The purpose of our study was to test whether any significant morphological differences exist between island and mainland plant populations of the north European White Sea. Six polymorphic species were studied: Atriplex nudicaulis (Chenopodiaceae), Euphrasia wettsteinii (Orobanchaceae), Achillea millefolium (Asteraceae), Parnassia palustris (Parnassiaceae), Potentilla egedii (Rosaceae) and Rhodiola rosea (Crassulaceae). Based on the multivariate analyses of our data, we found 10 cases where differences between island and mainland populations are best explained by the existence of short-scale evolutionary processes. These results suggest that plant populations on islands of recent origin may display local morphological divergence in a short evolutionary time frame.