Curly leaved endive varieties have curled and toothed leaves that form rosettes. The leaves can hold water, and are thus prone to leaf diseases, especially with fall-harvested plantings.
Flat-leaved endive varieties, called escarole, have leaves that are broader, flatter, and only slightly crinkled, and so are not as prone to diseases. They also form loose heads, are hardier, and are more tender and milder tasting than curly endive varieties.
Radicchio is a leaf chicory, grown as a leaf vegetable. It has a bitter and spicy taste, which mellows when it is grilled or roasted. It can be used to add color and zest to salads.
