected]; [email protected] 1Communicating author [Received 12.04.2017; Revised 15.06.2017; Accepted 22.06.2017; Published 30.06.2017]

Abstract The district of Darjeeling is found to be an ideal home to a remarkable number of endemic taxa like any other part of the Great Himalayas and, in turn, the endemic elements of the district will substantially contribute to the endemic flora of the country. Recent comprehensive study on monocotyledonous angiosperms of Darjeeling district documented 768 taxa at species and infra-specific ranks of which 76 species i.e. 9.9 % are found to be endemic in different phytogeographical divisions of the Himalayan context, with an interesting fact that twelve species are exclusively endemic to Darjeeling-Sikkim Hills. Conservation status of orchids in Darjeeling Hills has been discussed. Key words: endemic monocotyledonous angiosperms, Darjeeling Himalaya

INTRODUCTION Before the compilation of his Flora of British India, in 1849 Sir J.D. Hooker commented that Indian flora is the representation of migratory species. But, with the end of his own work in 1904 he reassessed his views as he recognized a very high proportion of endemic species in the area. Later on with the efforts of other explorers it has been proved that India is a suitable home for the endemic flora. It hosts about 6850 endemic species and of which almost half i.e. 3165 species (46.2 %) are growing in the Himalayan region (Chatterjee 1940). With the latter studies undertaken by many workers it is being estimated that about 60 % of the Indian flora is of Indian origin, and out of which 14 % being exclusively endemic to India (Chatterjee 1940, 1962). About 60 genera are found restricted to the Indian Himalaya (Nayar 1980) and many have restricted distribution extended to Tibet, S.W. and Myanmar (Ahmedulla 2000). About 40 genera are confined to the Eastern Himalaya while 11 are to the Western Himalaya (Ahmedulla 2000). According to Chatterjee (1940), distribution of 3161 endemic species are restricted to the Himalayas. In respect to the district of Darjeeling, it being a part of IUCN recognized Himalaya Biodiversity Hotspot (http://www.biodiversitya-z.org/content/biodiversity-hotspots.pdf; Mittermeier et al. 2005), is not contradictory with other regions of its parallel. Records prevail that 30 % of the recorded species of dicotyledonous are endemic to Eastern Himalaya (Das 1986, 1995, 2004; Bhujel 1996; Bhujel & Das 2002). Latest studies on dicotyledonous flora of the district Bhujel (1996) listed about 405 endemic dicot species (15.79 %) in Darjeeling district occurring along Eastern Himalaya and North-East India of which 29 species were restricted within the district. From a narrow tract of Senchal Mountains Suman Nirola & A.P. Das 117 from Kurseong to Lebong, Das (1986) reported over 10 % endemic angiosperms. In 2004, Das recorded a total of 404 dicotyledonous species occurring in Darjeeling district. While exploring the virgin vegetation of Neora Valley National Park, with an area of only 88 sq km, Rai (2001) recorded over 14 % of plant taxa as endemic to Himalayan region. Recent comprehensive studies on the monocotyledonous flora of Darjeeling district Nirola (2015) documented a total of 768 species, subspecies and varieties of monocotyledonous angiosperms and as much as 76 species of which are found to be endemic in different phytogeographical divisions of the Himalayas that expresses almost 10 % endemism among this major group of the plant kingdom. It becomes more interesting as ten species are exclusively endemic to Darjeeling and Sikkim Hills region only. Phytogeographically the Great Himalayas has been divided into 3 main divisions, namely Western Himalaya (Kashmir and Himachal Pradesh), Central Himalaya (Uttarakhand to Western Nepal) and Eastern Himalaya (East Nepal to Arunachal Pradesh) (Chatterjee 1962). The Eastern Himalaya comprises the Geographical boundaries of eastern Nepal, the Darjeeling-Sikkim Himalaya, Bhutan and Arunachal Pradesh. To assess the endemism, particularly of the Darjeeling district and to find out their status, the East Himalayan region can be divided into four phytogeographical divisions as (a) Nepal portion (Western quarter of E. Himalaya), (b) Darjeeling-Sikkim Himalaya (West-Central quarter of E. Himalaya), (c) Bhutan (East-Central quarter of E. Himalaya) and (d) Arunachal Pradesh (Eastern quarter of E. Himalaya). In accordance to above phytogeographical divisions the endemism of the floristic elements of Darjeeling district can also be studied as follows (Das 1986, 2004): 1. Taxa Endemic to Darjeeling and Sikkim 2. Taxa Endemic for Nepal to Bhutan 3. Taxa Endemic to Eastern Himalaya 4. Taxa Endemic for Eastern Himalaya and NE India 5. Taxa Endemic to Himalayas (Kashmir to Arunachal Pradesh) Following this framework of various zones of Himalayas as well as of Eastern Himalaya and little extending to the Northeast India, the recorded monocotyledonous flora showed endemism as follows:

