Alexander Karl (Carl) Heinrich Braun (Fig. 5.1) was born on May 10, 1805, in Regensburg, Bavaria. He studied botany in Heidelberg, Paris, and Munich. He took a post as a botany lecturer at the Karlsruhe Polytechnic from 1833 to 1846. He then became Professor of Botany at the Universities of Freiburg and Giessen but at a time when there was serious revolutionary unrest in those cities. The Prussian army restored order in late 1849, and Braun was involved in efforts to release prisoners in Rastatt. Despite these difficult times, he published his most important volume Betrachtungen über die Erscheinung der Verjüngung in der Natur, inbesondere in der Lebens-und Bildungsgeschichte der Planze (“The phenomenon of rejuvenescence in nature especially in the life and development of plants”) in parts over the period 1849–1850. From 1851 to 1877, he relocated to the University of Berlin as a Professor, where he also assumed duties as the Director of the Berlin Botanical Garden, joint positions that he occupied until his death (Anonymous 1877; Gregersen 2021).