Cutting his teeth as a member of the New Grass Revival, Bela Fleck helped smooth bluegrass, jazz, and groove-rock into a single sound, turning in a series of stadium-size cameos along the way. Yet, despite a stream of Grammy nominations and a clique of celebrity friends, Fleck has remained a musician in the truest sense of the word; a prime example of grassroots music's polished professionalism. So it makes sense that the Flecktones glued together the fifth annual Grassroots Music Festival, an excellent reference point to where bluegrass and jam-music collide.

Blending the traveling Acoustic Planet Tour into its backbone, Walther Productions rebuilt this year's Grassroots Arts and Music Festival as an amphitheater event. Awarding each act a plumb spot, the seven-hour acoustic summit featured two sections: the first devoted to a pair of modern bluegrass masters (the Del McCoury Band and Sam Bush) and the second to the newly emerging jam-grass genre (the Acoustic Planet Tour). With blankets, beach chairs, and the occasional bluegrass baby in-toe, a stream of families arrived early enough for McCoury's show opening seta fitting start both sonically and chronologically to the afternoon's activity. While McCoury is a true tie to Bill Monroe, the bluegrass' founder father, he will likely be remembered as the genre's most visible, grassroots ambassador, having turned in well-received performances with Phish, Steve Earle, and Leftover Salmon in recent years. Appearing a bit older and more conservative then his showmates, McCoury confidently sported his trademark three-piece suit, while allowing first-son Ron a few ripe solos during "Evangelina," from his CD Heartbreak Town.

Likewise, Sam Bush helped lay newgrass' foundation, both as a member of the New Grass Revival and as liaison to the Grateful Dead's tie-dye empire. Yet, placed earlier on this afternoon's bill, Bush seemed like a veteran next to his peers, leading his crowd in a slightly cheesy, yet still endearing, chant during "Banana's." Proof that the Grassroots Festival was truly an acoustic gathering, The Sam Bush Band was the weekend's only offering to feature a traditional drum-knit. Bela Fleck also sat in for "Same Old Man," revisiting their two-decade old friendship and offering the weekend's best quip: (Bush to Bela: "I am a little bit country, and he's a little bit rock).

After a half-hour intermission, during which time fans square-danced alongside the Maryland Folk Society, Grassroots resumed with the Acoustic Plant Tour. A traveling festival, Acoustic Plant is colored by a series of interlocking shows, featuring a healthy dose of cross-pollination between the tour's three headliners: Yonder Mountain String Band, Keller Williams, and Bela Fleck and the Flecktones. Hitting small-sheds and large theaters across the country, Acoustic Plant acclimated well to the large Merriweather Pavilion, a natural amphitheater dangerously close to being demolished in favor of urbanization and/or commercialization. In fact, throughout the festival, an eager group of grassroots activists handed out stacks of Save Merriweather flyers and used the day's events as proof that a union of independent musicians can turn an amphitheater setting into a cozy gathering.

Opening with "Years With Rose," Yonder Mountain turned into a high-energy set, which, unfortunately, was hampered by the uncontrollable, and unbearable, hot weather. At times a bit tame, Yonder's set did feature an interesting medley of "On the Run" and "Looking Back Over My Shoulder," with Jeff Austin's mandolin tying the second half of the group's set into a single suite of songs. Keller Williams offered his services as front man for a take on Michael Jackson's "Don't Stop Till Your Get Enough," before seamlessly segueing into his own solo spot. While his one-band jam band shtick is starting to run a bit thin, Williams' singing is still fresh, as evidenced on tight versions of "Love Handles" and "Five Long Years." Nodding to his days as a Dead Head, Williams offered a textured reading of "Feel's Like a Stranger," augmenting his bass-heavy loops with an appearance by Austin. With a Dave Matthews opening spot under his belt, Williams is also becoming an increasing confident showman, breaking out his own take on Matthews' patented duck-dance.

Unquestionable the evening's highlight, the Flecktones treated fans to two hours of continuous music, which climaxed during the cerebral "Big Country." Running through tight versions of "Hippie Dance," and "Sojourn of Arjuna," saxophonist Jeff Coffin turned in a series of breezy solos, while Futureman hinted at bluegrass' place in the year 2050. The evening also showcased Futureman's vocal stylizings, which have aged gracefully from female-shrieks to passionate jazz-scats since 1997. Ironically, though few months away from their first extended hiatus, the Flecktons are performing with new a new sense of tightness. In fact, while the flow of a traditional Flecktones' concert is chopped up with brief solo sets by each performer, the group's single-set offering provided the quartet with a bit of focus, forcing odd, musical-toy experiments to fall by the wayside. A well-oiled unit, the Flecktones still glue together the American sounds of jazz, bluegrass, and rock with polished precision.

Ninety minutes deep into their show, The Flecktones' set gave way to a structured power-jam, built around a series of classic rock anthems. Folding Williams, Bush, and Yonder Mountain into their lineup, the Flecktones' offered an elongated version of the Beatles' "Come Together, with Bush using his fiddle in lieu of the song's traditional guitar breakdown. The Flecktone's furthered this town meeting format during "All Along the Watchtower," bookending the live staple with another ubiquitous cut, "Stairway to Heaven." Long, flowing, and full of quick sonic bursts, "Watchtower" proved, as it has for years, that community will always lie at the core of grassroots music.