Johannes Paulus Lotsy (April 11, 1867 – November 17, 1931) was a Dutch botanist, specializing in evolution and heredity. Lotsy was born in Dordrecht and died in Voorburg.
After getting his PhD from Gottingen University he had a teaching positions at Johns Hopkins University (1891-1895) where he was director of the herbarium. From 1896 to 1900 he worked in Java. Then he taught at Leiden University (1904-1909), as a lecturer in Systematic Botany. He became director of the State Herbarium (Rijksherbarium) 1906-1909, then Secretary of the Hollandsche Maatschappij van Wetenschappen.
He founded the Association internationale des Botanistes and was editor of the Botanisches Centralblatt. He proposed a system of plant classification, based on phylogenetics.
India (1895-1900), the United States (1922), Australia and New Zealand (1925), South Africa (1926-27), and Egypt (1930). He also studied the flora of Italy and Switzerland.
1928. Voyages of exploration to judge of the bearing of hybridization upon evolution (Genetica : nederlandsch tijdschrift voor erfelijheids- en afstammingsleer). Ed. M. Nijhoff1922a. Van den Atlantischen Oceaan naar de Stille Zuidzee1922b. A popular account of evolution. The Cawthron institute, Nelson, Nueva Zelanda. Cawthron lecture. Ed. R.W. Stiles & Co. 22 pp.1915. Het Tegenwoordige Standpunt der Evolutie-leer1911. Série IIIA. Sciences exactes. 1-4. Rédigées par J. P. Lotsy1906a. Résultats scientifiques du Congrès international de botanique, Vienne, 1905. Wissenschaftliche Ergebnisse des Internationalen botanischen Kongresses, Wien, 1905 ... Redigiert von J. P. Lotsy ... Mit ... 1 Karte, etc1906b. Vorlesungen über Deszendenztheorien, mit besonderer Berücksichtigung der botanischen Seite der Frage, gehalten an der Reichsuniversität zu Leiden, etc.1899. Rhopalocnemis Phalloides Jungh: A morphological-systematical study. Ed. E.J. Brill1898. Contributions to the life-history of the genus Gnetum. Ed. E.J. Brill1894. A contribution to the investigation of the assimilation of free atmospheric nitrogen by white and black mustard. Bulletin / U.S. Department of Agriculture, Office of Experiment Stations. G.P.O. 19 pp.2008. Evolution By Means Of Hybridization. Reeditado Maudsley Press. 176 pp. ISBN 978-1-4097-0261-01928. A Popular Account of Evolution1925. Evolution considered in the light of hybridization. Ed. Canterbury College by Andrews, Baty & Co. 66 pp.1916. Evolution by Means of Hybridization. The Hague, Martinus Nijhoff, 166 pp.1907-1911. Vorträge über botanische Stammesgeschichte gehalten an der Reichsuniversität zu Leiden. Ein Lehrbuch der Pflanzensystematik. In drei Bände. Jena, Verlag von Gustav Fischer. With illustrations.Lotsy, J. P. (1911). Vorträge über botanische stammesgeschichte, gehalten an der Reichsuniversität zu Leiden. Ein lehrbuch der pflanzensystematick. III Cormophyta Siphonogamia. Jena: G. Fischer. Retrieved 28 January 2015. 