Silene latifolia alba, pratensis Caryophyllaceae

With the establishment of clear-cut flavone races, the next obvious question was how the pattern became established. One possibility discussed by Mastenbroek (1983) involved selection for flavone profiles in response to some environmental factor or factors, climatological or edaphic being the most obvious ones. Alternatively, the present-day distribution pattern may be the result of historical factors (1) migration involving long- or intermediate-distance dispersal (2) range extension 

In addressing the issue of postglacial history of S. latifolia (or its progenitor), it is necessary to consider where it existed during the time when ice covered most of northern Europe. The species is not well adapted to survive in cold conditions (Thompson, 1973), which Mastenbroek (1983) pointed out, likely accounts for the absence of this species in the more northerly parts of Europe. He went on to say that even southern Europe may not have provided the necessary conditions for growth, and that the species may have occupied refugia in Northern Africa during maximum ice cover. This issue cannot be resolved on the basis of the data at hand. 

---