Laura Totten for Plants and AnimalsWho: Plants and AnimalsWhere: Broad Street StageWhen: 2:15 p.m.The beginning of their set played like haunting, prophetic rock hymnals, all pedaled-out and swarming. Then just a few songs in, and The Plants and Animals from Parc Avenue had transformed into some other band. You see, in spite of all the symphonic layers of yawning strings and chatty guitars on the album, Plants and Animals actually only consists of three people. No matter. While other bands who run into this snag might choose to bring a few other folks on as touring members or to just strip the sound down into something simpler and softer, Plants and Animals just turn their energy on overdrive and make it just as thick and loud in a very different way. Switches between instruments allowed time for dramatic solis and breakdowns. “Mercy” crushed into a hypnotizing, anthemic jam, with bassist and frontman mirroring each others’ motions and pulling each others’ cues for some improv moments. The whole sound took on more of a classic rock sort of feel with brief moments of math rock lite, and it showed off a fast-flying, clever drummer who apparently had a lot more room to stretch onstage than in the studio.