Overview

My academic interests are in the area of systematic biology, the study of biotic diversity within and among species. As a plant biologist, my work principally involves the monocots, with a particular focus on the grass family. I use morphological (structural) characteristics, and variation patterns in DNA sequence and genomic organization to analyze species boundaries, relationships among closely related species, and higher-level relationships, including the divergence of monocots from related dicot lineages, and the origin and subsequent diversification of grasses within the monocots. The success of these studies is contingent upon the use of appropriate analytical methods, and my work also includes studies of the methods of systematics.

Research Focus

My principal areas of interest, within systematic biology, are in the theory and practice of phylogenetics and species delimitation. In the first of these areas I am engaged in studies of phylogenetic relationships within the grass family (Poaceae) and across monocots as a whole, using molecular and morphological character sets. My studies at the species level have involved the development of general approaches and specific methods for inferring species boundaries on the basis of population variation patterns. I have employed these methods in my studies of species boundaries in the grass genus Puccinellia, and these analyses have contributed to my floristic studies of this genus.

Instruction Focus

I teach two courses for undergraduates, one of them focusing on the systematics and diversity of vascular plants (BioPL 248), the other on the diversity and evolutionary biology of the grass family (BioPL 359). In both courses I emphasize the importance of different sources of evidence (structural characteristics, DNA sequence variation, etc.) and analytical procedures in interpreting relationships within these groups of plants. These courses also include lectures on the interface between systematics and related fields, such as pollination biology, other aspects of reproductive biology, evolution, ecology, and the history of biology. Each course includes a weekly laboratory in which the diversity of the target group is surveyed, and in which students develop and practice the skills of interpretation of plant structures and identification of plants.

Additional Links

• Cornell University Department of Plant Biology
• Link to CALS Research portal
• Link to CALS Impact statements

Selected Publications

• Davis, J.I. and L.M. Consaul. 2007. Puccinellia. Pp. 459-477 in Flora of North Amercia, vol. 24, ed. M.E Barkworth, .K.M. Capels, S. Long, LkK. Anderton, and M.B. Piep. Oxford Univ. Press, New York.
• Davis, J.I. and R.J. Soreng. 2007. A phylogenetic analysis of the grasses (Poaceae), with attention to subfamily Pooideae and structural features of the plastid and nuclear genomes, including an intron loss in GBSSI. Aliso 23: 335?348.
• Rudall P.J., D.D. Sokoloff, M.V. Remizowa, J.G. Conran, J.I. Davis, T.D. Macfarlane, and D.W. Stevenson. 2007. Morphology of Hydatellaceae, an anomalous aquatic family recently recognized as an early-divergent angiosperm lineage. Amer. J. Bot. 94: 1073?1092.
• Soreng, R.J. and J.I. Davis. 2007 (in press). A phylogenetic analysis of Poaceae tribe Poeae s. lat. based on morphological characters and sequence data from three chloroplast-encoded genes: evidence for reticulation, and a new classification for the tribe. Kew Bull.
• Davis, J.I., G. Petersen, O. Seberg, D.W. Stevenson, C.R. Hardy, M.P. Simmons, F.A. Michelangeli, D.H. Goldman, L.M. Campbell, C.D. Specht, and J.I. Cohen. 2006. Are mitochondrial genes useful for the analysis of monocot relationships? Taxon 55:857-870.
• Davis, J.I., K.C. Nixon, and D.P. Little. 2005. The limits of conventional cladistic analysis. Pp. 119-147 in Parsimony, Phylogeny, and Genomics, ed. V. Albert. Oxford Univ. Press, New York.
• Hardy C.R., J.I. Davis, and D.W. Stevenson. 2004. Floral organogenesis in Plowmanianthus (Commelinaceae). Int. J. Pl. Sci. 165:511-519.
• Davis, J.I., D.W. Stevenson, G. Petersen, O. Seberg, L.M. Campbell, J.V. Freudenstein, D.H. Goldman, C.R. Hardy, F.A. Michelangeli, M.P. Simmons, C.D. Specht, F. Vergara-Silva, and M.A. Gandolfo. 2004. A phylogeny of the monocots, as inferred from rbcL and atpA sequence variation, and a comparison of methods for calculating jackknife and bootstrap values. Syst. Bot. 29:467-510
• Grass Phylogeny Working Group (N.P. Barker, L.G. Clark, J.I. Davis, M.R. Duvall, G.F. Guala, C. Hsaio, E.A. Kellogg, H.P. Linder, R. Mason-Gamer, S. Mathews, M.P. Simmons, R.J. Soreng, and R.E. Spangler). 2001. Phylogeny and subfamilial classification of the grasses (Poaceae). Ann. Mo. Bot. Gard. 88:373-457.
• Davis, J.I. 1997. Evolution, evidence, and the role of species concepts in phylogenetics. Syst. Bot. 22: 373-403.

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