Hugo de Vries, along with Correns and Tschermak, was one of three scientists who independently rediscovered Mendel's work around 1900, decades after Mendel's original publication. While Correns and Tschermak also deserve credit, the question specifically asks about 'The Holland scientist' (Dutch scientist), which points to Hugo de Vries from the Netherlands. Darwin's work on evolution was separate from Mendel's genetics.