This drawing is one of a large group of botanical studies produced for Cassiano’s friend Federico Cesi, and acquired by Cassiano after Cesi’s death in 1630. It is a composite of two species of peony, a flowering branch of Paeonia mascula (‘male peony’) to which the root of Paeonia officinalis (then known as ‘female peony’) has been pasted. Both species were widely used in herbal remedies of the period.