Small, flat, oval leaves on stems. Usually sold with roots attached. Bittersweet, sharp, crunchy. Works best as an accent with other greens. Look for the little yellow-green torpedoes in the produce section.
Individual leaves are slightly lighter in color and oval.
Also has a pretty purple variety. Tender, mild and sweet. They're delicious as the main green, however. Bouquet-shape, light green head with short, rounded leaves. Tart enough to hold its own with strong-flavordressings.