Arugula travels under a variety of names—rugula, roquette, rocket, or garden rocket. In Europe, arugula is nearly as common in the salad bowl as iceberg lettuce is here. This peppery green has a nutty flavor, compared by some to horseradish and by others to mustard greens. If you haven’t tried arugula yet, toss a little to start with in your next salad. You will soon find you can’t do without this pungent counterpoint in your greens.