When it comes to defining the music of Donna the Buffalo, Jeb Puryear doesn't mind counting the years.

The guitarist and vocalist for the rhythmically charged, roots-driven troupe from upstate New York is eager to honor his band's recent 20th anniversary and the album Silverlined that went along with it. But discussing the origins and musical makeup of Donna the Buffalo means spinning back the years a bit further to the old-time folk and fiddle traditions that the band grew out of and to which it still owes considerable allegiance.

"Musicians have this good, protective mechanism," said Puryear, who performs with Donna the Buffalo at the Kentucky Theatre on Thursday. "It helps them not look too far into the future. But in a way, I'm not surprised at all the band has lasted 20 years, because we come from a tradition of old-time fiddle and folk roots music. Those types of musicians don't just play for a few years and then stop. It's a lifestyle. It's just who we are."

Pinning a specific musical style on Donna the Buffalo is a bit of a trick. Band founders Tara Nevins and Puryear are versed in the ways of old-time fiddle music, although Puryear also set his sights on guitar during his upbringing in Ithaca, N.Y. The resulting camaraderie between the two players yielded a band with accents of country, zydeco, reggae, folk, pop and more.

Jam-band fans favor the ways that Donna the Buffalo's churchy, cheery melodies give rise to hearty grooves. Americana audiences champion the traditional inspirations that fuel the story lines and the rhythms of the band's songs. Take the Puryear tune The Call. A highlight from Silverlined, it is steeped in the kinds of death, faith and regret that were cornerstones of Appalachian and pre-bluegrass country music.

"I would say almost all folk music and mountain music influence everything we do. And, yeah, having subject matter that deals with somebody dying is far more typical of old folk ballads than modern rock songs.

"It's interesting, really. People ask us all about our influences. I mean, I don't think there is anybody we've ever met that hasn't influenced us."

Given the artists with whom the band has collaborated of late, the level of inspiration that goes into a Donna the Buffalo album must be rich indeed. Nevins' singing and fiddle work gets a lift from West African kora pioneer Mamadou Diabate on Blue Sky (from the 2005 album Life's a Ride) and banjo colossus Bèla Fleck on Locket and Key (from Silverlined), and four of Puryear's tunes from the new album feature vocals from Ollabelle's Amy Helm.

But it is the sound that Donna the Buffalo produces regardless of the guest list that defines the band. That music might be drenched in tropical sunshine, lathered in bayou swamp water or served with a slice of old-fashioned charm, but it is never mapped out too exactly too far in advance.

"It's totally an organic process," Puryear said of the way Donna the Buffalo sets a stylistic course. "What we do, really, is totally in the vein of an old-time session. The thing about old-time music is you can play with so many people so easily. If there is a guitar player or banjo player, you just find them and go. A session can very easily just take off."

Old-time music, it turns out, was in generous supply while Puryear was growing up in Ithaca, N.Y. Fiddle tunes and players were so plentiful, in fact, that he thought the rest of the waking world was equally hip to the tradition.

"Back in the early '70s, when I was a kid, there was this really tremendous energy that came with old-time music. I thought that was going on all over the world. Then I got with an old-time band, took a little road trip and realized that wasn't the case. In fact, in the certain style we were playing in, it wasn't happening anywhere else."

It took connecting with Nevins in the mid-'80s, when both artists where playing Appalachian-based music in upstate New York clubs and coffeehouses, for a path to more electrified, rockish and stylistically diverse music to emerge.

"Ever since I met Tara long ago, we just had a real affinity for understanding what each other was doing, and have been able to build on that."

And the name? That was suggested by a patron at an Ithaca coffeehouse, although the idea was to call the then-new troupe "Dawn of the Buffalo." The misconstrued phonetics became the moniker for a band that continues to roam more than 20 years later.

"The good thing about music is that you learn so much about it every time you play," Puryear said. "Sometimes when you've been doing something for 18, 19 years together, you figure something out about a song or the way you can play it.

"But then, there is also a little bit of you that wants to reject that because you feel so stupid that it took you so long to figure whatever that was out."