But the genre defines itself by its progenitors more than its present. Any Americana artist working today ought to know his Woody Guthrie, his Carter Family, his Willie Nelson, his Blind Willie McTell.

Case in point: The nonprofit Americana Music Association formed in 1999, and held its first festival and conference the following year in Nashville. The big coup came in 2009, when the Grammy Foundation established an independent category for Best Americana Album. In the four years since, no musician under 60 has won the award.

And despite the genre's roots in gospel and the blues, the 20 Americana nominees to date have included only one black artist: the singer Mavis Staples, who won the award in 2011 for You Are Not Alone. (The album was produced by Wilco's Jeff Tweedy.)

Americana's proponents position themselves as anti-establishment gadflies to the left of commercial country. Many see themselves as preserving some bygone, purer strand of Americanness, and argue -- in distinctly rockist terms -- that this genre is just the modern-day manifestation of a timeless truth. (CBC radio personality Madonna Hamel gave a digestible synopsis in a recent radio special on Americana: The Americana Music Association, she said, is a brotherhood of "ex-industry types [who] quit their lucrative day jobs to get exposure for the artists they love. Their goal was simple: find a home for singers who can sing, writers who can write, players who can play.")

But you'll notice that it didn't take long for Americana to earn industry acceptance, which can be explained in much the same way as the existence of the genre's other, less flattering nickname: "dad rock." The music business was happy to create a niche for the country's most fiscally dependable demographic -- white, male Baby Boomers. Along the way, a handful of artistic traditions founded in rebellion (blues, Appalachian folk, outlaw country) got elided into a relatively conservative format.

Americana is music that sticks up for its drinking buddy, remembers the first time the flag was hoisted over the corner store, kicks up dust on its way out of town. After work, it watches TCM. But ultimately, if an art form is going to name itself after this country, it should probably stop weatherproofing itself against America's present-day developments. And it hardly seems like enough to say you're carrying on the legacies of black gospel and blues if the performers and listeners venerating them are almost all white.

In her book It Still Moves, a loving depiction of Americana's roots, Amanda Petrusich gets it right: "It sometimes seems like the Delta's legacy is most present in modern hip-hop" -- rather than Americana -- "where its basic tenets are still being perpetuated, even if the form has altered dramatically."

***

When Bob Dylan performs, he channels a whole universe of time-weathered emotions, ideas, and legacies. He refits himself to work as their vessel, but in the process, he makes them his own. In his memoir, Chronicles, Dylan describes songwriting as a form of inheritance: "Opportunities may come along for you to convert something -- something that exists into something that didn't yet." That, he said, is composition. And he's right; the vast American songbook and the styles that bind it together have always developed as a negotiation between self-sustaining tradition and venturesome experimentation. This is often lost on Dylan's latter-day disciples in Americana.