Tiegh.

Philippe Édouard Léon Van Tieghem (19 April 1839 – 28 April 1914) was a French botanist born in Baillleul in the département of Nord. He was one of the best known French botanists of the latter nineteenth century.

Van Tieghem's father was a textile merchant who died of yellow fever in Martinique before he was born, and his mother shortly thereafter. One of five children, he obtained his baccalauréat in 1856, and continued his studies at the École Normale Supérieure, where after receiving agrégation, he worked in the laboratory of Louis Pasteur (1822–1895). Here he performed research involving the cultivation of mushrooms. He is credited with creation of the eponymous "Van Tieghem cell", a device mounted on a microscope slide that allows for observing the development of a fungus' mycelium.

In 1864 he earned his doctorate in physical sciences with a thesis titled Recherches sur la fermentation de l'urée et de l'acide hippurique, and two years later obtained a doctorate in natural history. From 1873 to 1886, he taught classes at the École centrale des arts et manufactures, and from 1878 to 1914, was a professor at the Muséum national d'histoire naturelle. Within this time period (1899–1914), he was also an instructor at the Institut agronomique in Paris.

In 1871 he became a member of the Société philomathique de Paris, and in 1876 gained membership to the Académie des sciences. In 1874 he translated the third edition of Julius von Sachs' Lehrbuch der Botanik textbook (1873) from German into French as Traité de botanique conforme à l'état présent de la science. Van Tieghem's own Traité de botanique appeared in 1884, in which he outlined his schema for taxonomic classification.

...
Wikipedia