I. Endemic to Darjeeling and Sikkim Ten monocot species are identified to be exclusively endemic to the hills of Darjeeling and Sikkim Himalayas and the foothills and adjoining Dooars region. 40 % of these species are orchids. Three of these are the newly recognized taxa and are listed in Table 1. Table 1. Monocotyledonous species Endemic to Darjeeling and Sikkim Himalayas Names of Plants Family Acampe praemorsa var. flava Das et al Goodyera hemsleyana King & Pantl. Orchidaceae Liparis tigerhillensis A.P.Das & Chanda Orchidaceae Nervilia gammieana (Hook. f.) Pfitzer Orchidaceae Cyperus sikkimensis Kuk. Cyperaceae Gastrochilus corymbosus A.P.Das & Chanda Cyperaceae Globba teesta S.Nirola & A.P.Das Zingiberaceae Globba andersonii C.B.Clake ex Baker Zingiberaceae Musa sikkimensis Kurz Musaceae Typhonium roxburghii var. longispathum S.Nirola & Araceae A.P.Das 118 Endemic of Darjeeling Himalaya II. Endemic for Eastern Nepal to Bhutan There are also some elements those have quite restricted distribution from Eastern Nepal to Darjeeling-Sikkim Himalayas or Darjeeling-Sikkim Himalayas and Bhutan etc, their distribution have been assumed from Eastern Nepal to Bhutan. As such 8 species are reported from Darjeeling district are listed below in Table 2. Out of these three belongs to Cyperaceae (Carex spp.) and three of Poaceae. Table 2. Monocotyledonous species Endemic for Eastern Nepal to Bhutan region Names of Plants Family Carex daltonii Boott Cyperaceae C. decora Boott Cyperaceae C. pulchra Boott Cyperaceae Bromus himalaicus Stapf Poaceae Cymbopogon bhutanicus Noltie Poaceae Poa gammieana Hook. f. Poaceae Lecanorchis sikkimensis N.Pearce & P.J.Cribb Orchidaceae Tofieldia himalaica Baker Tofieldiaceae

III. Endemic to Eastern Himalaya The taxa having restricted distribution within the East Himalayan region as a whole that is extending from Eastern Nepal to Arunachal Pradesh are taken under this category. Maximum numbers of endemic species fall under this category. A record of 11 monocot plant species are recognized as endemic to this region as presented in Table 3. The record reveals that majority of these species are from Poaceae (4 species) and Orchidaceae (4 species). Table 3. Monocotyledonous taxa Endemic to Eastern Himalaya

Names of Plants Family Arisaema griffithii Schott Araceae Peliosanthes griffithii Baker Asparagaceae Drepanostachyum intermedium (Munro) Keng f. Poaceae Yushania microphylla (Munro) R.B.Mazumdar Poaceae Y. maling (Gamble) R.B.Mazumdar & Karthik. Poaceae Festuca polycolea Stapf Poaceae Agrostophyllum myrianthum King & Pantl. Orchidaceae Bulbophyllum yoksunense J.J.Sm. Orchidaceae Gastrochilus dasypogon (Sm.) Kuntze Orchidaceae Papilionanthe uniflora (Lindl.) Garay Orchidaceae Smilax wallichii Kunth Smilacaceae IV. Endemic to Eastern Himalaya and North-East India Considering a fact to be respected that due to much similarities in climatic, physical and geographical conditions, the similarities are also being reflected by the vegetation of many places of North Eastern sister states of India. The floristic elements of Garo, Jayanti and Khasia hills of Meghalaya, hills of Manipur, Nagaland, Mizoram, Tripura and even the plains of Assam exhibit co-relationship with that of the Eastern Himalaya in many aspects. In this regard a large number of endemic monocot plants of Eastern Himalaya showed a little leap towards these places. Therefore a category of monocot species of Darjeeling district found endemic to Eastern Himalaya including the one or more states North-East India has been Suman Nirola & A.P. Das 119 taken in consideration. The result revealed that these category of plants are occupied mostly by the members of Zingiberaceae (11 spp.), Orchidaceae (8 spp.), and Poaceae (4 spp.) A considerable number of 36 such elements are listed below in Table 4.

