Contribution to the pteridophytic flora of India : Nokrek Biosphere Reserve , Meghalaya

Nokrek National Park, located approximately 40km from Tura town in West Garo Hills district of Meghalaya, India, was added to the list of Biosphere Reserves by UNESCO in May 2009. Since there is no previous report from this area, the pteridophytes of the Nokrek Biosphere Reserve are catalogued in the present study. The checklist consists of 113 taxa (98 ferns, 15 fern allies), of which 25 species are newly reported for the Meghalaya State (Selaginella involvens, Selaginella semicordata, Selaginella subdiaphana, Selaginella tenuifolia, Asplenium gueinzianum, Asplenium perakanse, Microlepia hancei, Microlepia rhomboidea, Dicranopteris linearis, Coniogramme procera, Bolbitis sinensis, Loxogramme chinensis, Lygodium microphyllum, Lemmaphyllum microphyllum, Lemmaphyllum rostratum, Pleopeltis macrosphaera, Pyrrosia lanceolata, Pyrrosia longifolia, Pteris biaurita ssp. walkeriana, Pteris grevilleana, Tectaria fuscipes, Cyclosorus crinipes, Pseudocyclosorus falcilobus, Diplazium apicisorum and Diplazium pseudosetigerum) and 43 species are new for all the three Garo Hill districts of the Garo Hills in the Meghalaya State.


INTRODUCTION
Nokrek National Park or Nokrek Biosphere Reserve is a national park located approximately 40km from Tura Peak in West Garo Hills District of Meghalaya, India.UNESCO added this national park to its list of biosphere reserves in May 2009.The Nokrek range of hills situated at the eastern-most tip of the eastern Himalaya is notable for its very rich and diverse luxuriant vegetation, dotted with a high concentration of endemics as well as rare, endangered and threatened plants.It is considered to be a gene pool of Citrus species in the northeastern states of India, and the cultural meeting point of three Garo districts of Meghalaya State; rich in myths, folk traditional knowledge, biodiversity and associated cultural tribal practices.These Garo Hills form the major peaks (Nokrek Peak and Tura Peak), towards the tail end of Assam, before they abruptly fall into the low hills of Bangladesh.This is a compact range of hills with the main range descending equally steeply to all the three Garo districts of Meghalaya.The dense forests of these hills provide a home for many narrow endemics of phytogeographical significance, such as Vanda coerulea Griff.ex Lindl., Nepenthes khasiana Hook.f. and Citrus indica Tanaka species.Considering the immense need for conservation, the area is protected as a biosphere reserve since 1988.The angiosperm flora of the area has largely been explored by the Botanical Survey of India, Eastern Circle, Shillong which recorded more than 1000 species, the herbarium specimens are housed in Assam.Of these more than 51 are endemics and 57 species belong to various threat categories as revealed in the literature, viz., IUCN (1966), Baishya & Rao (1982), Kataki (1982), Chauhan (1983), Datta (1983), Das & Deori (1983), Haridasan & Rao (1984, 1985-87), Nayar (1980Nayar ( , 1996)), Jagtap & Singh (1999), Chowdhery & Murti (2000), Olson (2001) and Singh & Panigrahi (2005).However, no effort was done earlier to study the pteridophyte diversity in this rich biosphere reserve.

