Plants Climb and Plants Move

Francis Darwin moved back to Down House as an adult and worked with his father on several botanical projects. After his father died, Francis became a lecturer and then a reader in botany at the University of Cambridge.

A spiral-twining plant from the genus Manettia. Darwin determined that the stem of a species of Manettia (in family Rubiaceae, the madders) followed the sun, moving in a circle over a period of six to seven hours.

Darwin observed and measured the climbing movements of seven species of the leaf-climbing genus Tropaeolum (which includes nasturtiums).

On loan from L.H. Bailey Hortorium Herbarium, Cornell University.

The Harvard botanist Asa Gray sent Darwin seeds of Echinocystis lobata, the wild cucumber from North America. While ill, Darwin watched its tendrils twining about his study: “Their irritability is beautiful, as beautiful in all its modifications as anything in orchids.”

On loan from L.H. Bailey Hortorium Herbarium, Cornell University.

While the botanist Asa Gray (1810-1888) was the major supporter of Darwin’s ideas in the United States, he believed that a divine force played a role in evolution. During the 1860s, Gray and Darwin engaged in an extensive correspondence regarding design in nature. Portrait from Charles Darwin. More Letters of Charles Darwin … New York: D. Appleton, 1903.

In one of his last two published papers, read to the Linnean Society by Francis Darwin, Charles Darwin examined cellular changes in the common sundew when substances were placed on the leaves. A “time lapse” drawing illustrated what he called “aggregation” in the cells of the glandular hairs.

Darwin’s third son, Francis, was credited on the title page of The Power of Movement in Plants as assisting the author. The two Darwins meticulously measured the movement of roots, stems, petioles, and leaves in a wide range of plants, including movements made to “sleep.”