ABSTRACT
Long before chemosystematics or even biology and chemistry existed as sciences in our current definition the fact that morphologically similar plant species often resemble each other with regard to their (chemical) constituents was well known. According to Hänsel this fact was already described by James Pettiver in the late 17th century.1 The close association of plant morphology and certain other qualities of a plant, which today would be attributed to its chemical composition, like e.g., smell, color, or taste, was certainly already known to the earliest human societies.
