Eilif Dahl, who died in 1993, had one of the most original and creative minds in plant geography. His approach went far beyond the description of distribution patterns and the establishment of correlations between distributions and particular climatic variables. His understanding of physiological mechanisms that influenced and controlled the observed distributional patterns was a key feature of his numerous ideas and hypotheses. He was also aware of the importance of history as an influence on present day plant distribution, especially in arctic plants. In The Phytogeography of Northern...