On Thursday, the late Grateful Dead guitarist Jerry Garcia would’ve turned 72. Buffalo-area Deadheads and jamband fans are always eager to celebrate Garcia’s birthday, and all day long, Facebook was abuzz with the suggestion that the evening’s Canalside performance by Yonder Mountain String Band and Railroad Earth would be given over fully to a birthday party for Garcia and his music.

That didn’t turn out to be the case in whole, though both bands did indeed add Garcia/Dead tunes to their sets in honor of the man who is held to be the spiritual father of the jamband scene. No, the beautiful evening on the Inner Harbor did not resound with twin sets of Garcia tunes, but his influence hung over the rootsy “jamgrass” affair.

Colorado’s Yonder Mountain String Band has earned itself a reputation as one of the strongest and most agile contemporary bluegrass outfits extant, and they clearly take a page from Garcia’s bluegrass work with Old & In the Way, David Grisman, and the Dead. What makes Yonder Mountain so interesting is the way in which the drummer-less quartet is able to build grandiose, sweepingly dynamic tunes without the benefit of a traditional rhythm section. Much of this comes down to the considerable virtuosity of the individual musicians, but as Thursday’s show made plain, Yonder Mountain is all about the ensemble interplay.

Things got cooking pretty quickly as Yonder Mountain took to the stage amid a rapturous applause from the packed Canalside. Fronted by mandolin player and singer Jeff Austin, the band in truth comes across as a full-blown democracy – all four members sing, all take turns handling lead vocals, and all can solo themselves silly while simultaneously driving the audience to the point of happy hippie frenzy. By the third tune of the set, the area directly in front of the stage had turned into a massive dance floor, and banjo player Dave Johnston was in the process of building up to the first crescendo of what would need up being a dozen or so absolutely epic solos throughout the course of the evening.

Bassist Ben Kaufmann joked with the crowd, recalling the band’s 2009 appearance at Thursday at the Square, when the bassist performed in a neck brace after a serious accident left him with broken vertebrae in his neck.

“Buffalo is the only place where I can say I’d love to play with a broken neck,” the bassist quipped, and the crowd went nuts. Guitarist Adam Aijala then took his turn leading the band with several flat-picked solos that suggested the influence of the bluegrass great Jerry Douglas.

The centerpiece of the set was surely a lengthy, jam-filled take on the Grateful Dead’s “New Speedway Boogie,” played in honor of Garcia’s birthday. After much soloing from all four members, as well as special guest Tim Carbone, Railroad Earth’s fiddle player, the tune broke down to its gospel-flavored “One way or another/This darknesss has got to give” chorus, and Austin had the thousands singing along with him in full voice. An air of jubilation ensued, and endured for the remainder of the band’s set.

Railroad Earth was a perfect match with Yonder Mountain. Both bands play contemporary bluegrass, but each has a unique take on the form. Railroad Earth boasts a drummer, so it brings a rock element to the party. Guitarist and lead vocalist Todd Sheaffer acts as frontman and on Thursday, he provided an affable and easygoing conduit to the heart of the band, where a joyous interpretation of rootsy Americana is the lifeblood.

Railroad Earth’s set was as well-received as Yonder Montain’s, but the most visceral outpouring of love took place when the group took an elegant and refined stroll through the Garcia-associated classic “Peggy-O,” which Sheaffer sang with easygoing grace.

Canalside felt like a semi-utopian community bonded by music on Thursday, with several generations of music lovers commingling and basking in the good vibes. One imagines that Garcia would be smiling as he took it all in.