Journal of Threatened Taxa | www.threatenedtaxa.org | 26 October 2022 | 14(10): 22008–22015

 

 

ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print) 

https://doi.org/10.11609/jott.7740.14.10.22008-22015

#7740 | Received 05 November 2021 | Final received 15 June 2022 | Finally accepted 05 September 2022

 

 

 

Contribution to the moss flora of northern Sikkim, India

 

Himani Yadav 1, Anshul Dhyani 2  & Prem Lal Uniyal 3 

 

1,2,3 Department of Botany, University of Delhi, South Moti Bagh, Delhi 110007, India.

1 himani382@gmail.com, 2 anshuld42@gmail.com, 3 uniyalpl@rediffmail.com (corresponding author)

 

 

 

Abstract: Study of species composition and community structure is an essential requirement for maintaining the ecosystem functions, conservation, and sustainable use. Bryophytes are integral components of biodiversity and resilient during perturbation. The present investigation was, therefore, a survey in North Sikkim district (India) to study the diversity and distribution of mosses resulting in a total of 113 species in 74 genera and 28 families as new records to the study area. Of these, 14 species are considered rare based on their frequency of occurrence. The family Meteoriaceae which consists of mainly epiphytic taxa is found to be dominant and widely spread in the study area followed by Pottiaceae, Leucobryaceae, and Dicranaceae families. Sixteen species are found to be remarkable in contributing major biomass to the forest floors and as epiphytes. Five species are recorded to be endemic to this area. Most of the epiphytic species are found to be abundant in the area, indicating the good health of ecosystem. The data would be useful in the planning of conservation and management of biodiversity.

 

Keywords: Biodiversity, Bryophyta, ecosystem, endemicity, Hylocomium himalayanum, Meteoriaceae, northeastern India. 

 

 

 

Editor: Afroz Alam, Banasthali Vidyapith, Rajasthan, India.   Date of publication: 26 October 2022 (online & print)

 

Citation: Yadav, H., A. Dhyani & P.L. Uniyal (2022). Contribution to the moss flora of northern Sikkim, India. Journal of Threatened Taxa 14(10): 22008–22015. https://doi.org/10.11609/jott.7740.14.10.22008-22015

 

Copyright: © Yadav et al. 2022. Creative Commons Attribution 4.0 International License.  JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by providing adequate credit to the author(s) and the source of publication.

 

Funding: Partial funding for this study was provided by the Institute of Eminence, University of Delhi, and the University Grants Commission, New Delhi.

 

Competing interests: The authors declare no competing interests. 

 

Author details: Himani Yadav is currently pursuing her PhD from Department of Botany, University of Delhi, Delhi. Her research interest includes the taxonomy of bryophytes and pteridophytes, and tissue culture studies. Anshul Dhyani is a PhD research scholar at Department of Botany, University of Delhi. His research focuses on the taxonomy, ecology, and molecular phylogeny studies of bryophytes. He has also worked in a DST-SERB project as junior research fellow and senior research fellow. Prem Lal Uniyal is a senior professor at Department of Botany, University of Delhi. He has published more than 100 research papers. He is specialized in biosystematics of bryophytes, pteridophytes and gymnosperms.

 

Author contributions: HY and AD studied the detailed morphological characters for the identification and also prepared the herbarium of the samples. PLU surveyed the area and made the collection the of plant material and established the identity of the specimens.

 

Acknowledgements: Authors are highly grateful to The Directorate of Forest, Government of Sikkim for providing the necessary permission for the survey of the sites in North Sikkim [PR (REE) FEWMD/GOS/2012; Memo No. - 43-45, dated 30.12.2012]. Authors are thankful to the University Grants Commission and the Institute of Eminence, University of Delhi (IOE/FRP/LS/2020/27), for providing financial assistance.

 

 

 

Introduction

 

Ecosystem functioning and stability is dependent on the richness of biodiversity (Noble & Dirzo 1997). Forest composition, species richness, diversity pattern, and spatial or temporal distribution are important ecological attributes significantly correlated with prevailing environmental as well as anthropogenic variables (Gairola et al. 2014).  Bryophytes are abundant in some ecosystems and play an important role in providing resilience to environmental changes (Muscolo et al. 2014). Understanding species diversity and distribution patterns is crucial for evaluating the roles of plant groups in the ecosystem at a micro-level.  Regular surveys for species occurrence are required for developing models for biodiversity management and ecological restoration. Variations in species composition cover at spatial and temporal scales reflect the heterogeneity of the environmental conditions (Whitmore 1984), which is the basis for the complexity and diversity of any ecosystem. Climatic conditions and developmental activities have led to an unusual loss of biodiversity and ecosystem services (Dierick & Hölscher 2009).

