Felix Eugen Fritsch FRS (26 April 1879 – 2 May 1954) was a British biologist.
Fritsch started his career at the University of Munich before moving to research at University College London and also the Royal Botanic Gardens at Kew. He was Professor and Head of the Botanical Department, Queen Mary College (formerly East London College), University of London, from 1911-1948. He was elected a Fellow of the Royal Society in May 1932 and won their Darwin Medal in 1950. He served as President of the Linnean Society from 1949 to 1952 and was awarded the society's Linnean Medal in 1954.
He is best known internationally for his comprehensive two-volume The Structure and Reproduction of the Algae.; However his A Treatise of the British Freshwater Algae. was also important. Fritsch became a co-author of the revised edition in 1927. Fritsch had a great influence through his own research and also his encouragement to students (John, 2002 p. 8)1. As an aid to his own studies on algal taxonomy and morphology, Fritsch brought together published illustrations under the names of the species. After his death this was continued by Dr J.W.G.Lund at the Freshwater Biological Association and became The Fritsch Collection of Illustrations of Freshwater Algae (Lund 1961).
F. E. Fritsch (1945). "The Structure and Reproduction of the Algae.". I. and II. Cambridge, England: Cambridge University Press