How many melodies and harmonies are sung in O viridissima virga?

"O viridissima virga" features a single melody that is sung in a homophonic texture, where the main melodic line is supported by harmonies. The piece is characterized by its rich harmonization, typical of the medieval and Renaissance choral music style, but it primarily emphasizes one principal melodic line. The harmonies complement the melody, enhancing its beauty without introducing multiple distinct melodies.