Dan was born on September 5, 1933, in Kansas City, Missouri. He grew up in Shenandoah, Iowa, where his parents ran the Henry Field’s Seed & Nursery Co. They also had a summer home in Detroit Lakes, Minnesota. He graduated from Grinnell College and published his first paper on the milkweeds of Iowa with his botany teacher in 1955. He went to Stanford University and received an MBA degree in 1957, working as assistant in the Dudley Herbarium. Dan worked with George Lawrence in the Bailey Hortorium of Cornell University and earned an MS degree in 1959 and a PhD degree in 1964.
In August 1959, Dan married Alice Black Crawford, and they went to the Montreal Botanical Congress for their honeymoon. The next year they left for two years of thesis field work in Malaysia and Southeast Asia. John was born in late 1960 in Manila on the way out and Sally was born early in 1962 in Beirut (4th generation of Ally’s family born in the Middle East).
In 1964, Dan was hired by the Smithsonian Institution (by A. C. Smith, then assistant secretary) to fill the vacancy left by Dick Cowan who had been promoted to assistant director of the Museum of Natural History. The first year he went to the American Institute of Biological Science meetings, attended the Edinburgh Botanical Congress, spent three months collecting on Dominica, and their third child, David, was born. As the junior staff member he was put in charge of Moving Arrangements and Space Assignments and organized the department’s move in 1965 from the “Castle” to new quarters on the 4th and 5th floors of the new West Wing of the Natural History Building. In 1969 he organized the Herbarium Services Unit.
In 1966, Dan went collecting in Nepal for a year as a Senior Fulbright Fellow. From 1968 to 1974, he spent three months each year in Bangalore working with Father C. J. Saldanha on the flora of the Hassan District. In 1979, he was in Sri Lanka for a month of collecting Araceae (published in 1987) and in 1983 he collected in Yunnan for three months.
Dan’s work falls into three areas: (1) monographic work in Araceae (knowing a lot about little), (2) floristic work (knowing little about a lot), and (3), nomenclature (knowing a lot about nothing).
In 2005, Dan was awarded the Stafleu Medal by the International Association for Plant Taxomony in Vienna for the 2004 729 page book The Forsters and the Botany of the Second Cook Voyage (1772-1775). The Forsters’ publications, particularly George’s, underlie Pacific botany. Dan wrote (or was co-writer) of over 200 publications, several that are over 100 pages in length.
Dan was regional treasurer for the International Association for Plant Taxonomy since Dick Cowan retired in 1985. He has served the Association in many capacities, including nomenclature editor of their journal, Taxon, from 1979 to 1999, member of the editorial committee for the Code ongoing since 1981, acting vice president (again filling in for Dick Cowan, from 1985 to 1987), secretary of the general committee from 1987 to 2000, vice president from 1987 to 1993, and president from 1993 to 1999.
In later years Dan focused on interpretation of the Code of Botanical Nomenclature and took part in teaching trips to Brazil and China to train young botanists in correct usage. He attended a number of meetings of the Aroid Society and the Flora Malesiana Committee and every Botanical Congress from 1959 through 2004 (Montreal, Edinburgh, Seattle, Leningrad, Sydney, Berlin, Yokohama, St. Louis and Vienna).
Dan retired in 2007 and was diagnosed with Alzheimer's disease in 2008, but continued to field occasional nomenclatural questions for several more years. He dispersed his extensive botanical library to many fellow botanists when he vacated his Smithsonian office. Post retirement, he and Alice made several trips, to Tibet, Chile and Easter Island, and Lake Van in Turkey. In 2012 they moved from their longtime home in Arlington to Collington, a continuing care retirement community in Prince George's County, MD. Dan's family of three children has increased with eight grandchildren.
He was elected to the Washington Biologists’ Field Club in 1975 and served as treasurer from 1981 to1997, and chair of the finance committee from 1997 to 2001.
Dan died on June 2, 2016.