Table 4. Monocotyledonous Taxa Endemic to Eastern Himalayas Extending to North-East India Names of species Families Arisaema speciosum var. mirabile (Schott) Engl. Araceae Amorphophallus napalensis (Wall.) Bogner & Mayo Araceae Calamus latifolius Roxb. Arecaceae C. leptospadix Griff. Arecaceae Phoenix rupicola T.Anderson Arecaceae Ophiopogon wallichianus (Kunth) Hook. f. Asparagaceae Tupistra nutans Wall. ex Lindl. Asparagaceae Carex vesiculosa Boott Cyperaceae Dioscorea prazeri Prain & Burkill Dioscoreaceae Eriocaulon edwardii Fyson Eriocaulaceae Molineria crassifolia Baker Hypoxidaceae Bulbophyllum gamblei (Hook. f.) Hook. f. Orchidaceae B. sarcophylloides Garay, Hamer & Siegerist Orchidaceae Crepidium josephianum (Rchb. f.) Marg. Orchidaceae Dendrobium amoenum Wall. ex Lindl. Orchidaceae Esmeralda cathcartii (Lindl.) Rchb. f Orchidaceae Liparis nervosa var. khasiana (Hook. f.) P.K.Sarkar Orchidaceae Oberonia angustifolia Lindl. Orchidaceae Platanthera biermanniana (King & Pantl.) Kranzl. Orchidaceae Cephalostachyum capitatum Munro Poaceae Drepanostachyum khasianum (Munro) Keng f. Poaceae D. polystachyum (Kurz ex Gamble) R.B.Mazumdar Poaceae Himalayacalamus hookerianus (Munro) Stapleton Poaceae Smilax minutiflora A. DC. Smilacaceae S. orthoptera A. DC. Smilacaceae Curcuma zedoaria (Christm.) Roscoe Zingiberaceae Globba clarkei Baker Zingiberaceae G. multiflora Wall. ex Baker Zingiberaceae Hedychium densiflorum Wall. Zingiberaceae H. ellipticum Buch.-Ham. ex Sm. Zingiberaceae H. gardnerianum Sheppard ex Ker Gawl. Zingiberaceae H. glaucum Roscoe Zingiberaceae H. greenii W.W.Sm. Zingiberaceae H. thyrsiforme Sm. Zingiberaceae Hemiorchis pantlingii King Zingiberaceae Zingiber rubens Roxb. Zingiberaceae

V. Endemic to the Himalayas The floristic diversity of the district shows a great alliance with the Himalayan elements as discussed earlier. A remarkable amount of flora endemic to the Himalayas as a whole, from Kashmir to Arunachal Pradesh, are also been detected. A list of 11 such endemic monocots are shown below in Table 5. 120 Endemic monocotyledons of Darjeeling Himalaya Table 5. Monocotyledonous taxa Endemic to the Himalayas Names of species Families Allium stracheyi Baker Amaryllidaceae A. wallichii Kunth Amaryllidaceae Arisaema costatum (Wall.) Mart. Araceae A. propinquum Schott Araceae Carex pulchra Boot Cyperaceae Chiloschista usneoides (D. Don) Lindl. Orchidaceae Gastrochilus inconspicuus (Hook. f.) Kuntze Orchidaceae Garnotia polypogonoides Munro ex Oliv. Poaceae Trisetum spicatum (L.) K. Richt Poaceae Cautleya spicata (Sm.) Baker Zingiberaceae Roscoea purpurea Sm. Zingiberaceae

