Studies on the Pteridophytic Flora of Darjiling Hills
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Studies on the Pteridophytic flora of Darjiling Hills. Thesis Submitted to the University of North Bengal For the Award of Doctor of Philosophy in Botany By Nayan Thapa Guide Dr.Dorjay Lama Department of Botany University of North Bengal September 2016 ST. JOSEPH’S COLLEGE (Estb. 1927) P.O. North Point, Darjeeling - 734101 Phone (0354) 2252550, Fax: 0354 2252551 Email: [email protected] Dept. of Botany Web: www.sjcdarjeeling.edu.in _________________________________________________________ CERTIFICATE I certify that Mr. Nayan Thapa has prepared the Thesis entitled “Studies on the Pteridophytic flora of Darjiling Hills” for the award of PhD degree of the University of North Bengal under signed as guide. He has carried out the work at the Department of Botany,St. Joseph College North Point, District Darjeeling, West Bengal,India. He has carried out the work and submitted his Ph.D Thesis as per the New Ordinance. No part of this thesis has formed the basis for the award of any degree or fellowship previously. Dr. Dorjay Lama Associate Professor Department of Botany St. Joseph college, P.O North Point, District Darjeeling, West Bengal, India-734104 ABSTRACT The present study is based upon extensive survey and field collection over a period of covering years along various altitudinal zones of Darjiling Hills, West Bengal for enumeration, Phyto-sociological analysis and utilization of Pteridophytes. Darjiling Hills, a part of Darjiling district which lies between 26⁰ 27' 05 ̎ and 27⁰ 13' 10 ̎ N latitudes and between 87⁰ 59' 30 ̎ and 88⁰ 53' E longitudes has been covered in the study. The Darjiling hill is a segment of Eastern Himalaya, a part of Indo-Malayan realm and has an area of about 2436.55 km² or 77 % of the total area of the district. The study area ranged in altitudinal variation from 150 m amsl to 3660m amsl covering chiefly 4 climatic zone i.e. tropical, sub- tropical, temperate and sub-alpine. The study was based on the field survey and collection in forest tract, remote villages from 2010 to 2015 to assess the Pteridophytic wealth of the region. Collection, proper identification and enumeration of Pteridophytic flora and their taxonomic placement have been carried out. The family keys been provided and the present study documented 206 species under 70 genera belonging to 26 families. Three families belonging to fern allies have been documented which consist of 5 genera with 17 species, where lycopodiaceae with 3 genera and 8 species have shown the highest diversity (Thapa et al, 2015).Polypodiaceae with 13 genera and 40 species showed the highest diversity in the study area. Taxonomical analysis based upon the classification in terms of the habitat shows the lithophytes accounting 44.11% comprise the largest group followed by the mesophyte 27.13%,epiphyte 26.85 and 2% represented by climbers .The climbers chiefly Lygodium japonicum , Lygodium salicifolium ,Stenochlaena palustris occurring in warmer foot hills and Tricholepidium normale the sole representative from the cool temperate region has been found.The new record for the region is Botrychium lunaria collected from Sandhakphu ( Thapa et al.,2014; Thapa and Lama,2016 ), Pteris austrosinica collected from Singla( Thapa & Lama,2015), Huperzia ceylanica collected from Chitrey (Thapa and lama,2015). Exotic and adventives species that have naturalized in Darjiling hills are Adiantum concinnum and Pityrogramma calomelanos. A number of abnormal specimen have been collected during the course of study belonging to different groups that include Asplenium ensiforme, Lepisorus mehra, Botrychium lanuginosum, Equisteum arvense subsp.diffusum, Goniophlebium argutum( Plate3.22). In some case the differences exhibited is huge and proper identification required with i minute observation as superficial often tends to be misleading as in Goniphlebium argutum which resembled Goniphlebium metzense (Thapa and Lama, 2013). The present study observes that about 90% of the fern flora in Darjiling comprises of Sino –Himalayan and Malesian element. The single species representing the Afro-Arabian connection that may have migrated through Deccan in the foothills is represented by Aleuritopteris bicolor. The rarest of species from the study area collected from a single location are Huperzia ceylanica and Asplenium magnificum. One-time collected species Pteris barbigera, Cyathea contaminans, Dipteris wallichii, Pteridrys cnemidaria , Christopteris tricupsis could not be collected in the present study as well. This species tend to be rarest in the Indian sub- continent. Pteris barbigera is known only from one collection in Darjiling hills after which it could not be seen in the wild neither be collected for 100 years. Large scale deforestation and anthropological interference may have resulted in the disappearance of these rare species. The Phytsociological analysis of Fern and Fern-allies were studied in 4 different forest tract of Darjiling hills ranging from tropical to sub-alpine forest. The raw data collected by ground truth from 80 sample plots in 4 climatic zone recorded a total of 406 species. 