Rudolf Jacob Camerarius, a German botanist and physician, is credited with being the first to scientifically demonstrate the process of sexual reproduction in flowering plants. His seminal work, published in 1694, titled ``De sexu plantarum epistola" (Letter on the sex of plants), clearly outlined the role of male (pollen) and female (ovule) components in plant reproduction. This work provided the foundation for modern botanical genetics and was a monumental step forward in the study of plant biology.