While analyzing the endemism of the monocotyledonous flora of Darjeeling district 76 endemic elements were detected those comprises almost 10 % of total monocot flora [Plate I]. The figure is note worthy as it expresses the virginity of the area in respect of vegetation. It has been observed that in the earlier literatures we found a maximum percentage of endemism in one particular area due to poor exploration of the adjoining areas. On the other hand, it is also to be noticed that with the recent comprehensive exploration of different poorly or un-explored areas, the existence of different floristic elements revealed which lead to reduction of the percentage of endemism for a region for which a higher proportion was perceived earlier. The elements also extend their area of occupancy by their own natural methods of distribution and is related to the concept of time and space. Numerical strength of endemism of the Darjeeling district monocot species in respect of different vegetation zones within the Himalayan territory are shown in Table 6 below.

Table 6. Endemism of monocotyledonous flora of Darjeeling district

Total No. of Percentage of Category of Endemism monocot endemic total species species endemics Darjeeling and Sikkim 10 1.3 Nepal to Bhutan 8 1.04 Eastern Himalaya 11 1.43 768 Eastern Himalaya and NE 36 4.69 India Himalaya 11 1.43 Total 768 76 9.89

While studying the Eastern Himalaya, it is noteworthy to study it only by the front face but also to glance over to its back face that is Tibet, because the mountains are representing the two opposite slopes. In this regards, the floristic elements of this slope of the Himalayas may infiltrate to the other slope too. In the present study as many as 47 monocotyledonous species have been recorded which have been migrated little beyond the boundary of Indian Himalayas upwards to Tibet and east-wards from Arunachal or NE India to Southern most portion of China and Northern Myanmar. A list of such ele- ments are shown in the Table 9. Suman Nirola & A.P. Das 121

A B C

D E F

G H I PLATE-I. Some monocotyledonous endemic species from the flora of Darjeeling Himalaya: A. Amorphophallus napalensis (Wall.) Bogner & Mayo; B. Arisaema griffithii Schott; C. Globba teesta S.Nirola & A.P.Das; D. Hedychium gardnerianum Sheppard ex Ker Gawl.; E. Hedychium glaucum Roscoe; F. Hemiorchis pantlingii King; G. Nervilia gammieana (Hook.f.) Pfitzer; H. Esmeralda cathcartii (Lindl.) Rchb.f.; I. Gastrochilus inconspicuus (Hook.f.) Kuntze 122 Endemic monocotyledons of Darjeeling Himalaya Table 9. Flora endemic to Himalayas with little expanded distribution to Tibet (S. China), North Myanmar and Bangladesh

