About the database

About the Database

The term “Biodiversity” refers to the diversity that is found among life forms within a given ecosystem, biome, or on the globe. There are three levels of biodiversity: Genetic Diversity- genetic variation among the living organisms; Species Diversity - variation encountered within a genus and Ecosystem Diversity - diversity of ecological complexity showing variations in ecological niches, trophic structure, food web, etc.

            Biodiversity is not evenly distributed on the earth: rich in the tropics and in specific localized regions while poor in Polar Regions, where fewer species are found. Some regions of the earth are regarded as “Biodiversity Hot Spots” based on certain criteria or the term can be explained as a biogeographic region containing a significant reservoir of biodiversity and also rich in endemic taxa. The concept of biodiversity hotspots was conceived by Norman Myers in two of his publications in “The Environmentalist” (1988 & 1990), revised after thorough analysis by Myers and others in “Hotspots: Earth’s Biologically Richest and Most Endangered Terrestrial Ecoregions”. To qualify as a biodiversity hotspot on Myers 2000 edition of the hotspot-map, a region must meet two criteria: (a) it must contain at least 0.5% or 1,500 species of vascular plants as endemics; (b) it has to have lost at least 70% of its primary vegetation. Around the world, there are 34 biodiversity hotspots (Conservation International Founder: Spencer Beebe founded in 1987). These sites support nearly 60% of the world's plant, bird, mammal, reptile and amphibian species, with a very high share of endemic species. India has three Biodiversity Hotspots - Himalaya, Western Ghats and Indo –Burma.

            The North Eastern Region of India represents nearly 50% of the total biodiversity of the country. The first consolidated account on the flora of Assam was “Flora of Assam” by Upendra Nath Kanjilal and his associates but the work was an incomplete one because of non-inclusion of monocotyledons except Gramineae and most of the herbaceous species of the area. Later on, a checklist entitled “Assam’s Flora (Present status of Vascular Plants)”, was published by Assam Science Technology and Environment Council(ASTEC) during 2005 with the data available to them, but without any information in regard to distribution, habit and habitat of the taxa. Since then, several works have been completed and a number of publications appeared relating to the plants of the state. This resulted in accumulation of enormous data scattered in various publications. With the intension to bridge this gap and to disseminate information on biodiversity related issues to the academic institutions, students, teachers and researchers, organizations and all other beneficiaries, the idea of “Establishment of Biodiversity Data Bank” was conceived in the year 2009 by the Environment Division of ASTEC, which was supported by the Department of Environment and Forests, Government of Assam. Thus, under this project a checklist of phanerograms has been prepared using secondary data.

 

The checklist

The checklist of Angiosperms & Gymnosperms is based on primary and mostly secondary sources. The taxa are arranged in alphabetical order under each family. In determining the names of the taxa, an effort has been made to present as per the nomenclature accepted as valid in current literature. The checklist provides scientific name of each taxon followed by English name, local name, distribution, habitat, habit and conservation status.  Since, the data have been retrieved from mostly secondary sources they are retained as such particularly in case of the distribution of the taxa including the spelling, old names and political divisions of states and districts. In regard to distribution of taxa, the term “elsewhere” refers to distribution of taxa in India as well as in other parts of the world. The taxon for which place of occurrence is not known or occurring in all over Assam, has been provided with an asterisk (*) mark. The present political Assam has been divided into three parts to state the occurrence of plant taxa; (a) Western Assam comprising of Kokrajhar, Bongaigaon, Baksa, Chirang, Nalbari, Barpeta, Goalpara, Dhubri, Kamrup, Kamrup(M), Morigaon, Nagaon, Udalguri and Darrang districts; (b) Eastern Assam comprising of Golaghat, Sonitpur, Lakhimpur, Dhemaji, Dibrugarh, Jorhat, Dima Hasao, Karbi Anglong, Sivasagar and Tinsukia districts and (c) Barak Valley comprising of Cachar, Karimganj and Hailakandi districts. The conservation status of the taxa for the state of Assam, the work of Chowdhury(2005) has been mostly followed along with IUCN status of taxa. Besides, taxa included under CITES list, CAMP list and those endemic to Assam are also mentioned in the checklist.

