In their final concert of the season on Sunday afternoon, members of the Portland String Quartet and their guest musicians offered an intriguing trio of works at the Portland Conservatory of Music. Both formal and folksy musical approaches, sometimes within the same piece, enriched a program of compositions from the first half of the 20th century.

The Portland String Quartet is in the process of selecting two new members to replace founding second violinist Ronald Lantz, who retired at the end of last season, and cellist Andrew Mark, who stepped down for personal reasons. Throughout the season, remaining quartet members Dean Stein (violin) and Brianna Fischler (viola) have been rehearsing and performing with candidates for the positions. On Sunday, they were joined by Patrick Doane (violin) and Timothy Paek (cello) in the old church hall, now conservatory, which has been made even more hospitable by the addition of new seating.

First up was a performance of the “String Quartet No. 1 (1933)” by Walter Piston, a Rockland native who the PSQ has long championed. An ebullient spirit in the work was ably brought forth by the quartet, placing the piece in a neoclassical realm that recalled some of the compositions of Igor Stravinsky from the same period. The middle movement featured resonant lyrical passages highlighted by Fischler and Paek (who was a standout throughout the concert). An edgy finish paved the way, in a sense, for the complexity of the next work on the program.

Béla Bartók’s “String Quartet No. 1, Op.7 (1909)” was introduced by Stein as containing the composer’s reactions to a youthful, unhappy romance. Indeed, there was ardor in the slow opening lines brought out by Stein and Doane and yet a certain arduousness developed which challenged the determination of the PSQ to bring the weighty drama within the young composer’s vision to the fore while not ignoring its quickly evolving subtleties. Hints of Bartók’s interest in Eastern European musical traditions beyond the formal lineage of classical music could be discerned and were welcome amid the turbulence of the later moments of the lengthy piece.

It was a breathtaking and attention-grabbing performance of a work that demands much of listeners and, of course, the players. Violist Fischler, in introducing the final work in the program, even complained of still being under the sway of “Bartók brain” and kept her remarks brief.

The concert concluded on a joyful and much more relaxing note with a performance of the “Quintet No. 1 for Piano and Strings in A minor (1936)” by Florence Price. Pianist Anastasia Antonacos joined the PSQ for this highly engaging piece.

Due to the struggles of Price, an African American female composer, to be fairly recognized in her lifetime, this delightful work was not discovered until decades after her death. It proved as refreshing as the gentle breezes wafting through the hall on Sunday.

When compared to the earlier performed quartets of Piston and Bartók, this quintet draws on well-established classical forms in the service of celebration as well as struggle. Though some of its sources in spiritual and dance forms (on which Antonacos excelled in performing), might rival the approach employed by other composers, Price’s efforts seem not so much aimed at formalizing those influences as asserting their equal value.

It was a fascinating and ultimately fun spring afternoon spent with the Portland String Quartet and guests.

Steve Feeney is a freelance writer who lives in Portland.