of his Grundzuge der w isse nschaftliche Botanik; Die Botanik als 
inductive Wissenschaft (1842-1843) at once raised botany to the 
rank of a modern natural science. 
Hugo von Mohl 
( b . Stuttgart, Wiirtemberg, April 8, 1805. 
d. Tubingen, Wiirtemberg, April 1, 1872). 
One of the founders of plant anatomy. Professor of botany in 
Tiibingen (1835-1872). He introduced the name "protoplasm" , and 
was the first to describe vegetative cell-division (1835). Founder 
(with Schlechtendal) of the Botanische Zeitung (1843). Alikio- 
graphie (1846) . Skillful microscopist, for forty years an investi- 
gator in plant anatomy. He was acquainted with the entire range 
of botanical science, and was noted for the accuracy of his ob- 
servations, drawings, and descriptions. 
Nathanael Pringsheim 
(b. West Zieski, Silesia, November 30, 1833. 
d. Berlin, October 6, 1894). 
He demonstrated sexual reproduction in Vauchei ia , and was the 
first, in 1856, in the alga, Oedogonium , to observe fertilization, or 
the fusion of a plant sperm and an egg. He first described the 
alternation of generations in algae. Founder (1858) of the Jahr- 
biicher fur wissenschaftiiche Botanik. 
Wilhelm Friedrich Benedict Hofmeister 
(b. Leipzig, Germany, May 18, 1824. 
d. Lindenau, near Leipzig, January 12, 1877). 
Called by Bonnier “perhaps the greatest genius who has ever 
appeared in botanical science’’. Professor of botary in Heidel- 
berg (1863) and in Tubingen (1872). While a music dealer he 
demonstrated the fact of the alternation of generations in lower 
and higher groups of plants, which implied the doctrine of evolu- 
lution. He also demonstrated the origin of the plant embryo 
from the ovum. His epoch-making Vergleichende Untersuchungen 
was published in 1849-1851. 
Charles Robert Darwin 
(b. Shrewsbury’, England, February 12, 1809. 
d. Down, Kent, April 18, 1882). 
Co-discoverer, with Wallace, of the principle of natural selection. 
His Origin of species by means of natural selectiofi (1859) was one 
of the most influential works ever published in any language. 
The variation of animals and plants under domestication (1876). 
His voyage of exploration on the Beagle has been called “a 
Columbus voyage of science’’. His work gave direction to all 
modern thought. 
Karl Wilhelm von Nageli 
(b. Kilchberg, near Zurich, Switzerland, March 27, 1817. 
d. Munich, May 10, 1891). 
Swiss botanist and philosopher. Professor in Munich (1857). 
Early adherent to a strictly inductive method. With Schleiden 
he introduced into morphological study the idea of the history of 
development. First to determine that all vegetative cells are 
formed by the existence of pre-existing cells. He discovered the 
sperms of ferns, and made contributions to almost every’ depart- 
ment of botany. With Schleiden he founded the Zeitschrift fur 
wissenschaftiiche Botanik (1844). 
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