Observations on Phytogeography and Endemism in Clematis Dill. Ex Linn. (Ranunculaceae), with Special Reference to Indian Taxa

Clematis Dillex Linn. (Ranunculaceae) with 300-450 species, is essentially temperate but also found in elevated parts of the tropics. It is regarded to have originated around the eastern end of the Himalayas, and thence migrated to other parts of the world The largest concentration is in South China (with 76% endemism) The distribution pattern in the world indicates a high degree of endemism in areas that are isolated or are distantly situated from the region of largest concentration. Thus in North America it is 91%. West Indies, 85%. New Zealand and neighbouring islands, 88%, Malagasy. 90%. West Africa. 75%. and so on. In Indian subcontinent the endemism is only 30%. the low figure is explained because of its contiguity and proximity with South China.

In India proper occur 33 species (42 taxa including subspp and vars), of these 5 are endemic. Several Indian species are closely related to taxa occurring in neighbouring countries which when studied together might need merging or reduction in taxonomic status for want of clear-cut discontinuities. The distribution of interesting Indian species has been mapped.