Marcia Waterway

Associate Professor

Curator, McGill University Herbarium

T: 514-398-7864  | marcia.waterway [at] (Email) |  Raymond Building R2-0


BA (Calvin)
MS (Wisc.)
PhD (Cornell)

Research interests

Carex capricornis
Dr Waterway's research interests are plant systematics, phylogeny and ecological genetics, with emphasis on the Cyperaceae. One focus of her research program is to understand the patterns of species diversity and genetic diversity in plants in relation to the environments in which they grow, using the genus Carex as a model system. Patterns of species diversity vary widely among the groups of flowering plants. Within the monocotyledons, three large families account for most of the species: grasses (Poaceae), sedges (Cyperaceae) and orchids, (Orchidaceae). Each of these families has both small and large genera, with the genus Carex in the Cyperaceae being one of the ten most species-rich genera in the world. What accounts for this extreme diversity within a single group of plants? Can we identify the different evolutionary (genealogical) lineages within this genus? How is this diversity apportioned among the evolutionary lineages within Carex? What structural characteristics and ecological preferences are associated with these species-rich lineages? Can we discern biogeographic patterns related to ancient geological events or recent migrations associated with glaciation? Has there been co-evolution of this genus with its fungal pathogens? Are patterns of clonal diversity within rhizomatous species correlated with environmental heterogeneity? These are some of the questions that she and her students seek to answer in their research.

Carex grayi
The genus Carex is the largest genus in Canada and is widespread in temperate, boreal, subarctic and arctic habitats, including both wooded and open sites. Rhizomatous sedges dominate in many wetland habitats and woodland Carex species often account for as much as 10% of the herbaceous understory flora in temperate and boreal forests. Dr. Waterway is one of the leaders in an international collaboration funded by the U.S. National Science Foundation to develop a phylogenetic hypothesis for the genus Carex using DNA sequence data from most of the 2000+ species and using this phylogeny to reclassify the genus at the sectional level and study character evolution and the biogeographic patterns within the genus ( These studies of the correlations among lineage diversification, ecological preferences, and structural innovations contribute to understanding the evolutionary processes that generate diversity.

Selected Publications

Escudero, M., Hipp, A. L. Waterway, M. J., and Valente, L. M.  2012. Diversification rates and chromosome evolution in the most diverse angiosperm genus of the temperate zone (Carex, Cyperaceae).  Molecular Phylogenetics and Evolution 63: 650-655.

Flinn, K.F., Gouhier, T.C., Lechowicz, M. J., and Waterway, M .J.  2010.  The role of dispersal in shaping plant community composition of wetlands within an old-growth forest.  Journal of Ecology 98: 1292-1299.

Consaul, L. L., Gillespie, L. J. and Waterway, M. J..  2010.  Polyploid Speciation and Evolution in Arctic Puccinellia (Poaceae: Puccinelliinae) – A Review.  Pp. 645-662 in:Seberg, O, Petersen, G., Barfod, A.S., and Davis, J.W [eds.]., Diversity, Phylogeny and Evolution in the Monocotyledons. Aarhus University Press, Denmark.

 Flinn, K. F., Waterway, M. J., and Lechowicz, M. J.  2010. Disjunction between performance and distribution in the sedge Carex prasina.  Oecologia 163: 119-126.

Consaul, L.L., L.J. Gillespie, and M.J. Waterway. 2010. Evolution and polyploid origins in North American Arctic Puccinellia (Poaceae) based on nuclear ribosomal spacer and chloroplast DNA sequences.. American Journal of Botany 967: 324-336.

Waterway, MJ, Masaki, T., and Hoshino, T.  2009.  Phylogeny, species richness, and ecological specialization in Cyperaceae tribe Cariceae.  Botanical Review 75: 138-159

Flinn, K. F., Lechowicz, M. J., and Waterway, M. J. 2008. Plant species diversity and composition of wetlands within an upland forest. American Journal of Botany 95(10): 1216-1224.

Smith, T. W., and Waterway, M. J.  2008.  Evaluating species limits and hybridization in the Carex complanata complex using morphology, amplified fragment length polymorphisms, and restriction fragment analysis.  Botany 89: 809-826. [winner of Alf E. Porsild award from Can. Bot. Soc. for best paper in systematics & phytogeography in 2008]

Dabros, A., and Waterway, M. J. 2008. Segregation of sedge species (Cyperaceae) along environmental gradients in fens of the Schefferville region, northern Quebec. R. F. C. Naczi and B. A. Ford [eds.], Sedges: uses, diversity, and systematics of the Cyperaceae. Monographs in Systematic Botany from the Missouri Botanical Garden.

Waterway, MJ, and Starr, JR.  2007. Phylogenetic relationships in tribe Cariceae, Cyperaceae, based on nested analyses of three molecular data sets.  In:  Monocots: comparative biology and evolution. Vol. 2, Poales, edited J. T. Columbus, E. A. Friar, C. W. Hamilton, J. M. Porter, L. M. Prince, and M.G. Simpson [eds.], . pp. 165-192.  Rancho Santa Ana Botanic Garden, Claremont, CA, USA

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