The Botany of Desire: A Plant's-Eye View of the World

by Michael Pollan

Some plant toxins, such as nicotine, paralyze or convulse the muscles of pests who ingest them. Others, such as caffeine, unhinge an insect’s nervous system and kill its appetite. Toxins in datura (and henbane and a great many other hallucinogens) drive a plant’s predators mad, stuffing their brains with visions distracting or horrible enough to take the creatures’ mind off lunch. Compounds called flavonoids change the taste of plant flesh on the tongues of certain animals, rendering the sweetest fruit sour or the sourest flesh sweet, depending on the plant’s designs. Photosensitizers present in species such as the wild parsnip cause the animals that eat it to burn in the sun; chromosomes exposed to these compounds spontaneously mutate when exposed to ultraviolet light. A molecule present in the sap of a certain tree prevents caterpillars that sample its leaves from ever growing into butterflies.