LIKE THE chuckwagon and camp cooks who pleased the cowboys on the early trail drives and ranches in Southwest Texas, House Majority Leader James Wright (D-Tex.) knows the value of a good hunk of mesquite. Wright brings in his own supply from home and entertains friends with a Texas barbecue--mesquite-smoked beef brisket cooked in the congressman's homemade soy sauce and beer-based barbecue sauce.

Mesquite. Word of its unique, delicate, sweet and smoky flavor is traveling north and east from Texas, Arizona, New Mexico and California, where grilling with the exotic wood is all the rage.

Until now, mesquite in any form--charcoal; chips or nuggets, which are used along with regular charcoal; chunks or logs which can be used alone--has been next to impossible to buy in the Washington area, and the secret of the sources of those lucky enough to find it has been well kept.

But now mesquite is about to hit the local market in a big way, augmenting the otherwise skimpy supply available only in specialty stores or in bulk through suppliers. Nova, a company formed to bring mesquite to Washington, will be processing, bagging and distributing mesquite nuggets to hardware stores, supermarkets, drugstores and convenience stores by early July, in time for the height of the charcoal broiling season.

According to Nova's Henry Warren, nuggets are the best size for home cooking. Chips are too fine and burn too quickly, he says, and chunks--about the size of a fist--and logs are too big to be put on a home grill and would have to be chopped up--a difficult task, since mesquite is a very hard wood. Mesquite charcoal sparks when lighted and most of the volatile flavoring oils have been lost in the conversion of the wood to charcoal, according to Peter Felker, associate research scientist at Texas A&I University.

"No one has gone into nuggets because of the cost factor," says Nova's Warren. "Chunks are easy to package; chips are easy because you just throw the wood in a grinder; but nuggets are much harder to produce. We had to design the machinery to chop the logs," which are shipped here whole and processed in Nova's plant in Westminster, Md.

Warren contends that inch-size nuggets last the right length of time for most home barbecuing and can be reused if they don't burn completely. A half-hour soak in hot water encourages slow burning and proper smoking of nuggets or chips, both of which are used in conjunction with regular charcoal, for flavoring--just as hickory chips are. Kitchen Bazaar sells 1 1/2-pound bags of chips for $3. Nova nuggets sell for $1.98 to $2.29 for a 1/10th cubic foot packages containing about two pounds.

Two forms that need no supplementary charcoal--chunks and mesquite charcoal--also can be purchased locally, though all the stores say they find mesquite almost impossible to keep in stock because of its popularity. Sutton Place Gourmet carries mesquite chunks called Pek-O'-Wood in 5-pound bags for $4.99, and Williams Sonoma sells mesquite charcoal in 6 3/4-pound bags for $5.75.

Centuries ago, because mesquite was an abundant and dependable, easy-to-gather crop, its sugary seed pods were the dietary staple of Indians throughout the American Southwest and Mexico, where the scrubby tree grows profusely.

From the pods the Indians made mesquite gruel and mesquite bread. The macerated pulp of the immature pod was combined with water that sometimes was left to ferment into a mildly intoxicating beverage. The blossoms were roasted, squeezed into balls and eaten or steeped in boiling water for tea. The wood and bark served for fuel, shelter, weapons and tools. As a folk medicine mesquite was thought to cure rheumatism, hernias, skin eruptions, sore throats and colds, dysentery, measles, conjunctivitis and, in India, scorpion stings. Your basic all-purpose tree.

Today some believe in mesquite as "the ideal crop" to solve the world's food problems because it requires no cultivation--therefore no resources--and the pods are highly nutritious. In Malaysia, the pods are considered a delicacy, and they are still used for food in Chile, Africa, Indonesia and India.

Of course, there are those who are less than enamored of what they characterize as a pesky weed that encroaches on grazing land and depletes the grass cover that serves as fodder for cattle. Cattle ranchers, in fact, consider it a scourge. According to James Duke, a researcher at the U.S. Department of Agriculture, "Mesquite is an enemy to those who want their range land to look like a meadow and a boon to those who want their desert to look like a forest."

Whether mesquite will save the world, however, is immaterial to those who find it essential to the barbecuing of foods. Although many restaurants in Texas, Arizona and California regularly feature simple, mesquite-grilled foods, Washington is just catching on. The Tabard Inn uses mesquite charcoal for occasional forays into western-style cooking, and G.D. Graffiti's in Rockville grills fish over mesquite charcoal.

