Legendary 1981 Stephen Sondheim “Merrily We Roll Along,” helmed by frequent Sondheim collaborator James Lapine, kicks off the spring 2012 season of the Encores! series of semi-staged concert readings.

Rodgers and Hammerstein’s little-seen “Pipe Dream” and “Gentlemen Prefer Blondes” are also on tap.

“Merrily,” which recounts the dissolution of a friendship in reverse chronological order, flopped when it bowed on Broadway but has since seen its rep grow among theater aficionados. Lapine, whose has worked with Sondheim as a helmer and book writer (“Sunday in the Park with George,” “Into the Woods,” “Passion”), first directed “Merrily” in a reconfigured 1985 production at the La Jolla Playhouse. Encores! version runs Feb. 8-12.

The 1955 “Pipe Dream,” based on John Steinbeck novel “Sweet Thursday,” hasn’t played in the U.S. in some 20 years due to an underlying rights issue. Show, centering on an unlikely romance in 1950s Monterey, runs March 28-April 1.

“Blondes,” with music by Jule Styne, lyrics by Leo Robin and book by Anita Loos (based on her novel) and Joseph Fields, preemed on Broadway in a 1949 production starring Carol Channing prior to the 1953 screen version toplined by Marilyn Monroe. Plot follows a pair of young showgirls in Europe in the 1920s.

New York City Center’s Encores! series has yielded a handful of Broadway productions in its 19-year history. Long-running revival “Chicago” launched at Encores! in 1996, and since then Rialto revivals of “Wonderful Town,” “The Apple Tree” and “Finian’s Rainbow” were all inspired by stagings in the series. The recent Main Stem return of “Gypsy” first bowed in a summer version of Encores!