Herbaceous annual (Solanum tuberosum) in the nightshade family. One of the world's main food crops, the potato differs from other food crops in that the edible portion is a tuber. Highly digestible, potatoes are prepared for eating in many ways and are a major source of starch as well as amino acids, protein, vitamin C, and B vitamins. The stem grows 20–40 in. (50–100 cm) tall, sprouting spirally arranged compound leaves. Underground, stems extend as stolons, the ends of which enlarge into 1–20 tubers of variable shape and size. The tubers have spirally arranged buds (eyes) that may remain dormant after the tuber is fully grown for up to 10 weeks or more; they grow into plants identical to the parent plant. A native of the Andes, the potato (also known as the common potato, white potato, or Irish potato) was carried by Spaniards into Europe during the 16th century. A century later, it had become the major food crop in Ireland; disastrous damage to the crop by a fungal blight caused the Irish potato famine in the mid-1800s. See alsosweet potato.