Tender Greens: Watercress
The leaves look delicate but pack a tangy, peppery punch. They're wonderful raw or wilted (cooking mellows their flavor).
Beets are often sold with the sweet, earthy greens attached. They're tender in the spring, slightly tougher in the fall.
The inner rib is juicy, and the darker green leaf is mildly bitter. Popular in Italy, escarole is often paired with anchovies.
Tougher Greens: Swiss Chard
Cooked chard leaves are mild and silky. The thick stems, which come in many colors, are best cooked separately.
Tougher Greens: Mustard Greens
Popular in the American South and Asia, these greens have a pungent flavor that can be mellowed by cream or sesame oil.
Tougher Greens: Kale
Kale becomes sweet when cooked. Curly kale (pictured) is widely available, but search out dark-leafed Tuscan kale—it's even milder.
Tougher Greens: Collard Greens
The toughest of the bunch. Cooks often simmer them for hours, but young leaves are quite delicious when briefly braised.