He was born
Hugo Hellmut Iltis to Anni (née Liebscher) and
Hugo Iltis, a botanist and geneticist who was a life sciences teacher at the German-language
secondary school of
Brünn (Brno). His father was also the first biographer of
Gregor Mendel and a vocal opponent of
Nazi "racial science". In the fall of 1938, the Iltis family was granted visas to enter the United States thanks to the intercession of the
Emergency Committee in Aid of Displaced Foreign Scholars, along with affidavits of endorsement from
Albert Einstein and
Franz Boas. In January 1939, when
Hitler's military was preparing the
invasion of Czechoslovakia, thirteen-year-old Hugo escaped with his mother and his older brother
Wilfred on a harrowing train ride that traversed
Nazi Germany to France. He recalled that during a midnight stop at the
Stuttgart station,
Gestapo officers combed the train, removing ten passengers; the Iltises survived because the boys pretended to be asleep while their mother bluffed that she was the wife of a French diplomat. In
Cherbourg, they were joined by Hugo Iltis and boarded the passenger ship
RMS Aquitania for the Atlantic crossing. They settled in
Fredericksburg, Virginia, where the senior Hugo Iltis was soon appointed to a professorship in biology at
Mary Washington College and the younger Hugo Americanized his name to
Hugh Iltis. Iltis' undergraduate enrollment at the
University of Tennessee was interrupted by service in the U.S. Army from 1944 to 1946, initially as a medic. Because of his native proficiency in German, he was transferred to an
intelligence unit. After
World War II, Iltis was stationed in Germany, where he participated in the interrogation of captive
Wehrmacht and
SS officers, including
Heinrich Himmler, and processed documents to prosecute
Nazi war crimes at
Nuremberg. Iltis returned to the University of Tennessee, where he studied botany under
Aaron J. Sharp. He carried out graduate studies at
Washington University in St. Louis, where he received his Ph.D. in 1952 under the direction of
Edgar Anderson. He was primarily trained in plant systematics and taxonomy, with a focus on the caper family (
Capparaceae) and the spider-flower family (
Cleomaceae). His first academic appointment was at the
University of Arkansas from 1952 to 1955, and here he completed a study of the
Capparaceae of
Nevada. Later works formed a series, "Studies in the
Capparaceae", which includes 24 publications, including newly described species and genera. An associated series of papers describes his research in the
Cleomaceae. (At the time when he did his studies, the
Cleomaceae was included in the
Capparaceae.) In 1955, Iltis relocated to the Botany Department of the University of Wisconsin–Madison, where in addition to directing the herbarium he regularly taught plant geography, taxonomy, and grass systematics. He arranged to purchase much of the
Catholic University of America herbarium when it was deaccessioned. By the time of his retirement in 1993, he had directed 37 candidates pursuing graduate degrees, and he and his students had collected thousands of specimens throughout the Upper Midwest to document distributions of plant species, leading to the publication of the
Atlas of the Wisconsin Prairie and Savanna Flora (2000) coauthored with Herbarium Curator Theodore Cochrane. Anecdotes abounded concerning his colorful, often imperious manner. One colleague poked fun at Iltis by taping on his office door a cartoon that showed a boss dictating to a secretary and concluding, "Type that up, make ten thousand copies, and send them to all the important people in the world."At the end of a public lecture, when an audience member asked flippantly, "What good is nature?" Iltis shot back, "What good are you?" Yet students flocked to his course on "Man's Need for Nature", and he was generous with his knowledge and his counsel. He cultivated strong ties with Latin American botanists, often hosting them for extended stays at his home located within the
University of Wisconsin–Madison Arboretum. An avid
naturalist, Iltis conducted numerous expeditions to
Mexico and Central and South America to search for new discoveries. High in the
Altiplano of southern
Peru in 1962, he noticed a tiny flower that had not yet been classified by taxonomists. A full fifty years later, he and Harvey Ballard finally named it
Viola lilliputana, and it was selected as one of the top ten new species of the year by the
International Institute for Species Exploration. Iltis' work was of economic importance, because he identified new sources of genetic variability that have been used by
horticultural breeders. On the same 1962 expedition to Peru, he spotted a wild
tomato that he recorded as No. 832. He collected specimens for several herbaria, and sent samples and seeds to various specialists in the field. This plant turned out to be a new species of tomato with much higher sugar and solids content than domestically grown tomatoes. As a source for hybridization with domestic tomatoes, it has been used both to improve the flavor of tomatoes and to boost solids content. with
Zea diploperennis in his home garden] Iltis used taxonomic and morphological approaches to investigate the domestication of corn, tracing the changes that transformed an unpromising wild grass into one of the most important food crops. His work supported the view that domestic corn was derived from a species of
teosinte, a group of grasses that grows wild in many areas of Mexico. It was generally believed that the original wild corn was extinct in the wild. Iltis used a hypothetical illustration of this plant for a New Year's greeting card that he sent to family and friends in 1976. This drawing prompted a Mexican colleague, Luz María Villarreal de Puga (1913–2013), to launch an intensive search for just such a plant, and one of her students, Rafael Guzmán, found it (or so he thought) growing in the wild. In 1978, Iltis led a team of botanists to the site and determined that it was in fact a heretofore unknown species of teosinte,
Zea diploperennis, which is valued for its resistance to certain viruses. Iltis warned that the practice of collecting plants in tropical countries without involving local botanists and without depositing duplicate specimens in local herbaria would eventually cause trouble. And indeed, in recent years Brazil and some Andean countries have enacted laws that severely restrict field studies. Iltis was an outspoken
environmentalist and
conservationist, championing the preservation of threatened habitats to protect
biodiversity. Some species of teosinte are critically endangered, and all face a growing threat as agricultural land use expands in Mexico. He campaigned with colleagues at the
University of Guadalajara to protect the natural environment of
Zea diploperennis by creating the 345,000-acre
Sierra de Manantlán Biosphere Reserve. He cofounded the Wisconsin chapter of the
Nature Conservancy in 1960 and helped establish
Hawaii's Natural Areas Law of 1970. He was a leader in the campaign to ban
DDT in Wisconsin, which in 1968 was the first U.S. state to do so. He also called for a moratorium on cutting virgin timber in the state. In a 1970 article, "Man First? Man Last? The Paradox of Human Ecology", he wrote: "If we are to usher in an Age of Ecologic Reason, we must accept the certainty of a radical economic and political restructuring as well as ethical and cultural restructuring of society. No more expanding populations.... We must stop and limit ourselves now." Iltis fathered four sons, Frank and Michael by his first wife, Grace Schaffel, and David and John by his second wife,
Carolyn Merchant. He and his third wife, Sharyn Wisniewski (1950–2013), endowed a fund at the University of Wisconsin–Madison Department of Botany to support graduate student fieldwork in plant systematics. He remained active up to his death in Madison at age 91 from complications of
vascular disease. His papers are preserved in the archives of the University of Wisconsin–Madison. ==Honors==