John Hartford, who performed at last night's closing segment of the Smithsonian's American Country Music Series, is an eclectic songwriter who comfortably straddles the bridge between country tradition and folk revival. He's written a number of fine songs while delineating a county of the mind as strictly bounded as William Faulkner's. Hartford's rural reality revolves around riverboats, the people who ride them, and most especially the people who guide them on their journeys.

Hartford is a musician who works his whole body into his act, like a dancer.

After skipping onto the stage at Baird Auditorium, he was halfway into a song before he realized he'd forgotten to plug in the piece of plywood that he taps, skips and shuffles on. Once that was taken care of, Hartford's feet maintained a rhythmic pulse under his varied work on fiddle, guitar and banjo. Besides all this, the singer used not only an astounding variety of vocal effects, but soloed on moist gums and hollowed cheeks.

If Hartford has a major drawback, it's in the sameness of many of his songs. Riverboat life provides a colorful milieu, but after a while the songs begin to blur. Hartford's congeniality and humor -- at one point he wandered through the auditorium fiddling away, thanks to a wireless pickup -- make up for most of his material's deficiencies. As a performer, John Hartford jumps in head first and then lets both his feet and fingers do most of the talking.