Hermann Hoffmann
Heinrich Karl (or Carl) Hermann Hoffmann (; April 1819 – 26 October 1891) was a German botanist and mycologist born in Rödelheim. Career. He studied medicine at the University of Giessen, and in 1839 furthered his education in Berlin as a student of physiologist Johannes Peter Müller (1801–1858). In 1842 he earned his habilitation at Giessen, where he worked as a private lecturer. During this time his focus turned exclusively to botany, and in 1853 he became a professor of botany and director of the botanical gardens at Giessen. He maintained these positions until his death in 1891. Hoffmann was  a pioneer of botanical phenology (plant climatology). He also did important studies in the fields of plant physiology and phytogeography. He conducted research involving the biological aspects of fungi in relation to fermentation, putrefaction and disease, and also performed early investigations in the field of bacteriology. In 1869, Hoffmann wrote a book on species and varieties that included a long excerpt from Gregor Mendel's genetics paper of 1865. The book attempted to refute Charles Darwin's theory of evolution. Darwin had an annotated copy of the book.