Study area
The Nokrek proper, with its northern and western slopes, forms a compact block of hilly ranges towards the northern and western end of the Garo Hills and belongs to the three Garo districts of Meghalaya State; the southern slope falls into the plains of Bangladesh.The area is believed to be the abode of the Garo tribal community, belonging to the Tibeto-Chinese family of the Tibeto-Burman subfamily of the Bodo group, who live in about 132 villages situated in and around Nokrek (Tripathi et al. 2008).The people have conserved some forest patches as 'sacred groves' and thus this hilly area is considered sacred, and a symbol of conservation with deep cultural imprints of traditional beliefs.Topographically, the area steeply descends from all sides of the highest peak the Nokrek Peak, with an altitude of 1412m.A major portion of the area belongs to the Nokrek National Park and Citrus Wildlife Sanctuary, and the rest is in the reserved forests of the Garo wildlife forest division.The IUCN has identified Nokrek and its environs to be one of the three centers of plant diversity within India, and focused on the need for immediate conservation (IUCN 1987).The Nokrek Biosphere Reserve was also internationally recognized within the framework of UNESCO's Man and Biosphere (MAB) programme in 2009.
The temperature varies from 9.5-37.3 0C, typical of Assam, March-May being the hottest and December-February being the coolest months.Both south-west and northeastern monsoons bring rain to the area ranging from 3900 to 6800 mm/year.The soil is mainly red loamy and the area is drained by several perennial streams, which collect to form one major river system viz., Brahmaputra.The great diversity in ecological features and the high range of altitudinal variation are responsible for the very rich and diverse vegetation of the area.It belongs to the Indo-Malayan eco-region (Olson et al. 2001) with the major vegetation type: tropical forests (200-900 m) and subtropical forests (900-1412 m).The soil is very shallow and vegetation becomes active mainly after the monsoons and may dry up in the southern slopes during the dry season.There is a clear demarcation of vegetation types based on the altitudinal range.The Nokrek Biosphere Reserve, between 25 0 15'-25 0 29'N and 90 0 13'-90 0 30'E, was established on 13 September 1988(vide Govt. of India, MoEF Order No. 27/59/81-C5 dt. 13 September 1988) with an area of about 8,20km², of which 47.48km² (vide Govt. of Meghalaya Notification No. FOR.23/86/316 dated 23.10.1997) is the core area (Fig. 1).The NBR straddles the border of Assam State and Bangladesh.It is composed of Citrus Gene Pool Sanctuary and Mahseer Hatchery Centre and their adjoining areas of Hallaidang, Daihadubi, Darugiri and Rongrengiri ranges of Garo Hills Forest Divisions.It is the habitat of many varieties of medicinal plants, wild edible plants and plants of other economic importance (Images 1 & 2).The area is equally rich in faunal elements also with a large number of birds, butterflies, amphibians and reptiles.The rare mammals of the area include the Hoolock Gibbon, Asian Elephant, Gaur, Leopard, Sambar, Barking Deer, Malayan Bear, Assamese Macaque, Rhesus Macaque, Giant Squirrel, Slow Loris, Himalayan Palm Squirrel, Hare, etc.The Nokrek is also notable for being the home of the Garos, one of the hilly tribes, who have a thorough knowledge of the local biodiversity, its utilization potentials and with many cultural practices unique to them.According to the Garos of Nokrek, there is also a mammal locally called Badamanu-big feet man, in the core area, but not evidenced.
The pteridophyte specimens were collected from 2006 to 2010 and deposited in Assam Herbarium at the Botanical Survey of India, Eastern Circle, Shillong.The families are arranged alphabetically.Each species is listed with author citation (Brummitt & Powell 1992) followed by the field observations on the habitat on which it was found growing in the study area, the locality, altitude, the collector's name (acronyms: BS -Bikarma Singh; VNS -V.N.Singh; BKS -B.K. Sinha; DBD -D.B.Deb; RS = R. Shanpru; GP -G.Panigrahi; MKVR -M.K.V. Rao), collection number,

Aspleniaceae
Asplenium cheilosorum Kunze ex Mett.: Terrestrial Thailand, Malesia and Vietnam.Asplenium unilaterale Lam.: Epiphytic on moss covered tree trunks near the sides of streams and river.Tura Peak (670m) GP 22463 (Assam).Very common in Nokrek, and widely distributed throughout Himalayan regions of India; Africa, China, Japan, Myanmar, Philippines, Polynesia, Sri Lanka and Taiwan.(Assam).It is common in Nokrek, and is a new record for the Garo Hill districts.This species is widely distributed in pantropical regions.

Drynariaceae
Drynaria propinqua (Wall.ex Mett.)J. Sm.Epiphytic on moss covered tree trunks, rarely lithophytic on rock surfaces.Williamnagar to 5 km way to Peak (425m) VNS & BS 115933 (Assam).This species is common in the southern slopes of Nokrek, but rare in other parts in the reserve area.It is a new record for the Garo Hill districts.It is widely distributed in northern India (Kashmir, Uttaranchal), northeastern India (Arunachal Pradesh, Meghalaya (Assam), Bhutan, China, Malaya, Malesia, Myanmar and Nepal.
Drynaria quercifolia (L.)J. Sm.: Epiphytic on tree trunks in shady places.Foot hills of Nokrek Peak (300m) VNS & BS 114944 (Assam).This species is very common in Nokrek, and widely distributed throughout the Himalayan regions as well as northeastern India, Australia, China, Fiji, Malaya and Sri Lanka.

