This is the first of two columns on salad greens. More than just fancy lettuce, these greens are refreshing, filling, extraordinarily low in calories and provide much-needed nutrients. Here are a few "green" health and purchasing tips from some top foodies to use on your next trip to the supermarket or farmers market.

Arugula — also known as rocket

Appearance: Narrow, lobed green leaves about 3 inches long or longer.

Taste: Aromatic, peppery.

Health perks: It's a source of vitamin C (5 percent of daily values) and folate. And it's packed with vitamin K (10.9 micrograms). Studies indicate this combination is better for bone health than calcium alone or calcium plus vitamin D. Vitamin K helps bone hold on to the calcium it has.

In addition, arugula has a decent supply of magnesium, phosphorus and potassium, as well as significant quantities of beta carotene (for healthy skin and eyes), lutein and zeaxanthin (for healthy eyes).

Nutrition stats: 1 cup: 5 calories, 0.13 g fat, 0.73 g carbs, 0.3 g fiber, 0.52 g protein, 32 mg calcium, 3 mg vitamin C, 475 international units vitamin A.

Use: "Best used in a mix of baby salad greens but can stand alone as the basis for a salad. Delicious with sliced fresh pears and goat cheese," says Maria Walls, a nutritionist at Weight Watchers.

Purchasing: Available early spring through summer. Look for young, tender leaves. "Older leaves are shorter and tougher with a more peppery taste," says Walls.

Storage: Wash thoroughly. "It grows in sandy soil, so it needs to be rinsed well in cool water. Dry on paper towels, wrap in plastic wrap and store in the refrigerator crisper. Use within two days," adds Walls.

Romaine — also known as cos

Appearance: Sturdy, coarse leaves with a large center rib. Leaves range from dark green on the outside to light green at the inner core.

Taste: Mild and crisp. Outer, darker green leaves tend to have a stronger, more bitter taste.

Health perks: It's rich in vitamin K, vitamin A (55 percent of daily values — wow), beta carotene, lutein, zeaxanthin, vitamin C, folate, manganese, potassium and fiber. "The American Institute for Cancer Research lists it as one of the foods that helps fight cancer because of its antioxidant capabilities," says Walls.

Nutrition stats: 1 cup shredded: 8 calories, no fat, 0.52 g carbs, 1 g fiber, 0.58 g protein, 16 mg calcium, 11.3 mg vitamin C, 2,729 IU vitamin A.

Use: The standard lettuce in caesar salad. Delicious in a salad with apples and walnuts.

Purchasing: Available year-round. "Avoid heads with signs of rust or very dark green leaves with milky stems, which are signs of older lettuce," says Walls.

Storage: Store unwashed whole heads in plastic bags to retain crispness. Keep away from fruits that produce ethylene such as apples. Use within five to seven days.

Radicchio — also known as Italian chicory

Appearance: Comes in small, round, cabbagelike heads. "Radicchio is a leafy vegetable. The more common variety has red leaves with white veins, but can also be white or green speckled with red. Leaves vary depending on type, from rounder leaves resembling butterhead lettuce to a more elongated type that resembles Belgian endive," says Walls.

Taste: Tends to have a mildly bitter taste that mellows when cooked.

Health perks: Contains potassium and folate. Reportedly has high levels of antioxidants similar to other dark fruits and vegetables such as blueberries and strawberries, which helps reduce damage from free radicals.

Nutrition stats: 1 cup shredded: 9 calories, no fat, 1.79 g carbs, 0.4 g fiber, 0.57 g protein, 8 mg calcium, 5 mg magnesium, 16 mg phosphorous, 121 mg potassium, 24 mcg folate, 102 mcg vitamin K.

Use: Primarily in salads. In Italy, where it originates, it's also grilled with olive oil or cooked in risotto and pasta.

Purchasing: Available year-round but at its best in spring.

Storage: Should be kept in a cool, dry place separate from other vegetables that tend to be moist. Best stored at 34 to 36 degrees.

Mache — also called corn salad and lamb's lettuce

Appearance: Narrow, dark green, flat, almost spoonlike leaves that broaden at the top. The leaves form clusters (often referred to as rosettes) at soil level.

Taste: A tender texture and mild, delicate taste that can become bitter as the leaves age. Some varieties can have a hazelnutlike taste.

Health perks: According to Susan Moores, spokeswoman for the American Dietetic Association, mache is said to have "stimulant, diuretic and laxative effects." It is an excellent source of vitamin A and C, iron, folic acid and zinc, she adds. Additionally, it's known for its potassium, omega-3 fatty acids and B6. Overall, mache has many health benefits for blood pressure, heart health, brain health and the immune system.

Nutrition stats: 1 cup: 20 calories, no fat, 3.3 g carbs, 1.3 g fiber, 1.3 g protein, 66 mg calcium, 2.4 mg iron, 47.5 mg vitamin C, 1,650 IU vitamin A, 363mg potassium.

Use: In salads, alone or in combination with other lettuces. "Partnering with flavors that are too strong masks or overpowers its subtle nature. Like spinach, it can be eaten cooked or raw. Great in omelets, soups, grain and potato salads," says Moores.

Purchasing: Pick bunches of leaves that look crisp and glossy with an even green color.

Storage: Wash, drain and dry. Store wrapped in paper towels in an airtight plastic bag. Wilted leaves and age cause bitterness. Use within one to two days.

Charles Stuart Platkin is a nutrition and public-health advocate, founder and editor of www.DietDetective.com, an online source for nutrition, fitness, food, diet and wellness information.