Three centuries before Christ, Aristotle of Stagira, disciple of Plato, wrote extensively and systematically of all that was then known of the physical and living world. In this monumental task, he laid the foundations of inductive reasoning. When he died, he left his writings and his teaching garden to one of his pupils, Theophrastus (c. 370–285 BC), who also took over Aristotle's peripatetic school. Theophrastus’ writings on mineralogy and plants totalled 227 treatises, of which nine books of Historia Plantarum contain a collection of contemporary knowledge about plants and eight of De Causis Plantarum are a collection of his own critical observations, a departure from earlier philosophical approaches, and rightly entitle him to be regarded as the father of botany. These works were subsequently translated into Syrian, to Arabic, to Latin and back to Greek. He recognized the distinctions between monocotyledons and dicotyledons, superior and inferior ovaries in flowers, the necessity for pollination and the sexuality of plants but, although he used names for plants of beauty, use or oddity, he did not try to name everything.

To the ancients, as to the people of earlier civilizations of Persia and China, plants were distinguished on the basis of their culinary, medicinal and decorative uses – as well as their supposed supernatural properties. For this reason, plants were given a name as well as a description. Theophrastus wrote of some 500 ‘kinds’ of plant which, considering that material had been brought back from Alexander the Great's campaigns throughout Persia, as far as India, would indicate a considerable lack of discrimination.