“Individual tulip bulbs fetched higher and higher prices in the seventeenth century, setting off the frenzy known as tulip mania. . . .

The speculation was fed by a random, and poorly understood, element to the flower’s coloration. . . . [S]ome tulips had a tendency to “break”—to emerge with wild, flaming white or yellow streaks across the petals. The broken flowers were highly sought after, but no one knew what caused the flamboyant patterns. . . .

At the time, no once could have guessed that the true cause was a virus. In fact, it was not until the early twentieth century that the tulip breaking virus, also called tulip mosaic virus, was finally identified. The virus is spread by aphids and works by inhibiting the amount of anthocyanin . . . that is stored in the vacuoles of each cell. When that pigment isn’t present, the ordinary white or yellow surface of the petal shows through, creating streaks of white or yellow against a jewel-colored background.”

—Amy Stewart, Flower Confidential, 2007.