Key points are not available for this paper at this time.
H. E. Wright, Jr., J. H. McAndrews, Willem van Zeist, Modern Pollen Rain in Western Iran, and Its Relation to Plant Geography and Quaternary Vegetational History, Journal of Ecology, Vol. 55, No. 2 (Jul., 1967), pp. 415-443
Wright et al. (Sat,) studied this question.