Charles Darwin regarded natural selection as a “universal law of nature.” Its comprehensive scope led him to investigate the natural world with a breadth of vision that encompassed both plants and animals. Darwin’s last several books were detailed botanical studies, as the immense variety and complexity of the plant world offered Darwin ideal opportunities to extend his theory of natural selection.
- Insectivorous Plants, 1875; F1218
In a pioneering study of insectivorous plants, Darwin explored the adaptations by which plants are nourished in impoverished soils. He pointed out that the Sundew secretes a digestive fluid similar to an animal’s.
Darwin’s study of the movement of climbing plants, first published in the Linnean Society journal in 1865, appeared in book form in 1875. Darwin experimented with a variety of factors affecting plant growth and the movement of roots, vines and flowers. He demon-strated the importance of light sensitivity, which enabled a plant to move by elongating the stem on the side farthest from the light.
- The Effects of Cross and Self-Fertilisation in the Vegetable Kingdom, 1876; F1249
- The Different Forms of Flowers on Plants of the Same Species, 1877; F1277
Darwin published two books on plant fertilization and the different forms of flowers that appear on the same species. These studies suggested that cross-fertilization produces more vigorous offspring than self-fertilization.
In 1880 Darwin continued his investigation of plant movements. As was his custom, he employed a wide variety of visual diagrams throughout the book. In the image below left, Darwin plotted the motion of a single leaflet — one of nearly a hundred such depictions in this work. In the chart below center, one line shows a change in temperature and the other shows the angular movement of a leaflet. In the illustration below right, the Cassia plant extends its leaves during the day and folds them up at night.
Come see these works and others in the current exhibit, Darwin@theLibrary!