One of Darwin's main contributions to science was his study of insectivorous – now called carnivorous – plants. While staying with relatives in Sussex, he came across colonies of the round-leaved sundew (Drosera rotundifolia) growing on peat moss cushions. Following a series of simple experiments, which could be repeated in secondary schools, he became captivated, delighted and astonished by the sensitivity of the glandular hairs of this plant to physical and chemical stimuli.