 Theophrastus’ two main botanical treatises, Enquiry into Plants and Plant Explanations, have stood the test of time better than Aristotle’s zoological works. Especially, the Enquiry into Plants (Historia Plantarum) is considered as one of the most important books of natural history in antiquity, along with Pliny the Elder’s Natural History and Dioscorides’ De Materia Medica. It was written some time between c. 350 and c. 287 BCE in ten volumes, of which nine survive. Theophrastus seems to have continually revised the manuscript, and it remained in an unfinished state on his death. Judging from its condensed style and the many lists of examples, Theophrastus may have used it as notes for teaching purposes, rather than intending it to be read as a book. He investigated in it over 550 species of plants and showed great interest in their structure, growth and reproduction, their varieties around the world, the wood of different trees and the effects of climate on it, the wild and cultivated plants, the classification and uses of herbs, cereals and legumes; finally, in book 9 he presented the medicinal uses of plants, described the juices, gums and resins extracted from them, and explained how to gather them from different regions (see Desautels 1988).