Walter Max Zimmermann was a German botanist, born on May 9, 1892, in Walldürn. He studied at four institutions: the universities of Freiburg, Berlin, and Munich, and the Technological Institute in Karlsruhe, earning four diplomas.
From 1919 to 1925, Zimmermann taught at the University of Freiburg. He then taught at the University of Tübingen from 1925 to 1960 and was appointed professor there in 1930.
His research covered the systematics, geography, and phylogeny of spore-bearing and flowering plants, evolutionary morphology, paleobotany, and evolutionary theory. In 1930, he formulated the telome theory of the origin of vascular plants and the principle of hologeny. He also applied statistical methods to fossil floras to examine the relative abundance of tree species in fossil plant communities and compare those relationships with present-day ones. He focused particularly on the evolution of traits rather than the evolution of taxa.
Zimmermann died in Tübingen on June 30, 1980.