If there were tentative moments during the Country Gentlemen's Silver Anniversary Celebration at Wolf Trap last night, they were quickly compensated for by frequent and sterling reminders of the group's contribution to the emancipation and popularity of bluegrass. The occasionally forgotten lyric or flubbed transition was testimony to the expanse of the material covered; the four current Gentlemen were joined by a dozen alumni for the three-hour program.

The picking throughout the night was exemplary, featuring some of the best mandolin, guitar, banjo and Dobro in the field; yet it was the vocals of Charlie Waller and John Duffey that stood out. It's conceivable that Waller, the all-time Gentleman, could have made his mark in country music; his crystal-clear, virile tenor always managed to cut through the air, whether on a Hank Snow medley, Tom Paxton or Bob Dylan ballads, or more traditional gospel tunes.

Duffey, who left the Gentlemen after a decade, then resurfaced with the Seldom Scene, has a classic high tenor and when he, Waller and Eddie Adcock recreated their seminal '60s harmonies, it was easy to understand their immense influence on American folk music. Duffey also delighted the crowd with his vibrant and jazzy mandolin picking.

Highlights of the night included a rockabluegrass rendition of Carl Perkins' "Honey Don't" with collars turned up and knees bent and shaking; a "Swinging Sunrise" on which Adcock showcased his innovative banjo style; strong renditions of favorites like "Bringing Mary Home," "The Rebel Soldier," and "Fox on the Run." The original four Country Gentlemen even revived their debut single singing both sides with the clipped harmonies of the bluegrass style they eventually outgrew.

The concert was presented somewhat chronologically, which meant a lot of shuffling of personnel on and offstage, a bit of confusion and strain remembering exactly how everything went. But the eclectic repetoire and the enthusiasm at being able to celebrate 25 years of innovation and excellence kept everyone's spirits high. The night ended with everyone massed on stage for a rollicking "Orange Blossom Special." Had this been a festival, they would have played until dawn. Maybe backstage, they still are.