At a picnic billed in advance as the most extravagant and disorderly summer social ever to be held in the Washington area, the Oklahoma State Society entertained the state societies of Montana, Tennessee, Kansas and New Mexico in Upper Marlboro.

"We'll make peace with Tennassee just like Grant did with Lee - by accepting his surrender," said Gene Marianetti, Montana State Society president, before yesterday's big event.

But when the picnic began at 2 p.m. yesterday with softball games, hula hoop contests, watermelon seed spitting competitions and bingo games, the promised state rivalries yielded to the spirit of the occassion.

John Lovell, who displayed his state loyalties by carrying a miniature Montana flag and wearing a matching belt buckle, said, "When you get together like this you meet old friends, run into the sons of old friends, and you make new ones. I just wouldn't miss it - it's just like a neighborhood picnic."

Oklahoma State Society outgoing president Bob Haught said yesterday's picnic was the first such event involving more than one group.

"Every state has its own identity," Haught said. "We have our history to be proud of, our football teams to cheer - but there's one common denominator: we all are in Washington doing the same type of things.

Clifford A. Dougherty, 65, left his Montana home for Washington more than 25 years ago. But the retired Air Force colonel, who is now a D.C. lawyer, was out in full dress yesterday, wearing his pointed cowboy boots and turquoise bolero.

"We have about three meetings a year, and we usually have a summer picnic. But this is the first time states have gotten together like this," Dougherty said.

Oklahoman Louis Priebe had his own theory on why other states joined his society's picnic.

"All these other state societies joined Oklahoma (today) because they're social climbers - they want to be with the in crowd," Priebe joked.

Over on the softball field, Dick Crawford of the Tennessee Society was playing on the Montana team against Oklahoma.

"I'm a mercenary, a hired gun," he said after scoring the winning run to give Montana a 5-4 victory.

Later, Crawford admitted that "they stuck me in right field because I can't play."

Ellouise Cochrane, wearing the T-shirt uniform of Oklahoma Sen. Henry Ballmon's Cherokee Strippers softball team, said that members of other states' societies "may talk different, but people are people wherever they go." CAPTION: Picture 1, Marc Parsont, foreground, and Rob Monahan cook 600 chicken halves at picnic.; Picture 2, Mickey Vrooman has his hands full with beer, ballons and candy at picnic. Photos by Douglas Chevalier - The Washington Post