Comparison of the Tertiary flora of southwest China and northeast India and its significance in the antiquity of the modern Himalayan flora

A comparison has been made between the Tertiary floras of southwest China and northeast India in order to trace the antiquity of the Chinese elements in the present Himalayan flora of northeast India. The fossil flora on the either side of the border is quite different from each other as the Chinese flora is marked by temperate and sub-tropical elements, while that in northeast India was typically tropical during the Tertiary. The last major upheaval of the Himalayas, that had taken place during the Pleistocene, increased the height of the mountains too high to permit any migration of floral elements in the region during the interglacials. Therefore, a new route for the migration of Chinese elements into the Northeast Himalayas was formed and this is traced through Tibet and Kashmir on the basis of the fossil evidence occurring therein.