Plant Diversity
PLANT DIVERSITY OF ASSAM
Favourable geographical location, diversified topography and ideal climatic conditions have made Assam very rich in biodiversity. The vegetation of Assam is primarily of tropical type covering areas of evergreen, semi-evergreen, grasslands, deciduous forests, grasslands and riverside forests. Some important tree species found in Assam are Hoooong (Dipterocarpus macrocarpus), Gurjan (Dipterocarpus tubinatus), Mekai (Shorea assamica), Kurta (Palaquium polyanthum), Nahar (Mesua ferrea), Sia-nahar (Keyea assamica), Sissoo (Dalbergia sissoo), Khair (Acacia catechu) etc.
The large scale exploitation of forests both in legally and illegally and the encroachment of forest land for the settlement, agricultural use and others the productivity as well as the area under forest is de decreasing at an alarming rate in the state. Many dense forest area of the state have already come to the list of degraded forest. Another important cause of forest degradation in the state is the shifting agricultural practices especially in the Karbi-Anglong and North Cachar Hill districts. Many of the environmental problems facing by the people such as flood, soil erosion etc are directly related to the reckless exploitation of forest resources of the state. It also leads to the serious ecological crisis in the state.
General Statistical analysis of Flora of Assam:
|
Name of the plant group
|
No. of families
|
No. of Genera
|
No. of Taxa
|
Remarks
|
|
Fern Allies
|
4
|
6
|
40
|
Fern and Fern Allies with 315 and 40 species respectively in Assam represent 25.45% and 35.84% of Indian Pteridophytes.
|
|
Ferns
|
28
|
91
|
315
|
|
Angiosperms
|
|
Gymnosperms
|
7
|
14
|
22
|
This represent about 22.68% of the Indian flora
|
|
Dycolyledous
|
189
|
1012
|
2752
|
|
Monocolyledons
|
40
|
368
|
1080
|
|
Total
|
236
|
1394
|
3854
|
Dominance Flora Family of Assam:
|
Sl. No.
|
Name of the plant Family
|
No. of Texa
|
No. of Genus
|
|
1
|
Orchidaceae
|
328
|
96
|
|
2
|
Poaceae
|
295
|
108
|
|
3
|
Papilionaceae
|
198
|
51
|
|
4
|
Rubiaceae
|
141
|
57
|
|
5
|
Euphorbiaceae
|
139
|
48
|
|
6
|
Asteraceae
|
129
|
74
|
Status of Flora:
|
Flora
|
No. of Species (Including infraspecific taxa)
|
|
Flowering Plants
|
3854
|
|
Flowering Plants
|
236 Families
|
|
Angiosperm
|
|
|
Dicotyledons
|
2752
|
|
Monocotyledons
|
1080
|
|
Gymnosperm
|
22
|
|
Oorchids
|
328
|
|
Bamboo
|
42
|
|
Cane
|
14
|
|
Medicinal Plant diversity
|
About 952 plants species have been identified which have uses in medical practices in some form or other.
|
|
Plants of different Conservational Status
|
871
|
|
Endemic
|
167
|
|
Critically Endangered/Endangered/Vulnerable
|
318
|
|
Rare for Assam
|
386
|
|
Type of Vegetation
|
Percentage
|
|
Herbs
|
47%
|
|
Shurbs
|
22%
|
|
Trees/Small Trees
|
20%
|
|
Climbers/lianas
|
8%
|
|
Undershurbs
|
3%
|
|
Extinct:
|
Bambusa mastersii, Cleisostoma arietinum, Cyperus corymbosus, Dendrobium assamicum, Dendrobium aurantiacum, Hetaeria anomala, Liparis stachyurus and Sapria himalayana. Paphiopedilum specerianum etc. are reported to be extinct in wild.
|
(Source: Barooah C. and Ahamed I. 2014 and Environment and Forest Department, Assam)
Diverse Plant Communities: Because of its physiography, edaphic conditions and a conducive climatic as well as a number of protected areas, Assam boasts of profuse diversity of floristic elements. Altogether 3854 species of flowering plants have been recorded in Assam which constitutes 25.12% of total floristic wealth of India. The table below gives an account of various groups of vascular plants. In Assam plants belonging to family Poaceae with 303 species form the largest group of vascular plants. Herbaceous plants make 47% of the flora followed by shrubs 22%, trees/small trees 20%, climbers/lianas 8% and undershurbs 3%. Fern and Fern Allies with 315 and 40 species respectively in Assam represent 25.45% and 35.84% of Indian Pteridophytes.
