The region is estimated to have approximately 1,700 known medicinal plant species. Some of the sought after species of these regions are Aconitum heterophyllum Wall. Ex Royle, Ferula jaeschkeana Vatke and Saussurea costus (Balc.) Lipsd. S. costus is in fact confined to only the Himalayan region of Jammu and Kashmir. These critically endangered wild varieties are enlisted in the Convention on International Trade in Endangered Species of flora and fauna (CITES).
The section is estimated to harbour approximately 700 known medicinal plants. Some of the well known ones, existing in very cold and desert like conditions of the region are Ephedra gerardiana Wall., Hippophae rhamnoides L. and Arnebia euchroma (Royle) John etc.
Central and Eastern Himalaya
The biotic provinces, put together, are estimated to harbour around 1,200 known medicinal plant species. A few of the well known plants are Nardostachys grandiflora DC., Taxus wallichiana Zucc. (listed in CITES), Rhododendron anthopogon D.Don and Panax pseudoginseng Wall (only found in the Eastern Himalayas).
The region with an estimated 2000 medicinal plant species is yet another high biodiversity region of the country. This zone is amongst one of the 18 hot spots, which presents a high level of endemism. It consists of two biotic provinces namely Brahmaputra Valley and Assam Hills. Aquilaria malaccensis Lam.(listed in CITES), Smilax glabra Roxb., Ambroma augusta (L.) L.f. and Hydnocarpus kurzii (King) Warb are some of the well known medicinal plants found here.
The biogeographic zone consisting of Kutch and Thar biotic provinces is a haven for almost 500 known medicinal plant species. Some of the harvested plants of this region are Convolvulus microphyllus Seib ex Spreng (Syn C. pluricaulis Chois), Tecomella undulata (Sm.) Seem, Citrullus colocynthis (L.) Schrader and Cressa cretica L.
It covers the largest chunk of landmass amongst all the 10 biogeographic zones and consists of five biotic provinces – South Deccan Plateau, Central Plateau, Eastern Plateau, Chhotanagpur and Central Highlands. With a total number of known species estimated to be around 3000, the endemic species here are Pterocarpus santalinus L.f., Decalepis hamiltonii Wight & Arn., Terminalia pallida Brandis and Shorea tumbuggaia Roxb. of which Pterocarpus santalinus L.f. is enlisted in CITES.
Upper Gangetic Plain and Lower Gangetic Plain biotic provinces is estimated to have around 1000 known medicinal plant species. A few of the well known species found in the region are Holarrhena pubescens (Buch-Ham.) Wallich ex A.DC., Mallotus philippensis (Lam.) Muell.-Arg., Pluchea lanceolata C. B.Clarke and Peganum harmala L.
Semi arid zone
It consists of biotic provinces of Punjab and Gujarat-Rajwar and is estimated to be home to around 1,000 known medicinal plant species. Commiphora wightii (A.) Bhandari, Caesalpinia bonduc (L.) Roxb., Balanites aegyptiaca (L.) Delile and Tribulus rajasthanensis.
West and East Coast
The coastal biogeographic zone is estimated to harbour around 500 plant species of known medicinal plants. A few of the well known ones are Rhizophora mucronata Lam., Acanthus ilicifolius L., Avicennia marina (forsk.) Vierh and Sonneratia caseolaris (L.) Engl.
Andaman, Nicobar and Lakshadweep
Some of the important medicinal plants of this island biogeographic zone, which is estimated to have around 1000 species consists of Calophyllum inophyllum L., Adenanthera pavonina L., Barringtonia asiatica (L.) Kurz and Aesandra butyracea (Roxb.) Baehni.
The biogeographic zone consisting of Malabar Coast and the Ghats is also one of the 18 biodiversity hot spots recognised across the globe with nearly 2000 medicinal plants. Endemic species in this region are Myristica malabarica Lam., Garcinia indica (Dup.) Choisy, Utleria salicifolia Bedd. ex.Hook.f. and Vateria indica L. These species have been assessed to be under varying degree of threat of extinction ranging from vulnerable (VU) in case of Vateria indica L. to critically endangered (CR) for Utleria salicifolia Bedd. ex.Hook.f.