Bryophytes also play an important role in nutrient cycling, water retention, succession, and providing microhabitat for many plants and animals. Despite their small size, they comprise major components of biomass and photosynthetic production. The gap dynamics in the forest is influenced by the bryophyte diversity and micro- communities (Levin 1992; Kimmerer & Young 1996). Bryophyte diversity also adds to the aesthetic value and integrity of the environment. They are considered as bioindicators of air and water quality and can be used in developing an “Index of Atmospheric Purity” (IAP) (Larsen 2007). In recent years, bryophytes have been widely used for bioremediation and pollution monitoring as well as in molecular biology studies. The factors controlling the distribution of species and population dynamic of bryophytes is unfortunately poorly understood. Such studies can provide a model for the management of biodiversity.

Sikkim is situated within the Himalaya Biodiversity Hotspot and is rich in affluent flora and fauna diversity (Rahman 2012). It harbours tremendous biodiversity, though it just covers 0.2% of the geographical area of India. Currently, many species are subjected to various threats, including the biological, natural, and anthropogenic activities, which limit the regeneration of species. These concerns should be addressed with strategic methods.

Pradhan & Badola (2008) reported the use of Sphagnum squarrosum (peat moss) in dressing and bandaging cuts and wounds and as an important resource for fuel in the Dzongu Valley of Sikkim. Singh & Singh (2013) studied the liverworts of a part of Sikkim. Gangulee (1969–80) described the mosses of a few areas in Sikkim. The area of northern Sikkim is unexplored in terms of bryodiversity assessment and is home to many endemic and monotypic taxa. We wanted to check the influence of moss diversity on the community composition of the area. The present study is, therefore, planned to document the mosses of the North Sikkim district.

 

Area of Study

Sikkim State (27°31’58.699”N & 88°30’43.985”E) is located on the northeastern side of India bordered by Bhutan, Tibet, and Nepal. It has an altitudinal range varying from 300–4,000 m, representing tropical, temperate, sub-tropical, and alpine regions, and a small portion of cold desert. Approximately 80% of its geographical area is under forest cover (Sikkim Biodiversity Action Plan 2012). Present surveys were made in the North Sikkim District, especially in Lachung-Yumthang Valley and Lachen-Thangu Valley (Figure 1).

Lachung and Yumthang (27°49’33.3336’’N & 88°41’44.9916’’E)  is a mountain valley situated at an altitude of 2,900 m. The valley is filled with temperate vegetation, especially Rhododendrons and conifers, and is rich in myriad waterfalls and streams which maintain the moisture in the valley. The Lachen and Thangu (27°43’59.99”N & 88°32’59.99”E and 27°53’31.94”N & 88°32’11.33”E)  valley is situated at an altitude of 2,750 m, consisting of Rhododendrons, conifers, and alpine vegetation.

 

 

Materials and Methods

 

During March 2013, mosses were collected from various areas of the North Sikkim District, particularly the Lachung-Yumthang and Lachen-Thangu Vallies. The moss patches were peeled off with a knife and collected in small polythene bags. To keep the sample pure, each population was kept separate. The moss samples were air-dried and some related data such as date of collection, locality, and habitat along with the substratum type were  marked on the packets. Voucher specimens are deposited in the herbarium of Department of Botany, University of Delhi (DUH), Delhi (India). For identification of the samples, the dried materials were soaked in water for a few minutes. Morphologically, different speciemens were separated on the basis of microscopic observations. Different parts of each sample were observed under the microscope and identified with the help of various Floras (Gangulee 1969 ̶ 1980; Chopra 1975; Flora of North America Editorial Committee 2007; Flora of China 2008; Koponen & Sun 2017).

 

 

Results and Discussion

 

The study is based on the species diversity of mosses recorded during the survey undertaken in various sites of North Sikkim District. The present study reveals 113 species of mosses belonging to 74 genera and 28 families (Table 1). 

