The aim of this study was to examine the relationship between the colour of Achillea millefolium L. inflorescences and other morphological characters of the plant. Morphometric evaluation of 16 characters of the plant was carried out. All tested plants were grouped into eight groups according to colour of linguiform flowers. Morphological character data was subjected to multivariate statistical analysis. Results of ANOVA showed that the colour groups differed significantly (p<0.05) by the height of the plants and the size of linguiform flowers. Hierarchical cluster analysis indicated that plants with violet and white and rosy linguiform flowers were different from other groups according to the examined characters. The analysis of morphological characters of the A. millefolium plant allowed us to presume infraspecific differences within this species in Lithuania.
Keywords: Achillea millefolium, colour group, variability, phenotypic characters, multivariate analysis.