Walter S. Judd

Walter S. Judd (born 1951) was an American botanist and taxonomist, and distinguished professor in the Department of Botany, University of Florida beginning in 2009. Judd was born in Fairbanks, Alaska; his family relocated to Shiawassee CO, Michigan. Due to the rural setting, it inspired him to study natural history, botany, plant taxonomy and systematics, and phylogenetics.

Career Judd attended Michigan State University (B.S. 1973, M.S. 1974) and Harvard University (Ph.D. 1978). He became an assistant professor in the Department of Botany at the University of Florida (1978–1983), associate professor (1983–1991) and professor in 1991. He was president of the American Society of Plant Taxonomists 2000–2001. Angiosperm phylogeny and classification chart found in Overview of angiosperm phylogeny. Digital Encyclopedia of Ancient Life. Original: https://doi.org/10.7287/peerj.preprints.2320v6 APG I was an essential collaboration effort between researchers and was managed based on communication. APG II (2003) and APG III (2009) differed from their original. APG II was centered on the “bracketed” system and APG III was centered on the opposite and its focus was not as narrow as its predecessor. However, Christenhusz et al (2015) wrote that family circumscriptions and the impact of DNA-based classification was affecting the APGs.

While APG IV lacks focus on extinct groups of angiosperm, it does include a diverse mix of angiosperm that dates from the fossil record. About eight phylogeny families are included in APG IV with a diversity of 295,000 plants.

In 2001, Peter F. Stevens, a member of the APG published the “Angiosperm Phylogeny Website”, which still receives updates. It was last updated on June 6, 2025, and is an extensive resource for angiosperm classification and includes citations from Judd’s work. The website interlinks systematics and phylogeny, two essential principles in the study of angiosperm classification. Phylogeny allows researchers to push the limits of systematics to warrant further developments of evolution and diversification.

Awards American Society of Plant Taxonomists: Asa Gray Award 2011 National Museum of Natural History: José Cuatrecasas Medal for Excellence in Tropical Botany 2012.

Publications

(see Illustrating Tolkien)