Most frequently encountered species in the study area were Brachythecium kamounense, Rhynchostegiella humillima, Ptychostomum capillare, Bryum cellulare, Campylopus richardii, Dicranum scoparium, Entodon nepalensis, Hylocomium himalayanum, Hypnum sikkimense, Barbella pendula, Floribundaria sparsa, Trachypodopsis serrulata, Pogonatum microstomum, Barbula angustifolia, Hyophila rosea, and Thuidium sparsifolium. Few investigated sites act as refugia for native bryophyte species. These sites provide specific microhabitat and should be protected from any disturbance. Some of the photographs of mosses are presented in Image 1 and Image 2. Present study highlights the relationship between variability of habitat and the species diversity, which can be used as a model. These species are recorded from more than five distant locations of the study area found on variety of substrata. Seventeen species are of frequent occurrence which appear to be highly tolerant and possess adaptability and high regeneration potential. Epiphytic species were found in abundance and their occurrence in large number indicate congenial environment provided by associated vegetation. Species richness in the communities was found to be considerably higher. The family Meteoriaceae was found to be the most prevalent with the highest diversity and species richness in the study area, with 13 species, followed by Pottiaceae with 10 species, and Leucobryaceae and Dicranaceae with nine species each.  Meteoriaceae was found on tree bark and hanging from tree branches. Members of these families are ecologically important as they retain large amounts of water. The wide occurrence of these families is due to their habitat adaptation and favourable environmental conditions. Diverse tree and shrub species play a major role in the wide occurrence of epiphytic mosses.

A few species such as Hygrohypnum choprae, Oxyrrhynchium vagans, Climacium americanum, Ochrobryum kurzianum, Chaetomitriopsis glaucocarpa, Myurium rufescens, Dixonia orientalis, Polytrichastrum formosum, Oncophorus virens, and Oncophorus wahlenbergii are found only in very few locations (only one or two samples) and considered to be rare and highly specific to the habitats in the study area. Acrocarpous mosses are generally considered as more drought tolerant than pleurocarpous taxa. Most of the taxa are found growing on exposed sites with hard substrata like stones and rocks. Bryum cellulare and Hyophila rosea are observed to be common invader of every type of substrate such as rocks, cement floor, bricks, mortar, small rocks, and boulders. They are presumed to be highly tolerant to drought, disturbance, pollution etc. They have a high reproductive potential and found with capsules as well as gemmae. However, many of the taxa are found in sterile conditions which indicate their reproduction by vegetative means only.

Growing on calcium and magnesium rich substrata, Brachymenium longicolle, Fissidens geppi, F. grandifrons, Gymnostomum calcareum, Hydrogonium arcuatum, and H. pseudoehrenbergii can occupy exposed surfaces of rocks and boulders with no trace of vegetation. Members of Thuidiaceae are widely found and observed under shady conditions, specifically on the thick litter. Turf growth form is considered as dominant in the study area and their distribution can be correlated with local climate. Some green algae are also found to be associated with moss colonies of the collected taxa.

The taxa reported as new from the Sikkim region are: Barbella spiculata, Campylopus milleri, Fissidens geppii, and Mielichhoferia assamica. Earlier, they were recorded to be restricted to nearby regions such as Meghalaya and Darjeeling only. Extended distribution of Barbella spiculata (Mitt.) Broth., Campylopus milleri, Fissidens geppii, Mielichhoferia assamica, and Zygodon brevisetus were also recorded in the area. These species were earlier reported to be endemic to nearby areas of Darjeeling and Meghalaya also.

Most preferred colonization substrates were found to be exposed rocks where the representation was nearly 51% of the recorded taxa. This can be explained by the fact that in the favorable environment the rocky habitat was free of competition and thus available for mosses. Living tree trunks were the second most used substrate occupied by 32% of the recorded taxa. However, the biomass of the mosses on the living trees was found more usually. The tree trunk species followed by decaying trunks are reported as the suitable substrates for bryophytes in tropical forests (Richards 1984).