One place mesquite has been consistently available is Tunnicliff's Tavern on Capitol Hill, where hamburger, fish, steak and chicken are grilled over mesquite charcoal. Owner Drew Scallon says the response has been excellent. From the restaurateur's point of view, mesquite is better than ordinary charcoal because it burns hotter and longer, sears meat quickly to seal in juices and leaves less residue in the grill, he said.

Recently, the newly opened Caldwell's restaurant in Annandale has added foods cooked over two-foot long mesquite logs to the local mesquite scene. Since logs yield maximum flavor and heat intensity, the smoky taste of everything from london broil to seafood kebab is pleasantly strong. Caldwell's "secret" Texas source has shipped in a 25-ton load and the restaurant is packaging 6 pound bags for $3.95 of fist-size chunks for home use.

Many chefs swear by mesquite grilling when cooking fish. At Tunnicliff's, swordfish steak is the best seller. At the Trellis restaurant in Williamsburg, where a large grill flanked by an 800-pound pile of mesquite logs dominates the dining room and the sweet aroma of mesquite perfumes the air, Chef Marcel Desaulniers features fish.

"Because it burns so hot--the temperature gets to be about 800 degrees if the mesquite burns full force--fish cooks quickly and remains juicy," he explains. "I always marinate the fish in olive oil and lemon juice and cook it directly on the grill." He says a thick cut of fish fares best.

Desaulniers particularly recommends monkfish, sea trout, swordfish steaks, tilefish and especially bluefish, which, he says, "picks up the best char without interfering with the fresh taste and texture. But stay away from salmon and red snapper. In the restaurant we char fish on the grill and finish it in the oven, but the home cook could do the whole job on the grill."

Because he thinks it is trickier to grill pork and veal with a mesquite wood fire since the high heat intensity dries them out too quickly, Desaulniers suggests grilling chicken and steaks. Leg of lamb, lobster, shrimp, scallops, roast beef and fresh vegetables are other good choices. Even hot dogs and hamburgers taste better cooked with mesquite.

Since grilling with mesquite charcoal, logs or chunks poses a challenge because of the intense heat generated, Desaulniers recommends combining ordinary charcoal for heat with mesquite nuggets or chips for flavor in grilling at home. For strong mesquite taste, use a closed barbecue grill to cook foods slowly and with maximum smoke. For lighter smoke flavor, use an open grill. Prepare a bed of glowing coals, and just before cooking, scatter the wet mesquite over the top. JAMES WRIGHT'S TEXAS BARBECUE BEEF BRISKET (8 to 10 servings) 4 1/2 pounds beef brisket 1/2 cup soy sauce 1/2 cup lemon juice 2 cups beer 1/4 pound butter 1 clove garlic, minced 1 onion, minced 2 jalapen o peppers, diced 8-ounce can tomato sauce Hot pepper sauce and worcestershire sauce, to taste Coffee or beer as needed for thinning Salt and lemon pepper to taste Paprika, cayenne pepper, garlic powder to taste

Trim fat from beef. Combine soy sauce, lemon juice and 1/2 cup of the beer, and marinate meat in mixture overnight or longer.

In a large saucepan, combine butter, garlic, onion, peppers, tomato sauce, hot pepper sauce and worcestershire sauce. Bring to a boil. Remove meat from marinade and add marinade to saucepan with remaining beer. Simmer slowly at least 2 hours, thinning, if necessary, with beer or coffee.

Make a heavy foil pan to catch drippings. Place in the center of the grill and bank the charcoal on the sides. When coals are hot, place meat on the grill, 12 to 18 inches above the fire, season with salt, lemon pepper, paprika, cayenne pepper and garlic powder, and baste with sauce. Sprinkle soaked mesquite over coals and cover grill. Smoke meat, covered, 2 1/2 to 3 hours, turning every 20 minutes and basting with sauce. Sprinkle with additional seasonings twice during cooking and add additional charcoal and mesquite as needed. To serve, slice brisket and pour with remaining barbecue sauce augmented with pan drippings. MESQUITE GRILLED TENDERLOIN OF PORK WITH GRAPEFRUIT AND MINT (From The Trellis) (6 servings) 6 pork tenderloins 1 grapefruit, peeled 1/4 cup honey 4 tablespoons freshly chopped mint 1/2 pound unsalted butter, softened

Trim pork tenderloin of any excess fat. Place each tenderloin on a sheet of foil and cover with another sheet of foil. Pound tenderloins with a heavy meat cleaver or a heavy-duty saute' pan until they are less than 1/2 inch in thickness.

