Joseph Gottlieb Koelreuter is best know for his studies of plant hybrids and his experimental demonstration of the sexuality of plants. Plant hybridization was closely associated with the development of evolutionary theory and modern genetics. Koelreuter was born in Sulz, Germany, where his father was an apothecary. Koelreuter studied medicine at the University of Tübigen and graduated in 1755. For the next six years he managed the natural history collections of the Imperial Academy of Sciences in St. Petersburg, Russia. In addition to carrying out his main assignment, which was the classification of various specimens of fish, he began his research on the structure of flowers and pollen, and the mechanism of pollination and fertilization. A prize offered by the Academy for an essay on the experimental demonstration of sexuality in plants stimulated Koelreuter's efforts to produce plant hybrids.

After returning to Germany in 1761, Koelreuter was appointed...