Rhubarb

Rhubarb is a vegetable that often masquerades as a fruit. It is the startlingly sour leaf stalks of a large herb, Rheum rhabarbarum, that is native to temperate Eurasia and became popular in early 19th-century England as one of the first fruit-like produce items to appear in the early spring. The rhubarb root had long been used as a cathartic in Chinese medicine, and traded widely as a medicinal. The stalks were also used as a vegetable in Iran and Afghanistan (in stews, with spinach) and in Poland (with potatoes). By the 18th century the English were using them to make sweet pies and tarts. The 19th century brought better varieties and techniques for digging up mature roots and forcing rapid stalk growth in warm dark sheds, which produced sweeter, tenderer stalks. These improvements, cheaper sugar, and a growing supply resulted in a rhubarb boom, which peaked between the world wars.