Gymnosperms: Assam has 22 species of Gymnosperms and include Cycas pectinata, Podocarpaus neriifolia, P. Wallichianus, Pinus kesia) and Genetum gnemon with three varities and G. montanum. These species have restricted distribution but represent plants of high economic importance as source of timber, pulpwood, resins and turpentine and their seed as source of food and medicine and leaves as vegetables.
Angiosperms: Angiosperms form the largest category of plants in Assam with 3832 species. Assam has also 154 species of primitive Angiosperms better known as “Living fossils” belonging to family Magnoliaceae (19 species), Schizandraceae (1 species), Annonaceae (45 species), Myristicaceae (7 species), Chloranthaceae (2 species) and Lauraceae (80 species). The important species are Magnolia species, Pachylarnax pleiocarpa, Fissistigma species, Alseodaphne species, Cinnamomum species, Litsea species, Michelia species etc. Plants belonging to this category are the most economically important plants of Assam and meet the demand for timber, plywood, pulpwood, furniture, agricultural implements. Leaves of Litsea monopetala, L. cubeba etc. are used for rearing silkworm. The orchids of Assam: In Assam as many as 293 species of Orchids are reported which represent 44.39% of North East species and 24.42% of species occurring in India. Orchids as a group of flowering plants exhibit wide range of habits and have specific macro climatic requirements for their growth, development and regeneration. Assam orchids show all the habits and growth forms found in Orchidaceous taxa. Mostly they are epiphytes. Goodyera procera and Spiranthis sinesis are adapted to aquatic habitat whereas Vanilla pilifera and Galeola altissima are climbers. Orchids grow to their magnificent best in the Evergreen and Semi- Evergreen forest and to some extent in Moist Deciduous forests. Species belonging to genera Acanthephippium, Anoectochilus, Apostasia, Agrostophyllum, Coelogyne, Cymbidium, Dendrobium, Eria, Oberonia,, Calanthe, Eulophia, Geodorum, Habenaria, Malaxis, Nephelaphyllum, Vanilla, Zeuxine, Didymoplexis, Galeola, Bulbophyllum, Camarotis are the commonly found orchids.
Medicinal Plant diversity: Assam is home to a good number of plants having medicinal uses traditional village practitioners, Aurvedic, Unani, Homeopathic and even modern medical practices. Altogether, 952 plants species have been identified which have uses in medical practices in some form or other. Asparagus racemosa (Satmul), Curcuma aromatica (Ban-haldi), Emblica officinalis (bel), Terminalia species (Hilikha, Bahera), Eugenia jambolana (Loha-jam), Garcina species (Thekera), Holarrhina antidysentrica (Dudhkuri), Hydnocarpus kurzii (Chalmugra), Litsea cubeba (Mejankuri), Ocimum species (Tulsi), Phlogocanthus thyrsiflorus (Titaphul), Piper longum (pipoli), Saraca indica (Asoka), Wedelia calandulacea (Mahabhringraj), Zinziber officinalis (Ada) are some of the most commonly used plants in treatment of various ailments. But the list is not exhaustive.
Bamboos and Cane Diversity in Assam: Bamboos have gained considerable importance in the socio-economic life of people in Assam for the variety of uses. Altogether 42 naturally growing species of bamboo are recorded in Assam of which Bamboosa masrtersei is restricted in distribution to Dibrugarh district. Bamboosa cacharensis, Dinochlora compactiflora, D. india are restricted to Barak Valley. Chimnobabusa griffithiana and Oxetenanthera parviflora are restricted in distribution to N.C.Hills. Bambusa rangaensis grows wild in the Ranga R.F. of Lakhimpur district. Bamboosua vulgaris is the introduced species cultivated throughout Assam as ornamental plant. Bambusa jaintiana and Melocanna arundiana are the species reported only from Assam. There are no exclusive bamboo forests in the plains of Assam, bamboo grooves are found mostly along the edge of Reserve Forests. But pure bamboo forests occur in N.C Hills and Karbi Anglong districts predominated with Melocanna baccifera and Chimnobambusa griffithiana. Bamboo is cultivated widely in Assam and every household grows bamboo in its bari land. Commonly cultivated species are Bambusa balcooa (Bhaluka bamboo), Bambusa tulda (Jati bamboo), Malocanna bacciferra (Muli bamboo), Dendrocalamus hamiltonii (Koko bamboo) and Dendrocalamus giganteus (Mokalm bamboo).