The study area seems to harbour many new and unique taxa of mosses. Epiphytic species play an important role in protecting the host species by providing continuous moisture and retaining nutrients. Mosses are highly sensitive to the alteration of habitat by recreational activities, which may alter the distribution pattern of the sensitive species of their own kind and cause a decrease in their population size, which consequently may alter the species composition of the associated invertebrate fauna. Also, there is a need to explore and identify the moss species of the concerned contrasting sites to prepare a database. A comprehensive report of the species composition and their role in the functions of the ecosystem and, subsequently, for the conservation of these species together with their habitats is also required. Sikkim is typified by its richness, high diversity, and endemic species of plants (Singh et al. 2008; Singh & Pusalkar 2020). The high richness of species marks the area as a gene bank for many plant species.

Plant species composition is considered as a marker of ecosystem health and the existence of various ecological factors influences species diversity (Sefidkon et al. 2005). The present study area shows diverse topographic features and microhabitats, which has a great potential for prospering with a rich biodiversity. The use of such natural diversity can be related to the interaction among the species. Most of the habitats of the sites were covered during the present study, and species composition was variable in different aspects.

 

Table 1. List of recorded species of mosses, with their habitat and growth form. Families are arranged according to Shaw et al. (2009).

 

Taxa

Growth form and habitat

Polytrichaceae

1

Atrichum obtusulum (Müll. Hal.) A. Jaeger ++

Turf, shaded soil

2

Atrichum subserratum (Harv. & Hook. f.) Mitt.

Turf, exposed soil

3

Pogonatum fuscatum Mitt.

Turf, exposed soil

4

Pogonatum microstomum (R. Br. ex Schwägr.) Brid.

Turf, exposed soil

5

Pogonatum neesii (Müll. Hal.) Dozy

Turf, shaded Soil

6

Pogonatum urnigerum (Hedw.) P. Beauv.

Turf, shaded soil

7

Polytrichastrum formosum (Hedw.) G.L. Sm.  +

Turf, shaded soil

Fissidentaceae

8

Fissidens geppii M. Fleisch.

Turf, termite mound

9

Fissidens grandifrons Brid.

Turf, rocks in streams

Bruchiaceae

10

Trematodon conformis Mitt.

Tall turf, shaded soil

Rhabdoweisiaceae

11

Oncophorus virens (Hedw.) Brid.  +

Turf, wet rocks

12

Oncophorus wahlenbergii Brid.  +

Turf, wet rocks

13

Oreoweisia laxifolia (Hook. f.) Kindb.

Turf, shaded rocks

14

Symblepharis reinwardtii (Dozy & Molk.) Mitt.

Turf, shaded rocks

15

Symblepharis vaginata (Hook. ex Harv.) Wijk & Margad.

Turf, shaded rocks

Dicranaceae

16

Ceratodon stenocarpus Bruch & Schimp.

Turf, exposed rocks

17

Cynodontium polycarpum (Hedw.) Schimp.  +

Turf, wet rocks

18

Dicranoloma subreflexifolium (Müll. Hal.) Paris

Tall Turf, shaded rocks

19

Dicranum assamicum Dixon

Tall Turf, shaded rocks

20

Dicranum crispifolium Müll. Hal.

Tall Turf, shaded rocks

21

Dicranum himalayanum Mitt.

Tall Turf, tree base

22

Dicranum scoparium Hedw.  ++

Tall Turf, exposed rocks

23

Ditrichum flexicaule (Schwägr.) Hampe

Turf, exposed rocks

24

Ditrichum tortipes (Mitt.) Kuntze

Turf, exposed rocks

Leucobryaceae

25

Campylopus ericoides (Griff.) A. Jaeger

Tall Turf, rocks

26

Campylopus fragilis (Brid.) Bruch & Schimp.  ++

Tall Turf, exposed rocks

27

Campylopus milleri Renauld & Cardot

Tall Turf, exposed rocks

28

Campylopus richardii Brid.  ++

Tall Turf, exposed rocks

29

Campylopus savannarum (Müll. Hal.) Mitt.

Tall Turf, exposed rocks

30

Campylopus zollingerianus (Müll. Hal.) Bosch & Sande Lac.

Tall Turf, exposed rocks

31

Dicranodontium asperulum (Mitt.) Broth.

Tall Turf, shaded rocks

32

Dicranodontium didictyon (Mitt.) A. Jaeger

Tall Turf, shaded rocks

33

Ochrobryum kurzianum Hampe +

Turf, wet rocks

Pottiaceae

34

Anoectangium stracheyanum Mitt.

