Performing Shakespeare, With Help From Mandolin, Clarinet, and Saxophone "Under the Greenwood Tree," a musical adaptation of "As You Like It," is frequently too thin and clumsily staged. But when a moment works, it works beautifully. The show, at the Flea Theater, takes Shakespeare's text, truncates it substantially and inserts songs along the way, with the actors taking up instruments - mandolin, clarinet, saxophone and many more - to supplement a core band. The music and the adaptation are by Tyler Phillips, who directed the show, along with Carly Howard. Ms. Howard also plays Rosalind opposite Brett Benowitz's Orlando. Neither is a strong enough actor to carry the show, but Ms. Howard has a lovely voice, and so do many of the other cast members, right down to Kyle Sallee, whose Touchstone shares a delightful song with Bethany Taylor's Audrey. Trevor McGinnis has a winning turn as Silvius, the sad-sack shepherd. Mr. Phillips favors group numbers, and several of them are striking, especially "Sermon of the Stones." "Lost in the Woods" is a fine showcase for Ms. Howard, and "Idiot Love," featuring Mr. McGinnis, has a droll, melancholy wit. The mechanics of staging the big numbers overwhelm the narrow playing space, with musicians and singers trudging onstage and off again inelegantly, breaking what little storytelling momentum the adaptation has. It doesn't have much, because the story has been abbreviated to make room for all those songs. "As You Like It" is short on depth, of course, but there's more to it than comes across in this version. That said, enough memorable musical flourishes come along in "Under the Greenwood Tree" to leave you thinking that there's something worth pursuing here. A bigger playing space, a more fully realized script, a bit less showing off in the instrumentation, and this "As You Like It" could be pretty lovable.