Small islands and islets in the Kandalaksha Bay of the Russian White Sea are now rising. Thus, new islands are continuously appearing, these islands are settling from scratch and it is relatively easy to estimate the age of an island. We tried to find plant species that are polymorphic enough to show the differences between the mainland and island populations and the populations from the different islands. These differences could be the result of population bottleneck or even the evolutionary process on the isolated islands. Species of Carex (C. salina and C. aquatilis groups), Euphrasia, Achillea, Rhodiola, Atriplex and Parnassia were chosen for preliminary morphological analysis (~ 2200 plants were measured). In addition, geometric morphometrics methods were used for Rhodiola and Atriplex leaf shapes. We found that at least three groups show significant differences between mainland and insular populations. Some of our results are useful for the adjustment of the taxonomic boundaries in several taxonomically ``critical'' groups.