The mustard plant (family) is a group of plants in the Brassicaceae family, which includes cress (5 letters). Cress is an edible plant that is often used as a garnish or salad green. It has a peppery flavor and is related to watercress, garden cress, and mustard. The leaves are usually eaten raw, but can also be cooked. Cress is a popular ingredient in many dishes, including soups, salads, sandwiches, and wraps.