(3 species), coffee (2 species) and nightshade (2 species) families. local plants and their uses 104 plant species are used for treatment of fevers and malaria (inclusive of the 31 species specifically used for malaria). northeast india the dzüko valley on the border of nagaland and manipur. rainforest ecosystem in assam (at the hollongapar gibbon sanctuary). northeast india (officially north eastern region, ner) is a complex region of eight indian states and 45 million people. the region borders five countries: nepal, bhutan, china (tibetan autonomous region), myanmar, and bangladesh. geographically, northeast india is bounded on the north by eastern himalayan mountains, the east by the purvanchal/patkai mountain ranges, and the southwest by the gangetic plain. the northernmost states of sikkim and aryunachal pradesh are formed by himalayan valleys. the rugged eastern states (nagaland, manipur, and mizoram) are formed by the patkai mountains and a series of steep hill ranges. likewise, meghalaya is a hilly state stretching across the northern border of bangladesh. assam is largely the river valley of the broad bramaputra river. a euphorb plant venerated in the worship of shiva (state of assam). this plant is considered holy by the boro people, the largest scheduled tribe of ner. climatically, northeast india is largely defined by a subtropical climate with massive annual rainfalls. the flat sweep of the gangetic plain ending in the himalayas ensures that monsoons are particularly intense; the state of meghalaya receives more rain than anywhere else on earth (>1200 cm per year). northeast india is one of the most ethnically diverse regions in the world. these states contain 130 tribes with 300 distinct subtribes, over 200 ethnic groups, and 220 spoken languages. many of india's tribal peoples are concentrated here, with the hilly states of arunachal pradesh, meghalaya, mizoram, and nagaland being 90% adivasi by population. the largest state by population, assam contains 30 million people, of which a minority are adivasi. at least 4,000 plant species have been documented in northeast india with others likely undiscovered. the region is among the most biodiverse in india, containing half of all indian species diversity and more than 25% of indian endemic plants. 1,953 plants are used by tribal peoples of this region, accounting for 80% of all ethnomedicinal plants documented in india. medicinal plant taxonomy at least 37 members of the ginger family (zingiberaceae) have been identified as medicinal plants in ner, 88% of which were found in arunachal pradesh. a 2012 survey found the dimasa tribe (assam) used non-flowering plants like ferns and cycads. ner has over 80 species of rhododendron, with multiple documented ethnomedicinal uses. local plants and their uses because ner is one of the most ethnically and botanically diverse places on the planet, broadly characterizing the utilization of medicinal plants here is difficult. research into the indigenous use of plants in ner has been conducted since the 1970s. one of the most widely cited species in surveys, ageratum conyzoides (flowers, leaves, roots and whole plant) is used for throat pain, helminth infections, arthritis, fever, malaria treatment, dysentery, and liver disease. studies have identified this plant as carcinogenic. mimosa pudica (sensitive plant) is used as treatment for skin infections, helminths, urological disease, toothaches and as a contraceptive. the rhizome of acorus calamus (calamus, or vacā in sanskrit) is documented as a treatment for cough, cold, snake bite, asthma, rheumatic fever, and hemorrhoids. though calamus is used in ner folk medicine (and in ayurveda), this plant is considered extremely carcinogenic. andrographis paniculata has been cited for use in stomach pain, malaria, and jaundice. another plant widely referenced in ethnobotanical surveys, callicarpa arborea is used for skin disease, leukorrhea, and treating scorpion stings. the meithei manipuri people produce herbal vapors for the treatment of 41 diseases, using both single plant species and multi-species concoctions. rhododendron arboretum is used to treat diarrhea, dysentery, throat pain, headaches, and fish bones stuck in throat. western himalayas thenu village in himachal pradesh. photo by timothy gonsalves (2016) the western himalayas region consists of the states of himachal pradesh, uttarakhand and the union territories of jammu & kashmir and ladakh. the central (great) himalayas are mostly within nepal though a portion lie within uttarkand. these states forms part of the foothills of the largest mountains on earth. climatically, much of the region is defined by a polar or tundra type climate, but southern portions of himachal pradesh and uttarakhand are humid subtropical. vegetation includes alpine shrubs and meadows, subalpine conifer forests, himalyan broadleaf dry forests, and subtropical deciduous and pine forests. a portion of dry grassland (the bhabar) is found in lower uttarakhand. predominant trees include chir pine, blue pine, deodar, fir, and juniper. there is substantial ethnic diversity in this region. at the broadest level, these himalayan regions contain indic, tibetan-burman, and afghan-persian speaking peoples. in the western himalayas, ladakh contains the nomadic mountain changpas with agricultural laddakhis, dardi, and balti peoples inhabiting valleys. kashmir valley (jammu & kashmir) and the pirpanjal valley (jammu & kashmir, himachal pradesh) are inhabited by kashmiris, gujjars, and bakkarwal peoples. the central himalayas (uttarakhand) contain the agirucltural paharis in valley regions and the tibetan-speaking bhotiya peoples in the mountains. the paharis are a diverse group are also found in kashmir. between 4,000 and 5,000 plants are reported in the western and central himalayas. surveys have identified 1,338 medicinal plant species specifically from the state of uttarakhand, 948 species from jammu & kashmir, and 643 species from himachal pradesh. medicinal plant taxonomy a review found 109 different