39 The Crop That Grew Europe 1537 CULTIVATED BY PERUVIANS since 8000 B.C., potatoes were encountered by Spanish explorer Gonzalo Jiméénez de Quesada in 1537. Easy to grow (no tools required), they became, in one historian's estimation, "the difference between having one child and having five." And a lower infant mortality rate meant some children could leave the farm to work in factories. First, however, grain-fed Europe had to develop a taste for the potato. Confusing it with deadly nightshade, some thought it poisonous or, at least, the cause of flatulence or leprosy. But at the urging of scientists, leaders promoted the tuber; Marie Antoinette wore potato flowers in her hair in 1785. The Irish immediately welcomed the addition to their diet, consuming eight pounds per person per day by the 19th century. The country's population doubled but was ravaged by a potato blight beginning in 1845. As many as one million died; another 1.25 million emigrated to the U.S., eventually giving rise to the Kennedy dynasty and all that came with it. The potato's uses are legion: Potato-based alcohol powered German planes in WWII, potato acids are found in detergents, and potato starch is used as an adhesive in stamps and as an absorbing agent in disposable diapers.