Swiss chard (Beta vulgaris) is a leaf beet — the same species as beetroot and sugar beet, but bred for its foliage rather than its root. It is grown for large, glossy, deeply crinkled deep-green leaves carried on broad, juicy, celery-like stalks that run from white through gold, orange, pink and crimson; the multicoloured mix sold together is called rainbow chard. The flavour is earthy and mildly bitter, like a cross between beet greens and spinach.