This is high season for the most refreshing fruit ever cultivated: watermelon. According to the National Watermelon Promotion Board, cultivation probably started about 5,000 years ago in Egypt. A member of the squash family, watermelon is said to have come to the United States through Africa during the slave trade in the mid-1600s. Florida, California, and Texas are the leading states in watermelon production, and there are hundreds of varieties. Internationally, China is the major grower, followed by Turkey and Iran.

Watermelon, as you may have surmised, is 90 percent water and contains the largest amount of lycopene of any fresh fruit or vegetable. Lycopene gives the red color to fruits, like tomatoes, grapefruits, and guavas, and indicates a great source of Vitamins A and C. Two cups of watermelon have only 80 calories, 25 percent of the recommended daily allowance of Vitamin C, 20 percent of the recommended daily intake of Vitamin A, and more than a cup of water. That's not bad for quenching your thirst, satisfying your sweet tooth, and meeting a few dietary needs at the same time.

Tony Casieri, produce manager at Wilson Farms in Lexington for 17 years, says the best way to tell if a watermelon is good is to ''cut it open and look for that dark red color.''

''The sweetest watermelons are small to medium, between 5 and 12 pounds,'' he says. ''You know the world is shrinking and fruits and vegetables are available year round, but July and August are definitely associated with watermelon season, especially on the East Coast. They are awesome now.''

Scott Wilson, fourth generation at Wilson's, likes to tap on the watermelon: ''If you get that nice hollow sound, you can be pretty sure it's ripe.'' He says his tapping technique is not 100 percent accurate, but he seems to have a good track record, as he is the buyer for the melons. ''We are getting the Banner brand out of Texas right now,'' says Wilson.

If you don't trust your sense of sound (and you can't smell a watermelon for ripeness the way you can a cantaloupe), look on the bottom of the melon for a light yellow patch. This is where the melonsits on the ground, and it's a good indicator of ripeness. Unlike many other fruits, watermelon does not continue to ripen after it's been picked. In the off-season, Wilson's gets watermelons from Mexico and Central America.

Sales of seedless watermelons far surpass sales of the seeded variety. Says Casieri, ''I sell four or five seedless to one with seeds.'' A search in several markets for a watermelon with seeds yielded not a single one.

Some readers may remember those seed-spitting contests they had as kids, sitting on the stoop on
a steaming day. While watermelon juice dripped down your neck, the pits lined up inside your mouth while your tongue formed a funnel and readied to launch them farther than anyone else could. One can't do that with those pale white, flimsy seeds. ''A few old timers feel the seeded melonstaste better, but that is not really the case,'' says Wilson. ''There are a lot of other factors.''

Watermelon is grown in many countries around the world, and is highly prized in some. In Japan, for example, watermelon is not considered picnic fare. Instead, it is given often as a gift, a very expensive gift. The suika, watermelon in Japanese, is presented cradled among shreds of shimmery cellophane in a box, or incased in protective netting and then beautifully wrapped. The recipient knows this melon costs a bundle, anywhere from $30 to $100. When served, it is often a single small slice on a chilled plate to be eaten with a fork - not exactly a chin-dripping encounter.

All parts of the watermelon are edible. Watermelon pickles are made from the rind, and seeds can be baked and salted. The Mexicans also drink watermelon juice, calling it aguas frescas. It's watermelon pulp blended and mixed with cold water and ice cubes. Some even salt their watermelon and say that it enhances the flavor. Casieri and Wilson's favorite way to eat watermelon? ''A big huge slice,'' they both say.

There are many ways to enjoy this beautiful and thirst-quenching fruit. Let children scoop out little rounds with a melon baller. Place some ice cubes in individual bowls, top with melon balls and a spritz of lime juice, refrigerate for 15 minutes before serving, and garnish with a sprig of mint.

Also try this watermelon sorbet. It's quick and easy and can be made with or without an ice cream maker.

Watermelon sorbet

3 cups watermelon, seedless or seeded
one-third cup superfine sugar
2 teaspoons lemon juice

1. Mix all the ingredients in a food processor or blender.
2. Place mixture in an ice cream maker and process according to instructions until it holds together.
Remove sorbet to a container and place in the freezer.
3. Eat within a few days.
4. To make granita (a crushed ice dessert): Take the above mixture from the processor or blender and place in a shallow, rectangular glass dish and place dish in the freezer. Every 30 minutes, rake a fork through the mixture to break up the ice. It should become a slush-like consistency after 2 hours that is ready to enjoy.

Watermelon rind pickles

4 cups watermelon rind
1/4 cup salt
1 1/4 cups cider vinegar
1 cup sugar
1/2 teaspoon whole cloves
1 stick cinnamon

1. Peel the green skin from the rind, remove any pink pulp from the rind, and cut rind into 2-inch by 1-inch strips. Place strips in a pot.
2. Pour boiling water over the rinds to cover and simmer for about 5 minutes. Drain and cool.
3. Mix salt with 2 cups cold water. Place the rinds in a bowl and cover with the salted water. Let stand at room temperature for 4 hours.
4. Drain and rinse in cold water several times.
5. Mix vinegar, sugar, and half a cup of water in pot. Simmer until sugar dissolves.
6. Tie the cloves and cinnamon stick in a piece of cheesecloth and place it in the pot with the rinds.
Simmer until the rinds are soft and somewhat translucent. Discard spice bag.
7. Let rinds cool in the liquid before putting it all in a glass jar. Keep chilled in refrigerator.

Adapted from Fanny FarmerC ookbook