Distribution of the Dipterocarpaceae: some phytogeographic considerations on India
Meher-Homji, V. M.
The salient features of distribution, present and past, of this tropical humid family, reviewed in the paper raise several problems as to its origin - Gondwanian or Malesian -, the age of the Cuddalore Sandstone formation of S. E. India containing fossil dipterocarps, and the time when the drifting South Asian plate met the Asian landmass. The recent evidence from earth sciences suggests Borneo as the cradle of this family with subsequent westward migration, the conjunction of India with Asia in middle Eocene permitting its entry into the sub-continent. The rate of drift of India during Eocene has been estimated at about 12 cm per year. The uplifts of the Himalayas and the Western Ghats in the late Tertiary were among the principal factors that led to the onset of drier climate in major part of India, exterminating humid dipterocarps from S. E. and N. W. India.