Hugo de Vries was born in Haarlem, The Netherlands, and was educated at the universities of Leiden, Heidelberg, and Würzburg. In 1878, he became a lecturer in plant physiology at the University of Amsterdam, rising to become a professor during his 40-year tenure there. He suggested the concept of genes in the 1890s, unaware of Gregor Mendel's pioneering work in the 1860s. While raising evening primroses, he found new wild forms that appeared randomly among the cultivated specimens and gave these variants the name "mutations." His research into the nature of genetic mutations was summarized in his books The Mutation Theory (1901-1903) and Species and Varieties: Their Origin Through Mutation (1905). Among his other works were Intracellular Pangenesis (1889) and Plant Breeding (1907).