The main distinction between two species of Arabidopsis in leaf trichome production of plants in northern populations is shown. The lack of leaf trichomes in the A. l. petraea population is caused by a mutation in the regulatory gene GLABROUS1. Plants of A. thaliana populations had three types of trichomes on the adaxial epidermis: unbrancheed, two branched and three branched. Withinpopulation differences concerned the frequency of each of the three trichome types, but interpopulation differences – only the frequency of two branched trichomes. The high level of polymorphism, peculiarities of the genetic diversity and trichome distribution across the epidermis and its zones characterize the distinctions between the natural continental and insular populations. The established distinctions are connected with genetic factors and the environmental conditions that influence Arabidopsis populations structure at the northern limit of the species range.