PRINGSHEIM, NATHANAEL German botanist, was born at Wziesko in Silesia, on Nov. 3o, 1823. He studied at the universities of Breslau, Leipzig, and Berlin, gradu ated in 1848 as doctor of philosophy with the thesis De forma et increment° stratorum crassiorum in plantarum cellula, and rapidly became a leader in the great botanical renaissance of the 19th century. His contributions to scientific algology were of striking interest. Pringsheim was among the very first to demonstrate the occurrence of a sexual process in this class of plants, and he drew from his observations weighty conclusions as to the nature of sexuality. Together with the French investigators G. Thuret and E. Bornet, Pringsheim ranks as the founder of our scientific knowledge of the algae. The conjugation of zoospores, regarded by Pringsheim, as the primitive form of sexual reproduction, was a discovery of fundamental importance. A work on the course of morphological differentiation in the Sphacelariaceae (1873), a family of marine algae, is of great interest, inasmuch as it treats of evolutionary questions; the author's point of view is that of Naegeli rather than Darwin. Closely connected with Pringsheim's
algological work was his investigation of the Saprolegniaceae, a family of algoid fungi, some of which cause disease in fish. His career as a morphologist culminated in 1876 with the publication of a memoir on the alternation of generations in thallophytes and mosses.
From 1874 to the close of his life Pringsheim's activity was chiefly directed to plant physiology. He founded the Jahrbuch fur wissenschaftliche Botanik, and the German Botanical Society. His work was for the most part carried on in his private laboratory in Berlin ; he only held a teaching post of importance for four years, 1864-68, when he was professor at Jena. He died in Berlin on Oct. 6, 1894.