Radicchio ( or ; ) is a perennial cultivated form of leaf chicory (Cichorium intybus, Asteraceae) sometimes known as Italian chicory because of its common use in Italian cuisine. It is grown as a leaf vegetable and usually has colorful, white-veined red leaves that form a head. Radicchio has a bitter and spicy taste that mellows if it is grilled or roasted. History Pliny the Elder wrote in Naturalis Historia that radicchio was useful as a blood purifier and an aid for insomniacs. Radicchio contains intybin, a sedative/analgesic, as well as a type of flavonoid, called anthocyanin. Modern cultivation of the plant began in the fifteenth century in the Veneto, Friuli Venezia Giulia and Trentino regions of Italy, but the deep-red radicchio of today was engineered in 1860 by Belgian agronomist Francesco Van den Borre, who used a technique called imbianchimento (whitening), preforcing, or blanching to create the dark red, white-veined leaves. The plants are taken from the soil and placed in water in darkened sheds, where lack of light and ensuing inhibition of chlorophyll production cause the plants to lose their green pigmentation. Varieties The varieties of radicchio are named after the Italian regions where they originate: the most widely available variety in the United States is radicchio di Chioggia, the most popular and widely used variety. It is a round head of the plant, which means it offers the consumer the most uninterrupted surface of the deep red coloring. It was created through genetic selection by local farmers in the early 1900s for this reason. The IGP area for Chioggia includes just ten towns from the boroughs of Venice (where you find Chioggia itself), Padua, and Rovigo. Radicchio rosso di Treviso precoce is a longer head than Chioggia, and the white veins are more pronounced. It has a distinctive bitter taste, and the heads are blanched as per the endive procedure to achieve the coloring and flavoring (heads are tied and left without light for two to three weeks post-harvest). The IGP area includes 24 towns in the boroughs of Treviso, Venice, and Padua. Other varieties include 'Tardivo', Treviso tardivo is considered the king of radicchio in Italy. It involves weeks of painstaking manual labor using a traditional forced growing and blanching method to produce the white ribs with red tops. After harvest, the heads are left in tanks of running resurgence water for two weeks. They are