 

Floristic composition of Angiosperms & Gymnosperms in Assam

              The present work includes 3855 taxa (including infraspecific taxa) under 1394 genera and 236 families. Out of them, 2752 taxa are Dicotyledons, 1081 taxa are Monocotyledons and 22 taxa are Gymnosperms (Table – 2). This represents about 22.68 % of the Indian flora. A total of 40 sub-species (ssp.), 218 varieties (var.) and 3 forma (f.) are recorded so far. A total of 167 endemic taxa are found in Assam and 871 taxa have been categorized under different conservational status (Based on IUCN & Conservation status of plants of Assam). A conspectus of families showing the number of genera, number of taxa and number of endemic taxa are shown in Table – 1, while Table – 2 contains a general statistical analysis of Angiosperms & Gymnosperms of Assam.

Table-1:  A conspectus of families, genera, taxa, Threatened, Rare and Endemic taxa of flowering plants of Assam.

Sl. No.

Family*

No. of Genera

No. of Taxa

Threatened (CR, EN, VU)

Rare (R)

Endemic

Dicotyledones

1

Ranunculaceae

7

18

1

5

-

2

Dilleniaceae

2

5

-

-

-

3

Magnoliaceae

3

19

-

1

5

4

Schizandraceae

1

1

-

-

-

5

Annonaceae

15

45

-

8

5

6

Menispermaceae

14

19

-

5

1

7

Berberidaceae

1

2

-

2

-

8

Lardizabalaceae

2

4

-

-

-

9

Nandinaceae

1

1

-

-

-

10

Nymphaeaceae

2

4

-

-

-

11

Nelumbonaceae

1

1

-

-

-

12

Papaveraceae

2

4

-

-

-

13

Fumericaceae

1

1

-

-

-

14

Brassicaceae

10

27

-

4

-

15

Capparaceae

3

12

-

4

-

16

Cleomaceae

1

5

-

1

-

17

Violaceae

3

11

-

3

-

18

Bixaceae

1

1

-

-

-

19

Flacourtiaceae

5

10

-

2

-

20

Pittosporaceae

1

2

-

1

-

21

Polygalaceae

4

15

-

1

-

22

Xanthophylaceae

1

1

-

1

-

23

Caryophyllaceae

8

11

-

1

-

24

Portulacaceae

3

7

-

-

-

25

Tamaricaceae

1

1

1

-

-

26

Elatinaceae

1

1

-

2

-

27

Hypericaceae

1

9

-

4

2

28

Clusiaceae

4

21

-

10

3

29

Theaceae

7

23

-

-

2

30

Actinidaceae

1

2

-

2

-

31

Saurauiaceae

1

7

-

2

-

32

Dipterocarpaceae

3

7

-

-

2

33

Ancistrocladaceae

1

1

-

-

-

34

Malvaceae

16

53

-

4

-

35

Bombacaceae

2

3

-

-

-

36

Sterculiaceae

13

26

-

2

2

37

Byttneriaceae

1

3

-

-

-

38

Tiliaceae

4

28

-

-

-

39

Elaeocarpaceae

2

21

1

4

-

40

Linaceae

2

3

-

-

-

41

Ixonanthaceae

1

1

-

1

1

42

Erythroxylaceae

1

1

-

-

-

43

Malpighiaceae

2

7

-

-

2

44

Zygophyllaceae

1

1

-

-

-

45

Geraniaceae

2

5

-

-

-

46

Oxalidaceae

1

4

-

1

-

47

Averrhoaceae  

1

2

-

-

-

48

Balsaminaceae

2

13

-

3

2

49

Tropaeolaceae

1

1

-

-

-

50

Rutaceae

14

37

-

8

2

51

Simaroubaceae

3

6

2

-

1

52

Ochnaceae

1

2

-

1

-

53

Burseraceae

5

7

-

1

-

54

Meliaceae

11

29

1

6

2

55

Dichapetalaceae

1

1

-

-

-

56

Olacaceae

3

5

