Atmosphere: Attractive, efficient, modern.

Prices: Most entrees, which include salad and bread bar, from $6.75 to $9.95; children's menu from $2.25 to $3.50.

Reservations: Accepted for large parties only.

Credit cards: American Express, Master Charge, Visa/Bank Americard, Carte Blanche, Diners Club.

Hours: Monday through Thursday, 5 to 10 p.m.; Friday and Saturday, 5 to 11 p.m.; Sunday, noon to 8:30 p.m.

Special facilities: Accessible to patrons in wheel-chairs, surrounding parking lot, booster seats, special dining room for nonsmokers.

The Joshua Tree (Yucca brevifolia) lives up to its south western symbol and decor - serving Texas-type prime rib and steaks that have drawn waiting lines since it opened in 1971.

Its conspicuous location, the only commercial building at the corner of the heavily traveled Old Dominion Drive and Dolley Madison Boulevard, has not hurt business, of course.

Whatever the reason, the Joshua Tree, run by the Marriott Corp., has established a popular reputation, so we went early, at 5:30 p.m. on a recent Sunday, and were seated immediately. By the time we left, the line was forming. The manager said the wait is rarely longer than 20 minutes during peak dinner hours.

Our neighbor's children had recommended the fruit punch, so we ordered a pitcher, which provided both a refreshing drink and occupational therapy. The therapy involved the use of a long wooden spoon, thoughtfully provided so that we might fish out the fruit for our 5-year-old.

After we ordered, we made the circuit of the cut-your-own and make-your-own bread and salad bar, which provided the usual, plus an especially good sour dough bread. Despite the large plates provided, I had to make a second trip to supply the requests for more bread.

When the meat course arrived, we were glad we had brought our after-swim appetites. My brochette of beef tenderioir for $6.75 was done to my specifications, and more than adequate with its trimmings of onions, tomatoes and green pepper. My husband thoroughly approved of the expanse of red meat he was served under the heading of roast prime ribs of beef au jus, English cut, for $7.95. He could have had the traditional cut for a dollar more, but his slice was plently for him and our 18-month-old. He also ordered what turned out to be the largest 50-cent Idaho baked potato in recent memory, which he shared.

Other entrees included chopped beefsteak at $4.95, tenderloin steak at $8.95 and lamb chops or lobster and steak combination for $9.95. You can also request side orders of western-style mushrooms for $1.25 or vegetable casserole for 95 cents.

A complete dinner, including baked potato, dessert and beverage, could be had by adding $1.25 to any of the above.

Our 5-year-old ordered the chopped beefsteak from the children's menu for $2.25, which included the salad and bread bar and beverage. He could also have had prime rib for $2.95 or sirloin or lobster for $3.50.

We never seem to make it to desert, but we could have chosen whiskey pie, meringue with fruit or chocolate torte for 95 cents each.

Adults can order a glass or a pitcher of the house burgundy, chablis or sangria. These, along with the fruit punch, are on the house. You can also order, and pay for, selections from the wine list.

Our bill for the evening came to $21.15 including tip.

There is a specially marked level entrance at the rear of the building for wheelchair patrons.