Jones Beach Theater, Sunday Night.

During the course of her unpredictable but resilient career, Joni Mitchell has been the dewy-eyed sophomore, the slit-eyed hipster, the clear-eyed visionary. Her songs of innocence and experience have taken her from strum-along 1960s coffee houses to collaborations with the late Charles Mingus, one of this century's most indomitable jazz composers and bandleaders.

Each incarnation seems effortless, and that was the case Sunday night at Jones Beach, when Mitchell and a four-piece band played straightforward rock with a direct and seamless roll.

Of course, when Joni Mitchell plays rock and roll, it's not always of the conventional, kick-'em-in-the-solar-plexus variety. On the opening song, Coyote, the playing was fluidly graceful. Each line ended with stinging little burrs of sound, enhancing the long-breathed melodies that clung to the shaggy-dog logic of her lyrics.

Both her 1973 standard, Free Man In Paris, and Cotton Avenue, from the aptly-titled 1977 album DON JUAN'S RECKLESS DAUGHTER, did have an uncharacteristically blunt-edged hard rock approach. For a moment, one thought that Mitchell's band — bassist Larry Klein, drummer Vinnie Colaiuta, guitarist Mike Landau, and keyboard player Russell Ferrante — had been wood-shedding with Def Leppard.

The jazz attitude and phrasing that has given Mitchell's rock its Tiffany touch returned quickly. You Dream Flat Tires was vigorously uptempo, but Mitchell retained the sly, impressionistic delivery that made the song such a standout on her recent WILD THINGS RUN FAST album.

The bridge to what might be more precisely defined as jazz was easy to cross from that point. God Must Be A Boogie Man, composed by Mitchell in her 1979 tribute to, and partial collaboration with, Charles Mingus, showed traces of some of the master's kinetic swing. Klein took the spotlight, playing bass as if it were lead guitar and delivering the most perceptive and propulsive individual instrumental performance of the night.

Mitchell's band wasn't always as delicate, and the most memorable parts of the show were those performed by Mitchell alone, or with the band in a more passive frame. She performed Big Yellow Taxi, still the most lucid and flinty song anyone has ever written about ecology ("they paved paradise and they put up a parking lot") accompanying herself on electric guitar. Her tough chordings evoked a latter-day Eddie Cochran.

A second set after intermission rocked just as surely. Mitchell oldies such as Help Me, and Raised On Robbery were balanced by rock standards such as Leiber and Stoller's (You're So Square) Baby I Don't Care, initially recorded in 1957 by Elvis Presley, and a churning encore of I Heard It Through the Grapevine. Mitchell may be conscious of growing older — her reading of the poignant Chinese Café/Unchained Melody was both brittle and bittersweet — but her passionate artistry shows no sign of abating.