-

2

1

57

Icacinaceae

5

6

-

1

-

58

Cardiopterygaceae

1

1

-

1

-

59

Erythropalaceae

1

2

-

-

-

60

Opileaceae

1

1

-

-

-

61

Aquifoliaceae

1

4

-

1

1

62

Celastraceae

8

16

-

4

-

63

Hippocrateaceae

3

9

-

-

1

64

Rhamnaceae

7

21

-

1

1

65

Vitaceae

6

28

-

5

1

66

Leeaceae

1

8

-

1

-

67

Sapindaceae

11

17

-

2

-

68

Staphyleaceae

1

1

-

-

-

69

Aceraceae

1

2

-

1

-

70

Hippocastanaceae

1

1

-

-

-

71

Sabiaceae

2

14

-

1

-

72

Anacardiaceae

11

19

1

4

2

73

Moringaceae

1

1

-

-

-

74

Connaraceae

2

2

-

-

-

75

Mimosaceae

11

35

-

-

1

76

Caesalpiniaceae

10

41

-

-

-

77

Papilionaceae

51

198

5

25

1

78

Rosaceae

7

30

-

3

1

79

Saxifragaceae

3

3

-

1

-

80

Iteaceae

1

1

-

-

-

81

Hydrangiaceae

1

2

-

1

-

82

Crassulaceae

4

5

-

-

-

83

Droseraceae

1

1

-

-

-

84

Altingiaceae

1

1

-

-

-

85

Haloragidaceae

2

3

-

2

-

86

Rhizophoraceae

1

1

-

-

-

87

Combretaceae

4

22

-

4

1

88

Myrtaceae

5

34

-

-

-

89

Lecythidaceae

2

2

-

-

-

90

Barringtoniaceae

1

1

-

-

-

91

Melastomaceae

7

19

-

4

-

92

Memecylaceae

1

9

-

2

-

93

Lythraceae

6

18

-

2

1

94

Crypteroniaceae

2

2

-

-

-

95

Punicaceae

1

1

-

-

-

96

Onagraceae

3

6

-

-

-

97

Trapaceae

1

3

-

-

-

98

Samydaceae

2

6

1

-

-

99

Passifloraceae

2

7

-

2

-

100

Caricaceae

1

1

-

-

-

101

Cucurbitaceae

20

37

-

5

2

102

Begoniaceae

1

17

-

1

5

103

Datiscaceae

1

1

-

-

-

104

Cactaceae

6

8

-

-

-

105

Aizoaceae

1

3

-

-

-

106

Molluginaceae

1

1

-

-

-

107

Apiaceae

11

14

-

-

-

108

Araliaceae

7

11

-

1

-

109

Cornaceae

2

2

-

1

-

110

Nyssaceae

1

1

-

-

-

111

Alangiaceae

1

3

-

-

-

112

Caprifoliaceae

4

9

-

-

-

113

Rubiaceae

57

141

-

20

5

114

Asteraceae

74

129

-

2

3

115

Stylidaceae

1

1

-

1

-

116

Campanulaceae

2

4

-

-

-

117

Lobeliaceae

1

3

-

-

-

118

Sphenocleaceae

1

1

-

-

-

119

Vacciniaceae

1

3

-

2

1

120

Ericaceae

2

3

-

-

-

121

Plumbaginaceae

1

3

-

1

-

122

Primulaceae

2

2

-

1

-

123

Myrsinaceae

8

39

-

7

-

124

Sapotaceae

8

10

-

2

-

125

Ebenaceae

1

10

-

-

1

126

Styracaceae

2

2

-

-

-

127

Symplocaceae

1

11

-

1

-

128

Oleaceae

5

26

-

2

-

129

Apocynaceae

25

35

-

5

-

130

Asclepiadaceae

18

41

1

7

-

131

Periplocaceae

6

7

-

2

-

132

Loganiaceae

2

5

-

-

-

133

Buddleiaceae

1

2

-

1

-

134

Gentianaceae

6

13

-

-

-

135

Menyanthaceae

1

2

-

-

-

136

Polemoniaceae

2

2

-

-

-

137

Hydrophyllaceae

1

1

-

-

-

138

Boranginaceae

5

7

-

-

-

139

Ehretiaceae

4

8

-

1

-

140

Heliotropaceae

2

5

-

1

-

141

Convolvulaceae

11

46

-

2

-

142

Cuscutaceae

1

1

-

-

-

143

