By Harold McGee
Chard is the name given to varieties of the beet, Beta vulgaris, that have been selected for thick cardoon-like leaf stalks (subspecies cicla) or large leaves, not their roots. The beet is a distant relative of spinach, and its leaves—including ordinary, thin-midribbed beet greens—also contain oxalates. Chard stalks and leaf veins can be colored brilliant yellow, orange, and crimson by the same betain pigments that color the roots, which are water-soluble and stain cooking liquids and sauces. Some of the recently revived colored varieties are heirlooms that go back to the 16th century.