Medicinal plant. 16th century Italian illustration a medicinal plant with white flowers and orange fruit, by Gherardo Cibo, 1568. This plate is taken from Discorsi on Dioscorides' De Materia Medica by Pietro Andrea Mattioli, a work of herbal medicine first published in Italy in 1554. Pietro Andrea Mattioli (1501-1577) was an Italian doctor and naturalist who wrote commentaries on 'De Materia Medica', an encyclopaedia of herbal medicine by the first century Greek physician and botanist Dioscorides.