E-flat clarinet
The woodwind requires 1 piccolo, 2 flutes, 1 alto flute, 2 oboes, 1 cor anglais, 1 E-flat clarinet, 2 B-flat clarinets, 1 bass clarinet, 2 bassoons, and 1 contrabassoon. Messiaen remarks: "all of the woodwind parts are difficult."