Turf, wet rocks

35

Barbula angustifolia Brid.  ++

Short Turf, exposed rocks

36

Didymodon vinealis (Brid.) R.H. Zander

Short Turf, exposed rocks

37

Gymnostomum calcareum Nees & Hornsch.  ++

Cushion, wet rocks

38

Hydrogonium arcuatum (Griff.) Wijk & Margad. 

Short Turf, wet rocks

39

Hydrogonium pseudoehrenbergii (M. Fleisch.) P.C. Chen

Turf, wet rocks

40

Hymenostomum edentulum (Mitt.) Besch.  ++

Cushion, wet rocks

41

Hymenostylium recurvirostrum (Hedw.) Dixon ++

Cushion, exposed rocks

42

Hyophila rosea R.S. Williams ++

Turf, exposed rocks

43

Syntrichia princeps (De Not.) Mitt.

Turf, exposed rocks

Bryaceae

44

Brachymenium longicolle Thér.

Turf, shaded rocks

45

Bryum bessonii Renauld & Cardot

Turf, tree branches

46

Bryum cellulare Hook.  ++

Turf, shaded rocks

47

Bryum recurvulum Mitt.

Turf, shaded rocks

48

Bryum badhwarii Ochi

Turf, soil

49

Ptychostomum capillare (Hedw.) D.T. Holyoak & N. Pedersen ++

Turf, tree branches

Mniaceae

50

Epipterygium tozeri (Grev.) Lindb.

Turf, tree branches

51

Mielichhoferia assamica Dixon

Turf, rocks

52

Plagiomnium confertidens (Lindb. & Arnell) T.J. Kop.

Mat, wet rocks

53

Plagiomnium cuspidatum (Hedw.) T.J. Kop.

Mat, wet soil

54

Plagiomnium drummondii (Bruch & Schimp.) T.J. Kop.

Mat, wet soil

55

Plagiomnium japonicum (Lindb.) T.J. Kop.

Mat, wet rocks

56

Plagiomnium medium (Bruch & Schimp.) T.J. Kop.

Mat, tree branches

57

Pseudobryum cinclidioides (Huebener) T.J. Kop.

Mat, tree bases

Climaciaceae

58

Climacium americanum Brid.  +

Dendroid, tree base

Amblystegiaceae

59

Amblystegium serpens (Hedw.) Schimp.

Mat, aquatic

60

Hygrohypnum choprae Vohra

Mat, aquatic

Helodiaceae

61

Actinothuidium hookeri (Mitt.) Broth.

Mat, wet rocks

Thuidiaceae

62

Pelekium velatum Mitt.

Mat, moist rocks

63

Thuidium glaucinum (Mitt.) Bosch & Sande Lac.

Weft, forest floor

64

Thuidium pristocalyx (Müll. Hal.) A. Jaeger

Weft, forest floor

65

Thuidium recognitum (Hedw.) Lindb.

Weft, shaded rocks

66

Thuidium sparsifolium (Mitt.) A. Jaeger

Weft, shaded rocks

Brachytheciaceae

67

Brachythecium kamounense (Harv.) A. Jaeger +

Mat, exposed rocks

68

Brachythecium longicuspidatum (Mitt.) A. Jaeger

Mat, exposed rocks

69

Bryhnia decurvans (Mitt.) Dixon +

Mat, shaded rocks

70

Homalothecium nilgheriense (Mont.) H. Rob.

Mat, tree bark

71

Oxyrrhynchium vagans (A. Jaeger) Ignatov & Huttunen  +

Mat, wet rocks

72

Rhynchostegiella divaricatifolia (Renauld & Cardot) Broth.

Mat, wet rocks

73

Rhynchostegiella humillima (Mitt.) Broth.  ++

Mat, wet rocks

74

Rhynchostegiella menadensis (Sande Lac.) E.B. Bartram

Mat, wet rocks

Meteoriaceae

75

Aerobryidium filamentosum (Hook.) M. Fleisch.

Pendent, tree branches

76

Barbella convolvens (Mitt.) Broth.

Pendent, tree branches

77

Barbella pendula (Sull.) M. Fleisch.  ++

Pendent, tree branches

78

Barbella spiculata (Mitt.) Broth.

