Professor Emeritus and Adjunct Professor

Bachelor of Science (BSc cum laude), 1969, Tufts, Master of Arts (MA) 1971, Doctor of Philosophy (PhD), 1972, Washington University St. Louis

John C. Semple

                                          Nahanni N.P.R., NT, Canada, Aug 2003

Doctoral thesis title: The cytology, flavonoid chemistry and systematics of the Texas Sleepy Daisy Xanthisma texanum DC. (Asteraceae)

First publication: Semple, J.C. 1970. The distribution of pubescent leaved individuals of Conocarpus erectus L. (Combretaceae). Rhodora 72: 544-547. {based on undergraduate research and first term graduate research}

Nearly all publications have been on the cytology, morphology, phylogeny, and nomenclature of members of the Tribe Astereae.  This work has been done in collaboration with colleagues from around the world and graduate students and undergraduate students working in the Astereae Lab at the University of Waterloo since 1974.  Research was funded continuously by NRC and NSERC from 1975 to 2014 with supplements from specific projects (Flora of North America; Flora of China; DNA phylogeny of Solidago to James Beck PI from NSF).

Field work has been an important part of the research.  Ten minutes in the field examining habitat conditions and morphological variation can solve problems in a way research on herbarium specimens cannot.  Sometimes getting those ten minutes has taken days of traveling and hours of hiking up mountains or through swamps to find out-of-the-way populations.  My goal has been to see in the field every taxon of each group (species complex, subsection, section, genus, subtribe) that I have worked on and to get chromosome counts for every taxon.  This goal is incomplete ... but nearly done, at least in Canada and the U.S.  Most sabbaticals have been spent in the field finding rarer species of asters, goldenasters and goldenrods.  Along the way, I have had the opportunity to see large numbers of species in other genera of Astereae in North America.  Several graduate students have done molecular phylogenetic studies.  A few have done autoecology and pollination biology studies.  Several graduate students and the majority of undergraduates have worked on multivariate morphometric analyses generating a very large data base of numbers on which conclusions are based.

I gratefully acknowledge the larger number of students who have assisted on field trips over four decades.  Special thanks to my wife Brenda who has been on numerous trips across Canada and the U.S.

JCS, 29 September 2014, update 26 May 2023


Lab Space: Biology-2 246 (Müller Lab); no office

Many of my publications are available on line at

University of Waterloo

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