It's hard to exaggerate Gram Parsons' influence on Americana. Even The Rolling Stones, during the early ‘70s, looked to him for guidance to build the twangy sound that defined songs like “Dead Flowers.” Fellow country legend—and Parsons' close collaborator—Emmylou Harris shows what she learned from him with the cinematic grandeur of the orchestral “Boulder to Birmingham,” and Uncle Tupelo mixes punk with his country-rock vibes on “Whiskey Bottle.”