Darwin, Francis, Sir, 1848-1925

Francis Darwin was the son of British naturalist Charles Darwin, and followed his father into the study of botany. Dr. Harkness studied fungi. He was the president of the California Academy of Sciences, 1887-1896.

Francis Galton Darwin was a botanist.

English botanist.

Darwin, Francis (1848-1925, APS 1909) was a British botanist. With his father the famous naturalist Charles Robert Darwin he collaborated to publish The Movement of Plants in 1880. From his botanical lectures to undergraduates, he also published two textbooks, Practical Physiology of Plants, co-authored with E.H. Acton and The Elements of Botany. Darwin also collected and edited his father’s letters for publication in 1887 in an annotated edition that is considered one of the best collections of its kind. This collection, together with two subsequent volumes have provided the basis for all subsequent work on Charles Darwin.

Francis was the third son of Charles Robert Darwin and his wife Emma Wedgwood. Darwin was educated at home and later at Clapham Grammar School, before matriculating at Trinity College, Cambridge in 1866. In 1866 he took a degree in mathematics, and the following year first-class honors in the natural science tripos. Afterward, he entered St. George’s Hospital in London, aiming to become a physician, but under the influence of Dr. Emanuel Edward Klein, the father of British microbiology, he studied histology at the Brown Institute. He presented a thesis and received the M.B. degree in 1875.

For the next eight years Darwin worked as the secretary and botanical assistant to his father Charles Robert Darwin and lived at Down with his parents after the death of his first wife Amy in 1876. As a result of this eight-year collaboration with his father, Francis co-authored an 1880 work on The Movement of Plants. Although much continental research on the origins of plant curvature in response to light sought a physicochemical explanation, the Darwins were unconvinced, in part since Francis had demonstrated in his earlier work with Julius Sachs that roots grow more slowly in the light, than in darkness. Also, the experimental and evolutionary orientation of father and son left them uncommitted to discovering a direct relationship of cause and effect. Instead, they put forward the idea of irregular circumnutatory movements to explain phototropic responses in plants. They showed that geotropisms, like phototropisms and traumotropisms (the curvature away from an apical wound) were the result of differential growth rates. However, their most important contribution was to demonstrate that some substance in the apex of the root or shoot that is acted upon by light or gravity transmits its effects to other part of the plant, so that the effects of these stimuli on curvature are indirect. Francis Darwin later continued this research on his own, and refined his experimental techniques. Placing the tip of a root in a horizontal glass tube, he discovered that the rest of the root grew in irregular twists in response to continual signals from the apex “to get vertical”. As a result, he rejected the idea of circumnutation and showed that gravity affects shoots by apical stimulus the same way it affects roots. In this connection Darwin accepted the suggestion of Nemec and Gottlieb Haberlandt that gravi-perception depends on the falling of starch grains.

After his father’s death in 1882, Francis Darwin moved to Cambridge, where in 1883 he married Ellen Crofts, a lecturer in English literature at Newnham College. At Cambridge Darwin became university lecturer in botany, a fellow of Christ’s College, and in 1888, reader in botany. During this period his research interests shifted to the study of water movement within plants, while he taught botany and edited his father’s letters. Between 1886 and 1889 the stomatal openings of plants were first observed on the undersides of leaves under the microscope. Among the early researchers, Darwin published his first papers on the distribution of stomata and the transpiration of plants. In order to better investigate the function of stomata, he introduced the horn hygroscope in 1897. Later he invented the porometer to study transpiration by drawing air through the leaf and measuring its velocity. As in his earlier research, Darwin maintained that transpiration in plants was an indirect result of the effects of light. Unlike Weisner, who had suggested a direct effect of light on transpiration, due to its absorption by plant tissues and its transformation into heat, Darwin showed that the red light of the spectrum induced the opening of the stomata, and that the degree of their opening determined the transpiration rate.

Darwin’s major literary endeavors during these years included the publication of his undergraduate lectures on botany at Cambridge. These he published in two books, Practical Physiology of Plants, and The Elements of Botany, which presented a stimulating new approach to basic botanical principles. He also began collecting and editing his father’s letters for publication in 1887, finishing the final two volumes in 1903. In addition to this editorial work, Darwin authored biographies of his brother George Darwin, Francis Galton, Thomas Hearne, and the botanists Joseph Hooker and Stephen Hales.

For his many contributions to science, Francis Darwin received several important honors. In 1882 he became a fellow of the Royal Society of London. In 1909 he received an honorary Sc.D. from Cambridge. Also, in 1912, at the time of the Darwin centennial he received the Darwin medal of the Royal Society. The following year he was knighted. Darwin was married three times in his life; first to Amy Ruck, then to Ellen Crofts, and finally to Florence Fisher. He outlived all of his wives and died a widower in 1925.