“It is hardly an exaggeration to say that the tip of the radicle . . . having the power of directing the movements of the adjoining parts, acts like the brain of one of the lower animals; the brain being seated within the anterior end of the body, receiving impressions from the sense organs and directing the several movements.”
Charles Darwin, who in his later years became increasingly passionate about plants; and his son Francis thought of the plant as a kind of upside-down animal, with its main sensory organs and “brain” on the bottom, underground, and its sexual organs on top.