Pendent, tree branches

79

Chrysocladium flammeum (Mitt.) M. Fleisch.

Mat, tree branches

80

Diaphanodon blandus (Harv.) Renauld & Cardot

Mat, tree bark

81

Floribundaria sparsa (Mitt.) Broth.

Pendent, tree branches

82

Meteorium polytrichum Dozy & Molk.  ++

Pendent, tree branches

83

Pseudospiridentopsis horrida (Mitt. ex Cardot) M. Fleisch.

Mat, tree bark

84

Trachypodopsis auriculata (Mitt.) M. Fleisch.

Pendent, tree bark

85

Trachypodopsis serrulata (P. Beauv.) M. Fleisch.  ++

Pendent, tree branches

86

Trachypodopsis himantophylla (Müll. Hal. ex Renauld & Cardot) M. Fleisch.

Creeping and Pendent, tree trunk and branches

87

Trachypus bicolor Reinw. & Hornsch.

Creeping, tree trunk and branches 

Fabroniaceae

88

Levierella neckeroides (Griff.) O'Shea & Matcham

Mat, fallen logs

Hypnaceae

89

Ectropothecium dealbatum (Reinw. & Hornsch.) A. Jaeger

Mat, shaded forest floor

90

Hypnum macrogynum Besch.  ++

Mat, shaded soil and rocks

91

Hypnum sikkimense Ando

Mat, shaded soil

Hylocomiaceae

92

Hylocomium himalayanum (Mitt.) A. Jaeger ++

Feather, forest floor

93

Macrothamnium leptohymenioides Nog.

Weft, forest floor

94

Meteoriella soluta (Mitt.) S. Okamura

Pendent, tree branches

Rhytidiaceae

95

Rhytidium rugosum (Ehrh. ex Hedw.) Kindb.

Mat, forest floor

Symphyodontaceae

96

Chaetomitriopsis glaucocarpa (Reinw. ex Schwägr.) M. Fleisch.

Mat, tree

Plagiotheciaceae                            

97

Plagiothecium neckeroideum Schimp.

Mat, tree base

98

Plagiothecium nemorale (Mitt.) A. Jaeger

Mat, tree base

Entodontaceae

99

Entodon luteonitens Renauld & Cardot

Turf, exposed rocks

100

Entodon nepalensis Mizush. ++

Mat, fallen logs

Pylaisiadelphaceae

101

Brotherella pallida (Renauld & Cardot) M. Fleisch.

Mat, wet rocks

102

Pylaisiadelpha capillacea (Griff.) B.C. Tan & Y. Jia

Mat, forest floor

103

Taxithelium nepalense (Schwägr.) Broth.

Mat, rocks

Sematophyllaceae

104

Meiothecium jagorii (Müll. Hal.) Broth.

Mat, fallen wood

105

Sematophyllum humile (Mitt.) Broth.

Mat, tree branches

106

 Sematophyllum phoeniceum (Müll. Hal.) M. Fleisch.

Mat, tree bark

Pterobryaceae

107

Symphysodontella subulata Broth.

Mat, wet rocks

Neckeraceae

108

Dixonia orientalis (Mitt.) H. Akiy. & Tsubota +

Mat, wet rocks

109

Macrocoma tenuis (Müll. Hal.) Vitt

Turf, tree branches

110

Thamnobryum macrocarpum (Brid.) Gangulee

Feather, wet rocks

111

Zygodon brevisetus Wilson ex Mitt.  +

Turf, tree branches

Myuriaceae

112

Myurium rufescens (Reinw. & Hornsch.) M. Fleisch.  +

Mat, wood pieces

Anomodontaceae

113

Anomodon acutifolius Mitt.

Tail, tree trunk

+—Rare | ++—Widely distributed.

 

 

For figure & images - - click here for full PDF

 

 

References

 

Chopra, R.S. (1975). Taxonomy of Indian mosses (an introduction). Botanical Monograph [New Delhi] i-xl; 631 pp.

Dierick, D. & D. Hoelscher (2009). Species-specific tree water use characteristics in reforestation stands in the Philippines. Agricultural and Forest Meteorology 149(8): 1317–1326.

Flora of North America Editorial Committee (Ed.) (2007). Flora of North America, North of Mexico. Bryophyta. Oxford University Press, Pt. 1 (27), 713 pp.