Dryopteridaceae
Arachniodes aristata (G.Forst.)Tindale.Terrestrial in shady places.Nokrek Peak (1230m) VNS & BS 114706 (Assam).This species is rare in Nokrek, and recorded for the first time from Garo Hill districts.It is distributed in New Zealand (Raoul Island), Asia, Australia and the Pacific Islands.
Dicranopteris linearis (Burm.f.) Underw.: Terrestrial in open places.Khalakgre (750m) VNS & BS s.n.(Assam).Although this species is common in Nokrek, it is recorded for the first time from Meghalaya.It is also widely distributed in Southeast Asia.

Hemionitidaceae
Coniogramme procera Wall.ex Fée.Terrestrial in moist places near rivers.Nokrek Peak (1350m) VNS & BS 114691 (Assam).This is common in Nokrek, and recorded for the first time from Meghalaya, hence is a new record for the state.It is distributed in the Himalayan region of India.

Hymenophyllaceae
Mecodium tenellum (D.Don) Sarn.Singh & Panigrahi: On moss covered tree trunks in moist areas.Nokrek Peak (11200m) DBD 28917 (Assam).It is extremely rare in Nokrek, and recorded for the first time from Garo Hill districts of Meghalaya; although the cited specimens are housed in Assam herbarium, no publication appeared so far from the Garo Hills.This species is widely distributed in southern India, eastern Himalayan regions of India, Bhutan, China, Nepal, Malaya, Myanmar, Sri Lanka and Thailand.

Lindsaeaceae
Lindsaea odorata Roxb.ex Griff.(Image 14): Epiphytic as well as terrestrial.Tura ridge (750m) VNS & BS 118318A.It is very common in Nokrek, and is a new record for Garo District.It is widely distributed in northeastern India (Assam, Arunachal Pradesh, Meghalaya), tropical Asia from Ceylon to New Guinea.
Sphenomeris chinensis (L.) Maxon.: Terrestrial along river sides.Tura Peak (1100m) VNS & BS 118318 (Assam).This species is rare in Nokrek, and is a new record for the Garo Hill districts.According to Baishya & Rao (1982), this species is common in Khasi and Jaintia districts of Meghalaya.It is mostly indigenous to Hawaii Islands, parts of Polynesia, and east Asia.It is commonly found in forest openings and other disturbed areas such as along trails or roads, or on landslides when there is adequate moisture.

Lomariopsidaceae
Bolbitis sinensis (Baker) K. Iwats.: Terrestrial in deep gullies in shady places.Along Simsang River from Daribokgre (755m) VNS & BS 114662 (Assam).This species is rare in Nokrek, and recorded for the first time from Meghalaya and is a new record for the state.It is distributed in the eastern Himalaya.

Loxogrammaceae
Loxogramme chinensis Ching.: Epiphytic as well as lithophytic in dense forests.Nokrek Peak (902m) BS 118578A (Assam).This species is occasionally found in Nokrek, and recorded for the first time from Meghalaya.It is widely distributed in northeastern India (Assam, Arunachal Pradesh, Meghalaya), Bhutan, China, Japan, Myanmar, Thailand and Taiwan.
Loxogramme involuta (D.Don) C. Presl.: Epiphytic as well as lithophytic in dense forests in shady areas.Near Daribokgre along Simsang River (850m) VNS & BS 116733 (Assam), on the way to Nokrek Peak from Tura Peak (1210m) MKV Rao 64378 (Assam).This species is occasionally recorded from Nokrek.It is distributed in northeastern India (Arunachal Pradesh, Meghalaya), Bhutan, China, Malesia, Nepal, Polynesia and Sri Lanka.are new records for all the three Garo Hills districts of Meghalaya.Polypodiaceae stands the dominant family of the area with 31 species followed by Aspleniaceae and Selaginellaceae with 10 species each.Asplenium is the largest genus with a maximum number of nine species, which is followed by Pyrrosia with eight species and Pteris with seven species including two subspecies.The identity of some collection requires further studies.

Figure 1 .
Figure 1.Location map of Nokrek Bioshere Reserve in India