Nageli, Karl Wilhelm von (1817–1891)

Swiss botanist and early microscopist. He accurately described cell division, identifying chromosomes as ‘transitory cytoblasts’. He was also the first to describe the antheridia (male reproductive organs) and spermatozoids (male gametes) of the fern family. He and Hugo von Mohl were responsible for distinguishing the protoplasm from the cell wall in plants.

Nageli was responsible for several important discoveries in plant biology; however, he also held fast to several erroneous beliefs and he rejected Gregor Mendel's paper that outlined the Mendelian laws of inheritance (see Mendelism). His own work included the development of the idea of a meristem, a group of formative cells that are always capable of further division, but he wrongly believed that the apical cells (the growth cells at the tip of a plant's root) were the most important meristematic zone in all plants.

Nageli was born in Kilchberg, Switzerland and studied under Lorenz Oken and Augustin Pyrame de Candolle at the University of Geneva, and Matthias Jakob Schleiden at the University of Jena. He was made a professor at the Universities of Zürich, Freiburg, and Munich early in his career.