Variation of Essential Oils in Selected Species of the Genus Echinacea Moench During Vegetation

We have investigated the variation of essential oils in selected Echinacea species during the ontogenetic life of plants cultivated in three different locations. The contents of essential oil in the aerial and underground parts varied. The leaves and stems of E. purpurea were richer in essential oil, while E. sanguinea and E. species had relatively high essential oil contents in roots in the stage of biological maturity or in the prebud stage. With respect to climatic conditions, no significant differences in essential oil contents have been observed between particular locations.