Why are some plants more successful than others at escaping their predators? Have you ever had hives? Have you noticed that some housewives plant rue or thyme in a corner of their garden? Have you wondered why some animals eat certain herbs from the pasture, but leave others? Or why, even though many plants die when they are stepped on, other do not? Did you know that cinnamon, oatmeal, and tomatoes produce extremely toxic substances that can kill only certain fungi?
These questions are proof of the different interactions that occur between plants and their environment, and of the amazing plant machinery which produces a great variety of substances. Being incapable of moving, the different species of plants have had to come up with chemical defense mechanisms that allow them to survive the attack of pathogens and herbivores.