Emmylou Harris has grown from a country-rock princess to a rootsy queen mother in the decades since she left Washington's local bars for the national stage. At Wolf Trap on Tuesday, Harris presided over a bill crammed full of Americana talent.

Harris is touring as part of a hyper-gifted ensemble dubbed the Sweet Harmony Traveling Revue, which also features Buddy Miller, Gillian Welch and Dave Rawlings, and Patty Griffin. The first of what would be many ooh- and aah-inducing moments came when Harris led the troupe in "To Know Him Is to Love Him," the beautiful and creepy homage Phil Spector wrote to his suicidal father.

"I hope you didn't come hoping to hear happy songs," Harris told the crowd afterward. "We like 'em sad and dark." She brought out a mentor, local bluegrass legend John Starling, to help her and Miller on "The Other Side of Life." Then Miller, who cranks so much beautiful cacophony out of his electric guitars that it seems accidental, took center stage to croon a somber batch of his own: "Dark End of the Street," "Don't Tell Me" and the Louvin Brothers' "There's a Higher Power" among them.

Harris reappeared with proteges Welch and Griffin for an a cappella rendering of "Nobody but the Baby," the feel-bad smash from the "O Brother, Where Art Thou?" soundtrack. Welch and Rawlings allowed no fat in their half-hour out front. After years of letting Welch get all the attention, Rawlings has of late let his hair down, quite literally, and his long brown locks flopped around during "Time's the Revelator" as he threw himself into several aggressive solos on his trademark weather-beaten arch-top.

Griffin's set, which found her playing mostly newer material and backed by her own electric trio, detracted from the spirit of the event. But Harris got the proceedings back on a sublime track by bringing out the full cast for a show-closing, rambunctious version of the Band's "The Weight."

-- Dave McKenna

Emmylou Harris last year. At Wolf Trap on Tuesday she headed up an Americana revue.