American botanist (1924-2018).
Isa Irmgard Degener née Hansen (April 27, 1924, Berlin – April 13, 2018, Waialua, Hawaii) was a German-American plant collector and botanist, specializing in agrostology. She is known as the coauthor of Flora Hawaiiensis. Isa Hansen studied botany at the University of Berlin and worked there as an assistant to Hermann Otto Sleumer and Erich Werdermann. Later she worked at the Berlin Botanical Garden and specialized in the grasses. In 1952 she met Otto Degener, who had come to Berlin in search of a grass expert. They began a correspondence and married in January 1953. The couple worked together