POLLEN‐RAIN FROM THE VEGETATION OF NORTH‐WEST INDIA

Abstract

SummaryA general survey of the pollen‐rain from the vegetation of north‐west India is described. The survey is based on the study of 114 modern pollen spectra from sixty‐four different sites. It is revealed that with certain qualifications the major aspects of the extant vegetation belts of north‐west India are reflected in the pollen‐rain falling within them. In the territory as a whole, the pollen of herbs dominates that of trees and shrubs except in close proximity to one of the latter. Amongst the woody plant pollen that of shrubs is commonest in the arid belts but tree Pollen asserts itself as rainfall increases. The long‐distance transport of pollen from one region to another does not affect the overall picture of the pollen‐rain to any significant degree except in the areas bordering the Himalayas where pine pollen is over‐represented. Cerealia type pollen usually occurs in areas where there is cereal cultivation but remains unrepresented in the very arid belt which is free of cereal agriculture. The pollen frequencies of Acacia, Prosopis, Zizyphus, Salvadora, Maytenus and the species belonging to Leguminosae, Labiatae and Geraniaceae are Under‐represented. On the other hand 5% pine pollen occurs even as far as 600 km from the source.