Theophrastus tried to lift the veil of superstition to understand the natural world. He railed against those who advised to be guided by the moon when it came to practical garden matters: “One should not in fact be governed by the celestial conditions and revolution rather than by the trees and slips and seeds” and he dismissed other myths as having been revealed as “sheer fable.”

Among ancient naturalists, Theophrastus was uniquely sensitive to the relationship between plants and their environment. Habitat was so important, he wrote, because plants were bound to it. They were “not free from it like animals.” He explained that a plant thrives best in a “favorable place,” or as ecologist would say today, in its “niche.” He studied soil, moisture, temperature, wind, and exposure. He discussed the adaption of plants to a particular environment and even wrote about “mutation according to place.”

Theophrastus was interested in the effect plants had on each other and noted that olives, myrtles and pines thrived when growing together but that the almond tree was a “bad neighbor.” He saw how trees grew tall and more upright when they stood close together. He noticed that jays buried acorns, helping them to germinate, and that mistletoe “lives by taking the food that belongs to the tree’.”

Aristotle saw similar relationships between animals and their environment but believed that plants and animals had been created “specifically for the sake of man.” Theophrastus, on the other hand, insisted that plants had their own purpose and were not made to serve humans, to feed us, or to provide building materials. In the twentieth century, some historians and botanists began to call him the ‘father of plant ecology’.

Laërtius wrote that Theophrastus devoted “his whole leisure to learning” and that he was “a man of extraordinary acuteness.” He certainly must have been busy because he wrote almost 300 books and treatises with subjects ranging from politics, morals and law to others on animals voices, on love, history, and astronomy. “These works contain in all two hundred and thirty–two thousand and eight lines,” Laërtius reports rather precisely, but few have survived.

After Theophrastus succeeded his old friend and collaborator Aristotle as the head of the Lyceum, he taught there for more than three decades. Laërtius says 2,000 pupils attended his lectures. When Theophrastus died at 85, the whole of Athens mourned him, according to Laërtius. Nature and gardens were places of learning, Theophrastus believed, and bequeathed his garden and promenade to his friends “to hold a school in them and to devote themselves to the study of philosophy … and to use them in common as if they were sacred ground.”

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