Variations on The Willow song for flute, viola and guitar

Description

The Willow song is a traditional tune (first documented in a lute book dated 1583)
which was used for Desdemona’s lament “The poor soul sat sighing by a sycamore tree”
in Shakespeare’s tragedy Othello.
I have given the tune and a variation on the tune to the flute
while the viola provides countermelodies.