Karl Wilhelm von Nägeli

Karl Wilhelm von Nägeli (March 27, 1817 - May 11, 1891) was a Swiss botanist. He discovered what would later become known as chromosomes and apparently discouraged Gregor Mendel from further work on genetics.

Birth and education
Nägeli was born on March 27, 1817 in Kilchberg near Zurich where he studied medicine. From 1839, he studied botany under A. P. de Candolle at Geneva, and graduated with a botanical thesis at Zurich in 1840. His attention having been directed by Matthias Jakob Schleiden, then professor of botany at Jena, to the microscopical study of plants, he engaged more particularly in that branch of research.

Academic career
Soon after graduation he became Privatdozent and subsequently professor extraordinary, in the University of Zurich; in 1852 he was called to fill the chair of botany in the Albert Ludwigs University of Freiburg, Freiburg im Breisgau; and in 1857 he was promoted to Munich, where he remained as professor until his death.

Contributions
Among his more important contributions to science were a series of papers in the Zeitschrift fur wissenschaftliche Botanik (1844 1846); Die neueren Algensysteme (1847); Gattungen einzelliger Algen (1849); Pflanzenphysiologische Untersuchungen (1855 1858), with Carl Eduard Cramer; Beiträge zur wissenschaftlichen Botanik (1858-1868); a number of papers contributed to the Royal Bavarian Academy of Sciences, forming three volumes of Botanische Mitteilungen (1861-1881); and, finally, his volume, Mechanisch-physiologische Theorie der Abstammungslehre[scanned source], published in 1884. However, perhaps Nägeli is best known nowadays for his unproductive correspondence (1866-1873) with Gregor Mendel concerning the latter's celebrated work on Pisum sativum, the garden pea.

The standard botanical author abbreviation Nägeli is applied to species he described.