Alders (Alnus Mill.) are the common trees in Europe and Asia, and there are some taxonomically interesting forms on the border of the area. The examples of those forms are A. kolaensis Orlova (from Kola Peninsula and nearby North Karelia) and A. barbata C.A. Mey. (from Caucasus). Some researchers consider these forms as separate species, but others -- as subspecies of A. incana or A. glutinosa (respectively), or even as hybrids between these two species. We have checked mentioned hypotheses using multivariate methods based on classic morphometrics data and two variants of geometric morphometrics of alder leaf. We found that A. “kolaensis” is most probably the varieties or even the ecological form of A. incana. On the contrary, A. barbata must be considered as separate species. Our data show that the results of geometric morphometrics and classic morphometrics could be significantly different. The most productive way of placing the landmarks on the leaf is (in our case) to mark the end-points of the secondary veins.