Gairola, S., R.S. Rawal, N.P. Todaria & A. Bhatt (2014). Population structure and regeneration patterns of tree species in climate-sensitive subalpine forests of Indian western Himalaya. Journal of Forestry Research 25(2): 343–349.

Gangulee, H.C. (1969–1980). Mosses of Eastern India and Adjacent Regions. Fascicle I. 1969, Fascicle. II. 1971, Fascicle. III. 1972, Fascicle. IV. 1974, Fascicle. V. 1975, Fascicle. VI. 1977, Fascicle. VII. 1978 and Fascicle. VIII. 1980. Eastend Printers, Calcutta, India .

Kimmerer, R.W. & C.C. Young (1996). Effect of gap size and regeneration niche on species coexistence in bryophyte communities. Bulletin of the Torrey Botanical Club 123(1): 16–24.

Koponen, T. & Y. Sun (2017). Preliminary study on phylogenetic position and delimitation of the ciliate arthrodontous genera of the moss family Mniaceae. Journal of Bryology 39(1): 23–38.

Larsen, R.S., J.N.B. Bell, P.W. James, P.J. Chimonides, F.J. Rumsey, A. Tremper & O.W. Purvis (2007). Lichen and bryophyte distribution on oak in London in relation to air pollution and bark acidity. Environmental Pollution 146(2): 332–340.

Levin, S.A. (1992). The problem of pattern and scale in ecology: the Robert H. MacArthur award lecture. Ecology 73(6): 1943–1967.

Muscolo, A., S. Bagnato, M. Sidari & R. Mercurio (2014). A review of the roles of forest canopy gaps. Journal of Forestry Research 25(4): 725–736.

Noble, I.R. & R. Dirzo (1997). Forests as human-dominated, ecosystems. Science 277(5325): 522–525.

Pradhan, B.K. & H.K. Badola (2008). Ethnomedicinal plant use by Lepcha tribe of Dzongu valley, bordering Khangchendzonga Biosphere Reserve, in North Sikkim, India. Ethnobiology. Ethnomedicine 4: 22.

Rahman, H., R. Karuppaiyan, P.C. Senapati, S.V. Ngachan & A. Kumar (2012). An analysis of past three-decade weather phenomenon in the mid-hills of Sikkim and strategies for mitigating possible impact of climate change on agriculture. Climate Change in Sikkim: Patterns, Impacts and Initiatives, 1–18 pp.

Richards, P.W. (1984). The ecology of tropical forest bryophytes, pp. 1233–1270 In: Schuster, R.M. (ed.). New Manual of Bryology. Hattori Botanical Laboratory, Nichinan.

Sefidkon, F., R. Kalvandi, M. Atri & M.M. Barazandeh (2005). Essential oil variability of Thymus eriocalyx (Ronniger) Jalas. Flavour and Fragrance Journal 20(5): 521–524. https://doi.org/10.1002/ffj.1442

Goffinet, B., W.R. Buck & A.J. Shaw (2009). Morphology, anatomy, and classification of the Bryophyta. Bryophyte Biology, 2nd Edition. Cambridge University Press, Cambridge.

Sikkim Biodiversity Action Plan (2012). Sikkim Biodiversity Conservation and Forest Management Project, FEWMD, Government of Sikkim, CONCEPT, India.

Singh, D. & D.K. Singh (2013). Some new and noteworthy records of family Lejeuneaceae (Marchantiophyta) from Sikkim, India. Nelumbo 55: 153–165.

Singh, D.K., D. Singh & M. Dey (2008). A catalogue of the Hepaticae and Anthocerotae of Sikkim, pp. 93–135. In: Mohamed, H., B.B. Baki, A. Nasrulhaq-Boyce & P.K.Y. Lee (eds.). Bryology in the New Millenium. University of Malaya, Kuala Lumpur.

Singh, D.K. & P.K. Pusalkar (2020). Floristic Diversity of the Indian Himalaya. In: Dar, G. & A. Khuroo (eds). Biodiversity of the Himalaya: Jammu and Kashmir State. Topics in Biodiversity and Conservation. Springer, Singapore, 1097 pp.

Whitmore, T.C. (1984). A vegetation map of Malesia at scale 1: 5 million. Journal of Biogeography 11: 461–471.