Here's a vest-pocket guide to which green is which.
Kale: Today's darling salad green has always been one of the best cooking greens. The flavor mellows nicely; the texture is tender. Befitting its star status, there are a variety of kales available today, and the darkest tend to be the best flavored.
Collard: A Southern specialty, collards have a mild flavor, but the thick leaves have a rich, meaty texture when cooked.
Mustard: Wonderfully peppery, mustard greens have strong flavor but a delicate texture.
Chard: Slightly bitter when raw, the sweet, earthy side of chard comes out with cooking. Red chard has a touch of beet flavor. It's equally prized for its stalks and greens, which are usually cooked separately.
Dandelion: The bitterest of the greens, with cooking it remains assertive but turns more earthy and nutty.
Turnip and beet: Tender leaves that taste like milder versions of the roots.