Carmina Burana is manuscript with texts from 11th through 13th century, written by mischievous clerical students making fun of their bosses at the Catholic church. It is written in mixed language - Latin and old German with bits of English and French. Among the illustrations is the one of an imaginative forest, which reminded me a lot of a plant in the Voynich manuscript.
One mischievous clerical student in the 14th century was named Peter of Candia (later pope Alexander V), who started the drinking society at Greyfriars, Oxford (the same college that educated Roger Bacon). Peter of Candia may have come across the Carmina Burana's (or similar book) drinking songs.
Drinking and eating were the things that pope (anti-pope) Alexander V loved doing, according to his contemporary Theodiric of Niem, cited in Cormenin's History of the Popes.
In fact Alexander V was reportedly drunk when he signed the famous bull that resulted in the burning of the Wycliff's books in Prague - action that caused whole lot of troubles for the church in the aftermath.
Anyway, for the magical forest in Carmina Burana and for the unidentified plants in the Voynich Manuscript... Cheers!