Names of species Families Expanded upto Amorphophallus margaritifer (Roxb.) Kunth Araceae Bangladesh Bambusa jaintiana R.B.Majumdar Poaceae –do– Cymbopogon microthecus (Hook. f.) A.Camus Poaceae –do– Arisaema speciosum (Wall.) Mart. Araceae Tibet (S. China) A. intermedium Blume Araceae –do– Polygonatum cathcartii Baker Asparagaceae –do– P. cirrhifolium (Wall.) Royle Asparagaceae –do– P. oppositifolium (Wall.) Royle Asparagaceae –do– Rohdea nepalensis (Raf.) N.Tanaka Asparagaceae –do– Molineria crassifolia Baker Asparagaceae –do– Carex inanis Kunth Cyperaceae –do– C. teres Boott Cyperaceae –do– Juncus grisebachii Buchenau Juncaceae –do– Calanthe plantaginea Lindl. Orchidaceae –do– Coelogyne barbata Lindl. ex Griff. Orchidaceae –do– Coelogyne cristata Lindl. Orchidaceae –do– Diplomeris hirsuta (Lindl.) Lindl. Orchidaceae –do– Liparis resupinata Ridl. Orchidaceae –do– Platanthera clavigera Lindl. Orchidaceae –do– P. latilabris Lindl. Orchidaceae –do– Pleione humilis (Sm.) D. Don Orchidaceae –do– Satyrium nepalense D. Don var. ciliatum Orchidaceae –do– (Lindl.) Hook. f. Vandopsis undulata (Lindl.) J.J. Sm. Orchidaceae –do– Arundinaria racemosa Munro Poaceae –do– Cymbopogon pendulus (Nees ex Steud.) Poaceae –do– W.Watson Dendrocalamus sikkimensis Gamble ex Oliv. Poaceae –do– Eulalia mollis (Griseb.) Kuntze Poaceae –do– Himalayacalamus falconeri (Hook. f. ex Munro) Poaceae –do– Keng f. Isachne sikkimensis Bor Poaceae –do– Poa himalayana Nees ex Steud. Poaceae –do– P. sikkimensis (Stapf) Bor Poaceae –do– Thamnocalamus spathiflorus (Trin.) Munro Poaceae –do– Pollia subumbellata C.B.Clarke Zingiberaceae –do– Dendrobium hookerianum Lindl. Orchidaceae S. China, N. Myanmar Poa khasiana Stapf Poaceae –do– Arisaema concinnum Schott Araceae –do– A. nepenthoides (Wall.) Martius Araceae –do– Kobresia uncinioides (Boott) C.B.Clarke Cyperaceae –do– Dendrobium rotundatum (Lindl.) Hook. f. Orchidaceae –do– Suman Nirola & A.P. Das 123 Names of species Families Expanded upto Dendrobium rotundatum (Lindl.) Hook. f. Orchidaceae –do– Oreorchis micrantha Lindl. Orchidaceae –do– Papilionanthe vandarum (Rchb. f.) Garay Orchidaceae N. Myanmar Pinalia graminifolia (Lindl.) Kuntze Orchidaceae –do– Liparis deflexa Hook. f. Orchidaceae –do– Nervilia macroglossa (Hook. f.) Schltr. Orchidaceae –do– Dendrobium transparens Wall. ex Lindl. Orchidaceae –do– Dendrocalamus hookeri Munro Poaceae –do– Crinum amoenum Ker Gawl. ex Roxb. Amaryllidaceae –do–

Conservation status The distribution of most of these endemic species are highly restricted in distribution, especially the orchids. For many orchid species it is restricted to just one hill slope (i.e. Liparis tigerhillensis) or to a small stretch of few hundred meters (Das & Chanda 1988). And, in most of the cases these rare orchids and other endemic and rare plants are not growing within the boundary of the IUCN defined Protected Areas. Many of these plants are collected once only or are collected after a long gap from the time of their previous collection. On the other hand, the vegetation of well over 80 % areas is highly degradaded due to extremely high anthropogenic activities (Rai 2006). The highly restricted distribution of numerous species of orchids and other monocotyledonous angiosperms speaks for their sensitivity to the microclimatic set-ups of their habitat. So, with the change of the habitat structure, overall change in ambient climatic conditions, rampant collection for marketing (mostly across the boarder), etc. are endangering these species. There are four major Protected Areas within the boundary of Darjeeling District, namely: Mahananda Wildlife Sanctuary, Neora Valley National Park, Senchal Wildlife Sanctuary and Singalila National Park. In addition, the small Jore Bungallow Wildlife Sanctuary is meant for the conservation of Himalayan salamander only. It is true that some of the endemic and threatened plants are growing within these PAs but, at the same time, many of those are somehow surviving outside these either with their entire population or with one to very few small patches of their highly fragmented wild population. Ex situ conservation is also practiced in the district. There is good collection of wild orchids and other rare plants in Lloyd Botanical Garden and in Takdah Orchid Sanctuary (ex situ) but the available facilities are quite insufficient for their conservation than the actual requirement. Also, collaboration and/or assistance of experts for different group of plants is the basic requirement. There are many private collections but those are primarily not for long term conservation. The conservation status for the tropical orchids, especially the rich orchid flora of Tista Valley is even much poorer. It is suggested that more ex situ conservatories are to be established in different climatic tiers, preferably within the natural surroundings along with the facilities for their natural, vegetative and in-lab cultural facilities taking proper assistance of the local experts. We need to remember no species is useless and we have to conserve them all.

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