Who was Mendel's botany professor at the University of Vienna?

Franz Unger was Mendel’s botany professor at the University of Vienna. Mendel studied there from 1851 to 1853 after his abbot sent him to strengthen his scientific training.

Unger was an Austrian botanist and plant physiologist whose work on plant structure, development, and heredity helped shape Mendel’s scientific thinking. Mendel also encountered other influential teachers in Vienna, including the physicist Christian Doppler, but Doppler taught him physics rather than botany.

Mendel’s time in Vienna was important even though he later failed the oral portion of the examination required for a formal teaching certificate. He studied mathematics, physics, and natural history, gaining the quantitative approach that later distinguished his pea experiments.

A common mix-up is to name Doppler because he was Mendel’s best-known Vienna professor. The subject matters: Unger belongs to Mendel’s botanical education, while Doppler belongs to his physics education.