The tomatillo is a member of the nightshade family and is related to the Cape gooseberry, the strawberry tomato (both in the "ground cherry" genus) and, of course, the tomato. The tomatillo is also known as the husk tomato, jamberry, husk cherry, and Mexican cherry. Though sometimes called green tomatoes, they are not the same as unripe tomatoes. The word tomatillo is Spanish for small tomato, a name derived from the Aztec word tomatl, meaning "swell" and "water," or "round and plump." The Aztecs are credited with domesticating the tomatillo; archaeological evidence suggests it was grown and consumed as early as 800 BCE in the Tehuacan Valley. The vast majority of the ground cherry species originated in Mexico, and a few perennial species spread naturally to Canada. In the 16th century, Spanish explorers were introduced to the tomatillo, along with the Cape gooseberry and strawberry tomato. Like its other nightshade cousins—tomatoes, potatoes, and capsicum—tomatillos were then transported back to Asian and Europe. The tomatillo fruit is surrounded by an inedible, paper-like husk. In fact, it looks like a little green tomato wrapped in a husk similar to onions or garlic. As the fruit inside ripens, the husk begins to dry and split, revealing a yellow, red, green, or even purple tomatillo. Tomatillos taste similar to tomatowa, but with a mellower and tarter taste. Yellow and green varieties are more tart, while the purple and red varieties have a slight sweetness and are more suitable for jams and preserves. Like gooseberries, tomatillos are naturally high in pectin. Tomatillos can be kept in the refrigerator for two weeks (even longer if you remove their husks). They may also be frozen, whole or sliced. The husks must be removed before preparing, but tomatillos in the husk are often used as decoration. Wash the fruit with soap and water to remove the film left by the husk. Tomatillos may be used raw in salsas or salads or cooked for sauces. A raw tomatillo will have a more pronounced citrus taste and firmer texture than a cooked fruit.   Yellow-green cultivars are a key ingredient in Latin American sauces, the most popular of which is salsa verde. Chop raw for salads, guacamole or gazpacho, or use as a garnish for cold soups. Raw slivers enhance sandwiches. Pureed or chopped, tomatillos make for a delicious tart dressing. Tomatillos are nutritious for their size, but their smallness limits how much nutrition you can get. Still, they are high in dietary fibre, vitamins C and K and niacin. Half a cup of tomatillos contains 15 percent of your daily recommended vitamin C and 2 percent of your daily recommended iron intake.