Fifty-two folk musicians and singers traveled to Lisner Auditorium Saturday to celebrate the 25th anniversary of Dick Cerri's "Music Americana" radio show. All of them and more crowded the stage to sing the folk standard "Get Together" for the grand finale. Virginia's Jonathan Edwards sang a verse, and San Francisco's Kate Wolf sang another. Leading the harmonies were Boston's Tom Rush and Maine's Schooner Fare. Over in the corner was Cerri himself, decked out in a tentlike tuxedo and twisting the night away with the diminutive, red-sneakered Christine Lavin.

The evening was filled with warm, heartfelt tributes to Cerri, who through the years had introduced most of the performers to Washington audiences. There were also lots of jokes and a few surprises. The biggest surprise was the first reunion in 20 years of the Chad Mitchell Trio. The threesome had a little less hair, and the material still represented the most commercial, most wholesome end of the acoustic folk music spectrum. Nonetheless the three voices blended together surprisingly well after a two-decade sabbatical. Chad Mitchell, now working for New Orleans' Delta Queen steamboat, still supplied the chiming high harmonies; Joe Frazier, now an Episcopal priest in California, still contributed the sturdy tenor; and Mike Kobluk, now working for the Spokane Wash. Opera House, still lent the comic baritone interjections. They surprised an unsuspecting Cerri at the afternoon show and returned for the evening show with the satire of "It Was a Hell of a Funeral" and nostalgic harmonies of "Four Strong Winds."

The show ventured across an impressive range of styles: from the pop-folk of original Kingston Trio member Dave Guard to the new-grass of Grazz Matazz; from the sea shanties of Schooner Fare to the political folk of Cathy Fink. Barry Nickelsberg interpreted all the songs and introductions into sign language that was as much choreography as translation. Unfortunately, there was only one black performer on stage all night: Donal Leace, who did a stirring a cappella version of the protest hymn "Freedom."

Not every song was successful: The romanticism of Carolyn Hester's "I Have a Dream" and Dave Mallett's "Vital Signs" seemed a bit strained; the humor of Dave Guard's "They Love the Night" and Bob Gibson's "Heavenly Choir" seemed a bit forced. These moments, though, were far overshadowed by the evening's many highlights.

The new lineup of Washington's Mountain Laurel lent an astute understatement to a country arrangement of John Prine's "Unwed Fathers." Steve Gillette sang a gorgeously restrained version of his own folk standard, "Darcy Farrow." Christine Lavin had the crowd howling with her comic plea to the Reagan administration to become "The First Folk Singer on the Space Shuttle."

Jonathan Edwards and the Seldom Scene combined for flawless three-part harmonies on "Blue Ridge," which also featured a lonesome dobro solo by Mike Auldridge. Guitarist Pete Kennedy, who accompanied Wolf, Rush and Gibson, delivered an eerily fatalistic solo version of "Coal Tattoo." The duo of pianist David Buskin and fiddler Robin Batteau, who accompanied Wolf, Rush and Gillette, created hypnotic harmony for their own version of "The Boy With the Violin."

Doris Justis, the producer of this surprisingly smooth show, joined her musical partner in Side by Side, Sean McGhee, for a touching farewell song, "One for the Road." Bob Gibson pulled Cerri out from the wings and forced him to sing a verse of "Abilene." Tom Paxton, who had planned to come but was forced to cancel, was represented in spirit by a moving version of his song, "The Last Thing on My Mind." Backed by Kennedy, Auldridge, Buskin, Batteau and John Jennings, the resonant, well-seasoned voices of Tom Rush and Kate Wolf glided through the song, and the whole audience joined in on the chorus.