01/19/2026
The Root Brain
By Ed Perkins
With the publication of “On the Origin of the Species” in 1859 Charles Darwin made one of the greatest advances in the biological sciences in the 19th century. It was a grueling undertaking - long ocean voyages, trekking over remote landscapes observing and collecting exotic animals and sampling the volcanic geology - well suited to a young man. In his later years, Darwin focused on things closer and easier to study - plants. Most of his books after “Origins” were about plants, as he made many important discoveries in the field of botany.
In “On the Movement and Habits of Plants” (1865) he observed how plants (generally considered to be stationary) did move slowly. Some vines start growing, swaying in a circular motion until they can attach onto something to grow up on. Some flowers track the sun throughout the day.
“Insectivorous Plants” (1875) studied how these plants could move quickly to trap unsuspecting insects for dinner. Within the trap (actually a modified leaf) are trigger hairs. If a certain number of hairs over a certain time frame are disturbed, as by an exploring insect seeking the sweet nectar within the trap, the trap closes. If there is a struggling insect continuing to disturb the trigger hairs, the trap remains closed and digestive juices are secreted. If there is no insect and no hairs are disturbed, the trap will reopen.
“The Power of Movement in Plants” was his second to last publication. Darwin and his son Francis did many experiments with plant roots. They found that the very tip of the root, the root cap, acted as the root’s command center. Poke it and the root grows away from the offending jab. Put between a rock and soft clay, the root turns and grows toward the clay, even before it hits the rock. Place a root between dry and moist soil, and it always grows toward the moist soil. Most astonishingly, the root apparently can “hear” flowing water. Plumbers know this well since roots often grow into water pipes, plugging them up. Slice the cap off and the root will do none of these things, that is until it regrows in a few days.
The Darwins wrote, “We believe that there is no structure in plants more wonderful …than the tip of the radicle.” They called it the “root brain”. More recent studies have revealed the amazing abilities of plants. Zoe Schlanger in her book “The Light Eaters” (2024) describes “the unseen world of plant intelligence.” Plants respond to all facets of their surrounding environment. They communicate within their plant body, with neighboring plants and any animals, especially insects, in their environment. They transform their bodies to benefit the fertilization and dispersal of their propagating units.
Plant brains? Plant intelligence? These are controversial ideas now as they were in Darwin’s time. Of course plants do not have brains and central nervous systems like animals do. The plant’s structures and systems are different from those of animals. But they accomplish the same ends - to ensure the species survival.
Ed Perkins farms in Athens County.