The white potato (Solanum tuberosum), native to South America, was first introduced to Spain in the middle of the sixteenth century. It was not widely accepted as a food crop since European relatives of the potato, such as nightshade, mandrake, and henbane, were known to be poisonous or hallucinogenic. In fact, all of the above-ground parts of a potato plant are poisonous and only the tuber is edible. The potato was established as a food crop in Ireland as early as 1625 and became a staple of the diet, especially among the poor, during the eighteenth and early nineteenth centuries. The widespread dependence on potatoes as a main source of food led to massive starvation when the plant pathogen Phytophthora infestans destroyed potato fields in the 1840s. Over one million Irish people died from starvation or subsequent disease; another 1.5 million emigrated from Ireland.