CD’s son. Botanist. BA, Cambridge (Trinity College), 1870. Qualified as a physician but did not practise. CD’s secretary from 1874. Collaborated with CD on several botanical projects. Lecturer in botany, Cambridge University, 1884; reader, 1888–1904. Published Life and letters of Charles Darwin and More letters. President of the British Association for the Advancement of Science, 1908. Knighted, 1913. FRS 1882.