E-Mail This Article to a Friend Musicale Mark Morris at the Shubert BY MARCIA B. SIEGEL

Every performance by Mark Morris is a musical treat. The choreographer has terrific instincts for new and old repertory seldom heard in the concert hall. He insists that music be played live, even on tour, and what might seem like practical constraints — finding singers and musicians who can handle demanding, unfamiliar scores; limiting the size of the ensemble to what can be accommodated in a dance theater and supported by a modest budget — actually open up his musical opportunities, and ours.

Last weekend’s FleetBoston Celebrity Series programs at the Shubert Theatre featured the kind of post-ethnic 20th-century music that brings out the best in Morris. One of two pieces new to Boston, All Fours, is set to BŽla Bart—k’s String Quartet No. 4 (played by Jonathan Gandelsman, Andrea Schultz, Jessica Troy, and Wolfram Koessel). The music’s dissonances slide and scurry underneath the dance’s mathematical formality, yet the two elements never seem to part ways.

Morris introduces the dance with a double quartet in black, four men and four women who often work in four-part canonic couples, sweeping across the stage and pulling up into abrupt poses with the starts and stops of the music. At the end of the first movement, a couple in white stride into their midst. These "outsiders," joined by two others, take over the middle sections of the dance with almost identical male and female duets of fast skittering runs, tilting balances, and toppling falls. In between these, the full quartet come together, paired in different ways. Then the first group return for new sets of pumping, stomping patterns.

We got another Boston first in Serenade, a solo for Morris himself, to Lou Harrison’s Serenade for Guitar (Oren Fader, with Stefan Schatz on percussion). A year ago, before its premiere at the Brooklyn Academy of Music, Morris explained that he’d known the music and found it "so tender and finely webbed, so all over the world, that I realized it could be the basis of a new kind of dance." Although he taught the dance to company members Maile Okamura and Matthew Rose in order to see what he was doing, no one could have danced this as the inimitable Morris does.

The musicians are on stage, and as they begin to play Harrison’s sparse, Middle Eastern–tinged music, the lights come up on an apparition: sitting in a chair is this large, round, middle-aged man in bare feet wearing something that looks like a chef’s uniform on top and a long black skirt. (Isaac Mizrahi designed the costume.) Morris first does a prelude of snaky arm gestures, like a frenetic belly dance — but only with the top of his body. In the rest of the dance’s five short movements, he plays ingeniously with ambiguities of physique, gender, and hybridized folk art. He treads the space holding a shiny length of tubing with both hands, sometimes seeming to display it to the audience, sometimes dipping into a martial-arts lunge. He plays flirtatiously, flamenco-ishly, with a fan, making himself suddenly feminine and vulnerable by tilting his head or collapsing his neck into his shoulders. With a set of finger bells, he drifts and spins across the space, his arms and his whole body floating improbably, lighter than smoke. At last he plays castanets, accompanying himself and the musicians, skipping, running, hopping, accenting with two-footed clumps into the ground. No Spanish dancer has ever dreamed of anything like this.

Serenade could so easily be a campy display but it isn’t. The program opener, A Spell, showed how over-the-top Morris can get, with a coy Cupid (Bradon McDonald) and a lusty couple (Marjorie Folkman and Matthew Rose) pretending to be shy while they mime the poetic conceits of John Wilson’s Renaissance madrigals.

Heterosexual love seems to bring out Morris’s satiric/satyric side. But Lou Harrison’s music doesn’t have any pretexts of this sort, and Morris responds to it with true affection. The program romped to a close with Grand Duo, which is set to Harrison’s Grand Duo for Violin and Piano (Gandelsman on violin and Hochman on piano). Although you might think the big complement of 14 dancers would overpower Harrison’s intimate duo, the music provides plenty of structure for a rhythmic blowout.

Instead of lining itself up to address the audience, as it does in the Bart—k, the ensemble here often works within itself in ritualistic patterns — circles, running charges, small belligerent splinter groups. At last, to Harrison’s polka, with its bouncy tone clusters and headlong momentum, the dancers join in a tribal celebration zany enough to melt igloos.