53 species of Pteridophytes were recorded, 2 species were tree ferns and 2 species were climbers .The sub-tropical and temperate forest recorded the highest diversity of Pteridophyte i.e. 16 species each. Least diversity of Pteridophyte was recorded in sub-alpine forest. The utilization of Pteridophyte by people was also studied in the Darjiling hill. The data source includes the primary data obtained during numerous field trips in the forest village, local market (Hatt) were undertaken with questionnaires prepared to interview the village head and local healers. The survey found that 40 species of fern and fern allies are used by people for different purpose which has been categorized as Medicinal fern, Edible ferns, Cattle bed ferns and ornamental ferns.Study shows that It eleven species are used for medicinal purpose and the young croizer of sixteen species being utilized as vegetable belonging to genera Diplazium, Deparia and Cyathea .Four species of ferns were utilized as cattle bed fern (Sottar) for domesticated animals and nine species of fern find use as ornamental and decorative purposes. ii PREFACE India is a mega biodiversity hot spot region and accounts for more than 7% of vascular plant species. The Pteridophytes belong to the group of vascualr cryptogram comprising of fern and fern-allies, represented by 1100 species accounting to 10% of global diversity. Darjiling hills floristically rich account for 19% of the Indian Pteridophyte having 0.1% area of the country. After Mehra (1964) and Hara (1974) the enumeration has been undertaken to access the ecology with utilization of this alienated group in Darjiling Hills. The present work is an outcome of vigorous ground truth for a period of 5 years in different forest tract, villages and herbaria. Key to the families, genus and species with updated nomenclature, description, photographs and distribution has been provided. Ecological assessment has been carried out with detailed utilization of species by the common people. This work is an attempt to generate interest among the botanist to work out further this alienated group of vascular cryptogram. With sense of gratitude, I express my deepest appreciation to my supervisor Dr. Dorjay Lama, Department of Botany, St. Joseph College, Darjeeling, for his esteemed supervision and guidance. I would like to thank Prof. A.P Das for rendering valuable suggestion and correction during the course of Taxonomic enumeration. A heartfelt thank to Prof. C.R Fraser-Jenkins who always supported, help and update and made critical suggestion during the treatment of abnormal and difficult specimens. The study without co-operation of forest department cannot be imagined and I would like to thank Mr. A.Dubey(IFS),Mr. S.K Mollay(IFS), Raju Pradhan, Pawan Prasad and all the staff of Silviculture department for giving me a permission to be a part of MPCA program during which I could visit and carry out restricted collection from these areas. I would like to thanks officer in charge, Llyod’s Botanical garden and Bimal daju for cooperation during my research. I would thank Prof. P.C Lama and Digbir Tamang for allowing me to study the herbarium deposited in the Dept. Of Botany , Darjeeling Government College. iii I would like to thank Kuresong TRA, Barnesbeg Tea estate, Happy valley Tea estate for providing weather data for incorporation in my thesis. I express my gratitude to my seniors in the Department Dr.Upakar Rai, Dr. Anirudra Gurung, Dr. Manjulla Rai , Mr. Surya Rai and Mr. Rajendra Yonzone for their co-operation and helpful suggestion during the course of study and preparation of the thesis. Special thanks to the Principal , St. Joseph college for allowing us to carry research and will for registering the department to carry out researches with North Bengal University. To my juniors namely Abhijeet Cheetri, Puran Sarki,Ashis Chettri who were always there with me during my research, often accompanying me for the field trips. Heartfelt thanks to the people of rural belt in far flung area where I stayed in due course of research who always welcomed me with their smiling faces and gave homely treatment whose support me to achieve this milestone. Lastly I am indebted to my family Dad, Mum , Brothers ,in-laws who always supported me morally, financially during thin and thick period of my research, without their support and encouragement ,the work would not be possible. Nayan Thapa, Dept. of Botany, St Joseph College, Darjiling, Pin -734104 iv Contents Page No Abstract i-ii Preface iii-iv Chapter I INTRODUCTION 1. Introduction 1-2 1.1. Location 2-3 1.2. General feature 3 1.2.1. Topography 3-4 1.2.2. Geology 4-5 1.2.3. Soil 5 1.2.4. River and Drainage 6-7 1.3. Climate 7-8 1.3.1. Rainfall 8 1.3.2. Temperature 8-9 1.3.3.