families of medicinal plants in the former state of jammu & kashmir. local plants and their uses plants in this region most frequently used in medicinal preparations include terminalia chebula, terminlia bellirica, emblica officinalis, glycyrrhiza glabra (liquorice), justicia adhatoda, withania somnifera, and cyperus rotundus. the rhizome curcuma domestica (turmeric) is used for cuts, burns, and scalds. fruits of the piper nigrum species (black pepper) are popularly used for colds and coughs. the fruits from trachyspermum ammi (ajawain) and plants from the genus ferula are commonly used to treat gastrointenstinal disorders and in some cases, whooping cough. indo-gangetic region and central india the indo-gangetic plain is a flat arc dominating much of northern india as well as bangladesh. more than 400 million people live in an area of 700,000 km2, making it one of the most densely population regions on earth. the indo-gangetic region and central indian region consists of the 13 states of bihar, chhattisgarh, delhi, gujarat, haryana, jharkhand, madhya pradesh, punjab, rajasthan, uttar pradesh, west bengal, and chandigarh. these are the most populous region of india, with a combined total of almost 900 million people. geographically, the area is defined by outer himalays (siwalik mountains) to the north, the sprawling indo-gangetic plain in the middle, and the more rugged central india. central india consists of hills, a portion of the deccan plateau, and the aravalli and satpura mountains. flat coastal predominates in most of west bengal. the western border with pakistan features the thar desert, more than half of which lies within rajasthan. the dense population of the indo-gangetic region ensures that much of the land is taken up sprawling urban areas and intensive agriculture. the region is climatically diverse, featuring desert, semi-arid areas, coastal areas and the central plain. multiple forest ecosystems are found here, including tropical wet, tropical moist deciduous forests, tropical semi-evergreen, dry deciduous, and tropical thorn forests in the northern deccan, gangetic plains, and in semi-arid regions. the vast majority of the people are speakers of hindi languages. some 90 scheduled tribes are found in these 13 states, including the bhil and gond peoples, the two largest adivasi groups in india, together making up 70% of all members of scheduled tribes. other tribes surveyed for medicinal plants include the baiga, bharia, halba, kaul, korku, maria, and sahariya peoples. around half of the flowering plants of india are found in these states (11,000-12,000 species). a 2017 survey identified 528 plant species used for medicine in this region. another study records 610 species used by the tribal people of rajasthan alone, though this includes food and shelter plants. medicinal plant taxonomy the 528 medicinal plants used in this region belong to 112 families, the most important being the legume (74 species), mallow (30 species), asteraceae (29 species), mint (24 species), and dogbane (21 species) families. local plants and their uses leaves are the plant part most frequently utilized. azadirachta indica is a frequently cited species in ethnobotanical surveys, and used for the most diverse array of treatments. local uses include treatment for snake bite, scorpion stings, skin disease, wounds, malaria, eczema, diabetes, even leprosy and tuberculosis. andaman and nicobar islands the island of bompuka, part of the nicobar islands (2012, photograph by arne müseler). andamanese family (2006) the andaman and nicboar islands are a union territory located southeast of continental india, consisting of two island chains. these islands have a tropical wet/monsoon climate with tropical rainforest vegetation. the more northerly andaman islands have some mixed deciduous forest, with a landscape of steep hills and valleys. though dominated by a unique rainforest ecosystem, some nicobar islands are predominantly grassland and mangrove forests are found throughout coastal areas of both island chains. the islands are home to at least 2650 species of vascular plants and 150 plant families, with around 300 endemic species. the indigenous inhabitants of the andaman islands, the andamanese, number in total less than 500 people. surviving tribes include the great andamanese, the jarawa, the onge, and the sentinelese. the majority of the population is now constituted of people from the indian mainland (tamil, telugu, oriya, malayali, north indian) as well as bengali and malayali peoples. some 2000 karen people inhabit the city of mayabunder in middle andaman island. the nicobarese consist of some 22,000 people who share ancestry with southeast asians. on the island of great nicobar, the nichobarese share the island with the shompen people, a semi-nomadic tribe of hunter-gatherers confined to the island interior. about 200 shompen people have been documented. a 2009 study documented 289 plant species used for medicinal purposes by the indigenous peoples of both the andaman and nicobar islands. another study found 150 plant species used for 47 unique treatments by the people of car nicobar, the northernmost nicobar island. local plants and their uses the indigenous andamanese have lived a mixed agricultural/hunter-gatherer lifestyle for tens of thousands of years. food crops consist of rice, coconuts, area, fruit, palm oil and cashews. turmeric is an important spice used both in medicine and in cooking. the great andamanese chew and spray leaves of polyalthia jenkinsii in order to deter bee attacks during honey gathering. alstonia macrophylla is the plant most widely cited from ethnobotanical studies of both island chains.the bark, root, and leaves of this tree are used in the treatment of fever, gastric disorders, swelling, bone fractures, urinary tract infections, and skin diseases. ocimum sanctum (holy basil) is documented as a plant used for cough and cold treatment. the ginger plant zingiber squarrosum has petioles that are chewed to relieve thirst. significance and application