Solanaceae

14

38

-

2

-

144

Scophulariaceae

25

66

-

3

-

145

Orobanchaceae

2

3

-

1

-

146

Lentibulariaceae

1

6

-

-

-

147

Gesneriaceae

10

23

-

4

1

148

Bignoniaceae

15

18

-

1

-

149

Pedaliaceae

1

2

-

-

-

150

Acanthaceae

27

92

-

5

1

151

Thunbergiaceae

2

6

-

-

-

152

Verbenaceae

18

64

-

1

-

153

Lamiaceae

33

87

-

2

-

154

Plantaginaceae

1

1

-

-

-

155

Nyctaginaceae

3

4

-

-

-

156

Amaranthaceae

14

31

-

-

-

157

Chenopodiaceae

5

6

-

-

-

158

Basellaceae

1

2

-

-

-

159

Phytollacaceae

2

2

-

-

-

160

Polygonaceae

6

37

-

-

-

161

Podostemaceae

1

1

-

-

1

162

Nepanthaceae

1

1

-

1

1

163

Rafflesiaceae

1

1

-

1

1

164

Aristolochiaceae

1

5

-

-

-

165

Piperaceae

2

20

-

-

1

166

Saururaceae

1

1

-

-

-

167

Chloranthaceae

1

1

-

-

-

168

Myristicaceae

3

6

-

-

-

169

Lauraceae

14

81

-

2

22

170

Hernandiaceae

1

3

-

-

-

171

Proteaceae

2

2

-

-

-

172

Thymeliaceae

3

3

-

1

-

173

Elaeagnaceae

1

2

-

-

-

174

Loranthaceae

7

13

-

1

-

175

Viscaceae

1

2

-

-

-

176

Santalaceae

2

2

-

1

-

177

Balanophoraceae

1

1

-

1

-

178

Euphorbiaceae

48

139

-

1

5

179

Urticaceae

15

47

-

5

1

180

Ulmaceae

5

9

-

-

-

181

Moraceae

6

60

-

3

-

182

Cannabidaceae

1

1

-

-

-

183

Juglandaceae

1

3

-

-

-

184

Myricaceae

1

1

-

-

-

185

Casuarinaceae

1

1

-

-

-

186

Betulaceae

1

1

-

-

-

187

Fagaceae

3

21

-

4

-

188

Salicaceae

1

3

-

-

-

189

Ceratophyllaceae

1

1

-

-

-

Total

1012

2752

14

266

95

Gymnospermeae

1

Gnetaceae

1

4

2

1

-

2

Pinaceae

1

2

-

-

1

3

Cupressaceae

3

5

-

-

-

4

Taxaceae

3

3

1

-

-

5

Podocarpaceae

2

2

-

-

-

6

Cycadaceae

2

4

-

2

-

7

Araucariaceae

2

2

-

1

-

Total

14

22

3

4

1

Monocotyledones

1

Hydrocharitaceae

6

9

-

-

-

2

Burmanniaceae

1

1

-

1

-

3

Orchidaceae

96

328

301

86

35

4

Zingiberaceae

14

45

-

4

4

5

Strelitziaceae

2

2

-

-

-

6

Musaceae

2

12

-

2

-

7

Heliconiaceae

1

1

-

-

-

8

Costaceae

1

1

-

-

-

9

Cannaceae

1

2

-

-

-

10

Marantaceae

4

6

-

-

-

11

Bromeliaceae

1

1

-

-

-

12

Haemodoraceae

2

2

-

-

-

13

Iridaceae

1

3

-

-

-

14

Amaryllidaceae

6

10

-

-

-

15

Agavaceae

7

16

-

-

-

16

Hypoxidaceae

2

2

-

-

-

17

Taccaceae

1

1

-

-

-

18

Dioscoreaceae

1

20

-

-

-

19

Stemonaceae

2

2

-

-

-

20

Liliaceae

11

13

-

2

-

21

Alliaceae

1

3

-

-

-

22

Smilacaceae

2

10

-

1

-

23

Pontederiaceae

2

3

-

-

-

24

Xyridaceae

1

1

-

1

-

25

Commelinaceae

10

34

-

2

-

26

Flegillariaceae

1

1

-

1

-

27

Juncaceae

1

7

-

-

-

28

Arecaceae

18

36

-

1

1

29

Pandanaceae

1

6

-

-

-

30

Typhaceae

1

2

-

-

-

31

Araceae

