Anyone who has enjoyed the rare privilege of seeing a performance of Mark Twain Tonight! starring its originator has no doubt considered that, if Sam Clemens didn’t talk exactly like Hal Holbrook, he should have. With Twain, of course, we have no recordings with which to compare the imitation. With Groucho Marx, we’ve got entire libraries: film, records, radio, television. His imitators are legion. And most of them are bad. Having been, as the students used to say in Paris, a Marxist of the Groucho kind most of my life, trust me when I say that, with Frank Ferrante, you’re getting the next best thing to the original.

Frank Ferrante in an Evening with Groucho, presented twice on the Marvelous Music Series on September 24 by the Cary Parks, Recreation & Cultural Resources at the Cary Arts Center, was a brief, annealing balm in a world that has gone madder than any anarchy the Brothers Marx could have imagined. I’ve been reading of Ferrante’s gifts for a quarter of a century now; in performance they surpass all expectations. Although the material he performs comes from every stage of Marx’s career — indeed, much of it is taken from Groucho’s 1972 Carnegie Hall appearance — what Ferrante conjures on the stage is the absolute essence of Groucho in his 1930s heyday: The distinctive ethnic and geographic cadence of that voice in all the seemingly infinite variety that represents the much-aped but truly inimitable sound of the man; the raised brows (grease-paint, of course, like the mustache); the rolling eyes; the slouching stride; the antic disposition. He does push-ups on the piano, tosses errant chairs, and crawls up and onto the stage in the manner of the great scene with Thelma Todd on the patio in Monkey Business.

Ferrante also conjures Groucho the ad-lib master, kibitzing his audience wittily and with the enviable aplomb of supreme confidence. This is the Marx of “You Bet Your Life” to a veritable “T,” the sly, conspiratorial leer as much in place as the use of the cigar as an invaluable prop for timing. Even when he is, occasionally, up-staged by the spectators, he takes it with that patented, good-natured smile Groucho used in moments of indulgence.

Aside from these breathtaking bits of impromptu, most of Ferrante’s material is familiar to the dedicated Marxist: The Bert Kalmar-Harry Ruby songs (“Hooray for Captain Spalding” and “Hello, I Must Be Going” from Animal Crackers and, cut from A Day at the Races, “Dr Hackenbush”), the perennial Harold Arlen-Yip Harburg aria “Lydia, the Tattooed Lady” (Arlen-Harburg), Ruby’s charming “Father’s Day,” and, as a tribute to the saintly Margaret Dumont, another Kalmar-Ruby gem, “Show Me a Rose.” (Although I’ve always had a difficult time accepting Groucho’s oft-repeated assertion that Maggie never understood the jokes; watch that woman in action and tell me she didn’t have a sense of humor.)

Ferrante also drops in one-liners and monologues from the movies and stage shows with characteristic poise. No matter how recognizable the song or bit, and even when I wasn’t laughing outright, I wore throughout his performance a continual smile of deep pleasure, remarkably similar to the one that’s generated by watching Groucho go through his paces on film. Jim Furmston, Ferrante’s musical director and accompanist, got things off to a rousing start with a variation on the witty, Mozartian piano overture Marvin Hamlisch created for Groucho’s Carnegie concert and provided playful support throughout. He can even shoot the keys á la Chico.

A single gesture of Frank Ferrante’s — one I don’t recall seeing Groucho perform, although he may well have — summed up for me the charm of his performance. Telling an anecdote involving a cigar while getting back into the topcoat he had momentarily removed, Ferrante/Groucho retrieved his own cigar from the jacket pocket without using his hands. Anyone with a modicum of impersonational talent can mimic Groucho Marx; it’s the little things that separate the layman from the master.