MANY of Boston's hippies spend their nights outside the Sub Shop on Charles St., selling oregano to teeny-boppers from Marblehead who think they're getting marijuana. The middle-aged women with grocery bags who stop at the Brigham's next door in the afternoons stay off the streets after seven, and even the patrolman who occasionally strolls by looks stoned. Most nights, then, the hippies have the street to themselves, and the same ones usually show all the time, but they rarely know each other's names.

Charles Street, at the foot of Beacon Hill, is the heart of the hippie community's social life. One end of Charles skirts Boston Common, which used to be the community's commercial center for the sale and barter of drugs. The business has been forcibly de-centralized since last August, when 200 to 300 hippies who had been eating, sleeping and trading on the Common were challenged by a midnight curfew. To protest, they staged sleepins, and there were several nights of rioting with police before the hippies grew tired and scattered to other living places.

"The cops are playing tennis with us," said Mel, who wore blue striped bell-bottoms with a smiling yellow button in his navel. "They kick us out of the Common. They kicked us out of the Gardens. Where do they want us to go?"

Two 18-year-old boys who had just hitchhiked in from Ohio had no place to go at all. They asked Mel for 20 cents to take the MBTA to Central Square and look there. "We don't know what we're doing here," said the smaller one. "We really wanted to go to California." He added that they planned to start earning money right away. "There's never too many people dealing in dope."

But, "these lousy kids come in from outside and spoil the market," said Avery, an expensively groomed seller and an avid reader of science fiction. "The new cats burn (cheat) everybody," added his girlfriend, Stinger, in the suitable Hippese.

"It takes certain skills to be a dealer," Avery said. Kids laughed; an old man, drunk, was singing World War I songs as he passed on the street. Somebody brought out a pint of mocha almond from Brigham's. "The new kids haven't had the three years training on the street," Avery said. He had fairly long, neat blond hair, a twirled mustache, and steel-rimmed glasses. He says he rarely uses drugs himself, "but I've made $1000 in the last four days."

AVERY lives in an apartment somewhere with Stinger, but nobody knows where it is. It's safer that way. He wants to leave the business, though, and open a small jewelry store somewhere in Boston, because he hates the violence a dealer might possibly meet. Most of the hippies who sell drugs arm themselves with guns or knives, Avery said, although street fights are rare. He himself carries only a small silver cigar-like vial of tear gas that operates like a pistol.

"Avery is friends with all the bikeys," said Janet, an Emerson College sophomore / dealer. "They protect him." Bikeys are toughs with bicycle chains around their necks and iron crosses, who carry guns and threaten to shoot any dealer who cheats them, but they like Avery. "They used to hang around Avery on the Common, watching out for him," Janet added. "Of course, if he ever burned one of them, he'd be in trouble."

Janet talked on about the business. "The approach to dealing his changed since last year," she said. "People are more open about it now." Other things have also changed. "For one thing, prices have gone up." An ounce of grass now goes for twenty dollars in the street. "And an awful lot of the dealing is now done through the Mafia. They buy up all the stuff, and use local stores as their headquarters. We don't even know who exactly deals with them, but it makes it really hard to get a decent price."

"The police have been stopping people on Charles St., trying to crack down, asking for I.D.'s," Janet said. She was stopped last week. "I had almost a pound of grass and a lot of acid," she said, "so I showed my college I.D. and he let me go. If I didn't have stuff I would have refused; they will take you in to the station then and you can get them for false arrest."

"These people are great for annoying the police," said an officer from Boston's Tactical Patrol Service last Friday. "It's difficult to make an arrest for use of narcotics because they love to taunt the police by smoking ordinary cigarettes and tricking us into placing them in custody." That's the problem, he said, with the Sunday smoke-ins on the Cambridge Common. "We do make arrests, though."

THE BIGGEST sales are made on the weekends, Avery said, and the best customers are college students. "I'd be most likely to burn a college student," Janet said, "or people from Exeter."

Most of Boston's hippies live in apartments on the Hill or in the South End. The Hill is also the home of upper-class proper Bostonians, but the two groups live together with little friction, Avery said. "It goes in cycles. Sure they get sick of us sometimes [like last summer], but we appease them."

"The good Lord knows where these kids have come from," said the TPS man. "Most of them are transients."

According to Avery, during the winter this isn't really true; most of the Charles St. people are reasonably-permanent residents. During the summer, though, "there are mostly teenyboppers and runaways," he said. Business is good all during the week, and prices are high.