24

45

-

-

-

32

Lemnaceae

4

4

-

1

-

33

Alismaceae

2

3

-

-

-

34

Butomaceae

1

1

-

-

-

35

Najadaceae

1

3

-

-

-

36

Aponogetonaceae

1

2

-

-

-

37

Potamogetonaceae

2

4

-

-

-

38

Eriocaulaceae

1

12

-

-

-

39

Cyperaceae

24

132

-

11

7

40

Poaceae

108

295

-

3

24

Total

368

1081

301

116

71

*Families are arranged according to G. Bentham & J.D. Hooker's (1862-1883) system of Classification including split families.

 

Table 2.  General statistical analysis of Angiosperms & Gymnosperms of Assam

Sl. No.

Plant group

No. of families

No. of  Genera

No. of taxa

1

Gymnosperms

   7

   14

    22

2

Dicotyledons

189

1012

2752

3

Monocotyledons

  40

  368

1081

TOTAL

236

1394

3855

 

Angiosperms and Gymnosperms of Assam represent about 47% herbs, 22% shrubs, 20% trees/small trees, 8% climbers/lianas and 3% undershrubs. Out of 236 families of flowering plants recorded from Assam, in regard to taxa of dominance, Orchidaceae is the most dominant family with 328 taxa, followed by Poaceae of 295 taxa, Papilionaceae of 198 taxa, Rubiaceae of 141 taxa and Euphorbiaceae of 139 taxa, while in regard to genus dominance the five dominant families are Poaceae of 108 genera, followed by Orchidaceae of 96 genera, Asteraceae of 74 genera, Rubiaceae of 57 genera and Papilionaceae of 51 genera respectively.

Phytogeographical analysis for Angiosperms & Gymnosperms

            An analysis of the distribution patterns of the Gymnosperms and Angiosperms of Assam reveals that Assam being a state with land connections, plants had migrated in past from Africa, America, Australia, West Asia, South-East Asia through Afghanistan, Bangladesh, Myanmar, Pakistan, Nepal, etc. The presence of land connections, along with isoclimatic conditions probably promoted  this migration and distribution of plants from one place to another and vice versa, by natural as well as by artificial process of dispersal. Besides, it has also been found that floristic composition is much rich in Brahmaputra Valley than in Barak valley of Assam.

Plants of different threat categories

            Based on the study of available literature and herbarium materials, a total of 3855 taxa of Angiosperms and Gymnosperms have been mentioned in the taxonomic enumeration. A total of 871 taxa are categorized under different conservational status. Out of them 167 taxa are endemic, 318 are CR/EN/VU and 386 taxa are R for Assam. The different conservation status includes in the list are "CR" - Critically endangered, "EN" – Endangered, "VU" – Vulnerable, "NT" - Near Threatened, "LC" - Least Concerned, "DD" - Data Defficient, "NE" - Not Evaluated as given by IUCN while "R"- Rare, "S"- Scattered, "O"- Occasional, "DI" - Data Insufficient in lieu of sate status based on the works of S. Chowdhury (2005).

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