Theophrastus (thēˌōfrăsˈtəs) [key] [Gr., = divinely speaking], c.372–c.287 B.C., Greek philosopher, Aristotle's successor as head of the Peripatetics. The school flourished under his leadership. He wrote on many subjects, but his works on plants are perhaps the most important of his technical writings. His Characters, a series of sketches of various ethical types, provides a valuable picture of his time. It anticipates such studies as those by Sir Thomas Overbury, John Earle, and La Bruyère.