The word ‘mangrove’ is used for salt tolerant plants. Macnae (1968) proposed the term ‘Mangal’ to denote this mangrove ecosystem. Mangroves are specialized ecosystems developed along estuarine sea coasts and river mouths in the tropical and subtropical regions of the world, mainly in the intertidal zone. Hence, the ecosystem and its biological components are under the influence of both marine and freshwater conditions. These plants are specialized to tolerate high salinity, tidal extremes, high fluctuations in wind, temperature and muddy anaerobic soil. No other groups of terrestrial plants survive well under such conditions. A muddy substratum of varying depth and consistency is necessary for their growth. The plants have special adaptations such as stilt roots, viviparous germination, salt-excreting leaves, breathing roots, and knee roots by which these plants survive in water-logged, anaerobic saline soils of coastal environments. Mangroves comprise salt tolerant plant species that occur along inter-tidal zones of rivers and seas in the form of narrow strips or as extensive patches in estuarine habitats and river deltas of tropical and sub-tropical regions.