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The Malabar
coast, well known in the history of plant resource studies in Asia is remarkable
for the luxuriant growth of tropical forests. Hooker (1907) classified the
botanical regions of the erstwhile British India in to 9 regions based on
species distribution. The Malabar region is one among them consisting of Western
Ghats and the west coasts. Clarke (1898) proposed 11 phytogeographical provinces
for the British India. He also recognised the Western Ghats as a separate
province ‘Malabarica’. Prain (1903) classified the phytogeograpic region based
on moisture regimes into 6 regions. According to him ‘India Aquosa’ comprises
the tropical rainforests along the Western Ghats. Chatterjee (1940) based on
endemism among Dicotyledonous plants of the India-Burma region, recognised 10
botanical regions. He treated Malabar as a botanical region with a high
percentage of endemism. All the above classifications recognised the Malabar
region of the Western Ghats as a distinct phytogeographic region. |
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Because of the
past cretaceous shield of Gondwana Kingdom, the floristic elements in the
Peninsular India, especially the Western Ghats flora, shows differential
similarity in the distribution of families and genera between sister
geographical regions such as Malaysian Islands, Madagascar, Australia, S.
America and Africa. Among these countries Malaysian region is more similar to
the peninsular Indian Flora. The polyphyletic (Good, 1974) origin of the taxa
within this continents is widely accepted. Also the flora and fauna of this
region are influenced by Pleistocene glaciations. Homology in the evolution and
geographical similarity also influence the development of the flora. In a more
restricted sense the flora shows resemblance with Sri Lankan, north-eastern and
lower Himalayas. The distributional records of several taxa strengthen this
belief. Many taxa which were considered as endemic to Sri Lanka, north eastern
India and Himalaya are reported from the Southern Western Ghats, especially from
Kerala part. Western Ghats and Sri Lanka are more similar than other parts of
the country. As a whole, the distribution of many groups of plants is restricted
to this smaller bio-geographic zone. The peculiar endemic flora of this region
represents the remnants of older flora and generally termed as paleo-endemics
(Nayar 1996). About 30 percent of the Flora of Kerala are Peninsular Indian
endemics. Because of the relict charactors, they are very sensitive to changes
in the environment. Anthropogenic interference makes the situation more severe.
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