Total 14 species of cane grow in cane brakes in forests of Assam. Calamus flagellum, Calamus floribunadus, Calamus latifolius are found widely distributed throughout Assam. Plectomia assamica and Plectomia bractealis are endemic species.
Wetlands and Aquatic Plant Diversity: Assam has more fresh water wetlands than any other state in the North Eastern Region. The two major drainage systems of Assam-the Brahmaputra and the Barak and in the flood plains of these river systems exist patches of marshy depressions and swamps as well as perennial water bodies of varying shape, size and depth called locally as beels, haors, jalah, doloni, hola, pitoni etc. Man made tanks like Joysagar, Sibsagar, Dighalipukhuri, Jorpukhuri, Hazarapukhuri, Rajhuwa Borpukhuri etc. were also dug by ancient Rulers of Assam. Deepor beel near Guwahati is a Ramsar site. Besides Deepor beel and some others mentioned above wetlands of importantce are Chandubi, Rata, Sohola, Taralipather, Phokolai, Mer, Sonbeel, Jamjing, Sagunpara, Motapung, Sarlane, Sareswar, Roumari, Khalihamari, Goranga, Sapekhati, Koladuar etc.
The aquatic plants species of Assam belongs to diverse habits and have distinctive characteristics. More than 100 such aquatic species have been identified and they can be described into following broad categories.
· Free floating hydrophytes: Eichhornia cressipes, Pistia stratioles, Lemna minor etc.
· Suspended submersed hydrophytes: Ceratophyllum demersum, Utricularia gibba etc.
· Anchored submerged hydrophytes: Hydrilla, Potomogeton, vallisnaria etc.
· Anchored hydrophytes with floating leaves: Nelumbo, Euryle etc.
· Anchored hydrophytes with floating shoots: Ludwigia, Ipomea etc.
· Emergent amphibious hydrophytes: Sagittaria, Scrirpus.
· Wetland hydrophytes: Cyperus, Hygrophylla etc.
Endemic flora: Endemic floras are plants which occur in a restricted area. Altogether 165 species of plants have been recorded which are restricted in distribution to certain pockets in Assam, though some of them show extended destruction in the N.E. Region and elsewhere in India. However, more than 100 such species have distribution restricted to Assam only. These include trees e.g. Accacia gageana, Adiantum assamicum, Alseodaphne andersonii, Alseodaphane khasyana, Angiopteris assamica, Cedrela fabrifuga, Cinnamomum cacharensis, Coelogyne assamica, Combretum wallichii, Dinochloa indica, Diospyros cacharensis, Dipterocarpus mannii, Eugenia cyanophylla, bamboos e.g. Bambusa cacharensis, Bambusa mastersii, Chimnobambusa griffitheana, orchids e.g. Bulbophyllum elassonotum, Bulbophyllum vireus, Dendrobium assamicum etc.
Rare and Endangered Species: Categories of threatened plants recognized by the IUCN have been reported from Assam. Besides the above; 284 species of plants are observed to be critically endangered, 149 species as endangered, 58 species as vulnerable, 13 species as near threatened.
Assam Forest Protection Force Act 1986
Assam Forest at a Glance 2011-12
Assam Settlement of Forest Coupes and Mahals by Tender System Rules 1967
Rules Having the Force of Law and Executive Orders Relating to Forests
Rules and Orders in Force in Certain Districts
Forest Regulation 1891
Assam Bamboo Policy
Database:
Reserve Forest of Assam
Forest Report of Assam 2011
Forest Division wise area under Forest in Assam 2007
Forest Division wise area under Forest in Assam 2008
Forest Division wise area under Forest in Assam 2009
Forest Division wise area under Forest in Assam 2010
Forest Division wise area under Forest in Assam 2011
Forest Division wise area under Forest in Assam 2012
Source:
Ministry of Environment, Forest and Climate Change
Department of Environment & Forests, Government of Assam
Assam Project on Forest and Biodiversity Conservation Society
Maps of India
assamforest.in
http://natureconservation.in/
http://www.sanctuariesindia.com/
http://www.assam.org/
bhuvan.nrsc.gov.in