Squeeze juice from peeled grapefruit. Combine grapefruit juice with honey and 2 tablespoons of the chopped mint. Place the tenderloins in the juice and honey mixture and allow to marinate for 2 to 3 hours before cooking. (If you wish, you may remove meat from marinade, wrap in plastic and hold under refrigeration for at least 2 to 3 days.)

Chop the squeezed grapefruit into small pieces. Combine with remaining mint into the softened butter. Spoon butter mixture into small ramekins.

Grill the marinated tenderloins over a medium-hot fire. Pork will dry and get tough if cooked over too hot a fire. For extra flavor, baste pork with additional honey while it is grilling. Cook to desired doneness.

Serve with a ramekin of grapefruit and mint butter. MESQUITE GRILLED CHICKEN (From The Trellis) (8 servings) 4 whole 2 1/2-pound chickens, cut in quarters Salt and lemon juice to taste 3 cups dijon mustard 1 cup dry white wine

Score the chicken quarters (3 to 4 cuts, 1/4-inch deep). Sprinkle salt and lemon juice over the chicken and let stand for 30 to 40 minutes at room temperature. Combine mustard and wine. Place the chicken quarters in the mustard and wine marinade, cover, and refrigerate for 2 to 3 days before using.

Grill chicken quarters over a medium hot fire to desired doneness. MESQUITE GRILLED FISH (From The Trellis) (Makes 2 1/2 cups)

Pre-marinate fish for 20 to 30 minutes before grilling. The following marinade is suitable for fish. 2 pounds fish (monkfish, bluefish, sea trout, tilefish, swordfish or large sea scallops) 1 cup olive oil 1 cup vegetable oil 1/2 cup lemon juice Salt and pepper

For best grilling results, use a very hot fire. Place fish, flesh side down, on grates. Allow to cook for 4 to 8 minutes (depending on the thickness of the fish). Then turn fish very carefully and cook on the skin side for another 4 to 8 minutes. TABARD INN MARINADE (Makes about 2 cups)

Use for leg of lamb, flank steak or chicken. 1 cup soy sauce 1/4 cup shredded fresh ginger root 1 head garlic, crushed 3/4 cup red wine 3 star anise 3 threads fresh thyme or 1/4 teaspoon dried Juice of 1 lemon 1/4 cup olive or soybean oil

Combine all ingredients and mix. Pour over meat. Marinate in refrigerator overnight or longer. GRILLED CHICKEN BREAST (From Tunnicliff's Tavern) (2 servings) 2 chicken breasts 1/4 cup olive oil 1/4 cup lime juice 2 red bell peppers 1 cup creme fraiche Salt and pepper to taste Red bell pepper for garnish, optional

Marinate chicken breasts in olive oil and lime juice for 1 hour. Roast peppers in the oven or char them on a gas flame until skin is wrinkled and burned. Peel skin and seed peppers. Cool and pure'e in a food processor or blender with cre me fra iche. Season with salt and pepper.

Grill chicken to desired doneness. Place a spoonful of sauce on each plate and top with chicken. Garnish with sliced raw red peppers, if desired. GRILLED VEAL CHOPS (From Tunnicliff's Tavern) (4 servings) 4 10-ounce veal chops 1/4 cup olive oil 1/2 teaspoon chopped fresh rosemary 1 teaspoon chopped fresh thyme Freshly ground black pepper to taste

Marinate chops in olive oil, rosemary, thyme, salt and pepper for 1/2 hour. Grill to desired doneness. Serve with shallot mustard. SHRIMP BUTTER (From Tunnicliff's Tavern) (About 1 cup) 2 sticks butter 1 tablespoon pernod 1 tablespoon fennel seeds Shells from 2 pounds of shrimp

In a saucepan, simmer butter, pernod, fennel and shrimp shells for 1/2 hour. Pure'e and simmer for an additional 15 minutes. Strain through a fine sieve. Chill. Serve with grilled swordfish. OLIVE BUTTER (From Tunnicliff's Tavern) (About 1 cup) 2 sticks butter 1/2 pound seeded nicoise olives

Process butter and olives in a food processor or blender. Chill. Serve with grilled chicken. SHALLOT MUSTARD (From Tunnicliff's Tavern) (About 1 cup) 5 shallots 3 tablespoons mustard 2 sticks butter

Process all ingredients in a food processor or blender. Chill. Serve with grilled veal chops or steak.