Arctic Plants in the British Isles

Abstract

IT is well known that, after the final retreat of the Pleistocene ice in western Europe, the flora of the British Isles was for a time much more like that of the arctic regions of the present day than is now the case. The same must be true of the vegetation and its component plant communities. Following the subsequent amelioration of climate, there came waves of relatively mesothermic dominants before which the smaller and less aggressive microthermic species retreated. The picture is clear and our knowledge of the story seems sufficiently complete. But we still do not know what proportion of the present British flora persisted through the Pleistocene maximum; nor have we investigated the mechanisms which enabled certain plants of ‘arctic’ affinity to survive in Britain to the present day. My object here is to deal with aspects of this latter problem—in a manner which I would scarcely dare attempt if I had not spent much of the last decade in various arctic and subarctic lands—first by deciding which plants are to be considered as truly arctic and then by analysing the resultant list of species.